Warning
This documentation is for an old version of Cantera. You can find docs for newer versions here.
"""
A Rankine vapor power cycle
"""
import cantera as ct
# parameters
eta_pump = 0.6 # pump isentropic efficiency
eta_turbine = 0.8 # turbine isentropic efficiency
p_max = 8.0e5 # maximum pressure
def pump(fluid, p_final, eta):
"""Adiabatically pump a fluid to pressure p_final, using
a pump with isentropic efficiency eta."""
h0 = fluid.h
s0 = fluid.s
fluid.SP = s0, p_final
h1s = fluid.h
isentropic_work = h1s - h0
actual_work = isentropic_work / eta
h1 = h0 + actual_work
fluid.HP = h1, p_final
return actual_work
def expand(fluid, p_final, eta):
"""Adiabatically expand a fluid to pressure p_final, using
a turbine with isentropic efficiency eta."""
h0 = fluid.h
s0 = fluid.s
fluid.SP =s0, p_final
h1s = fluid.h
isentropic_work = h0 - h1s
actual_work = isentropic_work * eta
h1 = h0 - actual_work
fluid.HP = h1, p_final
return actual_work
def printState(n, fluid):
print('\n***************** State {0} ******************'.format(n))
print(fluid.report())
if __name__ == '__main__':
# create an object representing water
w = ct.Water()
# start with saturated liquid water at 300 K
w.TX = 300.0, 0.0
h1 = w.h
p1 = w.P
printState(1, w)
# pump it adiabatically to p_max
pump_work = pump(w, p_max, eta_pump)
h2 = w.h
printState(2, w)
# heat it at constant pressure until it reaches the saturated vapor state
# at this pressure
w.PX = p_max, 1.0
h3 = w.h
heat_added = h3 - h2
printState(3, w)
# expand back to p1
turbine_work = expand(w, p1, eta_turbine)
printState(4, w)
# efficiency
eff = (turbine_work - pump_work)/heat_added
print('efficiency = ', eff)