Study on Laminar Mixed Convection of Developing Flow in Vertical Pipe

Experiments on laminar mixed convection in a vertical pipe were performed for the Re range 1,000-3,000, fir Gr (H) range 10(5)-10(8), the Pr range 2,000 7,000, and aspect ratio range 1-7. Using the analogy concept, heat transfer systems were simulated by mass transfer systems. A cupric acid copper sulfate electroplating system was adopted as the mass transfer system, and the mass transfer rates were measured. The measured Nu values were far grater than those previously reported because of the large value of Pr in this experiment. As the aspect ratio in this study was not sufficiently large for fir flow to be fully developed, the test results were similar to those for mixed convection on a vertical plate rather than that inside a long vertical pipe. It was concluded that the behavior of laminar mixed convection of a developing flow in a vertical pipe at a low aspect ratio and low Gr(H) is similar to that of laminar mixed convection in the vertical plate. As the aspect ratio and Gr(H) increase, the laminar mixed convection phenomena becomes similar to that observed in a fully developed flow in fir vertical pipe.