Effect of a Turning Vane on Heat Transfer in Rotating Multipass Rectangular Smooth Channel

Abstract

This paper experimentally investigated the effect of a turning vane on hub region heat transfer in a multipass rectangular smooth channel at high rotation numbers. The experimental data were taken in the second and the third passages () connected by a 180 deg U bend. The flow was radial inward in the second passage and was radial outward after the 180 deg U bend in the third passage. Results showed that rotation increased heat transfer on the leading surface but decreased it on the trailing surface in the second passage. In the third passage, rotation decreased heat transfer on the leading surface but increased it on the trailing surface. Without a turning vane, rotation reduced heat transfer substantially on all surfaces in the hub 180 deg turn region. After adding a half-circle-shaped turning vane, heat transfer coefficients did not change in the second passage before turn, while they were quite different in the turn region and after-turn region in the third passage. Regional heat transfer coefficients were correlated with rotation numbers for a multipass rectangular smooth channel with and without a turning vane.