Effect of surface modification by selective laser melting on heat transfer during pool boiling and microjet cooling with water

Heat transfer on a surface with a relief obtained by selective laser melting of copper powder was experimentally studied under conditions of pool boiling of saturated water and microjet cooling with a subcooled liquid. Microjet cooling was carried out by a distributed system of impact microjet water at subcooling to a saturation temperature of 80$^\circ$C. In the experiments, 36 impact microjets were used, the nozzles of which, with a diameter of 174 $\mu$m, were located at a distance of 1 mm from the modified surface. It has been established that under conditions of saturated boiling, the heat transfer coefficients on the modified surface are 3.5 times higher, and the critical heat flux is 2.8 times higher than for a smooth surface. Under microjet cooling conditions at a jet speed of 1 m/s, the intensification of heat transfer from the modified surface was 35%, and an increase in the maximum heat flux was achieved from 493 W/cm$^2$ to 770.3 W/cm$^2$.