Motor-CAD thermal example script

This example provides a Motor-CAD thermal script.

Set up example

Setting up this example consists of performing imports, launching Motor-CAD, disabling all popup messages from Motor-CAD, and opening the file for the thermal analysis.

# Perform required imports
# ~~~~~~~~~~~~~~~~~~~~~~~~
# Import the required packages.
import os

import matplotlib.pyplot as plt

import ansys.motorcad.core as pymotorcad

if "QT_API" in os.environ:
    os.environ["QT_API"] = "pyqt"

Launch Motor-CAD

Initialize ActiveX automation and launch Motor-CAD.

print("Starting initialization.")
mcad = pymotorcad.MotorCAD()

Starting initialization.

Disable popup messages

Disable all popup messages from Motor-CAD.

mcad.set_variable("MessageDisplayState", 2)

Open relevant file

Specify the working directory and open the relevant file for the thermal analysis.

working_folder = os.getcwd()
mcad.load_template("e8")
mcad_name = "e8_mobility"
mcad.save_to_file(os.path.join(working_folder, mcad_name))

mcad.load_from_file(os.path.join(working_folder, mcad_name + ".mot"))

print("Initialization completed.")

Initialization completed.

Create analysis

Creating the analysis consists of showing the thermal context, displaying the Scripting tab, setting parameters, and saving the file.

# Show thermal context
# -----------------------
mcad.show_thermal_context()

Display the Scripting tab.

mcad.display_screen("Scripting")

Change the housing diameter.

mcad.set_variable("Housing_Dia", 250)

Set the flow rate of the WJ fluid volume.

mcad.set_variable("WJ_Fluid_Volume_Flow_Rate", 0.002)

Set the temperature of the WJ fluid inlet.

mcad.set_variable("WJ_Fluid_Inlet_Temperature", 25)

Change the cooling fluid.

mcad.set_fluid("HousingWJFluid", "Dynalene HF-LO")

Set the heat transfer correlation.

mcad.set_variable("Calc/Input_h[WJ]_Rear_Housing", 1)
mcad.set_array_variable("HousingWJ_CalcInputH_A", 0, 1)

wj_fluid_k = mcad.get_variable("WJ_Fluid_Thermal_Conductivity")
wj_fluid_rho = mcad.get_variable("WJ_Fluid_Density")
wj_fluid_mu = mcad.get_variable("WJ_Fluid_Dynamic_Viscosity")
wj_fluid_u_a = mcad.get_array_variable("HousingWJ_Velocity_A", 0)
wj_fluid_u_r = mcad.get_variable("WJ_Channel_Fluid_Velocity_[Rear]")

h_A = 0.005 * wj_fluid_k * wj_fluid_rho * wj_fluid_u_a / wj_fluid_mu
h_R = 0.005 * wj_fluid_k * wj_fluid_rho * wj_fluid_u_r / wj_fluid_mu

print("h_A = ", h_A)
print("h_R = ", h_R)

mcad.set_array_variable("HousingWJ_InputH_A", 0, h_A)
mcad.set_variable("Input_Value_h[WJ]_Rear_Housing", h_R)

h_A =  178.49062082139457
h_R =  0.0

Save the file.

mcad.save_to_file(os.path.join(working_folder, "../MotorCAD_Thermal_Python.mot"))

Calculate steady state

Calculate the steady state.

try:
    mcad.do_steady_state_analysis()
    print("Thermal calculation successfully completed.")
except pymotorcad.MotorCADError:
    print("Thermal calculation failed.")

Thermal calculation successfully completed.

Retrieve the magnet temperature.

node_temperature = mcad.get_node_temperature(13)
print("Node Temp = ", node_temperature)

Node Temp =  128.171296913135

Retrieve the minimum, maximum, and average winding temperatures.

winding_temperature_min = mcad.get_variable("T_[Winding_Min]")
winding_temperature_max = mcad.get_variable("T_[Winding_Max]")
winding_temperature_average = mcad.get_variable("T_[Winding_Average]")
print("Min = ", winding_temperature_min)
print("Max = ", winding_temperature_max)
print("Average = ", winding_temperature_average)

Min =  116.272225696292
Max =  144.596942536281
Average =  137.440314758973

Run simulation

Run the transient simulation.

mcad.set_variable("Transient_Calculation_Type", 0)
mcad.set_variable("Transient_Time_Period", 60)

try:
    mcad.do_transient_analysis()
except pymotorcad.MotorCADError:
    print("Thermal calculation failed.")

Get the transient results.

num_time_steps = 51
winding_temp_average_transient = []
time = []

for timeStep in range(num_time_steps):
    try:
        (x, y) = mcad.get_temperature_graph_point("Winding (Avg)", timeStep)
        time.append(x)
        winding_temp_average_transient.append(y)
    except pymotorcad.MotorCADError:
        print("Export failed.")

Plot results

Plot results from the simulation.

plt.figure(1)
plt.plot(time, winding_temp_average_transient)
plt.xlabel("Time")
plt.ylabel("WindingTemp_Average_Transient")
plt.show()

Exit Motor-CAD

Exit Motor-CAD.

mcad.quit()