Model of heat transfer in the stagnation point of rapidly evaporating microjet

The paper presents investigation into the single water microjet surface cooling producing evaporating film. Reported tests were conducted under steady state conditions. Experiments were conducted using the nozzle size of 70 and 100 [my]m respectively. In the course of investigations obtained were experimental relations between heat flux and wall superheating. It was proved that the phenomenon is similar to that of pool boiling but the boiling curves are showing a smaller value of critical heat flux (CHF) that the stagnant pool boiling. Values of CHF are also reduced with decreasing liquid subcooling. Theoretical model of surface cooling by evaporating microjet impingement in the stagnation point was described theoreticaly. Results of experiments were compared with predictions by the model showing a good consistency.