EAGER: Combined Innovative Methods in Immersion Cooling for High Density Power Electronics

电力电子设备的小型化是电动飞机和车辆发展和普及的关键障碍。 交通电气化有助于保护环境和减缓气候变化。 功率密度以及因此而导致的功率电子器件的小型化最终受到散热能力的限制。 对于表面积小的热源，需要更有效和可靠的冷却机制。 例如，具有最高功率密度的功率半导体开关直接连接而无需封装，从而提供最低的成本、故障率和热阻。 这些优点通常由于芯片表面的热传递不足而丧失。 众所周知，浸没式冷却为芯片级器件提供最可靠和最高性能的热界面;然而，传统上，浸没式冷却依赖于重力依赖（物理取向依赖）对流或物理泵送，这限制了其在航空和移动的应用中的应用和小型化。 最终，该项目的目标是创建一个没有移动部件的高可靠性密封冷却系统。 该项目将有助于支持女性和少数民族的本科生研究，并为电力电子热管理的课堂揭示新概念。该项目的目标是研究组合方法和材料，以大大提高浸入式冷却的性能，而不会沸腾。 这将涉及：（1）研究涉及以前没有研究和建模的不同物理的组合冷却机制;（2）使用新的测量方法组合来定量地确定有效传热系数提高的条件;（3）定量地确定新的浸入式冷却材料在热和物理应力下的稳定性。 将研究在不沸腾的情况下发生相变的新材料。 测量方法将包括使用流量和温度标记的纹影成像以及直接测量氮化镓半导体器件的沟道温度。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

The miniaturization of power electronics is a key obstacle in the advancement and proliferation of electric aircraft and vehicles. Electrification of transportation helps safeguard the environment and mitigates climate change. The power density and consequently the miniaturization of power electronics is ultimately limited by the ability to remove heat. More effective and reliable cooling mechanisms for heat sources with small surface area are needed. For example, power semiconductor switches that have the highest power density are directly connected without packaging offering the lowest cost, failure rate, and thermal resistance. These advantages are often undone by inadequate thermal transfer from the surface of the chip. Immersion cooling is known to provide the most reliable and highest performance thermal interface for chip-scale devices; however, conventionally, immersion cooling relies on gravity-dependent (physical-orientation dependent) convection or physical pumping, which limits its application and miniaturization in aviation and mobile applications. Ultimately, the goal of this project is to create a high reliability sealed cooling system with no moving parts. This project will help to support of undergraduate research for women and underrepresented minorities and to uncover new concepts for the classroom in the thermal management of power electronics.The goal of this proposal is to investigate combined methods and materials to greatly enhance the performance of immersion cooling without boiling. This will involve: (1) investigating the combined cooling mechanisms that involve different physics that have not been previously examined and modeled; (2) using new combinations of measurement methods to quantitatively determine the conditions under which the effective heat transfer coefficient is improved; and (3) quantitatively determining the stability of new immersion cooling materials under thermal and physical stress. New materials that undergo phase change without boiling will be studied. Measurement methods will include Schlieren imaging using markers for flow and temperature and direct measurement of the channel temperature of gallium nitride semiconductor devices.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.