def calc_P_delta_h(T_in,T_out,m_dot,p_chamber):
"""Calculate power required to raise temperature of flow with mass flow m_dot
Arguments:
T_in {K} -- Inlet temperature
T_out {K} -- Outlet temperature
m_dot {kg/s} -- Mass flow
p_chamber {Pa} -- Chamber pressure
Returns:
{W} - Required power
"""
# Check if outlet state is gaseous
fp = FluidProperties("water")
outlet_phase = fp.get_phase(T=T_out,p=p_chamber)
if not (outlet_phase == "gas" or outlet_phase == "supercritical_gas"):
print(fp.get_phase(T=T_out,p=p_chamber))
raise ValueError("Assumed outlet temperature is not not in gas phase")
Delta_h = fp.get_enthalpy(T=T_out, p=p_chamber) - fp.get_enthalpy(T=T_in, p=p_chamber)
return m_dot*Delta_h
def run2():
#Calcuate heating efficiency of heaters in literature
m_dot = 0.83e-6 # [kg/s] mass flow
T_in = 24+273.15 # [K] Inlet temperature
T_out = 426.65 # [K] Outlet temperature
p = 5.15e5 # [Pa] Pressure
P_total = 8.19 # [W] Total electrical power
fp = FluidProperties("water")
# Specific enthalpy at inlet and outlet
h_in = fp.get_enthalpy(T=T_in, p=p) # [J/kg] Inlet
h_out = fp.get_enthalpy(T=T_out, p=p) # [J/kg] Outlet
P_delta_h = m_dot*(h_out-h_in) # [W] Power raising enthalpy
efficiency = P_delta_h/P_total # [-]
print("Exit phase: {}".format(fp.get_phase(T=T_out,p=p)))
print("P_delta_h: {:1.2f} W".format(P_delta_h))
print("Micro-heater efficiency: {:1.2f} ".format(efficiency))
print("T_in = {:3.0f} K \t\t T_out = {:3.0f} K".format(T_in,T_out))
print("Mass flow = {:2.2f} mg/s".format(m_dot*1e6))
def ideal_enthalpy_change(T_inlet, p_inlet, T_outlet, p_outlet, fp: FluidProperties):
"""Returns specific enthalpy change based on simple chamber inlet and outlet conditions.
This should give the power the micro-heater must transfer in ideal conditions with no heat losses.
In addition returns a warning if the final state is not gaseous.
Arguments:
T_inlet {K} -- Inlet temperature
p_inlet {Pa} -- Inlet pressure
T_outlet {K} -- Outlet temperature
p_outlet {Pa} -- Outlet pressure
fp {object} -- FluidProperties object
Returns:
delta_h {J/(kg*K)} --
"""
h_inlet = fp.get_enthalpy(T=T_inlet, p=p_inlet)
h_outlet = fp.get_enthalpy(T=T_outlet, p=p_outlet)
outlet_phase = fp.get_phase(T=T_outlet,p=p_outlet)
if not (outlet_phase == 'gas' or outlet_phase == 'supercritical_gas'):
print("Warning: Phase at chamber exit is not gaseous but {}".format(outlet_phase))
return h_outlet-h_inlet