Well-type mercury manometer with inert gas pressure

[Irene Jin]

A well-type mercury manometer has a well of 0.02m^2 area and a tube of 40mm^2 area. The liquid has a density of 13,534 kg/m^3.Given that the tube is open to the atmosphere and the well is connected to the inert gas manometer was to measure:
Calculate the pressure of the inert gas in kN/m^2 if the height of the measuring column is 500 mm.

The answer given is 167.82kN/m^2.

 

[Irene Jin]

I can't get the ans, need help with this question

 

[anorlunda]

You must show us your work. What have you tried so far?

 

[Irene Jin]

You must show us your work. What have you tried so far?

So sorry is my first time asking a question here. The main problem here is, I don't really know how to start, totally don't understand the question. Need some guides

 

[anorlunda]

Well, what have you studied? Do you know the math of fluid dynamics? What course does this homework come from?

 

[Irene Jin]

Well, what have you studied? Do you know the math of fluid dynamics? What course does this homework come from?

Currently I am in the marine engineering course. And we are not studying the chapter "measurement of process pressure" we just learned how to find the differential pressure, so there are a few equation u can use to find it.

 

[anorlunda]

This website https://www.brighthubengineering.co...ometer-for-measuring-fluid-and-gas-pressures/

considers four cases of U tube manometer. Which one best fits your problem?

 

[Irene Jin]

This website https://www.brighthubengineering.co...ometer-for-measuring-fluid-and-gas-pressures/

considers four cases of U tube manometer. Which one best fits your problem?

I think Liquid under average pressure

 

[Irene Jin]

Manage to solve it. So basically I use the formula p2-p1=density*g*h(a/A+1)
So for this question since it stated that its open to the atmosphere thus p1 will equal to the standard atmospheric pressure which is 1.013*10^5 N/M^2, which I didn't know it at first.
So this is how I did it :
P2- (1.013*10^5) =13534*9.81*0.5(40*10^6/0.02 +1)
P2=167817 (N/m^2) / 167.82 (kN/m^2)