Computation of Laminar Heat Transfer in Rotating Rectangular Ducts

Abstract

Cooling passages are often used in the rotor windings of large electrical generators, where the flow channel rotates about an axis parallel to but displaced from its axis of symmetry. In such a rotating passage, Coriolis accelerations and density gradients caused by the heated wall lead to the development of secondary flows which can have strong effects on heat transfer and pressure drop characteristics. Finite difference solutions were obtained for laminar flow of air in a rotating rectangular duct with aspect ratio 2/1, where the duct wall is subjected to a uniform heat flux. The solutions show the effect of rotation on the development of the flow patterns and velocity and temperature variations. Results for Nusselt number and friction factor are presented in both the inlet and fully developed regions over a range of Grashof and Reynolds numbers.