1994 Volume 34 Issue 10 Pages 777-783
Convection heat transfer coefficient between a spherical particle and a liquid was measured for the range 50<Rep<5000 and the applicabilities of empirical equations proposed previously to the estimation of convection heat transfer coefficients of solid-liquid system were investigated experimentally. An aluminum sphere, 32 mm in diameter, which was kept at about 60°C initially was dipped into a flow of water at about 25°C and the temperature change of the sphere was measured. The heat transfer coefficient was obtained from the temperature drop curve of the solid. The relationship between the Nusselt number, Nu, and the Reynolds number, Rep, was obtained from the results.
Convection heat transfer coefficients at several flow systems were measured and the applicability of the equation corrected for the liquid velocity in the bed was examined. For packed bed system, it was found that the local velocity around a sphere became comparatively large, and convection heat transfer coefficients for packed beds tended to become large.