1. Calculate the experimental head loss from the readings taken in the manometer

ID: 2088484 • Letter: 1

Question

1. Calculate the experimental head loss from the readings taken in the manometer below and compare them with theoretical predictions. NOTE: The table is only provided for inputting the answers. The only given parameters are the temperature of the water, flow rate and manometer reading. Calculate the velocity, Reynolds Number, Darcy Friction Factor, Theoretical Head Loss and Experimental Head Loss.

2. Compare the differences of using a Moody Chart and the Haaland Approximation of the Darcy Friction Factor by calculating the theoretical and experimental head loss (hL) from the conditions above in Q1.

HINT: Use the Darcy Equation and Reynolds Number provided below.

Temperature (degrees Celsius) Flow Rate (L/min) Manometer Reading (mmHg) Velocity (m/s) Reynolds Number, Re Darcy Friction Factor, f Theoretical Losses, hL (m) Experimental Losses, hL (m) 24.0 8 6 24.0 16 22 24.0 24 46 24.0 32 79 24.0 40 117 ?? = ??? 2gd

Explanation / Answer

Solution:

Here velocity is calculated by V= ?(2gh), where h = x (sm/sw-1)

All other calculation is done by the formulae given in the hint portion of the problem.

The experimental data for head loss is taken from Moody Diagram. Temperature is constant throughout the process 240 C and dynamic viscosity of water at this temperature is 8.90×10-4 Pa-s.

Flow Rate (L/min)

Manometer Reading, x (mm Hg)

Velocity (m/s)

Reynolds No.

1/?f

Darcy Friction factor, f

Theoretical Head Loss, hL (m)

Experimental Friction factor, fE

Experimental Head Loss, hL (m)

Difference, ( f-fE )

2.217

18925

6.16

0.026

0.174

0.0195

0.1297

0.0443

2.332

36265

6.65

0.022

0.550

0.0192

0.4691

0.0809

3.372

52436

6.93

0.0208

1.063

0.0185

0.9450

0.118

4.419

68721

7.12

0.019

1.665

0.0180

1.5792

0.086

117

5.37

83632

7.26

0.0189

2.448

0.0175

2.2673

0.1807