Influence of Non-Uniform Wall Temperature on Local Heat Transfer Coefficient in a Rotating Square Channel

This paper presents the results of an experimental examination of the effect of non-uniform wall temperature on local heat transfer coefficient in a rotating smooth-walled square channel. Three different thermal boundary situations were investigated: (a) even and odd (four) wall uniform temperature, (b) even and odd (four) wall uniform heat flux, and (c) even (leading and trailing) walls hot with two side walls kept cold. It is demonstrated that the local heat transfer coefficients on the trailing edge are much higher than that of the leading edge. For situation (a) of even (leading and trailing) walls with two sides uniform temperature, the leading edge heat transfer coefficient decreases and then increases with increasing rotational numbers. And the trailing edge heat transfer coefficient increases monotonically with rotational numbers increasing. However, the trailing edge as well as the side walls heat transfer coefficient for situation (b) is higher than situation (a) and the leading edge local heat transfer coefficients for situations (b) and (c) are significantly higher than situation (a). The obtained results suggest that the local non-uniform wall temperature creates the local buoyancy force that diminishes the effect of the Coriolis force. Consequently, the local heat transfer coefficients on leading, trailing, and side edges are affected by the wall non-uniform temperature.