Thermodynamics and conservation laws

Question 1

Explain the difference between adiabatic process and isentropic process

Answer 1

both adiabatic and isentropic processes involve the absence of heat transfer, the key distinction lies in the reversibility. An adiabatic process only ensures the absence of heat exchange, while an isentropic process goes further to guarantee reversibility and constant entropy.

Question 2

Explain the difference between the model of ideal gas and the perfect gas

Answer 2

Perfect gas = ideal gas with constant heat capacities

cp = const, cV = const, γ = const u = cV T, h = cpT

This approximation works well if temperature does not vary too much in the process.

Question 3

what are the conditions where the model of perfect gas is accurate enough?

Answer 3

This approximation works well if temperature does not vary too much in the process.

Question 4

How the ratio of specific heat capacities is related with the number of atoms in the molecule of gas

Question 5

Explain why it is appropriate to deal with specific values for gas flow properties in Gas Dynamics

Question 6

Explain the concept of entropy in application to Gas Dynamics

Question 7

The change of mass in a control volume equals mass flux through its boundary with the sign minus. Explain
why the minus should be used.

Question 8

Derive the integral form of the mass conservation law for a compressible flow of fluid

Question 9

A gas stored in a large reservoir is discharged through a converging nozzle. Considering the process as
adiabatic derive the relation between the pressure in the reservoir and the mass of gas stored in the
reservoir