expt. 2 - fluid flow (pre & post)

Experiment 2:

Mechanical Energy Losses due to Straight

Pipes and Fittings in a Viscous Pipe Flow

CAPILI, Mark Lorenz

SAN MIGUEL, John Andre

SILVESTRE, Ces Angelin

VALENCIA, Camille Ann

Introduction

The term pipe flow is used to describe flow through round pipes, ducts, nozzles,

sudden expansion, and contractions,

valves, and other fittings.

Viscous dissipation

http://www.eng.fsu.edu/~alvi/EML4304L/webpage/experiment_5.htm

Introduction

Fluid Flow

Laminar

happens when dealing with small pipes , low flow velocities and with

highly viscous fluids

At low velocities fluids tend to flow without lateral mixing,and adjacent

layers slide past one another

3http://solve.nitk.ac.in/dmdocuments/Chemical/theory_pipes.pdf

Introduction

Fluid Flow

Turbulent

the fluid moves erratically in the form of cross currents and eddies.

happens in general at high flow rates and with larger pipes


Introduction

Fluid Flow

Transitional

a mixture of laminar and turbulent flow, with turbulence in the center of

the pipe, and laminar flow near the

edges


Introduction

When a gas or liquid flows through a pipe, there is a loss of pressure

frictional loss

loss through fittings

to overcome frictional losses

pump providing power to the fluid

arranging for the fluid to fall under gravity from a higher to a lower elevation (potential energy is reduced)

http://www.eng.fsu.edu/~alvi/EML4304L/webpage/experiment_5.htm

Introduction

Steady-State, Viscous Pipe Flow

Pipe flow in a constant-diameter pipe may be driven by gravity and/or pressure forces

For horizontal pipe flow, gravity has no effect

Pressure difference forces the fluid through the pipe

7

Objectives

The objectives of the experiment are:

To measure the energy losses through the straight pipe and fittings in a pipe flow

system.

To determine the relation of energy losses to the volumetric flow rate in a pipe flow

system from the actual data.

Objectives

To measure the performance of the fluid flow system in the lab by computing the

design calculations with the experimental

data

Materials Needed

10

U-tube Manometer Fluid Flow Apparatus-Pipes

20mm Tee connection

20 mm elbow

25 mm straight pipe

-Pump

-Valves

-Hose

Water and lastly patience

Procedure

Before doing the experiment:

Choose 10 flow rates (100-1000 gal/hr) and

calculate for its Reynolds Number. The flow of the water within the system should

be turbulent (>2100)

Formula to be used: Re = 4q/D

where: = 995.647kg/m3

= 8.222x10-4

Procedure

Close drain valve and pour

water into the feed tank

(3/4 full)

Open all isolating valve

before switching the pump

on

Procedure

Slowly increase the degree

of opening of the entry valve

until bubble formation

becomes minimal

Set the opening of the entry

valve to the designated

degree/flow rate

Procedure

Measure the Pressure head

using the U-tube manometer

and record these pressure for

at least 3 trials

Use another flow rate

setting

Data

Flow Rate gal/hr RM mmHg

o 20mm Tee connection:

Flow Rate 1000 940 900 860 840

Trial 1 25 25 20.325 15.625 15.625

Trial 2 26.5625 25 31.875 18.75 15.625

Flow Rate 800 760 740 700 680

Trial 1 14.0625 14.0625 9.375 9.375 4.6875

Trial 2 14.0625 12.5 10.9375 9.375 6.25

Data


o 20mm elbow:

Flow Rate 520 500 440 420 380

Trial 1 40.625 34.375 32.8125 31.25 28.125

Trial 2 42.5 35.9375 32.8125 29.6875 25

Flow Rate 340 300 260 220 180

Trial 1 21.875 12.5 8.3 6.2 4.6875

Trial 2 18.75 13.5625 10.9375 6.25 3.90625

Data


o 25mm Straight Pipe:

Flow Rate 520 500 440 420 380

Trial 1 68.75 64.0625 56.25 53.125 46.875

Trial 2 65.625 65.6 57.8125 51.5625 48.4375

Flow Rate 340 300 260 220 180

Trial 1 37.5 31.25 28.125 21.875 20.3125

Trial 2 35.156 33.6 26.5625 24.22 22.66

Sample Calculation

Formula to be used: Re = 4q/D

where: = 995.647kg/m3

= 8.222x10-4Pas

Data chosen: 180 gal/hr at 25mm straight pipe

=4(180

)(

1 3600 )(

3.7851 )(

13

1000 )(995.6473

)

(8.2222 1042

)(25)(1

1000)

Re=11671.71 >2100

Sample Calculation

Manometer Reading

in mmHg

= 92 78

= 14

Rm

Recommendation

Start the pump only when the water level inthe tank is almost full.

Make sure that the U-tube manometer hasno water added into it

Place the manometer in the ground level

Timing and Patience is a key factor

Slowly adjust the flow rates and operateonly in a set of range.

Recommendation

Keep all unused valves closed.

Hoses that connect the pipe andmanometer must be observed carefully

and bending must be avoided.

Bring plastic cover or paper.

Be sure that the one who measuresdoesnt have eye problems

Extra clothes is a must!

Always keep your workplace

clean

ENJOY minsan ditonagsisimula ang lahat

expt. 2 - fluid flow (pre & post)

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