Low Mass Flux Laminar Jet Cooling with Different Additives: An Enhancement-cum-Comparative Study

Abstract

The low flow rate laminar water jet is the most economical and efficient cooling methodology; however, the low heat removal capacity makes this process inappropriate for fast cooling operations. In the current work, the heat transfer rate has been increased by enlarging the stagnation zone length. This was attained by reducing the viscosity, surface tension and altering other thermo-physical properties of the coolants. The thermal analysis reveals that the maximum critical heat flux is achieved in case of 240 ppm Cetyltrimethylammonium bromide + water i.e., 1.7 MW/m2, which is 1.39 times higher than pure water. This is attributed to the significant reduction in the surface tension and viscosity. Use of additives like sodium carbonate and surfactant enhance the stagnation zone length. Furthermore, due to foaming nature of the coolant (500 ppm Ethanol + water), the heat transfer rate declines and a critical heat flux of 1.37 MW/m2 is observed. The visual observations are consistent with the results obtained for each coolant. Based on the high heat removal capacity, the low mass flux laminar jet cooling methodology with additives provide better cooling than that of the high-pressure laminar jet and high mass flux spray cooling.