Probleemstelling:

An electrical drivetrain incorporates power electronics to convert the DC voltage provided by the batteries to an AC waveform to drive the electric motor. To develop electric vehicles with a higher driving range, these components need to become more compact and efficient. One of the issues of the power electronics is the risk of overheating, whereby high temperature damage the components. Highly performant cooling techniques are a necessity to avoid these problems.

Most cooling techniques for highly power-dense power electronics use liquid cooling on the base plate, optionally with heat transfer enhancing structures such as pin fins or turbulators. However, a thermal resistance between the junction (component) and case (base plate) is inevitably present when utilizing these techniques. This thermal resistance is avoided when cooling directly onto the power electronic components. The cooling fluid has to be chosen carefully, such that it does not interfere with the electrical behaviour of the power electronics.

Doelstelling:

The goal of this master thesis is to model the heat transfer from a power electronics module to a fluid by direct immersion cooling of the power electronics components. Using computational fluid dynamics (CFD), numerical simulations will be performed to analyze the flow and heat transfer in and around the power electronics components. Both the conductive heat transfer in the module and the convective heat transfer in the fluid will be simulated. The effect of different boundary conditions (flow rates, flow structures) and different coolants will be analyzed. From the simulation results, a lumped parameter model taking into acount conduction and convection will be derived, which allows for quickly analyzing and optimizing the cooling technique for different cases.

This master thesis is in corporation with Dana, a US-based company with a corporate R&D-center in Bruges and Ghent. The goal of this center is to increase revenue by innovation in supplying the automotive market (passenger cars), commercial vehicle market (busses and trucks) and off - highway vehicle market (cranes, excavators, fork lift trucks, etc.) with highly efficient and performant drivetrain products. The Advanced Powertrain Engineering team is continuously looking to model and analyze new driveline systems. Apart from conventional drivetrains, the team is highly recognized within the company for developing electric driveline concepts. This thesis proposal fits within this framework.