29260 Experimental investigation of flow boiling heat transfer under non-uniform and non-constant heat flux conditions
Begeleider(s): ir. Jana Rogiers

Richtingen: Master of Science in Electromechanical Engineering


There is no doubt that electrics vehicles are the future. Their evolution has initialized a shift from physically separated motor and drive systems to integrated motor drives in which the motor and power electronics are embedded in the same housing. The major bottleneck for this integration is the increased heat dissipation in a reduced volume, resulting in very challenging cooling requirements. With conventional cooling methods, like liquid cooling and air cooling, a further increase in power density is not possible. Therefore, cooling by flow boiling is proposed. Flow boiling exhibits a high heat transfer and low pressure drop, but there is an inherent risk of dry-out. Dry-out happens when the critical heat flux is reached (see figure). Correlations already exist which predict the heat transfer coefficient and critical heat flux for flow boiling through tubes. However, they assume a uniform and constant heat flux as boundary condition, which is not the case in integrated motor drives where the heat fluxes are transient and locally more intense. Therefore, new correlations for the heat transfer coefficient and critical heat flux should be developed that take temporally and spatially varying heat fluxes into account.





The experimental setup is in development. The goals of this master thesis are:

• Helping with the development and construction of the experimental setup

• Modelling the flow conditioning of the refrigerant

• Perform measurements with first version of test section (see figure)

This project aids in achieving sustainable development goal (SDG) 7: affordable and clean energy, by enabling the replacement of fossil fuels by renewable electricity as an energy source for the transport sector.