Heat Transfer and Liquid Motion of Forced Convective Flow in a Mini-Tube Evaporator for Aqueous Solutions with Nonlinear Surface Energy

摘要

Evaporation heat transfer of aqueous solution with nonlinear surface energy was experimentally investigated. Butanol aqueous solution was adopted as the test fluid. The direction of thermocapillary force in liquid film of nonlinear surface energy solution on a heated surface acts in the same direction to Marangoni force. The aim of the present study is to investigate the effect of the nonlinear surface tension of butanol aqueous solution on the liquid motion and heat transfer in convective boiling in single mini channel. From the convective boiling experiments, it was found that the temperature of the outer surface of the tube was much lower in the case of the butanol aqueous solution at the region where the vapor quality was unity. The liquid motions were also observed by CCD video camera system.