Experimental study of vibration effects on local interfacial parameters in boiling flow

Abstract

In this paper, the subcooled boiling flow experiments in a vertical annulus were conducted to study the effect of vibration on local interfacial characteristics. The local interfacial parameters including void fraction, bubble velocity, interfacial area concentration and Sauter mean diameter were measured by four-sensor conductivity probe. The time-averaged local parameters under vibration conditions were firstly measured and analyzed. It is found that the effects of vibration on time-averaged void fraction and interfacial area concentration are very limited. Therefore, we have developed the phase partitioning method to obtain the instantaneous variation of void fraction for further investigation. The instantaneous void fraction along the radial direction varies periodically with the vibration phase. The additional forces induced by vibration are analyzed and compared with each other. Among them, the tangential force is the dominant, which can account for the change tendency of void fraction under vibration. Besides, the variations of void fraction depend on different working conditions. The change tendencies of void fraction near the inner wall and outer wall are opposite in relatively low averaged void fraction regime while those in relatively high averaged void fraction regime are consistent.