## Related questions with answers

A flow of 4 kg/s ammonia goes through a device in a polytropic process with an inlet state of 150 kPa, −20$^{\circ} \mathrm{C}$ and an exit state of 400 kPa, 60$^{\circ} \mathrm{C}$. Find the polytropic exponent n, the specific work, and the heat transfer.

Solution

VerifiedWe are given following data for flow of Ammonia in a polytropic process:

$P_1=150\text{ kPa}$

$P_2=400\text{ kPa}$

$T_1=-20\text{ C}=253\text{ K}$

$T_2=60\text{ C}=333\text{ K}$

Relation between temperature and pressure in a polytropic process:

$\begin{align*} \dfrac{P_2}{P_1}&=\left(\dfrac{T_2}{T_1} \right)^{\dfrac{n}{n-1}}\\ \end{align*}$

We can find polytropic exponent:

$\begin{align*} \dfrac{n-1}{n}&=\log_{\dfrac{P_2}{P_1}} {\dfrac{T_2}{T_1}}=\log_{\dfrac{400}{150}} {\dfrac{333}{253}}={0.28}\\\\ n&=\dfrac{1}{1-0.28}=\boxed{1.39} \end{align*}$

From Properties table A.5. we can find Ammonia specific heat and gas constant:

$C_p=2.130\frac{\text{ kJ}}{\text{ kg K}}$

$R=0.4882\frac{\text{ kJ}}{\text{ kg K}}$

## Create a free account to view solutions

## Create a free account to view solutions

## Recommended textbook solutions

#### Fundamentals of Electric Circuits

6th Edition•ISBN: 9780078028229 (2 more)Charles Alexander, Matthew Sadiku#### Physics for Scientists and Engineers: A Strategic Approach with Modern Physics

4th Edition•ISBN: 9780133942651 (8 more)Randall D. Knight#### Advanced Engineering Mathematics

10th Edition•ISBN: 9780470458365 (5 more)Erwin Kreyszig#### Fundamentals of Thermodynamics

10th Edition•ISBN: 9781119405963 (2 more)Claus Borgnakke, Richard E. Sonntag## More related questions

1/4

1/7