UNIVERSITI TEKNOLOGI MARAFAKULTI KEJURUTERAAN KIMIA

PROCESS ENGINEERING LABORATORY II(CPE554)

NAME : SHEH MUHAMMAD AFNAN BIN SEH HANAFISTUDENT ID : 2013210382GROUP : EH2214AEXPERIMENT : SHELL AND TUBE HEAT EXCHANGERDATE PERFORMED : 8TH APRIL 2015SEMESTER : 4PROGRAMME / CODE : EH221/ CPE554SUBMIT TO : MS HABSAH ALWI

No. Title Allocated Marks (%) Marks

1 Abstract/Summary 52 Introduction 53 Aims 54 Theory 55 Apparatus 56 Methodology/Procedure 107 Results 108 Calculations 109 Discussion 20

10 Conclusion 1011 Recommendations 512 Reference 513 Appendix 5

TOTAL MARKS 100Remarks:

Checked by: Rechecked by

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Date: Date :

ABSTRACT

In this experiment, the objective is to determine the efficiency of enhanced concentric

shell-tube heat exchanger using water as the heat exchange medium for counter-current flow heat

exchanger. The experiment was also to evaluate the heat transfer and heat loss for energy balance,

LMTD, heat transfer coefficient, overall heat transfer coefficient (U) and the pressure drop of the

shell and tube heat exchanger. The instrument was combined with thermometer , thus the TT1(hot

in) , TT2(hot out) , TT3(cold in) , TT4( cold out) can be measured. At first, the hot water water

flow rate (FT1) was set to fixed which is 10LPM and cold water flow rate (FT2) was varied.The

experiment then repeated by varied the hot water water flow rate (FT1) and fixing the cold water

flow rate (FT2) to 10LPM . The data is being recorded for temperature and pressure for each flow

rates within 10 minutes interval. From the results, it can be concluded that the pressure drop is

depends on flow rate not the temperature. Furthermore, for shell and tube heat transfer coefficient

is depends on flow rate, which is for tube coefficient is constant because the flow rate is constant

but for shell coefficient, the shell coefficient is increase as the flow rate is increase

INTRODUCTION

Heat exchanger is a device which is used for transferring energy in the form of heat from

one fluid to another.  In some cases, a solid wall may separate the fluids and prevent them from

mixing. In other designs, the fluids may be in direct contact with each other. In the most efficient

heat exchangers, the surface area of the wall between the fluids is maximized while simultaneously

minimizing the fluid flow resistance. Fins or corrugations are sometimes used with the wall in

order to increase the surface area and to induce turbulence. Heat exchangers are widely used in the

process industries so their design has been highly developed. Most exchangers are liquid-to-liquid,

but gas and no condensing vapours can also be treated in them.

Shell and tube heat exchanger is most common type of heat exchanger been used in

industrial applications. Shell and tube heat exchanger placed a large number of tubes, about

several hundred packed in a shell with their axes parallel to that of their shell. Heat transfer take

place as one fluid flows inside the tube, while the other tube flows throughout the shell. Baffles

installed inside the shell functions to force shell-side fluid to flow across the shell and to

increase residence time so that enhance heat transfer between the fluids. Besides, baffles

also placed in the shell to maintain uniform spacing between the tubes. Note that the tubes in

shell tube heat exchanger are connected to large flow area called header at both ends of the shell,

parts where fluid accumulates before entering the tubes and after leaving them. In the counter-

flow heat exchanger, the fluids enter the exchanger from opposite sides. This is the most efficient

design because it transfers the greatest amount of heat. Next, counter current heat exchangers

allow the highest log mean temperature difference between the hot and cold streams. Many

companies however do not use single pass heat exchangers because they can break easily in

addition to being more expensive to build. Often multiple heat exchangers can be used to

simulate the counter current flow of a single large exchanger. In the parallel-flow heat

exchanger, the fluids come in from the same end and move parallel to each other as they flow to

the other side. The coss-flow heat exchanger moves the fluids in a perpendicular fashion.

Figure 1: Concurrent and countercurrent flow

Figure 2 : the schematic of a shell-and-tube heat exchanger (one shell pass one tube pass)

OBJECTIVES

1. To determine the function of the shell and tube heat exchanger

2. To evaluate the value of heat transfer and heat loss, LMTD, heat transfer coefficient, overall

heat transfer coefficient and the pressure drop

THEORY

The Heat Exchanger Design Equation

Heat exchanger theory leads to the basic heat exchanger design equation:

Q = U A ΔTlm , where

Q is the rate of heat transfer between the two fluids in the heat exchanger in W,

U is the overall heat transfer coefficient in W/m2.k,

A is the heat transfer surface area in m2,

and ΔTlm is the log mean temperature difference in K, calculated from the inlet and outlet

temperatures of both fluids.

The basic heat exchanger design equation can be used to calculate the overall heat transfer

coefficient for known or estimated values of the other three parameters, Q, A, and ΔT lm. Each of

those parameters will now be discussed briefly.

Heat Transfer Rate, Q

Heat transfer rate, Q can be calculated from the known flow rate of one of the fluids, its heat

capacity, and the required temperature change. Following is the equation to be used:

Qhot = mt Cpt (THin - THout) = Ws Cps (TCout - TCin) , where

mt = mass flow rate of hot fluid, kg/s,

Cpt = heat capacity of the hot fluid, J/s,

Ws = mass flow rate of cold fluid, kg/s,

Cps = heat capacity of the cold fluid, J/s,

The required heat transfer rate can be determined from known flow rate, heat capacity and

temperature change for either the hot fluid or the cold fluid. Then either the flow rate of the other

fluid for a specified temperature change, or the outlet temperature for known flow rate and inlet

temperature can be calculated.

Log Mean Temperature Difference

The driving force for any heat transfer process is a temperature difference. For heat exchangers,

there are two fluids involved, with the temperatures of both changing as they pass through the heat

exchanger, so some type of average temperature difference is needed. Log mean temperature is

defined in terms of the temperature differences as shown in the equation at below. Th,inand Th,out are

the inlet and outlet temperatures of the hot fluid and Tc,in and Tc,out are the inlet and outlet

temperatures of the cold fluid.

For Counter current flow,

ΔT1 = T hot, in – T cold, out ΔT2 = T hot, out – T cold, in

T hot, in = Inlet temperature of hot fluid (oC ) , T hot, out = Outlet temperature of hot fluid (oC )

T cold, in = Inlet temperature of cold fluid (oC), T cold, out = Outlet temperature of cold fluid (oC

For the counter flow direction as in Figure 3, the fluids enter at opposite ends, flow in opposite

directions, and leave at opposite ends. Once value of ΔTLM and area, A is obtained, the overall

heat transfer coefficient can be determined. Heat transfer rate, Q also can be calculated using

this formula

Q = m x Cp x ΔT

For constant specific heats with no change of phase, the heat balance for both co-current and

counter current flow is Q = (mc Cpc)cold (Tc2 − Tc1) = (mh Cph)hot (Th1 − Th2)

Cp at specified temperature of liquid water as given in appendices Table A1. Interpolation

required the efficiency or effectiveness, Ɛ of the heat exchanger is ration of actual heat transfer

rate, Q over the maximum possible heat transfer rate, Qmax . The equation is

Ɛ = Q

Qmax

Where Qmax is calculated from following equation: Qmax = Cmin (T hot in - T cold in ).Cmin

value is chosen either from Ch or Cc value calculated. The lowest value between these two is

chosen as Cmin.

Chot = mh cp hot , Ccold= mc cp cold

The temperature profiles in the heat exchanger can be study by looking at the

characteristics of the heat exchangers which are the flow arrangement ( either the hot and cold

fluids move in the same or opposite directions) and type of construction. The temperature

profile obtained from chart of temperature difference between the hot fluid and cold fluid at inlet

and outlet. It may vary along the length of the heat exchanger. This is due to the fact that the hot

fluid temperature decreases as it transfers heat to the cold fluid, while the cold fluid temperature

increases. As shown in the figure 3.1 below, for co-current flow arrangement, the temperature

difference is maximum at the inlet and decreases slowly towards the outlet. For counter-

current flow arrangement, the difference between the temperature of the hot and cold fluid

almost uniform, means that the heat transfer rate at any location is usually maximum at any

location throughout the tube. The temperature difference decreases less dramatically compared

to parallel flow arrangement as we move towards hot fluid exit. For either flow arrangement, it

can be observed that the ∆T is not constant and changes along the length of a heat exchanger.

12

Figure 3 : Counter current flow Temp. profile

APPARATUS AND MATERIAL

Figure 4 : SOLTEQ Heat Exchanger Training Apparatus (HE 158C)

13

1. Spiral heat exchanger 12. TT1 (hot water inlet reading)

13. TT2 (hot water outlet reading)

14. TT3 (cold water inlet reading)

2. Concentric heat exchanger

3. Shell and tube heat exchanger

4. Valve 1715. TT4 (cold water outlet reading)

5. Valve 1516. TT5

6. Valve 16

7. Valve 1817. ΔPT1 reading

8. Hot water centrifugal pump18. ΔPT2 reading

9. Cold water centrifugal pump 19. Heater switch

10. Flowrate meter 1 (Hot water) 20. Hot water pump switch

11. Flowrate meter 2 (Cold water) 21. Cold water pump switch

14

EXPERIMENTAL PROCEDURES

General Start-Up Procedure

Note : Whenever the annunciator TAH3 is activated during the course of the experiment,

press the red acknowledge button to stop the buzzer.

1. All the pump suction valves (for PH, PC1, PC2) was checked to make sure all valves are

fully opened at the time.

2. The BVC2 is fully opened but the CV2 is fully shut so that PC2 shall operate as a

backing-mixing pump for tank T2 in the next experiment. Both CV1 and BVC1 are fully

opened. Only PC1 shall be used here to pump CW into the Heat Exchanger in the next

experiment. (CW pumps (PC1 and PC2) were not opened yet).

3. The HV was shut fully while the BVH is fully opened.

4. The pump PH was started to circulate the around tank T1 via only BVH.

5. Then, the heater was switched on and the temperature of TIC5 was noted. When the HW

in the tank T1 was almost 50 (see TT5), the HV was fully opened. Then, the HW

flowrate was adjusted to about 25 USGPM by regulating the by-pass valve BVH.

6. The CW pumps PC1 and PC2 were switched on simultaneously. Then, the CW flowrate

was adjusted to 10 LPM by regulating the by-pass valve BVC1.

7. The DP Selector Switch was switched to the DP (Shell) position.

Experiment 1 : Counter- Current Flow Direction inside Shell and Tube Heat

Exchanger

1. General start-up procedures was performed.

2. The valves were switched to the counter-current Shell & Tube Heat Exchanger

arrangement. V15 and V18 were opened while V16 and V17 were closed.

3. Heater switch, Pump P1 and P2 was switched on. TT5 is ensured to be at 50

4. The valves V3 and V14 were adjusted to desired flow rates for hot water and cold water

stream .

5. The system is left ,run for 10 minutes until steady state operating condition is reached.

6. FT1, FT2, TT1, TT2, TT3 and TT4 readings were recorded after next 3 minutes to

after the process has stable.

7. Pressure drop measurement for shell-side and tube-side was taken at DPT1 and DPT2

readings

8. Steps 4 till 7 was repeated for different combination of flow rates FT1 and FT2.

9. V15 and V18 is tightly closed.

General Shut-down Procedures

1. Heater is switched off and waits until hot water temperature drops below 40℃.

2. Pump P1 and P2 was switched off.

3. All water was drained off in the process lines. Water retained in the hot and cold water

tanks for next laboratory session.

4. All valves are closed.

RESULT

Counter current flow for constant hot water flow rate

FT1(LPM) FT2(LPM) TT1(OC) TT2(OC) TT3(OC) TT4(OC) DT1(mmH2O) DDT2(mmH2O)

10 2 49.2 47.8 31.5 44.8 91 3

10 4 49.0 46.7 31.4 39.6 92 17

10 6 49.3 46.0 30.5 36.7 93 67

10 8 48.9 45.4 30.2 35.2 93 126

10 10 48.9 45.1 30.9 34.5 93 243

Counter current flow for constant cold water flow rate

FT1(LPM) FT2(LPM) TT1(OC) TT2(OC) TT3(OC) TT4(OC) DT1(mmH2O) DDT2(mmH2O)

2 10 48.7 39.9 30.8 32.4 -5 243

4 10 49.2 43.5 30.9 32.8 2 238

6 10 49.4 44.1 30.6 33.4 22 242

8 10 49.5 45.0 30.5 34.3 50 240

10 10 49.4 45.4 30.5 34.5 87 245

FOR FIXED HOT WATER FLOW RATE AT 10LPM

TEST 1 TEST 2 TEST 3 TEST 4 TEST 5

Hot water (Tube)

Volumetric flow rate L/min 10.0 10.0 10.0 10.0 10.0

Mass flow Kg/s 0.1647 0.1647 0.1647 0.1647 0.1647

Inlet temperature 0C 49.2 49.0 49.3 48.9 48.9

Outlet temperature 0C 47.8 46.7 46.0 45.4 45.1

Heat transfer rate J/s 962.65 1581.50 2269.11 2406.63 2612.91

Pressure drop mmH20 91 92 93 93 93

Cold fluid (Shell)

Volumetric flow rate L/min 2.0 4.0 6.0 8.0 10.0

Mass flow Kg/s 0.0332 0.0664 0.1000 0.1328 0.1659

Inlet temperature 0C 31.5 31.4 30.5 30.2 30.9

Outlet temperature 0C 44.8 39.6 36.7 35.2 34.5

Heat transfer rate J/s 1846.43 2276.81 2582.23 2776.59 2498.93

Pressure drop mmH20 3 17 67 126 243

Temp difference

Hot side inlet T,TT1 0C 49.2 49.0 49.3 48.9 48.9

Hot side outlet T,TT2 0C 47.8 46.7 46.0 45.4 45.1

Cold side inlet T,TT3 0C 31.5 31.4 30.5 30.2 30.9

Cold side outlet T,TT4 0C 44.8 39.6 36.7 35.2 34.5

T log mean, Tlm 0C 9.09 12.11 14.00 14.44 14.30

Heat loss W -883.78 -695.31 -313.12 -369.96 113.98

Efficiency % 191.81 143.97 113.80 215.37 95.64

Overall heat transfer

coefficient

Total exchange area m2 0.15 0.15 0.15 0.15 0.15

Overall heat transfer

coefficient

W/m2.K 706.01 870.63 1080.53 1111.09 1218.14

Exchanger layout

Tube 1 1 1 1 1

Shell 1 1 1 1 1

Length of tubes m 0.5 0.5 0.5 0.5 0.5

Tube ID mm 7.75 7.75 7.75 7.75 7.75

Tube OD mm 9.53 9.53 9.53 9.53 9.53

Tube pitch mm 18 18 18 18 18

Tube surface area m2 0.0150 0.0150 0.0150 0.0150 0.0150

Number of tubes 10 10 10 10 10

Shell diameter mm 85 85 85 85 85

Baffle distance mm 50 50 50 50 50

Tube side

Cross section area m2 0.0000472 0.0000472 0.0000472 0.0000472 0.0000472

Number of tubes 10 10 10 10 10

Total cross section area m2 0.000472 0.000472 0.000472 0.000472 0.000472

Mass velocity Kg/m2.s 349.13 349.13 349.13 345.64 342.15

Linear velocity m/s 0.3533 0.3533 0.3533 0.3498 0.3462

Reynolds number 4924.98 4924.98 4924.98 4875.73 4826.48

Prandtl number 3.56 3.56 3.56 3.56 3.56

Type of flow turbulent turbulent turbulent turbulent Turbulent

L/ID 64.52 64.52 64.52 64.52 64.52

Heat transfer factor,

Jh

0.0039 0.0039 0.0039 0.0039 0.0039

Tube coefficient,

Hi

W/m2.K 2426.16 2426.16 2426.16 2401.90 2377.64

Shell side

Cross flow area m2 0.002 0.002 0.002 0.002 0.002

Mass velocity Kg/m2.s 16.60 31.53 46.47 60.57 75.51

Linear velocity m/s 0.0167 0.0317 0.0467 0.0608 0.0758

Equivalent diameter mm 27.78 27.78 27.78 27.78 27.78

Reynolds number 575.88 1094.17 1612.46 2101.96 2620.25

Prandtl number 5.44 5.44 5.44 5.44 5.44

Type of flow laminar laminar laminar laminar laminar

Baffle cut % 20 20 20 20 20

Heat transfer factor,jh 0.023 0.018 0.016 0.014 0.012

Shell coeffient,hs W/m2.K 513.18 763.08 999.59 1140.16 1218.25

Pressure drop across

heat exchanger

Tube-side friction

factor, Jf

0.0058 0.0058 0.0058 0.0058 0.0058

Shell-side friction

factor, Jf

0.098 0.086 0.075 0.072 0.070

Tube-side pressure drop,

DPtube (Pa)

338.8 338.8 338.8 332.1 325.4

Tube-side pressure drop,

DPtube (mmH20)

33.4 33.4 33.4 32.8 32.1

Shell-side pressure drop,

DPshell (Pa)

0.3 10.5 19.9 32.5 49.1

Shell-side pressure drop,

DPshell (mmH2O)

0.3 1.0 2.0 3.2 4.8

FOR FIXED COLD WATER FLOW RATE AT 10LPM

TEST 1 TEST 2 TEST 3 TEST 4 TEST 5

Hot fluid (Tube)

Volumetric flow rate L/min 2.0 4.0 6.0 8.0 10.0

Mass flow Kg/s 0.0329 0.0659 0.0988 0.1318 0.1647

Inlet temperature 0C 48.7 49.2 49.4 49.5 49.4

Outlet temperature 0C 39.9 43.5 44.1 45.0 45.4

Heat transfer rate J/s 1210.19 1567.75 2186.60 2475.39 2750.43

Cold fluid (Shell)

Volumetric flow rate L/min 10.0 10.0 10.0 10.0 10.0

Mass flow Kg/s 0.1659 0.1659 0.1659 0.1659 0.1659

Inlet temperature 0C 30.8 30.9 30.6 30.5 30.5

Outlet temperature 0C 32.4 32.8 33.4 34.3 34.6

Heat transfer rate J/s 1110.64 1318.88 1943.61 2637.76 2776.59

Temp difference

Hot side inlet T,TT1 0C 48.7 49.2 49.4 49.5 49.4

Hot side outlet T,TT2 0C 39.9 43.5 44.1 45.0 45.4

Cold side inlet T,TT3 0C 30.8 30.9 30.6 30.5 30.5

Cold side outlet T,TT4 0C 32.4 32.8 33.4 34.3 34.6

T log mean, Tlm 0C 12.35 14.42 14.71 14.85 14.85

Heat loss W 99.55 248.87 242.99 -162.37 -26.16

Efficiency % 91.77 84.13 88.89 106.56 100.95

Overall heat transfer

coefficient

Total exchange area m2 0.15 0.15 0.15 0.15 0.15

Overall heat transfer

coeffient

W/m2.K 653.27 724.80 990.98 1111.29 1234.76

Exchanger layout

Tube 1 1 1 1 1

Shell 1 1 1 1 1

Length of tubes m 0.5 0.5 0.5 0.5 0.5

Tube ID mm 7.75 7.75 7.75 7.75 7.75

Tube OD mm 9.53 9.53 9.53 9.53 9.53

Tube pitch mm 18 18 18 18 18

Tube surface area m2 0.0150 0.0150 0.0150 0.0150 0.0150

Number of tubes 10 10 10 10 10

Shell diameter mm 85 85 85 85 85

Baffle distance mm 50 50 50 50 50

Tube side

Cross section area m2 0.0000472 0.0000472 0.0000472 0.0000472 0.0000472

Number of tubes 10 10 10 10 10

Total cross section area m2 0.000472 0.000472 0.000472 0.000472 0.000472

Mass velocity Kg/m2.s 69.79 139.57 209.36 279.15 348.93

Linear velocity m/s 0.0706 0.1412 0.2119 0.2825 0.3531

Reynolds 984.48 1968.82 2953.29 3937.77 4922.11

Prandtl number 3.56 3.56 3.56 3.56 3.56

Type of flow Laminar Laminar turbulent turbulent Turbulent

L/ID 64.52 64.52 64.52 64.52 64.52

Heat transfer factor, Jh 0.0050 0.0030 0.0036 0.0039 0.0040

Tube coefficient, hi W/m2.K 621.54 745.80 1342.46 1939.13 2486.02

Shell side

Cross flow area m2 0.002 0.002 0.002 0.002 0.002

Mass velocity Kg/m2.s 82.97 82.97 82.97 82.97 82.97

Linear velocity m/s 0.0833 0.0833 0.0833 0.0833 0.0833

Equivalent diameter mm 27.78 27.78 27.78 27.78 27.78

Reynolds number 2880.69 2880.69 2880.69 2880.96 2880.69

Prandtl number 5.44 5.44 5.44 5.44 5.44

Type of flow laminar laminar laminar laminar Laminar

Baffle cut % 20 20 20 20 20

Heat transfer factor, Jh 0.01 0.01 0.01 0.01 0.01

Shell coefficient, hs W/m2.K 1510.37 1510.37 1510.37 1510.37 1510.37

Pressure drop across

heat exchanger

Tube-side friction

factor, Jf

0.0058 0.0058 0.0058 0.0058 0.0058

Shell-side friction

factor,Jf

0.098 0.086 0.075 0.072 0.070

Tube-side pressure

drop,DPtube (Pa)

13.05 41.37 100.39 184.97 292.26

Shell-side pressure

drop,DPshell (Pa)

8.53 8.53 8.53 8.53 8.53

Temperature Profile for Counter-current Shell and Tube Heat Exchanger

1 20

10

20

30

40

50

60

TT2

TT4

Temperature Profile

Hot waterCold water

Tem

pera

ture

Figure 5 : Temperature profile of heat exchanger

Overall heat transfer coefficient

2 4 6 8 100

200

400

600

800

1000

1200

1400

Overall heat transfer coefficient against cold water flowrate

Cold water flow rate(L/min)

Ove

rall

hea

t tr

ansf

er

coef

fici

ent(

W/m

2K

Figure 6 : Graph of overall heat transfer coefficient against cold water flow rate

2 4 6 8 100

500

1000

1500

2000

2500

3000

3500

4000

Overall Heat Transfer coefficient Vs Cold Water Flow rate

tube sideshell side

Cold water flow rate(L/min)

Ove

rall

heat

tran

sfer

coe

ffici

ent(

W/m

2K

Figure 7 : Graph of relationship between heat transfer coefficient and cold water flow rate

CALCULATIONS

Typical Chemical Data :

HOT WATER COLD WATER

Density (kg/m3) 988.18 995.67

Heat Capacity (J/kg.K) 4175.00 4183.00

Thermal cond. (W/m.K) 0.6436 0.6155

Viscosity (Pa.s) 0.0005494 0.0008007

For fixed Hot Water Flowrate (10 LPM)

Cold Water Flowrate = 2.0 LPM

HOT WATER (tube side) COLD WATER (shell side)

Volume flow (L/min) 10.0 2.0

Inlet temperature,(℃) 49.2(TT1) 31.5 (TT3)

Outlet temperature(℃) 47.8 (TT2) 44.8 (TT4)

1. Calculation of Heat transfer and heat lost :

The heat transfer rates of both hot and cold water are both calculated using the heat balance

equation.

Heat transfer rate for hot water,

QH=mHCpH (T1−T2 )=10.0Lmin

×1m3

1000L×

1min60 s

×988.18kg

m3 ×4175Jkg .℃

× (49.2−47.8 )℃

¿962.65W

Heat transfer rate for cold water,

QC=mCC pC (t 2−t 1)=2.0L

min×

1m3

1000 L×

1min60 s

×995.67 kg

m3 ×4183 Jkg .℃

× (44.8−31.5 )℃

¿1846.43W

Heat lost rate = QH−QC=(962.65−1846.43 )W=−883.78W

Efficiency =

QC

QH

×100 %=1846.43W962.65W

×100 %=191.81 %

2. Calculation of LMTD

∆T 1=T h ,∈¿−T c,out=49.2−44.8=4.4 ℃ ¿

∆T 2=T h ,out−Tc ,∈¿=47.8−31.5=16.3℃¿

∆T lm=∆T 1−∆T 2

ln (∆T1

∆T2

)= 4.4−16.3

ln ( 4.416.3

)=9.09℃

3. Calculation of the tube and shell heat transfer coefficients by Kern’s method :

For 1-shell pass; 1-tube pass, ∆T m=∆T lm

Heat transfer coefficient at tube side :

Cross flow area, A=π d i

2

4=π ×0.007752

4=0.0000472m2

Total cross flow area, At=A×numberof tubes=0.0000472m2×10=0.000472m2

Mass velocity ,Gt=mt

A t

= 0.16470.000472

=349.13kgm2 . s

Linear velocity , ut=Gt

ρ=

349.13kg

m2 . s988.18kg/m3 =0.3533m /s

Renolds number ,ℜ=Gt×de

μ=

349.13 kg

m2 . s×7.75m

0.0005494 Pa . s×

11000

=4924.9(turbulent flow)

Prandtl , Pr=μ×CpH

k=

0.0005494 Pa. s×4175J

kg . K

0.6436W

m .K

=3.56

Tube side heat transfer factor, jh = 0.0039 (From Appendix)

Tube side coefficient ,h i=jhℜPr0.33 k

d i

=0.0039×4924.9×3.560.33×0.64360.00775

=2425.2W

m2. K

Heat transfer coefficient at shell side :

Cross flow area, A s=[ (tube pitch−TubeOD )× (shell diameter )× (baffle distance )]

tube pitch=¿¿

Mass velocity ,G s=W s

A s

=

0.0332kgs

0.002m2 =16.60kg

m2 . s

Linear velocity , us=G s

ρ=

16.60kg

m2 . s995.67 kg/m3 =0.0167m /s

Equivalent diameter , de=1.1d0

( ρt2−0.917d02 )= 1.1

9.53(182−0.917 (9.53 )2 )mm=27.78mm

Reynolds number ,ℜ=G s×de

μ=

16.60kg

m2. s×27.78mm

0.0008007 Pa . s×

11000

=575.93 (laminar flow)

Prandtl number ,Pr=μ×CpC

k=

0.0008007 Pa. s ×4183J

kg . K

0.6155W

m .K

=5.44

Shell side heat transfer factor, jh = 0.022 ( From Appendix)

Shell side coefficient , hi=jh ℜPr0.33k

de=0.022×575.93×5.440.33×0.6155

0.02778=490.95

Wm2 .K

Overall heat transfer coefficient :

Total exchange area, A=numberof tube×π ×tubeOD×lenght of tube=10×π×0.00953m×0.5m=0.15m2

Overall heat transfer coefficient ,U=QH

A ∆T lm

= 962.65W0.15m2×9.09℃

=706.01W

m2 .℃

4. Calculation of pressure drop across tube and shell

∆ Pt=N p

ρu t2

2 [8 j f ( Ld i )( μμw )

−m

+2.5 ]=1×988.18kg /m3×(0.3533

ms)

2

2¿

Jf = 0.0057 (from appendix)

∆ P s=8 j f (Ds

de)( LIB ) ρ us

2

2 ( μμw )

−0.14

=(8×0.092 )( 0.085m0.02778m )( 0.5m

0.05m )( 995.67kgm3 )¿¿

DISCUSSION

This experiment was conducted in order to determine the performance and

effectiveness of heat transfer between hot fluid and cold fluid in a shell and tube heat

exchanger with different flow pattern for counter current flow. Besides that are to study the

heat balance, Log mean temperature (LMTD) and overall heat transfer coefficient. In order to

get pressure drop, Reynolds number and Prandtl number at the shell-tube heat exchanger

need to be determined. This experiment was also affected by flow rate of the fluid when hot

water flow rate is constant, the cold water flow rate become the manipulated variable at

interval of 2 LPM, and vice versa.

For counter current flow and constant hot water flow rate, the data of hot fluid

collected shows temperature of hot water out is lower than the temperature of hot water in,

meanwhile for cold fluid it shows that the temperature of cold water in is higher than the inlet

temperature of cold water. For data of constant cold water and manipulated hot water flow

rate, it shows that outlet temperature of hot fluid is lower than the inlet temperature and as for

cold fluid, the inlet temperature is lower than the outlet temperature.

The heat balance was calculated for all sets of data. As we can see, the efficiencies of

counter current flow heat exchanger are increase as the cold water flow rate increase. For

tube side heat transfer coefficient, the value is constant at 2425.2 W/m2K. Type of flow of

tube side is turbulent flow which is constant at 4924.9. Next for shell side, the shell

coefficient is increase as the cold flow rate is increase. This conclusion is proved by looking

at the graph at Figure 9. Type of flow is laminar flow which is the range is between 513.18

and 1218.25. For overall heat transfer coefficient, the value for test 1 is 706.01 W/m2K, for

test 2 is 870.63 W/m2K, for test 3 is 1080.53W/m2K, test 4 is 1111.09 W/m2K and test 5 is

1218.14 W/m2K. Based on result we can conclude that the value of overall heat transfer

coefficient is increase as the cold flow rate increase and it is proved by looking at graph at

Figure 6.

For pressure drop in hot water which is tube side, 338.8 Pa was calculated but for

measured value is increase from 3 to 243 mmH2O. For pressure drop in cold water which is

shell side, the value is 0.3 Pa for test 1, 10.5Pa for test 2, 19.9Pa for test 3, 32.5Pa for test 4

and 49.1Pa for test 5.

For pressure drop in cold water which is shell side, 8.53 Pa was calculated but for

measured value is increase from -5 to 87 mmH2O. For pressure drop in hot water which is

tube side, the value is 13.05 Pa for test 1, 41.37Pa for test 2, 100.39Pa for test 3, 184.97Pa for

test 4 and 292.26Pa for test 5. But for measure value of pressure drop, the value is 243

mmH2O for test 238 mmH2O for test 2, 242 mmH2O for test 3, 240 mmH2O for test 4 and

245mmH2Ofor test 5. Maybe some error had been done while handling the equipment.

The graph plotted in Figure 5 shows inlet temperature of hot fluid is higher than the

outlet and as for cold fluid the inlet temperature is lower than the outlet temperature as it

increases throughout the process.

From result above, the pressure drop is depends on the flow rate not the temperature. The

pressure drop is increase as the cold flow rate increase and constant at tube side because the

flow rate is constant at 10 LPM. Same goes to heat transfer coefficient for tube side and shell

side. For tube side, the value of tube coefficient is constant as the hot water flow rate is

constant at 10 LPM but for shell coefficient, the value is increasing as the cold water flow

rate increase. The pressure drop is depend on the flow rates as the flow rates is changed the

pressure drop also change. This is due to the flow does not achieved the steady state yet.

CONCLUSION

The purpose of this experiment is to analyze the efficiency and performance of

enhanced concentric tube and shell and tube heat exchangers using water as the heat

exchange medium for counter-current flow heat exchanger. Based on evaluate and study the

performance of shell and tube heat exchanger at counter current flow was determined.

Besides that, the heat balance, LMTD and overall heat transfer coefficient also determined.

The Reynolds number at the shell and tube heat exchanger was identified. From the results, it

can be concluded that the pressure drop is depends on cold water flow rate not the

temperature. The pressure drop for shell side is increase as the flow rate increase but constant

at tube side because the flow rate is constant at 10 LPM. Furthermore, for shell and tube heat

transfer coefficient is depends on flow rate, which is for tube coefficient is constant ecause

the flow rate is constant but for shell coefficient, the shell coefficient is increase as the flow

rate is increase. Next, Heat transfer and heat loss, heat transfer coefficient, overall heat

transfer coefficient and the pressure drop are depend on the changes of the flow rates of the

stream. The lower the pressure drop of the shell and tube heat exchanger, the higher the

efficiency of the heat exchanger.

RECOMMENDATION

As recommendation, firstly make sure the system is fully drain after each use of water

on tube side and steam condensate on shell side in order to avoid corrosion build-up during

down-times. Next, the eye position should be perpendicular to the meniscus and the scale to

prevent from parallax error. Beside that, the water to the tube side should be the first and last

flow rate to be turned on. The steam should be turned on only after the water is flowing

through the tube side. Avoid any leakage of the instrument, the instrument should be working

properly and lastly make sure that the time taken to collect the data is punctually followed.

REFFERENCES

1. Equipment for Engineering Education, Instruction and Operation Manuals, Gunt

Hamburg Germany,02/98

2. Cengel, Y. A., and Turner, R. H. 2005. Fundamentals of Thermal-Fluid Sciences,

2nd Edition, McGraw-Hill.

3. YunusA.Cengel, 2006, Heat and Mass Transfer: A Practical Approach. McGraw Hill,,

3rd Edition

4. Christie John Geankoplis, Transport Process AND Separation (includes unit

operations) , 4thEdition

APPENDIX

Figure 8 : Tube side heat transfer factors

Figure 9 : Shell side heat transfer factors, segmental baffles