Important parameters affecting critical heat flux from horizontal cylindrical heaters in saturated pool boiling.

摘要

Recently, attention has given to the boiling process as an efficient means of cooling various high heat exchanger devices such as nuclear reactors, heat exchangers, large electronic machines, and robot engines due to the high heat transfer rates made available by the boiling process. It is believed that different surface parameters have a strong influence on the heat flux in different boiling regimes. One such parameter is the contact angle. The contact angle is believed to play an important role in determining the critical heat flux in pool boiling. This thesis undertake a closer look at the contact angle role and its effects on the critical heat flux on horizontal cylindrical heaters in saturated pool boiling. An improved correlation that incorporates the contact angle as independent parameter for predicting the Critical Heat Flux was developed. The effect of gravity on the receding contact angle for boiling surfaces was also studied and a correlation establishing the dependence of the gravity on the contact angle is presented.