Question

a) Describe a polytropic process in your own words.

b) If a system undergoes a polytropic process, is it necessarily an ideal gas?

c) A system undergoes a polytropic process from v1= 0.5cm to v2= 1.0cm , when it
is at v= 0.75cm , is the system at equilibrium?

d) Can a non-ideal system, such as a liquid vapour mixture, go through a polytropic process?

Answer 1

A) The polytropic process is the one in which the pressure-volume relation is given as

PTT* = constant

where P is the pressure,

V is specific volume,

n is the polytropic index.

I. Any reversible process applicable to  any open or closed system of gases or vapors,

II. which includes both as well as work transfers, in such a way that A combination of these properties were maintained constant throughout their life cycle.

B. Yes, for polytropic process applicable to only for ideal gases or vapors.

C. May be at equilibrium or May not be at equilibrium, it will depends on other parameters like Temperature, and pressure etc.. also.

D. No, it applicable to either gases or vapors of single phase only. For liquid mixtures polytropic process is not applicable.