Boiling Heat Transfer Effect Evaluation From Microporous Coated Surfaces In Saturated FC-72

Due to the boiling heat transfer enhancement, microporous coatings have become more widely available for making efficient devices to transfer heat. This paper reports the results of the experiments which systematically investigated nucleate boiling of saturated FC-72 on a plain surface with/without sintered microporous coatings using copper powder. Results demonstrated that, in saturated FC-72, nucleate boiling heat transfer coefficient and critical heat flux (CHF) from microporous coated surfaces were as much as 8.5 and 2 times those on the plain surface. Besides, compared with the plain surface, incipient boiling superheat from microporous coated surfaces was decreased by 60%, and the surface superheat corresponding to the CHF was just the half of that on the plain surface. In saturated FC-72, the effect of surface orientation could be neglected before the advent of the maximum nucleate boiling heat transfer coefficient, occurring at or near the end of the fully developed nucleate boiling region; however, after the maximum, the decline rate of nucleate boiling heat transfer coefficient would increased with increasing surface orientation until the arrival of CHF. Also, the value of CHF decreased with surface orientation increasing. In addition, on the base of some actual demand, compared to the performance of heat transfer enhancement by other microporous coatings with different surface constructional parameters, the optimal microporous coating was finally identified for the saturated FC-72.