A fractal model for critical heat flux in pool boiling

In this paper, a fractal model for the high heat flux nucleate boiling region and for the critical heat flux (CHF) is proposed. The expression for the critical heat flux (CHF) is derived based on the fractal distribution of nucleation sites on boiling surfaces. The proposed fractal model for CHF is found to be a function of wall superheat, the contact angle and physical properties of fluid. The relation between CHF and the number of active nucleation sites is obtained from the fractal distribution of active nucleation sites on boiling surfaces. The contact angle and the physical properties of fluid have the important effects on CHF. The predicted CHF from a boiling surface based on the proposed fractal model is compared with the existing experimental data. An excellent agreement between the proposed model predictions and experimental data is found.