Answer to Question #116903 in Mechanical Engineering for alex

Question #116903
Air initially at 75 psia and 65 0F is compressed to a final pressure of 300 psia and temperature of 320 0F. Find the polytropic exponent for the process
1
Expert's answer
2020-05-19T09:13:05-0400

Equation of polytropic process in terms of pressure and temperature is p1nTn=constp^{1-n}T^{n} = const.

Writing this explicitly for initial and final state, obtain p11nT1n=p21nT2np_1^{1-n} T_1^{n} = p_2^{1-n}T_2^n, from where (p1p2)1n=(T2T1)n\left( \frac{p_1}{p_2} \right) ^{1-n} = \left( \frac{T_2}{T_1} \right)^n, or p1p2=(p1T2p2T1)n\frac{p_1}{p_2} = \left( \frac{p_1 T_2}{p_2 T_1} \right)^n. Using last equation, n=log(p1T2p2T1)p1p26.7n = log_{\left( \frac{p_1 T_2}{p_2 T_1} \right)}\frac{p_1}{p_2} \approx -6.7.


Need a fast expert's response?

Submit order

and get a quick answer at the best price

for any assignment or question with DETAILED EXPLANATIONS!

Comments

No comments. Be the first!

Leave a comment