Experimental study on single-phase flow resistance characteristics of rectangular channels with lateral non-uniform heating

The state-of-the-art studies on single-phase flow and hear transfer in narrow rectangular channels shows some difference with the conventional theory. In this paper, the experimental study of vertical upward flow resistance of single-phase water in rectangular channels is carried out under isothermal and non-isothermal conditions. The purpose of this study is to reveal the flow resistance of narrow rectangular channels and focus on the effect of transverse non-uniform heating. The geometric dimensions of the test section are as follows: depth 2.0 mm, aspect ratio 30. The experimental results show that the friction coefficient of rectangular narrow channel under isothermal condition is obviously larger than that of conventional channels, and the transition zone is 2600 < Re < 3400. The frictional resistance coefficient under non-isothermal conditions is slightly smaller than that under isothermal conditions. The transition zone is 2800 < Re < 3600, with slight hysteresis. The frictional coefficient under different non-isothermal conditions shows a large dispersion, especially in the transition zone. By introducing the viscous ratio correction, the results show good consistency.