Nitrogen gas is compressed from 80 kPa and 27oC to 480 kPa by a 10 kW compressor. Determine the mass flow rate of nitrogen through the compressor assuming the compression process is …
a.) Isentropic, gamma = 1.4
b.) Polytropic with delta = 1.3
c.) Isothermal
d.) Ideal, two-stage polytropic with delta = 1.3
8 comments:
where can we find gamma(ratio of cp and cv) for nitrogen?
Y:
Doh ! Use gamma = 1.4
Following the equation from the summary sheet, I got -0.063 instead of +0.063. Why is that?
does the negative sign just mean the "work consumed"?
Why 1:06 & 1:15 AM:
I think you used 10kW instead of -10kW for the power of the compressor. Yes, the minus sign means the work is input or consumed.
does anyone know how to get T2 for part a, and if we even need T2?
Nutella:
You could get by without calculating T2 in part (a). Use one of the PVT relationships for polytropic processes. Here, delta = gamma. I used T*P^((1-gamma)/gamma) = constant.
Best of luck.
But then how do I get from that constant to the mass flow rate?
I was going to use the isentropic equation for ideal gas
Wsh,dot/mdot=...
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