Abstract:
This course covers the thermal analysis of an induction motor using a powerful, dual-method approach. The study begins by developing an analytical model, a Lumped Parameter Thermal Network (LPTN), which is then implemented in MATLAB. Subsequently, the results from the LPTN are validated against numerical simulations performed using Computational Fluid Dynamics (CFD) in ANSYS Fluent. For comprehensive analysis, the heat transfer coefficients calculated from the CFD simulations are also integrated back into the LPTN model to perform a rigorous cross-validation between the analytical and numerical performance.
Course Contents (Part #1):
Fundamentals of Heat Transfer & Fluid Dynamics:
- Governing Physics: Understanding heat transfer modes (Conduction, Convection, Radiation), the Fourier Equation, and the Energy Equation.
- Fluid Dynamics Basics: Introduction to CFD, Laminar vs. Turbulent flow regimes, and defining boundary conditions.
- Thermal Parameters: Deep dive into the Nusselt number, Heat Transfer Coefficient (h), thermal conductivity, and emissivity.
- Material & Application: Study of potting materials, high-emissivity coatings to increase heat transfer, and standard cooling techniques (natural vs. forced convection).
Lumped Parameter Thermal Network (LPTN):
- Theoretical Deduction: Transitioning from continuous Energy Equations to discrete LPTN space. Defining nodes, State-Space equations, and Thermal Resistance/Capacitance.
- Advanced Modeling: Handling heat transfer in complex regions like the Airgap and end spaces.
- Input Definitions: Applying power losses as input sources and modeling cooling method impacts.
- Dynamic Analysis: Calculating thermal time constants and analyzing transient thermal performance.
- MATLAB Implementation: Coding the full LPTN structure to solve for critical temperatures.
Course Contents (Part #2):
Conduction & Solid Domain Analysis:
- Geometry & Meshing: Creating the motor geometry and organized/disorganized meshing strategies for solid parts.
- Solver Setup: Selecting the appropriate solver in ANSYS Fluent for conductive heat transfer.
- Boundary Conditions: Applying convective terms in the air gap, end spaces, and environment using Heat Transfer Coefficients (h) rather than simulating the fluid.
- Temperature distribution: Analyzing the local hotspots and comparing them with the average temperature achieved.
- Validation: Comparing these initial CFD thermal results against the LPTN model to validate the solid domain physics.
Course Contents (Part #3):
Conjugate Heat Transfer (CHT):
- Full Domain Modeling: Geometry and meshing, including the fluid domain (air/coolant).
- Conjugate Solver: Configuring Fluent for simultaneous Fluidic and Thermal studies (Conduction + Convection via fluid motion).
- Output Calculation: Extracting the Heat Transfer Coefficient (h) as a simulation output rather than an input.
- Cross-Validation: Comparing the calculated h values with those used in the LPTN to refine and validate the analytical model.