Study of slit wall aspect ratio effect on the flow stability and heat transfer in rotating concentric cylinders
AbstractThe slit wall aspect ratio effect on the flow instability and heat transfer characteristics in Taylor-Couette flow was studied by numerical method, the reliability of the numerical simulation result was verified by PIV experiment. Four different models with aspect ratio of 0.5,0.75,1 and 1.25 were investigated . By comparing the result in different models, it is found the axial size of Taylor vortex increases with the increasing of slit aspect ratio at constant temperature gradient condition, and the slit aspect ratio also has significant influence on the distribution of radial velocity in the annular gap, the fluid radial velocity in model with 0.75 aspect ratio was found has the maximum value among four models. Comparing with the temperature distribution in different slit models, the temperature gradient of the fluid near the inner cylinder to the wall has the maximum value in the model with aspect ratio of 0.75. The average Nusselt number has the largest value in the model with aspect ratio of 0.75. When the aspect ratio is larger than 0.75, the heat transfer ability of the fluid was not strengthened obviously as the further increasing of slit depth. Among four different models in this study, the model with 0.75 aspect ratio has the best heat transfer ability, and the heat exchange between fluid and wall can be strengthened as the increasing of the slit depth in a certain range.
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