Date of Graduation


Document Type


Degree Name

Doctor of Philosophy in Engineering (PhD)

Degree Level



Mechanical Engineering


David Huitink

Committee Member

Hu, Han

Second Committee Member

Zhao, Yue

Third Committee Member

Walters, Keith


Dielectric Fluid, Jet Impingement Cooling, Power Electronics, Thermal Management


Convective heat transfer by jet impingement cooling offers a suitable solution for high heat flux applications. Compared to techniques that rely on bulk conduction in series with convection, direct liquid impingement reduces the thermal resistance between power device hot spots and the coolant. Using additive manufacturing processes, location specific jets can be integrated into high voltage power electronics systems. Custom manifolds can be designed to reduce pressure drop, while simultaneously fine-tuning the thermal management efficiency. Although capable of highly efficient cooling, static impingement devices must be designed for the worst-case cooling requirements for a transient power profile, possibly resulting in wasted hydraulic performance. This work seeks to understand the balance between high performance external jet impingement with internal immersed cooling of high voltage power electronics. With the use of a variable area iris mechanism, high frequency pulsations are introduced into the jet cooling of a base-plate level testbed. This same actuator is then used to analyze the impact on thermal cycling and pressure drop during real-world power profiles. From a thermal packaging perspective, the base plate layer and other insulation features will inherently increase the base line resistance value. Therefore, the second portion of this work is to evaluate the applicability of direct immersion jet impingement cooling using dielectric fluids. In this part, a thermal test vehicle is first built to understand the thermal performance of a single jet of dielectric fluid. Then, this cooling method is imbedded into the housing of a 1.2kV SiC power module to analyze the trade-off between conductive thermal spreading and reduced convective thermal resistance.

Available for download on Thursday, February 05, 2026