HEAT TRANSFERS AND PRESSURE DROPS IN ROTATING HELICAL PIPES

Helical pipes are employed extensively in chemical reactors, reservoir s, nuclear generators, evaporators and condensation flow systems as we ll as energy saving applications. In this study, in older to increase the heat-transfer rates in helical pipes of various diameters, the rot ation of the pipes was considered experimentally. An experimental set- up for determining the heat-transfer rates and pressure drops occurrin g, because of the centrifugal effects on the rotating helical pipes, w as designed. The heat-transfer rates and pressure drops were measured for various air-flow rates and helical pipe rotational speeds. Althoug h the rotation caused an increase in pressure drop, heat-transfer capa cities of the helical pipes were observed to improve notably. The Nuss elt numbers rose due to the increases in Reynold's numbers and heat in puts into the system. Beside these, further improvements in heat trans fer were observed with the decreasing curvature diameter of the helica l pipe.