Session: 6.1.2 - Student Competition

Paper Number: 108951

108951 - Design/Development of an Ultra-Compact Jet Impingement Thermal Management System Integrated With Micro-Fins for High Power Applications: A CFD Modeling 

GaN high electron mobility transistors (HEMT) are used in radar, portable power supplies, electric vehicles, and renewable energy. The implementation of GaN transistors in compared with Si based packages are attracting many attentions recently, due to high switching speeds. However, the performance of the GaN HEMTs is limited due to the device rapid temperature rise as a result of the high amount of pulsed power applied. Consequently, the temperature of the device is restricted not to exceed 200 ℃ to negate the thermal stress failures. To overcome this malfunction, a thermal management system (TMS) is required. The GaN transistors thermal management solutions can be categorized into different methods such as the application of high thermal conductivity substrates, e.g. silicon carbide (SiC), GaN-specific packaging solutions, and heat spreaders. As these methods do not sufficiently reduce GaN self-heating, GaN HEMTs are generally operated in pulsed mode instead of continuous mode, effectively reducing the average power delivered and limiting the duty cycle. Integrated chip cooling is being widely used to dramatically increase the operational time of high-power transistors. In this study, an ultra-compact jet impingement (UJI) TMS is investigated to evaluate the performance of the GaN HEMT in high power applications. The proposed UJI-TMS includes a single or array of jets impinging the heat transfer fluid (HTF) to the base plate which is normally a flat surface. Due to the high turbulency created by the convective heat transfer, a higher heat dissipation can occur compared with the traditional cooling techniques where natural convection is dominant. The proposed UJI-TMS is integrated with arrangement of fins in order to increase the effective surface area, therefore increasing the cooling capabilities of the impinging jets. To the best of the authors’ knowledge, the application of UJI-TMS integrated with micro-fins in small-scale (compact) cooling solutions has not been studied. A parametric study is performed to develop a mathematical model for the design of UJI-TMS integrated with micro-fins. The thermal analysis of the GaN transistor will be performed through a computational fluid dynamics (CFD) modeling with ANSYS fluent. A mesh independent study will be completed to ensure the reliability of the achieved results. The effects of material selection of the TMS, different types of HTF, and the thermal interface layer will be explored. The proposed JI-TMS in this study is capable of maintaining the GaN transistor temperature below the threshold at a heat flux of 2 kW/cm². The preliminary CFD model developed in this study will be validated with the literature. Once the modifications are applied, the obtained results will be compared with the said traditional cooling techniques to demonstrate the reliability of the UJI-TMS in enhancing the GaN HEMT performance in high power operations.

Keywords: High power applications; Thermal management system; Jet impingement cooling; CFD modeling.

Presenting Author: Samual Sisk University of Missouri-Kansas City

Presenting Author Biography: Samual Sisk is a senior pursuing a Bachelor of Science in Mechanical Engineering at UMKC, born and raised in Kansas City, Missouri. He has won various awards from research competitions and other academic competitions such as 2020 Regional AMATYC, UMKC SUROP, and undergraduate research fellowship. He is currently working on ultra-compact jet impingement thermal management systems (TMS) for semiconductors, by computational fluid dynamics (CFD) modeling and experimental analysis . Before college he competed in tennis and is trying to get back into the sport. In his free time, he looks for a creative outlet such as pottery or painting.