A hybrid CFD-mathematical model for simulation of a MEMS loop heat pipe for electronics cooling applications

A hybrid CFD-mathematical (HyCoM) model was developed to predict the performance of a micro loop heat pipe (MLHP) as a function of input heat rate. A micro loop heat pipe is a passive two-phase heat transport device, consisting of microevaporator, microcondenser, microcompensation chamber (CC) and liquid and vapor lines. A CFD model was incorporated into a loop solver code to identify heat leak to the CC. Two-phase pressure drop in the condenser was calculated by several two phase correlations and results were compared (Izenson and Crowley 1992 AIAA Paper A92-47847). Capillary tube correlations (Blevins 1984 Applied Fluid Dynamics Handbook (New York: Van Nostrand-Reinhold)) were used for pressure drop calculations in fluid lines. Effects of working fluid and change in geometry were studied. For a heat transport distance of 10 mm, the base model MLHP was 50 mm long, 16 mm wide and 1 mm thick. In the base model, widths of the grooves, liquid and vapor lines, evaporator and condenser were 55 mum, 200 mum, 750 mum, 2 mm and 4 mm, respectively.