Experimental and Analytical Characterization of Copper Fin Patterns for Heat Sinks in Liquid Cooling Loops for Motor Drives

A numerical and experimental study of heat transfer and fluid flow in heat sinks that may be used for cooling loops for motor drives is presented. An experimental study of 4 heat sinks was completed: a serpentine 4-pass copper tube in an aluminum plate, a design having folded aluminum fins brazed in an aluminum housing, a minichannel aluminum extrusion, and two molded copper fin designs. In addition, using the results from the experimental analysis, a CFD and similarity study was performed on models of a serpentine 4-pass copper tube in a copper plate, a design having corrugated copper fins brazed in a copper housing, and a minichannel copper heat sink. Temperature, pressure drop, flow rate, and other pertinent data were recorded during the experiments and compared to the computational models. Nondimensional numbers and dimensional values were calculated from the results. The data was then normalized for thermal resistivity (°C-cm²/W) and normalized for flow rate (l/min-cm²) to allow comparison of different size cold plates, with different size heat sources at different flow rates. Finally, the data was used in CFD simulations to improve the baseline thermal performance of the IGBT/cold plate assembly of a 2004 Toyota Prius. Compared to the stock cold plate, size of the IPEM was reduced by 50%, total weight was reduced by 59%, and junction temperature was reduced by 2.7°C,