the characterization of liquefied petroleum gas (lpg) using

Research ArticleThe Characterization of Liquefied Petroleum Gas (LPG) Using aModified Bunsen Burner

Bader A Alfarraj Ahmed A Al-Harbi Saud A Binjuwair and Abdullah Alkhedhair

King Abdulaziz City for Science and Technology (KACST) Riyadh 11442 Saudi Arabia

Correspondence should be addressed to Abdullah Alkhedhair akhoderkacstedusa

Received 22 February 2022 Revised 29 March 2022 Accepted 18 April 2022 Published 2 May 2022

Academic Editor Ashwani K Gupta

Copyright copy 2022 Bader A Alfarraj et al is is an open access article distributed under the Creative Commons AttributionLicense which permits unrestricted use distribution and reproduction in any medium provided the original work isproperly cited

e equivalence ratio ranges were found between 2277 and 4293 for the Saudi LPGair mixture using a traditional Bunsenburner An operation problem was found with a traditional Bunsen burner for the Saudi LPGair mixture especially in a leanmixture erefore a Bunsen burner was successfully modied to overcome the limits of operation with dierent mixtures ofSaudi LPGair and a stable ame was obtainede equivalence ratio ranges were found between 068 and 130 using the modiedBunsen burner A premixed ame was used for the modied Bunsen burner A MATLAB algorithm was successfully applied toame image processing and measurement of laminar burning velocity e laminar burning velocity was determined to beapproximately 35plusmn 091 cms under stoichiometric conditions using the modied Bunsen burner for the Saudi LPGair mixturee half-cone angle of the ame was found to be 1620plusmn 076deg e minimum ame height was observed to be 2150plusmn 022mmabove the Bunsen burner exit

1 Introduction

e laminar burning velocity is an important parameter forthe understanding of the structure of the ame and com-bustion characteristics It can be useful to determine fuelcombustion characteristics optimize combustion processesand studying premixed combustion [1ndash4] Laminar burningvelocity is essential to study the properties of the reactingpremixed mixture in combustion applications Additionallyan increase in the laminar burning velocity leads to anincrease in combustion eciency

Many factors impact the laminar burning velocity [3 4]the equivalence ratio (V) and the properties of the fuel arechemical factors while pressure ame temperature andparticle size (such as soot dust or coal particles) are physicalfactors For example Lee et al added coal particles withmethaneair mixtures in the lean fuel ey obtained that thelaminar burning velocity was increased [5] However animportant factor is the equivalence ratio e equivalenceratio is dened as the ratio between the oxidizer-to-fuel ratioat stoichiometric condition and the actual oxidizer-to-fuel

ratio e laminar burning velocity depends on the equiv-alence ratio (V) [6 7] Laminar burning velocity will in-crease when the equivalence ratio is increased in leanmixtures (less than one) while the decrease in the laminarburning velocity was found with increasing the equivalenceratio in rich mixtures (greater than one) As a result a highlaminar burning velocity is found near the stoichiometriccondition which is around the equivalence ratio of 1 (Vsim1)e highest ame temperature is also found around thestoichiometric condition [3 6] Khudhair et al mentionedthat an increase in the laminar burning velocity will result inan increased thermal energy and chemical reaction eyfound that the highest laminar burning velocity was ob-tained in rich and stoichiometric mixtures [3] e stabilityperformance was investigated using porous medium burners[8] e heat transfer coecient was also improved How-ever the properties of the fuel inuence the laminar burningvelocity A multiple opposing jetsrsquo burner was developed byKamal [9] He extended the ame stability limits using 12fuelair jets A cross-ow was also used to control com-bustion performance with measuring NOx emissions [10]

HindawiJournal of CombustionVolume 2022 Article ID 6977930 9 pageshttpsdoiorg10115520226977930

+e effect of NOx emissions for the natural gas (NG) andliquefied petroleum gas (LPG) was also investigated [11]+elaminar burning velocity has been determined for differentfuels such as natural gasair [12] H2air [2] and C3H8air[6] Khudhair and Shahad [3] reported that the laminarburning velocity would decrease with an increase in thenumber of carbon atoms in the fuel molecule due tochanging thermal diffusivity +e thermal diffusivity can bechanged by increasing the number of carbon atoms Laminarburning velocity for many alkanes was measured by Farrellet al [13] +ey found that methane had the lowest laminarburning velocity which has the lowest number of carbonatoms in this study due to chemical kinetic mechanismsespecially the flux of fuel atoms In addition Fu et al [2]found that the properties of fuels impact the laminar burningvelocity +e fuels which have a large number of hydrogenatoms had a high laminar burning velocity O2 gas is alsoimportant for increasing laminar burning velocity [3] Asensitivity of the laminar burning velocity around thestoichiometric condition was found for fuels with a largenumber of hydrogen atoms [14] Fuel combustion charac-teristics of the LPGair were studied by Lee and Ryu [15]they optimized combustion processes under different engineconditions An increase in laminar burning velocity indi-cates an improvement in the burner designs and explosionprotection in combustion units +e laminar burning ve-locity was found to be 16 to 403 cms for the LPGairmixture under stoichiometric conditions [16]

Bunsen burners have been extensively used to measurelaminar burning velocity in many studies [2 17 18] +eBunsen burner is used tomaintain a stable flame for differentconditions (eg pressure temperature and equivalenceratios) In addition it can be easily used to determinelaminar burning velocity [2 19] Wei et al [20] determinedthe minimum flame height above the burner exit understoichiometric conditions +ey obtained a lower flameheight under stoichiometric conditions using biogashy-drogen fuel+ey also obtained a laminar burning velocity ofapproximately 32 cms Moreover Bouvet et al [19] foundthat the laminar burning velocity depends on the compo-sition of each mixture +ey also obtained good flame sta-bilization with a fine-edge burner +e laminar burningvelocity for flames of propane n-butane and their mixtureswas measured by using a Bunsen burner [21] Chu et alstudied the effects of N2 dilution on the laminar burningvelocity for CH4-air premixed flames by using a Bunsenburner [22] Goey et al [23] used the Bunsen-type flames onmultislit burners for understanding heat release +ey in-vestigated experimentally and numerically A Bunsen burnerwas manufactured for high-performance hydrocarbon fuelsby Hwang et al [24] +ey used a Bunsen burner to measurelaminar burning velocity A lab-scale Bunsen burner wasused to measure the laminar burning velocity of oxy-CH4flames [25] +e authors used Schlieren photography tomeasure the laminar burning velocity using a Bunsenburner +e laminar burning velocity of premixed CH4-airflames was investigated by using the Bunsen burner method[5] John [17] studied different kinds of Bunsen burners fornatural gas He compared these burners to determine the

limits of the operation when some gas mixtures are usedHowever a straight tube with a flame burner was mostlyused +e Bunsen burner properties are a port area of7097mm2 a port diameter of 953mm a burner height of13970mm a mixing tube length of 8890mm and an orificeof 074mm +is orifice port was designed for natural gas[17] Barakat et al [26] used multiple air ports of the burnerto enhance the diffusion flame +ey found that pollutantemissions were reduced by using the burner with multipleair ports Cyclonic burners were numerically investigated toreduce combustion emissions [27 28] However the laminarburning velocity was easily measured using the Bunsenburner to match other techniques such as the spherical flamepropagation technique [29] A high-speed camera is re-quired For example 3-D measurements of flame structurewere achieved by using chemiluminescence imaging with sixCMOS cameras operating at 5 kHz [30]

In this study the laminar burning velocity was obtainedfrom the composition of various mixtures of Saudi LPG andair as listed in Tables 1 and 2 A straight tube Bunsen burnerwas used +e mixture of Saudi LPG and air was mixed afterinjecting the orifice port (primary port) in the mixing tubeFurthermore the Bunsen burner was modified to measurethe laminar burning velocities of Saudi LPGair mixtures+e mixture of Saudi LPG and air was mixed in the mixingtube +e laminar burning velocities were also comparedusing original and modified Bunsen burners for differentflow rates of the Saudi LPGair mixture Batch processingwas successfully applied to improve the images of the flameA MATLAB algorithm was also used to determine heightand angle of the half-cone of the flame as well as the laminarburning velocity Our aim of this research is to study thecharacteristic of Saudi liquefied petroleum gas (LPG)airflames by using a Bunsen burner and a modified Bunsenburner

2 Materials and Methods

21 Laminar Burning Velocity Measurements A Bunsenburner is extensively used to measure laminar burningvelocity +e flame shape is pronounced as a conical flameunder most of the conditions as shown in Figure 1 +eBunsen burner maintains a stable flame for different con-ditions+e laminar burning velocity can be easily measuredusing a Bunsen burner

Table 1 +e mixture of Saudi LPGair for the Bunsen burner

Flow rate of LPG(lmin) Flow rate of air (lmin) AFRlowast Φlowast

047 018 038 2277051 017 033 2616054 016 030 2943058 015 026 3372061 014 023 3799064 013 020 4293067 012 018 4869070 011 016 5549073 010 014 6366lowastAir-fuel ratios (AFR) and equivalence ratio (Φ)

2 Journal of Combustion

Measurement of the surface area of the flame is one ofthe main problems in determining the laminar burningvelocity [3 19 31]+e flame surface area can be determinedusing the surface area of a cone by measuring the height ofthe flame and the radius of the flame +e contour of theflame was used to compute many parameters of the flame(for example the height of the flame (h) the angle of thehalf-cone angle of the flame (α) and the radius of the flame(r)) as shown in Figure 1(a) +e flame contour for theboundary layer flame was obtained by using the functionprofile in the MATLAB software +e function profile is thefunction between the intensity profile of the image and thedistance on the x-axis as shown in Figure 1(b) +e flame of

the boundary layer was determined on the x-axis for eachflame height using the peaks (P2 and P1) of the intensityprofile for five points above the exit of the burner as shownin Figure 1(c)+e resolution of the camera was calculated tobe 007mmpixel +e flame height ranges were used atdistances above the burner exit of 1 to 5mm to avoidturbulent flame regions or lower illuminance of the layerflame in the top flame as indicated by the blue points inFigure 1(b) +e blue points are obtained using peaks (P1and P2) +en the entire contour of the surface of the flamewas fitted by using the Polyfit function for the degree of thefirst polynomial in the MATLAB software as indicated bythe red dashed line for P1 points and P2 points +e total

Table 2 +e mixture of Saudi LPGair for the modified Bunsen burner

Flow rate ofLPG (lmin)

Flow rate ofair (lmin) AFRlowast Φlowast Flow rate of

LPG (lmin)Flow rate ofair (lmin) AFRlowast Φlowast Flow rate of

LPG (lmin)Flow rate ofair (lmin) AFRlowast Φlowast

072 481 668 131 072 751 1043 084 076 581 764 114072 501 696 125 072 761 1057 083 076 621 817 107072 503 698 125 072 771 1071 082 076 641 843 104072 505 702 124 072 781 1085 08 076 661 87 1072 507 705 124 072 791 1099 079 076 681 896 097072 51 708 123 072 801 1113 078 076 701 922 095072 551 765 114 072 811 1126 078 076 721 949 092072 551 765 114 072 821 114 077 076 741 975 09072 571 793 11 072 831 1154 076 076 761 1001 087072 591 821 106 072 841 1168 075 076 781 1028 085072 601 835 105 072 861 1196 073 076 801 1054 083072 611 849 103 072 871 121 072 076 821 108 081072 631 876 1 072 881 1224 071 076 841 1107 079072 651 904 097 072 901 1251 07 076 861 1133 077072 671 932 094 072 921 1279 068 076 881 1159 075072 681 946 092 076 481 633 138 076 901 1186 074072 691 96 091 076 501 659 132 076 921 1212 072072 711 988 088 076 521 686 127 076 941 1238 071072 725 1007 087 076 541 712 123 076 961 1264 069072 741 1029 085 076 561 738 118 076 981 1291 068

Bunsen burner

r

h

α

Boundary layer flame

(a) (b)

-14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 1210 14Distance (mm)

80

70

60

50

40

30

20

10

0

Inte

nsity

pro

file

P2 P1

(c)

Figure 1 Illustration of the parameters of the Bunsen flame (a) schematic of flame height h flame half-cone angle α and flame radius r(b) the contour of the flame and (c) flame intensity profile

Journal of Combustion 3

contour is shown by the red dashed line in Figure 1(b) +eMATLAB algorithm was developed to calculate the half-cone angle of the flame the flame height the flame surfacearea and the laminar burning velocity for each image +eMATLAB algorithm was written to trace the boundary layerflame +e mean Bunsen flame images were used usingVargas et al [32] In this study we obtained the meanBunsen flame images with a good fitting of the contour of thesurface A good approximation was obtained to avoid theerror of the laminar burning velocity measurements in thisstudy +is process involves automated analysis

+e laminar burning velocity (SL) can be calculated as afunction of the velocity of the unburnedmixture (Uo) and thehalf-cone angle of the flame (α) [18 20 33 34] It is given by

SL Uosin(α) (1)

Uo can be expressed by (2) It is associated with the totalvolumetric flow rate of unburned gases (such as air andSaudi LPG) and the surface area of the flame

Uo _Vair+

_VLPG

A (2)

where _Vair is the volumetric flow rate of air _VLPG is thevolumetric flow rate of LPG and A is the flame surface area+e velocity of the unburned mixture is the rate of the totalvolumetric flow rate of the unburned gases with respect tothe flame surface area (A) +e flame surface area can beexpressed by (3) As an approximation the boundary layerflame was detected using the MATLAB program +en theheight and radius of the flame were obtained from the flamein the boundary layer

A πr r +h2+r2

11139681113874 1113875 (3)

where r is the radius of the flame and h is the height of theflame

22 Experimental Details +e LPG cylinder contained a265-liter mixture consisting of 50 propane (C3H8) and50 butane (C4H10) mixture +is gas cylinder was acommercial gas cylinder in Saudi Arabia +e pressureregulator of the gas cylinder was set to be 50mbar in theoutlet [33 35] +e air was provided by an air compressorthrough a pressure of 7 bar

Original andmodified Bunsen burners were used For theoriginal Bunsen burner themixture of Saudi LPG and air wasmixed before getting injected into the orifice port (primaryport) as presented in Figure 2(a) A 6-mmdiameter tee fittingwas used to mix Saudi LPG and air before injecting them intothe orifice port For the modified Bunsen burner Saudi LPGwas injected into the orifice port (primary port) while air wasinjected into theairhole (secondaryport)using the ringwhichwas carried out as presented in Figure 2(b) +is ring wasplaced around the air hole which was near the bottom andoutside of themixing tube as shown in Figure 2(c) As a resultthe mixture of Saudi LPGair was mixed after injecting theorificeport (primaryport) into themixing tube in themodifiedBunsen burner +e diameter and height of the mixing tubewere 94 and 878mm respectively

+e experimental setup used for the laminar burningvelocity measurement is shown in Figure 3 Laminar burningvelocity was obtained from the mixture of Saudi LPG and airfor mixing both before injection into the orifice port and inthe mixing tube +e orifices port diameter was 074mm+e air and Saudi LPG flow rates were controlled by a massflow controller (Bronkhorst Hi-Tec) Each gas was con-trolled by an El flow meter Each El flow meter was con-nected to a mass flow controller (MFC) +e range of massflow for the El flow meter was 0 to 30 lmin (accuracy lt1)+e Bunsen flame images were successfully improved tomeasure laminar burning velocity by using batch imageprocessing A CCD FlowMaster II camera (LaVision) wasused to capture 500 Bunsen flame images for each air-fuelratio +e luminous flame technique was used to determinethe laminar burning velocity +e CCD camera resolution is1280times1024 pixels at 5Hz+e average of 100 accumulationswas found to produce a better flame shape with a lowerstandard deviation in the laminar burning velocity mea-surements using batch processing in DaVis 7 +e flameimages were also improved by using the average of 100accumulations +e standard deviation of laminar burningvelocity measurements corresponded to five Bunsen flameimages after image processing with each image being theaverage of 100 accumulations

3 Results and Discussion

A premixed flame was used for both the Bunsen burner andthe modified Bunsen burner An average of 100 accumu-lations of the Bunsen flame images were used+e contour ofthe Bunsen flames was created by using a MATLAB algo-rithm it was useful to determine the flame height the half-cone angle of the flame and the flame radius for laminarburning velocity measurements using original and modifiedBunsen burners

31 Laminar Burning Velocity Measurements Using BunsenBurner Nine flow rates of Saudi LPGair mixtures wereused as listed in Table 1 Air-fuel ratios (AFR) were de-termined to be between 014 and 038 Fuel volume fractionswere used +e air-fuel ratio is 873 under stoichiometricconditions for the Saudi LPGair mixture and could not beachieved using a traditional Bunsen burner Images of SaudiLPGair flames for different air-fuel ratios (AFR) withmixing before the orifice port using a traditional Bunsenburner are shown in Figure 4

+e limits of operation were determined using the tra-ditional Bunsen burner for the Saudi LPGair mixtures mixedbefore the orifice port An increase in the airflow decreasedthe flow rate of Saudi LPG+e flow rate of the Saudi LPGairmixture was difficult to control for passage through the orificeport because the density of Saudi LPG was greater than the airdensity According to Poiseuillersquos law the resistance of flowincreases with increasing viscosity It also decreases the portarea +e viscosity of the Saudi LPG was greater than that ofthe air Hence the resistance to flow for Saudi LPG is greaterthan that of air in the same port area as an air barrier When


the Saudi LPGair mixture was mixed before the orifice portthe Saudi LPGair mixture was injected into the orifice portwhich had a diameter of 074mm In addition the volumetricflow rate can be decreased by increasing the resistance of theflow +e flow rate of air was less than the flow rate of SaudiLPG which passed through the orifice port using the tra-ditional Bunsen burner A flame flashback was generatedwhen the traditional Bunsen burner was used Because theflow rate of Saudi LPG was decreased unit 047 lmin whenairflow was increased unit 018 lmin as listed in Table 1 +etotal volumetric flow rate of the unburned gases was too small(less than 065 lmin) In addition the diameter of the mixingtube can lead to the flashback of the flame when the totalvolumetric flow rate is small [19]

+e laminar burning velocity was found to be less than1227 cms as shown in Figure 5 For example laminarburning velocities were determined to be less than 269 cms

for a higher equivalence ratio +e shape of the flames wasnot similar to a conical flame because the half-cone angle ofthe flame was found to approach zero (αsim0) as shown inFigure 5(a)

A high standard deviation of laminar burning velocitycan be obtained by changing the asymmetrical boundarylayer flame [19] Many factors impact the flame shapeExhaust gases heat losses and changing pressure could becaused by unburnt mixture this effect will increase thelaminar burning velocity error+e laminar burning velocityerror can also be produced by changing pressure or exhaustgas [3]

32 Laminar Burning Velocity Measurements UsingModifiedBunsen Burner +e mixtures of Saudi LPG and air weremixed after the orifice port in the mixing tube using the

Orifice(Primary port)

Closed air hole(Secondary port)

LPG gas + Air

(a)

AirOrifice

(Primary port)

Modified air hole(Secondary port)

LPG gas

(b)



(c)

Figure 2 Illustration of Saudi LPG and air inlet connections of the Bunsen burner for the mixture of LPG and air (a) the Bunsen burner(b) the modified Bunsen burner and (c) photograph of the modified Bunsen burner

MFC

CH4 Air

LPGgas

Air

PTU

El-flow metersPC

BunsenBurner

FlowMastercamera

(a)

CH4 Air

MFC

LPGgas

Air

PTU

El-flow meters

PC

Modified BunsenBurner

FlowMastercamera

(b)

Figure 3 +e experimental setup used for laminar burning velocity measurement MFC the mass flow controller PC personal computerPTU programmable timing unit


modified Bunsen burner +e resistance to air flow wasdecreased by increasing the port area which was 6 mm indiameter Various air flow rates and a fixed 072 lmin flowrate of Saudi LPG were used as listed in Table 2 to de-termine the laminar burning velocity Various air flow ratesand a fixed 076 lmin flow rate of Saudi LPG were also usedas listed in Table 2 to measure the laminar burning velocity

In Figure 6 the minimum flame height was found to bearound the stoichiometric condition+is result was in goodagreement in the literature+e air-fuel ratio was found to be873 under stoichiometric conditions for the Saudi LPGairmixture for the modified Bunsen burner +e flame heightswere not significantly different for the Saudi LPG flow ratesof 072 and 076 lmin

In many studies a high flame temperature was found tooccur under stoichiometric conditions [3 15] In additionthe flame thickness was found to be a function of the flametemperature As a result it was clear that the flame thicknesswas higher under stoichiometric conditions than underother air-fuel ratios+e flame thickness effect can negativelyinfluence laminar burning velocity measurements Someflame images for Saudi LPGair were observed to be slightlythe flame asymmetry images using the modified Bunsenburner especially above the equivalence ratio of 085 asshown in Figure 6 +e contour of the flame surface wasmore precisely fitted using the MATLAB algorithm with alayer flame for a flow rate of 076 lmin for Saudi LPG thanfor a flow rate of 072 lmin for Saudi LPG +e flameasymmetry images can be processed to set the flame imagesat the central image plane [30 36] As a result the mea-surement of the laminar burning velocity will be improved

with less error (less than 26) and overcome the effect offlame thickness by using the peaks of the intensity profile ofthe flame image as shown in Figure 1(c) However a goodlinear relationship was found between the half-cone angle ofthe flame and the air-fuel ratio in the combustion regions ofthe rich and lean mixture as shown in Figure 7(a) +ehighest half-cone angle of the flame was found to be1620plusmn 076deg at the stoichiometric condition at an air-fuelratio of around 873 No significant differences were found inthe half-cone angle of the flame measurements for the flowrates 072 and 076 lmin of Saudi LPG in different air-fuelratios especially in the region of combustion of the leanmixture

+e lowest flame height was found to be 215mm abovethe modified Bunsen burner exit when using Saudi LPGflow rates of 072 and 076 lmin as shown in Figure 7(b)+e type of gas mixture will affect the laminar burningvelocity and flame height measurements around the stoi-chiometric condition For example the laminar burningvelocity was found to be sensitive to stretching around thestoichiometric condition such as between 08 and 12 aswhen there was shown in Figure 8 a greater number ofhydrogen atoms in the fuel molecule [14 39] In additionthe flame height did not change significantly in anequivalence ratio ranging from 08 to 115 because themixture of Saudi LPG and air has a large number of hy-drogen atoms In Figure 8 the increase in laminar burningvelocity was obtained with a lean mixture with increasingequivalence ratio while the laminar burning velocity wasdecreased by increasing the equivalence ratio in a richmixture +e maximum value of the laminar burning

Φ = 6366 5549 4869 4293 3799 3372 2943 2616 2277

Figure 4 Images of the Saudi LPGair flames for different equivalence ratios with mixing before the orifice port using the traditional Bunsenburner

06

04

02

Hal

f con

e ang

le o

f the

flam

e (deg)

00

20 30 40Equivalence ratio

50 60 70

(a)

6070

50403020

Flam

es h

eigh

t (m

m)

010


50 60 70

(b)

1416

1210

86

The l

amin

ar b

urni

ng v

eloc

ity (c

ms

)

0

42


50 60 70

(c)

Figure 5 Flame parameters half-cone angle of flame (a) flame height (b) and laminar burning velocity (SL) (c) using Bunsen burner (SL) forthe Saudi LPGair mixture mixed before the orifice port


AFR =

(a)

(b)

Ф =664132

691126

765114

819107

846103

873100

900097

927094

947092

981089

1004087

1028085

1055083

1082081

1164075

1191073

1211072

Figure 6 Images of the Saudi LPGair flames for different air-fuel ratios (AFR) (a) at fixed 072 of the Saudi LPG flow rate and (b) at fixed076 lmin of the Saudi LPG flow rate mixing in the mixing tube using the modified Bunsen burner

072 lmin of LPG gas076 lmin of LPG gas

Hal

f con

e ang

le o

f the

flam

e (deg)

Lean mixture Rich mixture

2

4

6

8

10

12

14

16

18

07 08 09 10 11 12 13 1406ϕ

(a)

Flam

es h

eigh

t (m

m)



20

30

40

50

60

70

07 08 09 10 11 12 13 1406ϕ

(b)

Figure 7 Half-cone angle of the flame measurements (a) and flame height (b) for different equivalence ratios at different Saudi LPG flowrates ( black solid square) for 072 lmin and ( red solid circle) for 076 lmin LPG flow rates using the modified Bunsen burner

Yang (2006)Miao et al (2014)This work

e l

amin

ar b

urni

ng v

eloc

ity (c

ms

)

06 07 08 09 10 11 12 13 14 15 16 1705ϕ

10

15

20

25

30

35

40

Figure 8 Comparison laminar burning velocity (SL) between present work with previous work in literature ( green solid diamond) for50 of C3H8 + 50 of n-C4HlOair mixture by Yang [37] ( blue solid triangle) for LPG gas by Miao et al [38] and ( black solid square)for Saudi LPGair using the modified Bunsen burner in this work


velocity was calculated to be approximately 35plusmn 091 cmsas shown in Figure 8 About 072 and 076 lmin Saudi LPGflow rates were used to obtain a laminar burning velocity ofapproximately 35 cms while the laminar burning velocitywas found to be lower than 269 cms at a flow rate of 073 lmin for Saudi LPG using a traditional Bunsen burner As aresult the high performance of the Bunsen burner wasfound using the modified Bunsen burner for the SaudiLPGair mixture +e highest laminar burning velocity wasfound under stoichiometric conditions +e behavior of thelaminar burning velocity was validated as the highest understoichiometric conditions in many studies Laminarburning velocities were also not significantly different forSaudi LPG flow rates of 072 and 076 lmin at differentequivalence ratios +is is in good agreement with thedependence of the laminar burning velocity on theequivalence ratio Wei et al found that the laminar burningvelocity of biogashydrogen fuel was 32 cms using aBunsen burner [20] In addition the laminar burningvelocity was found to be 35 cms and 32 cms for SaudiLPG-air and biogas-hydrogen respectively

+e laminar burning velocities (SL) were observed to bemore sensitive to the equivalence ratio in rich mixturescompared to lean mixtures this is because exhaust gas isproduced in rich mixtures more than in lean mixtures +isis one of the problems that leads to a decrease in laminarburning velocity [3] +e laminar burning velocity wasimproved using the modified Bunsen burner compared tothe traditional Bunsen burner for Saudi LPGair mixtures+e laminar burning velocity of the Saudi LPGair flame wasincreased from 1227 cms to 35 cms using the modifiedBunsen burner

+e laminar burning velocity the height and the half-cone angle of the flame measurements had very similarvalues at the same value of the air-fuel ratio for Saudi LPGair mixtures mixed in the modified Bunsen burner mixingtube Flame stability was monitored using 100 Bunsen flameimages Additionally the laminar burning velocity error wasfound to be less than 26 A stable flame and a conical flamewere obtained using the modified Bunsen burner whenmixed in the mixing tube for Saudi LPG

4 Conclusion

In this study a traditional Bunsen burner had an operationalproblem in a lean mixture of Saudi LPGair mixtures Amodified Bunsen burner was developed to overcome thelimits of operation of the traditional Bunsen burner whenusing different mixtures of Saudi LPGair +e equivalenceratio range between 06 and 13 can be operated using themodified Bunsen burner +e laminar burning velocity wasexperimentally measured using traditional and modifiedBunsen burners for different ranges of Saudi LPGair flowrates +e effect of mixing Saudi LPG and air on the per-formance of the Bunsen burner was studied A MATLABalgorithm was developed to compute the half-cone angle ofthe flame the height of the flame and the surface area of theflame +e layer flame was precisely fitted using theMATLAB algorithm +e laminar burning velocities were

successfully determined +e maximum value of the laminarburning velocity was calculated to be approximately35plusmn 091 cms for Saudi LPG using the modified Bunsenwhile the laminar burning velocity was found to be lowerthan 269 cms for Saudi LPG using a traditional Bunsenburner A stable flame of the Saudi LPG mixture was alsoobtained using the modified Bunsen burner

Data Availability

+e results are experimentally obtained in this study thathave not been previously published

Conflicts of Interest

+e authors declare that they have no conflicts of interest

Acknowledgments

+e authors acknowledge financial support from the Waterand Energy Research Institute King Abdulaziz City ofScience and Technology +e authors also thank Prof DavidL Monts for proofreading the manuscript

References

[1] E V Vega and K Y Lee ldquoAn experimental study on laminarCH4O2N2 premixed flames under an electric fieldrdquo Journalof Mechanical Science and Technology vol 22 no 2pp 312ndash319 2008

[2] J Fu C Tang W Jin and Z Huang ldquoEffect of preferentialdiffusion and flame stretch on flame structure and laminarburning velocity of syngas bunsen flame using OH-plifrdquoInternational Journal of Hydrogen Energy vol 39 no 23pp 12187ndash12193 2014

[3] O Khudhair and H A K Shahad ldquoA review of laminarburning velocity and flame speed of gases and liquid fuelsrdquoInternational Journal of Current Engineering and Technologyvol 7 pp 183ndash197 2017

[4] V Katre and S K Bhele ldquoA review of laminar burning ve-locity of gases and liquid fuelsrdquo International Journal ofComputational Engineering Research vol 3 pp 33ndash38 2013

[5] M Lee S Ranganathan and A S Rangwala ldquoInfluence of thereactant temperature on particle entrained laminar methane-air premixed flamesrdquo Proceedings of the Combustion Institutevol 35 no 1 pp 729ndash736 2015

[6] D K Kuehl ldquoLaminar-burning velocities of propane-airmixturesrdquo Symposium (International) on Combustion vol 8no 1 pp 510ndash521 1961

[7] A Michalakou P Stavropoulos and S Couris ldquoLaser-in-duced breakdown spectroscopy in reactive flows of hydro-carbon-air mixturesrdquo Applied Physics Letters vol 92 no 8Article ID 081501 2008

[8] M M Kamal and A A Mohamad ldquoEffect of swirl on per-formance of foam porous medium burnersrdquo CombustionScience and Technology vol 178 no 4 pp 729ndash761 2006

[9] M M Kamal ldquoDevelopment of a multiple opposing jetsrsquoburner for premixed flamesrdquo Proceedings of the Institution ofMechanical EngineersmdashPart A Journal of Power and Energyvol 226 no 8 pp 1032ndash1049 2012

[10] M Kamal ldquoCombustion via multiple pairs of opposingpremixed flames with a cross-flowrdquo Proceedings of the


Institution of Mechanical EngineersmdashPart A Journal of Powerand Energy vol 231 no 1 pp 39ndash58 2017

[11] H Z Barakat M M Kamal H E Saad and B IbrahimldquoBlending effect between the natural gas and the liquefiedpetroleum gas using multiple Co-and cross-flow jets on NOxemissionsrdquo Ain Shams Engineering Journal vol 10 no 2pp 419ndash434 2019

[12] H S Zhen C W Leung C S Cheung and Z H HuangldquoCharacterization of biogas-hydrogen premixed flames usingbunsen burnerrdquo International Journal of Hydrogen Energyvol 39 no 25 pp 13292ndash13299 2014

[13] J T Farrell R J Johnston and I P Androulakis ldquoMolecularstructure effects on laminar burning velocities at elevatedtemperature and pressurerdquo SAE Transactions vol 2004-01-2936 pp 1404ndash1425 2004

[14] J Quinard G Searby B Denet and J Grantildea-Otero ldquoSelf-turbulent flame speedsrdquo Flow Turbulence and Combustionvol 89 no 2 pp 231ndash247 2012

[15] K Lee and J Ryu ldquoAn experimental study of the flamepropagation and combustion characteristics of LPG fuelrdquoFuel vol 84 no 9 pp 1116ndash1127 2005

[16] M Akram and S Kumar ldquoMeasurement of laminar burningvelocity of liquified petrolium gas air mixtures at elevatedtemperaturesrdquo Energy and Fuels vol 26 no 6 pp 3267ndash32742012

[17] H A John ldquoStudy of laboratory bunsen burners for naturalgasrdquo Journal of Research of the National Bureau of Standardsvol 4 pp 541ndash556 1949

[18] J Fu C Tang W Jin L D +i Z Huang and Y ZhangldquoStudy on laminar flame speed and flame structure of syngaswith varied compositions using OH-plif and spectrographrdquoInternational Journal of Hydrogen Energy vol 38 no 3pp 1636ndash1643 2013

[19] N Bouvet C Chauveau I Gokalp S-Y Lee andR J Santoro ldquoCharacterization of syngas laminar flamesusing the bunsen burner configurationrdquo International Journalof Hydrogen Energy vol 36 no 1 pp 992ndash1005 2011

[20] Z L Wei H S Zhen C W Leung C S Cheung andZ H Huang ldquoHeat transfer characteristics and the optimizedheating distance of laminar premixed biogas-hydrogenbunsen flame impinging on a flat surfacerdquo InternationalJournal of Hydrogen Energy vol 40 no 45 pp 15723ndash157312015

[21] S M Kumaran D Shanmugasundaram K Narayanaswamyand V Raghavan ldquoReduced mechanism for flames of propanen-butane and their mixtures for application to burners de-velopment and validationrdquo International Journal of ChemicalKinetics vol 53 no 6 pp 731ndash750 2021

[22] H Chu L Xiang S MengW DongM Gu and Z Li ldquoEffectsof N2 dilution on laminar burning velocity combustioncharacteristics and NOx emissions of rich CH4-air premixedflamesrdquo Fuel vol 284 Article ID 119017 2021

[23] P de Goey V Kornilov R Rook and J T +ije BoonkkampldquoExperimental and numerical investigation of the acousticresponse of multi-slit bunsen burnersrdquo Proceedings ofMeetings on Acoustics vol 4 2008

[24] B J Hwang S Kang H J Lee and S Min ldquoMeasurement oflaminar burning velocity of high performance alternativeaviation fuelsrdquo Fuel vol 261 Article ID 116466 2020

[25] J Oh and D Noh ldquoLaminar burning velocity of oxy-methaneflames in atmospheric conditionrdquo Energy vol 45 no 1pp 669ndash675 2012

[26] H Barakat M Kamal H Saad and W Eldeeb ldquoPerformanceenhancement of inverse diffusion flame burners with

distributed portsrdquo Proceedings of the Institution of MechanicalEngineers - Part A Journal of Power and Energy vol 229no 2 pp 160ndash175 2015

[27] K B Kekec S Karyeyen and M Ilbas ldquoColorless distributedcombustion OF diffusion methane flame using two cyclonicinlet burnersrdquo International Journal of Energy for a CleanEnvironment vol 23 2022

[28] M S Cellek ldquoEvaluation of oxygen enrichment effects ondistribution combustion mode in a laboratory-scale furnacerdquoInternational Journal of Energy for a Clean Environmentvol 23 2022

[29] A A Yousif S A Sulaiman S A Sulaiman and M S NasifldquoExperimental study on laminar flame speeds and marksteinlength of propane air mixtures at atmospheric conditionsrdquoInternational Journal of Automotive and Mechanical Engi-neering vol 11 pp 2188ndash2198 2015

[30] L Ma Y Wu Q Lei W Xu and C D Carter ldquo3D flametopography and curvature measurements at 5 KHz on apremixed turbulent bunsen flamerdquo Combustion and Flamevol 166 pp 66ndash75 2016

[31] Y Chen J Wang X Zhang and C Li ldquoExperimental andnumerical study of the effect of CO2 replacing part of N2present in air on CH4 premixed flame characteristics using areduced mechanismrdquo ACS Omega vol 5 no 46pp 30130ndash30138 2020

[32] A C Vargas A M Garcıa C E Arrieta J Sierra Del Rio andA Amell ldquoBurning velocity of turbulent methaneair pre-mixed flames in subatmospheric environmentsrdquo ACS Omegavol 5 no 39 pp 25095ndash25103 2020

[33] National Gas amp Indust Co (GASCO) httpswwwgascocomsa

[34] C Luo Z Yu Y Wang and Y Ai ldquoExperimental investi-gation of lean methane-air laminar premixed flames at en-gine-relevant temperaturesrdquo ACS Omega vol 6 no 28pp 17977ndash17987 2021

[35] A M A Nasser ldquoGas distribution network for households inSaudi arabia economic and demand estimation studiesrdquoInternational Journal of Oil Gas and Coal Technology vol 4no 2 pp 174ndash191 2011

[36] Y N Mishra P Boggavarapu D Chorey et al ldquoApplicationof FRAME for simultaneous LIF and LII imaging in sootingflames using a single camerardquo Sensors vol 20 no 19 p 55342020

[37] B Yang Laminar Burning Velocity of Liquefied Petroleum GasMixtures PhD +esis Loughborough University Lough-borough UK 2006

[38] J Miao C W Leung Z Huang C S Cheung H Yu andY Xie ldquoLaminar burning velocities markstein lengths andflame thickness of liquefied petroleum gas with hydrogenenrichmentrdquo International Journal of Hydrogen Energyvol 39 no 24 pp 13020ndash13030 2014

[39] P Dirrenberger L H Gall R Bounaceur et al ldquoMeasure-ments of laminar flame velocity for components of naturalgasrdquo American Chemical Society vol 9 pp 3875ndash3884 2013


+e effect of NOx emissions for the natural gas (NG) andliquefied petroleum gas (LPG) was also investigated [11]+elaminar burning velocity has been determined for differentfuels such as natural gasair [12] H2air [2] and C3H8air[6] Khudhair and Shahad [3] reported that the laminarburning velocity would decrease with an increase in thenumber of carbon atoms in the fuel molecule due tochanging thermal diffusivity +e thermal diffusivity can bechanged by increasing the number of carbon atoms Laminarburning velocity for many alkanes was measured by Farrellet al [13] +ey found that methane had the lowest laminarburning velocity which has the lowest number of carbonatoms in this study due to chemical kinetic mechanismsespecially the flux of fuel atoms In addition Fu et al [2]found that the properties of fuels impact the laminar burningvelocity +e fuels which have a large number of hydrogenatoms had a high laminar burning velocity O2 gas is alsoimportant for increasing laminar burning velocity [3] Asensitivity of the laminar burning velocity around thestoichiometric condition was found for fuels with a largenumber of hydrogen atoms [14] Fuel combustion charac-teristics of the LPGair were studied by Lee and Ryu [15]they optimized combustion processes under different engineconditions An increase in laminar burning velocity indi-cates an improvement in the burner designs and explosionprotection in combustion units +e laminar burning ve-locity was found to be 16 to 403 cms for the LPGairmixture under stoichiometric conditions [16]

Bunsen burners have been extensively used to measurelaminar burning velocity in many studies [2 17 18] +eBunsen burner is used tomaintain a stable flame for differentconditions (eg pressure temperature and equivalenceratios) In addition it can be easily used to determinelaminar burning velocity [2 19] Wei et al [20] determinedthe minimum flame height above the burner exit understoichiometric conditions +ey obtained a lower flameheight under stoichiometric conditions using biogashy-drogen fuel+ey also obtained a laminar burning velocity ofapproximately 32 cms Moreover Bouvet et al [19] foundthat the laminar burning velocity depends on the compo-sition of each mixture +ey also obtained good flame sta-bilization with a fine-edge burner +e laminar burningvelocity for flames of propane n-butane and their mixtureswas measured by using a Bunsen burner [21] Chu et alstudied the effects of N2 dilution on the laminar burningvelocity for CH4-air premixed flames by using a Bunsenburner [22] Goey et al [23] used the Bunsen-type flames onmultislit burners for understanding heat release +ey in-vestigated experimentally and numerically A Bunsen burnerwas manufactured for high-performance hydrocarbon fuelsby Hwang et al [24] +ey used a Bunsen burner to measurelaminar burning velocity A lab-scale Bunsen burner wasused to measure the laminar burning velocity of oxy-CH4flames [25] +e authors used Schlieren photography tomeasure the laminar burning velocity using a Bunsenburner +e laminar burning velocity of premixed CH4-airflames was investigated by using the Bunsen burner method[5] John [17] studied different kinds of Bunsen burners fornatural gas He compared these burners to determine the

limits of the operation when some gas mixtures are usedHowever a straight tube with a flame burner was mostlyused +e Bunsen burner properties are a port area of7097mm2 a port diameter of 953mm a burner height of13970mm a mixing tube length of 8890mm and an orificeof 074mm +is orifice port was designed for natural gas[17] Barakat et al [26] used multiple air ports of the burnerto enhance the diffusion flame +ey found that pollutantemissions were reduced by using the burner with multipleair ports Cyclonic burners were numerically investigated toreduce combustion emissions [27 28] However the laminarburning velocity was easily measured using the Bunsenburner to match other techniques such as the spherical flamepropagation technique [29] A high-speed camera is re-quired For example 3-D measurements of flame structurewere achieved by using chemiluminescence imaging with sixCMOS cameras operating at 5 kHz [30]

In this study the laminar burning velocity was obtainedfrom the composition of various mixtures of Saudi LPG andair as listed in Tables 1 and 2 A straight tube Bunsen burnerwas used +e mixture of Saudi LPG and air was mixed afterinjecting the orifice port (primary port) in the mixing tubeFurthermore the Bunsen burner was modified to measurethe laminar burning velocities of Saudi LPGair mixtures+e mixture of Saudi LPG and air was mixed in the mixingtube +e laminar burning velocities were also comparedusing original and modified Bunsen burners for differentflow rates of the Saudi LPGair mixture Batch processingwas successfully applied to improve the images of the flameA MATLAB algorithm was also used to determine heightand angle of the half-cone of the flame as well as the laminarburning velocity Our aim of this research is to study thecharacteristic of Saudi liquefied petroleum gas (LPG)airflames by using a Bunsen burner and a modified Bunsenburner

2 Materials and Methods

21 Laminar Burning Velocity Measurements A Bunsenburner is extensively used to measure laminar burningvelocity +e flame shape is pronounced as a conical flameunder most of the conditions as shown in Figure 1 +eBunsen burner maintains a stable flame for different con-ditions+e laminar burning velocity can be easily measuredusing a Bunsen burner

Table 1 +e mixture of Saudi LPGair for the Bunsen burner

Flow rate of LPG(lmin) Flow rate of air (lmin) AFRlowast Φlowast

047 018 038 2277051 017 033 2616054 016 030 2943058 015 026 3372061 014 023 3799064 013 020 4293067 012 018 4869070 011 016 5549073 010 014 6366lowastAir-fuel ratios (AFR) and equivalence ratio (Φ)









072 481 668 131 072 751 1043 084 076 581 764 114072 501 696 125 072 761 1057 083 076 621 817 107072 503 698 125 072 771 1071 082 076 641 843 104072 505 702 124 072 781 1085 08 076 661 87 1072 507 705 124 072 791 1099 079 076 681 896 097072 51 708 123 072 801 1113 078 076 701 922 095072 551 765 114 072 811 1126 078 076 721 949 092072 551 765 114 072 821 114 077 076 741 975 09072 571 793 11 072 831 1154 076 076 761 1001 087072 591 821 106 072 841 1168 075 076 781 1028 085072 601 835 105 072 861 1196 073 076 801 1054 083072 611 849 103 072 871 121 072 076 821 108 081072 631 876 1 072 881 1224 071 076 841 1107 079072 651 904 097 072 901 1251 07 076 861 1133 077072 671 932 094 072 921 1279 068 076 881 1159 075072 681 946 092 076 481 633 138 076 901 1186 074072 691 96 091 076 501 659 132 076 921 1212 072072 711 988 088 076 521 686 127 076 941 1238 071072 725 1007 087 076 541 712 123 076 961 1264 069072 741 1029 085 076 561 738 118 076 981 1291 068

Bunsen burner

r

h

α


(a) (b)

-14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 1210 14Distance (mm)

80

70

60

50

40

30

20

10

0

Inte

nsity

pro

file

P2 P1

(c)





SL Uosin(α) (1)


Uo _Vair+

_VLPG

A (2)


A πr r +h2+r2

11139681113874 1113875 (3)

















LPG gas + Air

(a)

AirOrifice

(Primary port)


LPG gas

(b)



(c)


MFC

CH4 Air

LPGgas

Air

PTU

El-flow metersPC

BunsenBurner

FlowMastercamera

(a)

CH4 Air

MFC

LPGgas

Air

PTU

El-flow meters

PC


FlowMastercamera

(b)








Φ = 6366 5549 4869 4293 3799 3372 2943 2616 2277


06

04

02

Hal

f con

e ang

le o

f the

flam

e (deg)

00


50 60 70

(a)

6070

50403020

Flam

es h

eigh

t (m

m)

010


50 60 70

(b)

1416

1210

86

The l

amin

ar b

urni

ng v

eloc

ity (c

ms

)

0

42


50 60 70

(c)



AFR =

(a)

(b)

Ф =664132

691126

765114

819107

846103

873100

900097

927094

947092

981089

1004087

1028085

1055083

1082081

1164075

1191073

1211072



Hal

f con

e ang

le o

f the

flam

e (deg)


2

4

6

8

10

12

14

16

18

07 08 09 10 11 12 13 1406ϕ

(a)

Flam

es h

eigh

t (m

m)



20

30

40

50

60

70

07 08 09 10 11 12 13 1406ϕ

(b)



e l

amin

ar b

urni

ng v

eloc

ity (c

ms

)

06 07 08 09 10 11 12 13 14 15 16 1705ϕ

10

15

20

25

30

35

40






4 Conclusion



Data Availability




Acknowledgments


References



















































072 481 668 131 072 751 1043 084 076 581 764 114072 501 696 125 072 761 1057 083 076 621 817 107072 503 698 125 072 771 1071 082 076 641 843 104072 505 702 124 072 781 1085 08 076 661 87 1072 507 705 124 072 791 1099 079 076 681 896 097072 51 708 123 072 801 1113 078 076 701 922 095072 551 765 114 072 811 1126 078 076 721 949 092072 551 765 114 072 821 114 077 076 741 975 09072 571 793 11 072 831 1154 076 076 761 1001 087072 591 821 106 072 841 1168 075 076 781 1028 085072 601 835 105 072 861 1196 073 076 801 1054 083072 611 849 103 072 871 121 072 076 821 108 081072 631 876 1 072 881 1224 071 076 841 1107 079072 651 904 097 072 901 1251 07 076 861 1133 077072 671 932 094 072 921 1279 068 076 881 1159 075072 681 946 092 076 481 633 138 076 901 1186 074072 691 96 091 076 501 659 132 076 921 1212 072072 711 988 088 076 521 686 127 076 941 1238 071072 725 1007 087 076 541 712 123 076 961 1264 069072 741 1029 085 076 561 738 118 076 981 1291 068

Bunsen burner

r

h

α


(a) (b)

-14 -12 -10 -8 -6 -4 -2 0 2 4 6 8 1210 14Distance (mm)

80

70

60

50

40

30

20

10

0

Inte

nsity

pro

file

P2 P1

(c)





SL Uosin(α) (1)


Uo _Vair+

_VLPG

A (2)


A πr r +h2+r2

11139681113874 1113875 (3)

















LPG gas + Air

(a)

AirOrifice

(Primary port)


LPG gas

(b)



(c)


MFC

CH4 Air

LPGgas

Air

PTU

El-flow metersPC

BunsenBurner

FlowMastercamera

(a)

CH4 Air

MFC

LPGgas

Air

PTU

El-flow meters

PC


FlowMastercamera

(b)








Φ = 6366 5549 4869 4293 3799 3372 2943 2616 2277


06

04

02

Hal

f con

e ang

le o

f the

flam

e (deg)

00


50 60 70

(a)

6070

50403020

Flam

es h

eigh

t (m

m)

010


50 60 70

(b)

1416

1210

86

The l

amin

ar b

urni

ng v

eloc

ity (c

ms

)

0

42


50 60 70

(c)



AFR =

(a)

(b)

Ф =664132

691126

765114

819107

846103

873100

900097

927094

947092

981089

1004087

1028085

1055083

1082081

1164075

1191073

1211072



Hal

f con

e ang

le o

f the

flam

e (deg)


2

4

6

8

10

12

14

16

18

07 08 09 10 11 12 13 1406ϕ

(a)

Flam

es h

eigh

t (m

m)



20

30

40

50

60

70

07 08 09 10 11 12 13 1406ϕ

(b)



e l

amin

ar b

urni

ng v

eloc

ity (c

ms

)

06 07 08 09 10 11 12 13 14 15 16 1705ϕ

10

15

20

25

30

35

40






4 Conclusion



Data Availability




Acknowledgments


References














































SL Uosin(α) (1)


Uo _Vair+

_VLPG

A (2)


A πr r +h2+r2

11139681113874 1113875 (3)

















LPG gas + Air

(a)

AirOrifice

(Primary port)


LPG gas

(b)



(c)


MFC

CH4 Air

LPGgas

Air

PTU

El-flow metersPC

BunsenBurner

FlowMastercamera

(a)

CH4 Air

MFC

LPGgas

Air

PTU

El-flow meters

PC


FlowMastercamera

(b)








Φ = 6366 5549 4869 4293 3799 3372 2943 2616 2277


06

04

02

Hal

f con

e ang

le o

f the

flam

e (deg)

00


50 60 70

(a)

6070

50403020

Flam

es h

eigh

t (m

m)

010


50 60 70

(b)

1416

1210

86

The l

amin

ar b

urni

ng v

eloc

ity (c

ms

)

0

42


50 60 70

(c)



AFR =

(a)

(b)

Ф =664132

691126

765114

819107

846103

873100

900097

927094

947092

981089

1004087

1028085

1055083

1082081

1164075

1191073

1211072



Hal

f con

e ang

le o

f the

flam

e (deg)


2

4

6

8

10

12

14

16

18

07 08 09 10 11 12 13 1406ϕ

(a)

Flam

es h

eigh

t (m

m)



20

30

40

50

60

70

07 08 09 10 11 12 13 1406ϕ

(b)



e l

amin

ar b

urni

ng v

eloc

ity (c

ms

)

06 07 08 09 10 11 12 13 14 15 16 1705ϕ

10

15

20

25

30

35

40






4 Conclusion



Data Availability




Acknowledgments


References



















































LPG gas + Air

(a)

AirOrifice

(Primary port)


LPG gas

(b)



(c)


MFC

CH4 Air

LPGgas

Air

PTU

El-flow metersPC

BunsenBurner

FlowMastercamera

(a)

CH4 Air

MFC

LPGgas

Air

PTU

El-flow meters

PC


FlowMastercamera

(b)








Φ = 6366 5549 4869 4293 3799 3372 2943 2616 2277


06

04

02

Hal

f con

e ang

le o

f the

flam

e (deg)

00


50 60 70

(a)

6070

50403020

Flam

es h

eigh

t (m

m)

010


50 60 70

(b)

1416

1210

86

The l

amin

ar b

urni

ng v

eloc

ity (c

ms

)

0

42


50 60 70

(c)



AFR =

(a)

(b)

Ф =664132

691126

765114

819107

846103

873100

900097

927094

947092

981089

1004087

1028085

1055083

1082081

1164075

1191073

1211072



Hal

f con

e ang

le o

f the

flam

e (deg)


2

4

6

8

10

12

14

16

18

07 08 09 10 11 12 13 1406ϕ

(a)

Flam

es h

eigh

t (m

m)



20

30

40

50

60

70

07 08 09 10 11 12 13 1406ϕ

(b)



e l

amin

ar b

urni

ng v

eloc

ity (c

ms

)

06 07 08 09 10 11 12 13 14 15 16 1705ϕ

10

15

20

25

30

35

40






4 Conclusion



Data Availability




Acknowledgments


References

















































Φ = 6366 5549 4869 4293 3799 3372 2943 2616 2277


06

04

02

Hal

f con

e ang

le o

f the

flam

e (deg)

00


50 60 70

(a)

6070

50403020

Flam

es h

eigh

t (m

m)

010


50 60 70

(b)

1416

1210

86

The l

amin

ar b

urni

ng v

eloc

ity (c

ms

)

0

42


50 60 70

(c)



AFR =

(a)

(b)

Ф =664132

691126

765114

819107

846103

873100

900097

927094

947092

981089

1004087

1028085

1055083

1082081

1164075

1191073

1211072



Hal

f con

e ang

le o

f the

flam

e (deg)


2

4

6

8

10

12

14

16

18

07 08 09 10 11 12 13 1406ϕ

(a)

Flam

es h

eigh

t (m

m)



20

30

40

50

60

70

07 08 09 10 11 12 13 1406ϕ

(b)



e l

amin

ar b

urni

ng v

eloc

ity (c

ms

)

06 07 08 09 10 11 12 13 14 15 16 1705ϕ

10

15

20

25

30

35

40






4 Conclusion



Data Availability




Acknowledgments


References












































AFR =

(a)

(b)

Ф =664132

691126

765114

819107

846103

873100

900097

927094

947092

981089

1004087

1028085

1055083

1082081

1164075

1191073

1211072



Hal

f con

e ang

le o

f the

flam

e (deg)


2

4

6

8

10

12

14

16

18

07 08 09 10 11 12 13 1406ϕ

(a)

Flam

es h

eigh

t (m

m)



20

30

40

50

60

70

07 08 09 10 11 12 13 1406ϕ

(b)



e l

amin

ar b

urni

ng v

eloc

ity (c

ms

)

06 07 08 09 10 11 12 13 14 15 16 1705ϕ

10

15

20

25

30

35

40






4 Conclusion



Data Availability




Acknowledgments


References















































4 Conclusion



Data Availability




Acknowledgments


References












































the characterization of liquefied petroleum gas (lpg) using

Documents