Ultra-thin flattened heat pipe with a novel band-shape spiral woven mesh wick for cooling smartphones

In this work, a novel spiral woven mesh (SWM) wick was developed to enhance the thermal performance of ultra-thin flattened heat pipe (UTHP) for cooling thin portable electronics. The SWM overall structure was woven in a band-shape to realize an ultra-thin and tight structure. Three different SWM structures were designed to study the effect of the wick on the UTHP thermal performance. The maximum heat transport capacity data of UTHPs were compared with the calculated capillary and entrainment limits. The effects of the cross-sectional area ratio of the wick to the UTHP on the heat transfer performance were analyzed. The heat dissipation performance of the UTHP cooling module at different inclination angles was experimentally investigated. The results indicate that the cross-sectional area ratio affected the flow characteristics of the vapor and liquid in the UTHP, thereby affecting its heat transfer performance. A further increase in the number of SWM wires did not significantly improve the UTHP thermal performance. Gravity had little effect on the heat dissipation performance of the UTHP cooling module. Compared with a copper sheet cooling module, the maximum heat dissipation power of the UTHP cooling module increased by 28.57-42.86%, and the weight reduced by 64.51%. (C) 2019 Elsevier Ltd. All rights reserved.