Question

Define the isentropic efficiency for each of the following 3. a. i. Adiabatic turbine ii. Adiabatic compressor iii. Adiabatic nozzle

Answer 1

Answer:

a)$\eta_{st}=\dfrac{\Delta h_{actual}}{\Delta _{ideal}}$

b)$\eta_{sc}=\dfrac{\Delta h_{ideal}}{\Delta _{actual}}$

c)$\eta_{sn}=\dfrac{\Delta h_{actual}}{\Delta _{ideal}}$

Explanation:

a)

Adiabatic turbine

Adiabatic turbine means turbine can not reject or take heat from surrounding.

Isentropic efficiency of turbine can be define as the ratio of actual work out put to the Ideal or isentropic work out put.Ideal means when turbine will give maximum work and there is no any friction losses we can say when process is isentropic.

Isentropic efficiency of turbine=(Actual work output)/(Ideal work output)

$\eta_{st}=\dfrac{\Delta h_{actual}}{\Delta _{ideal}}$

b)

Adiabatic compressor

Isentropic efficiency of compressor can be define as the ratio of ideal or isentropic work in put to the actual work  in put.

Isentropic efficiency of turbine=(Ideal work input)/(actual work input)

$\eta_{sc}=\dfrac{\Delta h_{ideal}}{\Delta _{actual}}$

c)Adiabatic nozzle

We know that nozzle is device which used to accelerate the fluid.

Basically it covert pressure energy to kinetic energy.

Isentropic efficiency of nozzle can be define as the ratio of actual enthalpy drop put to the Ideal or isentropic enthalpy drop.

$\eta_{sn}=\dfrac{\Delta h_{actual}}{\Delta _{ideal}}$