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Homework Statement
I need to know how much the temperature drops after an inline heater which heats an airflow of 5 lbs/min up to 88 °C with an pressure of 54 PSI. When the air exits the heater it is released into the free air where it is 20 °C.
I know that the air will expand to a bigger volume then, which will lead to a temperature drop. So I need to know how much this drop will be.
Homework Equations
P1 * V1^γ=P2 * V2^γ
T1 * V1^(γ-1)=T2 * V2^(γ-1)
The Attempt at a Solution
γ= 1.4
V1= 5 lbs = 1.853 m3
T1= 88 °C = 361 K
P1= 54 PSI = 3723163.9
P2= 101325 Pa
V2= ?
T2= ?
P1 * V1^γ=P2 * V2^γ
V2 = 4.69447 m3
T1 * V1^(γ-1)=T2 * V2^(γ-1)
T2 = 248 K
This will say that the temperature decreases to -25 °C which sounds like a wrong answer in my opinion.
I also thought to use the ideal gas law with --> P*V= m*Rs*T
But I don't know how I should use it in my case..
Anybody who can give me a solution?