## Venturi tube help needed in determining pressure difference

1. The problem statement, all variables and given/known data

Water flows through venturi tube at 0.3 litres/s. Diameter of venturi tube is 32mm to 20mm to 32mm and the water density is 1000kg/m^3.

2. Relevant equations

a) Assuming head loss is neglible, what is pressure difference between 1 and 2.

b) If pressure head difference between these is 45mm what is head loss.

3. The attempt at a solution

So far I have V2 = P1A1V1/P2A2 = 0.9548 and V1 (Q/A) = 0.3731

delta H 1/2 = H1 - H2 = 1/2g (V2^2-V1^2))
delta H 1/2 = 39.3mm

Where do I go from here, if this is even correct ?

Thanks a lot for your help.
 PhysOrg.com science news on PhysOrg.com >> Galaxies fed by funnels of fuel>> The better to see you with: Scientists build record-setting metamaterial flat lens>> Google eyes emerging markets networks
 Blog Entries: 27 Recognitions: Gold Member Homework Help Science Advisor hi timothy1875! welcome to pf! (try using the X2 and X2 icons just above the Reply box ) i don't follow you … use the fact that the volume per time is constant, and Bernoulli's equation
 Hi Tim, Thanks for getting back to me.I am trying to answer the question but think I may be going about it the wrong way. Using the Bernoulli equation do I need to transpose to find P ?

Blog Entries: 27
Recognitions:
Gold Member
Homework Help

## Venturi tube help needed in determining pressure difference

show us what you have so far
 V2 = P1A1V1/P2A2 = 0.9548 and V1 (Q/A) = 0.3731 delta H 1/2 = H1 - H2 = 1/2g (V22-V12) delta H 1/2 = 39.3mm This where I have got to so far, :(

Blog Entries: 27
Recognitions:
Gold Member
Homework Help
 Quote by timothy1875 V2 = P1A1V1/P2A2 = 0.9548
what does this mean?

where does it come from?
 Basically we have been set this question and there are numerous equations on the back that we have to pick from. I take it from your response I have selected the wrong equation initially. Should it be 1/2g (V22 - V1 2) ??