NUCLEATE BOILING HEAT-FLUX ENHANCEMENT ON MACRO MICRO-STRUCTURED SURFACES COOLED BY AN IMPINGING JET/

An experimental investigation of nucleate boiling heat transfer from a surface cooled by a circular jet impinging normally to the surface is reported. To enhance the nucleate boiling and maximum heat fluxes, ma cro and micro modifications were made to the boiling surface. Macro-mo dification consists of forming radial grooves on the surface while mic ro-modification is achieved by sintering the surface. With macro/micro -modification, the boiling curve is shifted to the left and upwards. A t least two fold enhancement in nucleate boiling heat fluxes and CHF i s observed over that for a plane surface. In the experiments water and Freon-113 were used as test fluids. The data also delineate the effec t of oxidation of the heated surface on nucleate boiling curve.