Heat transfer from heated bodies in air-water mist flow. 4th report. An experiment on a horizontal cylinder with uniform wall temperature under the influence of blockage.

Abstract

An experimental study has been made on convective heat and mass transfer from a horizontal heated cylinder in downward flow of air-water mist at a blockage ratio of 0.4. Measured two-phase local heat transfer coefficients agree fairly well with the authors' numerical solutions, obtained previously of the front surface of a cylinder, over the ranges of a mass flow ratio of 0-4.5 ×10-2, a temperature difference between cylinder and air of 10∼43 K, a gas Reynolds number of (7.9∼23)×103, a Rosin-Rammler size parameter of 105∼168μm, and a dispersion parameter of 3.4∼3.7. Heat transfer augmentation, two-phase to single-phase, of over 19 times was attained at the forward stagnation point. As for heat transfer of the rear part of the cylinder, an empirical formula is derived by taking into account the dimensionless governing variables, i.e., coolant-feed and evaporation parameters.