View article

Investigation on the effect of heat sink orientation on the flow boiling performance in a rectangular microgap channel of width (w) 20 mm, length (L) 30 mm and depth (d) 220 µm with a hydraulic diameter (D_h) of 435 µm were performed. Experiments were conducted in different orientations such as horizontal downward facing (HD), horizontal upward facing (HU), horizontal with heating area vertically aligned (HV), vertical up flow orientation (VUF) and vertical downflow orientation (VDF) with mass fluxes (G) ranging from 193 to 911 kg/m² s using deionized water as the working fluid. The experimental results were compared with the results of 31 parallel ‘U’ shaped microchannel study conducted by the authors earlier. The experimental results in microgap channel showed more or less similar critical heat flux (CHF) and heat transfer coefficients across all the orientations tested, indicating that the effect of gravity …