Experimental study on the heat transport capability of micro-grooved oscillating heat pipe

This paper presents an experimental study to investigate the heat transfer limit of a micro-grooved OHP at the vertical bottom heat mode. The internal hydraulic diameter of the micro-grooved OHP is about 2.0 mm, and deionized water was used as a working fluid at volumetric filling ratios (FRs) ranging from 30% to 60%. Experimental results demonstrated that the micro-grooved OHP could significantly enhance the allowable maximum input heat flux before the occurrence of dry-out owing to the capillary action provided by micro-grooved structures to facilitate condensate backflow to the evaporator. The OHP obtained a maximum effective thermal conductivity of 41.8 kW/(m degrees C) at 40% FR, corresponding to a dry-out heat flux of 36.9 W/cm(2) with respect to the heat transfer limit. The allowable maximum input heat flux was found to be greater than 80 W/cm(2) for 50% and 60% FRs, and could be further increased by increasing the OHP turn number. This study provides a promising option to address thermal management demand for high-density power devices.