Abstract: A thin spring-metal blade was attached in front of the nozzle jet, and its mechanical vibrations of composite-frequency of 500 to 30 000 cycles per second were excited by a stream of steam or water when forced through the nozzle. The effects on increase of burn-out heat flux and increase of coefficient of heat transfer in the subcooled water by such mechanical vibration and jet turbulence were investigated experimentally. The test section was heated by large direct electrical current. It was observed that the coefficient of heat transfer by boiling was increased by 56-126% depend upon the degree of subcooledness. The increase of heat transfer was larger at higher subcooledness. The effect of increase of burn-out heat flux was also measured experimentally. At different rates of mass flow velocity(240-640 kg per square meter per second) and different degree of subcooledness (?tH=15-36C) the rates of increase of burn-out heat flux were averaged about 33%. An empirical equation(Eq.1) was derived from the experimental results shown in Figure 10. Evidently, the jet flow turbulence and the vibration effect can be utilized to increase the burn-out heat flux and to delay the occurance of boiling crisis. Such technique of jet flow and vibration may be used in certain boiling heat-transfer apparatus or regenerative cooling wall in order to increase its heat-transfer rate and reliability.