Effects of inclination angle on pool boiling heat transfer of near horizontal tubes

An experimental study is performed to identify the effect of inclination angle on pool boiling heat transfer of a nearly horizontal tube. For the test, three stainless steel tubes having a smooth surface and the water at atmospheric pressure are used. The effect of inclination angle, ranging from 0° to 12°, on heat transfer depends on the ratio of the length divided by the diameter of a tube. The inclination angle changes the amounts of liquid agitation and bubble coalescence. A distinct change in heat transfer is observed when the inclination angle and the ratio have higher values. To evaluate the inclination effect on heat transfer an empirical correlation, which predicts the experimental data within ±10%, is newly suggested.