Register to reply

Fluid Mechanics: Determine volumetric flowrate

Share this thread:
Jan23-12, 02:54 PM
P: 3
1. The problem statement, all variables and given/known data

*See attachment for diagram*

With steady-state operation, an energy balance between point 1 and point 2 along the A side dictates:

*See attachment for equation 1*

And an energy balance between points 1 and 2 along the B side dictates:

*see attachment for equation 2*

Comparing the two balances, the following can be determined:

*See attachment for equation 3*

Which states that frictional losses over parallel segments are equal. With this in mind, develop a model for the system and fill in the missing entries in the table below.

gpm ft in ft in gpm gpm

150 85 4 100 4 ? ?
80 100 4 400 3 ? ?
300 120 2 120 3 ? ?
300 120 6 50 4 ? ?
180 80 ? 80 4 60 ?
300 ? 3 70 3 140 ?
? 300 6 100 4 100 ?

2. Relevant equations
Use chen equation for friction factor:

1/(f)^1/2 = -2.0log((e/D)/3.7065 – 5.0452A/Re)
A = log((e/D)^1.1098/2.8257 + (5.8506/Re^0.8981))

3. The attempt at a solution

We are allowed to use Excel goal seek (I think we HAVE to). However, i cannot seem to get a system of equations that will solve for Va and Vb. I believe that if I had those terms, I could easily calculate Qa and Qb. If that's not the direction I need to be going, then I am completely lost.

For the first row, we were given the answers so that we could check our model. Qa=83.1 gpm and Qb=66.9 gpm.

Thanks for any help!
Attached Thumbnails
scan0009.jpg   eqn1.JPG  
Phys.Org News Partner Science news on
NASA team lays plans to observe new worlds
IHEP in China has ambitions for Higgs factory
Spinach could lead to alternative energy more powerful than Popeye

Register to reply

Related Discussions
Compresible volumetric strain rate-fluid mechanics Engineering, Comp Sci, & Technology Homework 0
Simple question about object submerged in a fluid (fluid Mechanics) Mechanical Engineering 1
Fluid mechanics :fluid in motion Advanced Physics Homework 1
Volumetric flowrate of one substance to another General Engineering 5
Fluid Dynamics Question: A glass tube... areas, pressure, determine height. Introductory Physics Homework 0