In: Mechanical Engineering
Consider a turbine; working substance is air.
cp=1.0 kJ/kgK , k=1.4
v1=0.03 , v2=0.08 m3/kg , p1=2.5 bar; state 1 is enterance, state 2 is the exit of the turbine. The turbine is not ideal (isentropic); the air goes through a state change according to pv^n=constant , n=1.6 Compute the ideal and actual specific works and turbine efficiency.
pvn=constant , n=1.6
One assumption is made while solving the problem is that the exit condition given is for actual condition and considering it the ideal condition is calculated.
one important concept while dealing with the ideal and the actual condition is that the pressure at entry and exit are the same so there is a need to calculate the specific volume at the entry and the exit condition for the actual and the ideal case.
all the above entry and exit condition for the actual and ideal case is evaluated to calculate the work done for both the condition with the help of direct formula for an adiabatic and polytropic process for open system and then determine the required efficiency of the turbine.
comment if any query.