Evaluation of Nucleate Boiling Heat Flux Predictions at Varying Levels of Subcooling and Acceleration

The heat flux predictions of six different models proposed to explain the nucleate boiling phenomenon are compared with the corresponding heat flux measurements at the same levels of subcooling and acceleration. It is shown that none of these models can adequately predict nucleate boiling heat flux for other than saturated boiling conditions at standard gravity and that all of the models agree in predicting decreasing values of heat flux as subcooling and acceleration increase. This observation suggests the omission of some additional mechanism which is inoperative under saturated boiling conditions at standard gravity but very sensitive to the level of subcooling and acceleration. An empirical procedure is presented for correlating the results used in making the comparisons.