Convective Heat Transfer Enhancement Due to Gas Injection Into an Impinging Liquid Jet

An experimental parametric investigation has been performed to assess the effect of gas injection on convective heat transfer from a constant heat flux surface to an impinging liquid jet in the absence of boiling. Capillary tubes were inserted into a planar nozzle and extended to a point near the nozzle opening along the nozzle midplane. Air was used as the gas phase and water was used as the liquid phase. The air was injected into the capillary tubes and combined with the water to form a two-phase jet. Convective heat transfer coefficients were enhanced by factors as high as 2.2 near the stagnation line and 1.6 at a distance of five jet widths with no discernible change in pressure drop in the water supply system. Results are generalized and referenced to conditions for single-phase, liquid jet correlations to facilitate heat transfer estimations in applications.