NUCLEATE BOILING AND THE CHEN CORRELATION FOR FLOW BOILING HEAT TRANSFER

In flow boiling experiments on water in a vertical tube, the Chen correlation predicted the convective heat transfer coefficient satisfactorily but overpredicted the nucleate boiling contribution. The tube material had rather low densities of bubble nucleation sites, measured by observation in boiling and by gas bubble nucleation: the methods agreed only if the gas measurements were made after boiling, which reduced the surface-liquid contact angle. Since nucleate flow boiling is just as sensitive to surface conditions as pool boiling, the suppression factor S proposed by Chen must be reexamined using pool boiling curves appropriate to each experiment.