Pressure v Temperature Calculation 1

[Bottle]

During a pressure test of a HRSG with demin water, if the following was true;

P = 50 barg
Temp = 30 Deg C
Volume = 60 m3

What effect on pressure would a 5 degree drop in temperature have. How is this calculated.

Also, assuming no temperature drop, if there was a drop in pressure of 5 barg, how can I calculate the amount of water lost through leakage.

Thanks in advance.

 

[eliebl]

This would be largely dependent on the configuration of the HRSG.

As water can easily be assumed to be incompressible the volume of water lost (leak or contraction due to temperature) would have to equal the change in volume of the HRSG due to the change in pressure.

I've thought about trying to calculate this in the past but never could justify the time it would take.

Regards,
EJL

 

[BigInch]

hoop stress S = PD/2/t
change in circumference = S * C/E
calculate the new vessel cross-sectional area.
change in length = PAL/As/E - p * S/E
P = pressure
A = vessel cross-sectional area
As = vessel cross-sectional area of steel
E = Young's modulus
p = Poisson's ratio



**********************
"Pumping systems account for nearly 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies)

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[BigInch]

If pressure is high or there is a significant temperature difference, you should account for water's change in volume with those factors.

**********************
"Pumping systems account for nearly 20% of the world’s energy used by electric motors and 25% to 50% of the total electrical energy usage in certain industrial facilities." - DOE statistic (Note: Make that 99.99% for pipeline companies)

http://virtualpipeline.spaces.live.com/