Calculating Pressure Difference Between Sections 1 and 2

[timothy1875]

Trying to calculate pressure difference between sections 1 and 2.
1=32mm 2=20mm
density = 1000 kg/m^3

I have done P1-P2 = 1/2 density x (vi^2 - vj^2)

Is this right?

How do I now find head loss if difference between 1 and 2 were 45mm ?

45/density x gravity ?

Thanks,

 

[edgepflow]

Your equation for P1 - P2 looks OK (in the absence of friction and assuming the discharge coefficient = 1).

The relation between static pressure difference and fluid column height ("head loss") is:

P2 - P1 = density X g X h1 - h2. Is your head loss 45 mm or was that just an example?

 

[timothy1875]

Ye 45mm is the head loss but it's theoretical and not related to the initial equation. Would the formula be h1 - h2 = p2 - p1 / density x g ?

Thanks for your help

 

[edgepflow]

Ye 45mm is the head loss but it's theoretical and not related to the initial equation. Would the formula be h1 - h2 = p2 - p1 / density x g ?

Thanks for your help

Yes.

 

[paranormal]

I would like to commend you for taking the initiative to calculate the pressure difference between sections 1 and 2. Your formula for calculating pressure difference (P1-P2 = 1/2 density x (vi^2 - vj^2)) is correct. However, I would suggest using the units of meters for consistency, so the formula would be P1-P2 = 1/2 density x (vi^2 - vj^2) in m^2/s^2. This will ensure that your final answer is in units of pressure (Pascal or Pa).

To find the head loss, you can use the formula H = (P1-P2)/(density x gravity), where H is the head loss in meters, P1-P2 is the pressure difference in Pa, density is in kg/m^3, and gravity is in m/s^2. So for your example, the head loss would be (45/1000 x 9.8) = 0.441 m.

It is important to note that this formula assumes a constant density and does not take into account any other factors that may affect the pressure, such as friction or changes in velocity. Therefore, it is always best to perform experiments or simulations to confirm your calculations and consider any other factors that may affect the pressure difference. I hope this helps and good luck with your calculations!