Optimization design of a novel closed-loop spray cooling system
Due to the superiority of spray cooling system in removing high waste heat flux generated by the electronics, a novel spray cooling system combined with ejective condenser is proposed and its work procedure is introduced. Most previous relevant studies are only focus on the influences of parameters on the spray cooling performance. In the present paper, a multi-objective optimization function on the overall system is provided through the analysis of fluid flow and heat transfer characteristics, and the Particle Swarm Optimization (PSO) is applied to solve this problem. The optimized results of the total mass, the total pump power consumption and the heat surface temperature are obtained at different heat power. The optimal system structure parameters of the sprayer, the ejective condenser, the radiator are obtained. The work conditions of the sprayer mass flow and the heat surface temperature are also got under the performance of minimum power consumption, minimum system mass and the lowest heat source temperature at heat source power 500 W (heat flux 500 W/cm2).
Two-phase spray cooling of hybrid vehicle electronics
As part of the U.S. Department of Energy (DOE) Advanced Power Electronics (APE) program, DOE's National Renewable Energy Laboratory (NREL) is currently leading a national effort to develop next-generation cooling technologies for hybrid vehicle electronics. Spray cooling has been identified as a potential solution that can dissipate 150- 200 W/cm2 while maintaining the chip temperature below 125degC. This study explores the viability and implementation of this cooling scheme. First, commercial coolants are assessed for their suitability to this application in terms of thermal, environmental, and safety concerns and material compatibility. In this assessment, HFE-7100 is identified as the optimum coolant in all performance categories. Next, spray models are used to determine the HFE-7100 spray conditions that meet such stringent heat dissipation requirements. These findings are verified experimentally, demonstrating that spray cooling is a viable thermal management solution for hybrid vehicle electronics.
衝突噴流沸騰系のバーンアウトの研究 : 第3報,バーンアウト熱流束の無次元整理式の拡張
加熱面の中心あるいは周辺部に水噴流を一つおくことによって液体を加熱面に供給する形の衝突噴流沸騰系の研究をおこなっている.実験は,前報で示した無次元整理式の適用範囲を拡張するため,流速ue=0.3～15m/s,D/d=5～36.4(D:加熱面径d:噴流径)の範囲について行う.そして,この沸騰系のバーンアウト熱流速は,前報の整理式にD/dの弱い影響を示す修正係数を加えた新しい無次元整理式で非常に精度良く与えられることを示す.