Influence of spray characteristics on heat flux in dual phase spray impingement cooling of hot surface

AbstractThe effects of variation of spray characteristics (mass flux, inlet pressure, flow rate, nozzle tip to target distance and plate thickness) on heat flux were systematically investigated. The round spray released from a full cone internally mix atomizing nozzle was impinged with a wide range of air and water pressures on stationary hot steel surface of definite dimension. The effect of each parameter was examined while keeping others nearly fixed. Four different plate thicknesses i.e., 4mm, 6mm, 8mm and 10mm were tested and effect of plate thickness on heat transfer was determined. Surface heat flux at each experimental condition was computed from the transient temperature history measured by K-type thermocouples embedded at bottom surface of the plate. The mass impingement density was measured by the help of a simple mechanical patternator. The maximum surface heat flux of 4895.525kW/m2 was achieved at an inlet water pressure of 4bar, air pressure of 3bar and nozzle height of 120mm for an initial temperature of 850°C of the 4mm steel plate