Development of Bubbly Boiling in Refrigeration Heat Exchangers

摘要

The paper describes results of experimental investigations and numerical analysis to determine the velocity of propagation of disturbances that give rise to the development of bubbly boiling in channel flow. It is found that the first vapour bubbles emerge under condition of certain liquid superheat at the wall of the heated channel near its exit section. With the inception of generation of vapour bubbles, the so-called boiling front is formed and begins propagating upstream. The boiling front propagation velocity depends on the magnitude of the disturbance that stimulates the development of boiling, also on the level of liquid superheat and void fraction in the channel. The results of experimental investigations are compared with computational results, showing a good agreement between the two.