Pressure measurement with Manometer

[Toof]

See Attached...

Homework Statement

A manometer is used to measure drop across an orifice plate measuring the flow of brine (salt water, s.g. = 1.260).

A) If the pressure drop is expected to be approx 1000 Pa, suggest an appropriate fluid. Why?

B) If the flow rate is anticipated to increase, leading to a pressure drop of approximately 50,000 Pa, suggest an appropriate fluid. Why?

C) If mercury is chosen as the working fluid, and the height differential (h) is 6.5 inches, determine the pressure differential across the orifice plate.

D) Which direction is the brine flowing?

Homework Equations

P1 - P2 = (pf - p)gh

The Attempt at a Solution

I'm not sure where to even begin... :(

 

[KataKoniK]

Thank you for your post. I can help you with your questions about the manometer and fluid selection.

A) For a pressure drop of approximately 1000 Pa, a suitable fluid would be water. This is because water has a density of approximately 1000 kg/m3, which is close to the specific gravity of brine (1.260). This will allow for accurate measurement of the pressure drop using the manometer.

B) If the flow rate is anticipated to increase and the pressure drop is expected to be around 50,000 Pa, a more suitable fluid would be a heavier oil with a higher density. This is because the heavier oil will have a higher specific gravity and will be able to accurately measure the larger pressure drop.

C) If mercury is chosen as the working fluid and the height differential (h) is 6.5 inches, the pressure differential across the orifice plate can be determined using the equation P1-P2 = (pf-p)gh. In this case, the density of mercury (p) is 13,600 kg/m3, and the acceleration due to gravity (g) is 9.8 m/s2. Plugging in these values, we get P1-P2 = (13,600-1,260) * 9.8 * 6.5 inches = 82,236 Pa. Therefore, the pressure differential across the orifice plate is 82,236 Pa.

D) Based on the direction of the pressure drop, we can determine the direction of the brine flow. If the pressure is higher on the side of the manometer connected to the brine, then the brine is flowing from P2 to P1. If the pressure is higher on the side connected to the atmosphere, then the brine is flowing from P1 to P2.

I hope this helps guide you in solving your problem. Let me know if you have any further questions or need clarification on any of the concepts. Best of luck with your research!