Heat transfer modelling of motor

Hi, I am having difficulty modeling a heat exchange process from the casing of an electric motor to the environment (a fan is blowing air over the case).

Here's the basic overview of what I did.

I have split the motor into 4 sections with the surface area for each section known. I used the controlled mass flow rate block (the gas properties, reservoir and solver blocks are also connected) connected it to the inlets of the 4 gas pipe blocks (the four sections of the motor case), with the outlet of these four connected to a reservoir. The thermal port is connected to a controlled heat source.

The problem

The issue I'm facing is when I check the temp just after the controlled mass flow block, the temp is not what's put in the reservoir configuration, it's much higher. When I check the temp just before the reservoir (the one which is connected to the exit of the 4 pipes) the temp is lower than 1st reservoir. I don't understand how this is possible. Could someone help me out.

Answer 1

[Sam Chak]

Hi @Kranz,

Before modeling, I recommend creating a sketch of the heat transfer process in the form of a Piping & Instrumentation Diagram (P&ID) or a Process Flow Diagram (PFD). This will provide you with a clear and comprehensive visual representation of the entire process, helping you better understand its components.

If you are using Simulink / Simcape, you can model the system based on the P&ID or the PFD. Simply search for and insert the relevant equipment (blocks) or use the MATLAB function block, which describes the mathematical relationship between the input and the output.

Regarding the issue you are facing, it's essential to check the mathematical model of the thermal system. This will help identify what went wrong with the thermal controller's mathematical equation and provide insights into resolving the problem.