Compressor - Constant Isentropic Efficiency Model

Model description

The constant isentropic efficiency model is a simple model based on the assumption that the isentropic efficiency stays constant.

\[\varepsilon_{is} = \frac{h_{su} - h_{ex, is}}{h_{su} - h_{ex}}\]

where \(\varepsilon_{is}\) is the isentropic efficiency, \(h_{su}\) is the supply specific enthalpy, \(h_{ex, is}\) is the isentropic exhaust specific enthalpy and \(h_{ex}\) is the exhaust specific enthalpy.

Based on the isentropic efficiency definition, the exhaust specific enthalpy can be calculated and thus also the exhaust temperature.

Class description

class component.compressor.compressor_csteff.CompressorCstEff[source]

Component: Compressor

Model: Constant isentropic efficiency

Descritpion:

This model determines the exhaust specific enthalpy and the exhaust temperature of a compressor. This model can be used for on-design models of systems.

Assumptions:

  • Steady-state operation.

  • Isentropic efficiency stays constant for all the conditions.

Connectors:

su (MassConnector): Mass connector for the suction side.

ex (MassConnector): Mass connector for the exhaust side.

W (WorkConnector): Work connector for the mechanical work.

Parameters:

eta_is: Isentropic efficiency. [-]

Inputs:

P_su: Suction side pressure. [Pa]

T_su: Suction side temperature. [K]

P_ex: Exhaust side pressure. [Pa]

fluid: Working fluid. [-]

m_dot: Mass flow rate of working fluid. [kg/s]

Ouputs:

h_ex: Exhaust side specific enthalpy. [J/kg]

T_ex: Exhaust side temperature. [K]

Example of use

from labothappy.component.compressor.compressor_csteff import CompressorCstEff

# Example usage
CP = CompressorCstEff()
# CP.print_setup()

"If the inputs are not set directly BUT through the connectors"
# CP.su.set_properties(P=319296.5575177148, T=331.033964665788, fluid='R1233ZDE', m_dot = 0.1)
# CP.ex.set_properties(P=606240.1433176235)

"If the inputs are set directly"
CP.set_inputs(
    P_su=319296.5575177148,
    T_su=331.033964665788,
    P_ex=606240.1433176235,
    fluid='R1233ZDE',  # Make sure to include fluid information
    m_dot=0.1  # Mass flow rate
)
CP.set_parameters(eta_is=0.8)
# CP.print_setup()

CP.solve()
CP.print_results()

fig = CP.plot_Ts()
fig.show()

References

/