Experiments on heat transfer and pressure drop in a horizontal tube with internal solidification

The results of a series of experiments on liquid solidification in the thermal entrance region of a horizontal tube are presented. All involved steady hydrodynamically developed laminar flow with a steady-state frozen deposit at the inside wall, a constant and uniform wall temperature, and a Graetz number in a range of significant natural convection. Heat transfer and pressure drop data is presented to further define the influence of free convection on solidification. It is shown that Oliver's correlation of combined forced and free convection is applicable when the ratio length of test section to internal diameter of tube is significantly greater than 50, and that the correlation is more accurate when corrected for the presence of a solid phase thickness. It is also shown that a parabolic velocity profile should not be used in the analytical prediction of pressure drop when natural convection effects are included. The results of these experiments confirm and strengthen previously reported data and conclusions.