General semi-empirical correlation for condensation of vapor on tubes at different orientations

Analytical and experimental investigations for condensation of saturated vapor on smooth tube at different orientations are presented. An analytical model was developed starting from mass, momentum and energy equations. The model was solved analytically by the method of characteristics with the aid of a computer program. In the experimental work, heat transfer due to film wise condensation of saturated steam on smooth tube has been investigated for different tube inclinations. Seven series of experiments were conducted at tube inclination angles of 0°, 10°, 20°, 30°, 45°, 60° and 90° with the vertical. Variation of Nusselt number with temperature difference and inclination angles are investigated from the theoretical and experimental results. Both experimental and theoretical results showed the increase of the Nusselt number with the decrease of the temperature difference and the increase of the tube inclination angle from the vertical. Comparison between the experimental and theoretical results showed fair agreement for vertical and horizontal tubes. However, the deviation increased with tilting the tube from horizontal or vertical position. General semi-analytical correlation was deduced from the experimental and theoretical results to fairly predict the Nusselt number for any tube inclination.