def test_table(self):
# Page 1410 of Span2000
fp = FluidProperties("nitrogen")
pressure = 1e5 # 1 bar of pressureM
# T in, cpout
in_out = ((300, 1041.2844102196514, 0), (330, 1041.6413812207552, 0),
(450, 1049.4947432450376, 0), (600, 1075.1966553245081, 0),
(1000, 1167.2951736092768, 0))
for T, cp, places in in_out:
res_cp = fp.get_cp(T=T, p=pressure)
self.assertAlmostEqual(res_cp, cp, places=places)
# Testing again, but for another pressure
pressure = 1e6
in_out = ((300, 1055.9202212649052, 0), (320, 1054.1353662593865, 0),
(400, 1052.3505112538678, 0), (550, 1068.4142063035367, 0),
(800, 1123.7447114746187, 0), (1000, 1168.3660866125879, 0))
for T, cp, places in in_out:
res_cp = fp.get_cp(T=T, p=pressure)
self.assertAlmostEqual(
res_cp, cp, places=places
) # Must be divided by molar mass as CoolProp gives enthalpy for J/kg
def h_conv_from_Stanton(Stanton, u, T_ref, p_ref, fp: FluidProperties):
"""Return heat transfer coefficient dependent on Stanton number and thermodynamic state\
Temperature and pressure are passed instead of T and p, as these abstract away constant computations of cp and rho\
and it is easier to pass around the same state variables time and time again
WARNING: REFERENCE THERMODYNAMIC STATE (T_ref, p_ref) MUST BE EQUAL TO THOSE WITH WHICH NUSSELT NUMBER WAS DETERMINED
Args:
Stanton (-): Stanton number: dimensionless flow characteristic
u (m/s): flow velocity
T_ref (K): Temperature
p_ref (Pa): Pressure
fp (FluidProperties): object to use to obtain properties of fluid
Returns:
h_conv (W/(m^2*K)): convective heat transfer coefficient based on Stanton number, flow velocity and thermodynamic state
"""
cp = fp.get_cp(T=T_ref, p=p_ref) # [J/kg] Specific heat capacity under constant pressure
rho = fp.get_density(T=T_ref,p=p_ref) # [kg/m^3] Fluid density
return Stanton*rho*u*cp # [W/(m^2*K)] h_conv: Convective heat transfer coefficient
h_channel = 100e-6 # [m] Channel height/depth
w_channel = 212e-6 # [m] Channel width
channel_amount = 5 # [-]
m_dot = 0.55e-6 / channel_amount # [kg/s]
# Hydraulic diameter and area
A_channel = h_channel * w_channel # [m^2] Channel area through which fluid flows
wetted_perimeter = wetted_perimeter_rectangular(
w_channel=w_channel, h_channel=h_channel) # [m] Wetted perimeter
D_h = hydraulic_diameter(A=A_channel, wetted_perimeter=wetted_perimeter) # [m]
print("\n Hydraulic diameter: {:4.4f} um".format(D_h * 1e6))
# Determine remaining variables at inlet
rho_inlet = fp.get_density(T=T_inlet, p=p_inlet) # [kg/m^3]
cp_inlet = fp.get_cp(T=T_inlet, p=p_inlet) # [J/(kg*K)]
u_inlet = velocity_from_mass_flow(m_dot=m_dot, rho=rho_inlet,
A=A_channel) # [m/s]
mass_flux = m_dot / A_channel # [kg/(m^2*s)]
Re_Dh_inlet = fp.get_Reynolds_from_velocity(
T=T_inlet, p=p_inlet, L_ref=D_h,
u=u_inlet) # [-] Reynolds number at inlet, based on hydraulic diameter
Pr_inlet = fp.get_Prandtl(T=T_inlet, p=p_inlet) # [-] Prandtl number at inlet
print("\n----- INLET -----")
print("Density: {:4.8f} kg/m^3".format(rho_inlet))
print("C_p: {:4.8f} kJ/(kg*K)".format(cp_inlet * 1e-3))
print("Flow velocity: {:3.4f} m/s".format(u_inlet))
print("Mass flux: {:3.2f} kg/(m^2*s)".format(mass_flux))
print("Re_Dh: {:4.4f}".format(Re_Dh_inlet))
print("Pr {:4.4f}".format(Pr_inlet))