Two-dimensional heat transfer distribution in a rotating smooth rectangular channel with four surface heating boundary condition

Abstract

In this study, two-dimensional heat transfer distribution on the leading surface and trailing surface in a rotating smooth channel with typical boundary condition of four surface heating was investigated experimentally for the first time. The Reynolds number, based on channel hydraulic diameter (80 mm) and the bulk mean velocity, ranges from 15,000 to 30,000, and the highest rotation number is 0.359 with the Reynolds number of 15,000. The mean density ratio is about 0.11 in this work. The obtained result showed that rotation has an important effect on the heat transfer distribution along the span-wise direction. On the leading side, rotation-induced secondary flow makes the Nu/Nu 0 at the edge area of the wall surface (Z/D = 0 and Z/D = 1) is higher than that on the middle area (Z/D = 0.5). On the trailing surface, the trend of Nu/Nu 0 ratio along the span-wise direction is reversed. Along the stream-wise direction, the Nu/Nu s ratio increases with the rotation number monotonously on the trailing side. However, on the leading side, with the increase in rotation number, the Nu/Nu s does not decrease monotonously along the stream-wise direction, there is a slight enhancement along the stream-wise direction. The secondary flow induced by rotation enhances Nu=Nu s ratio up to 1.35 on the trailing side and weakens the Nu=Nu s ratio close to 0.75 on the leading side with the Re = 15,000, and Ro = 0.359. More details of two-dimensional distribution of temperature and Nu on the leading and trailing side are shown in this work.