Effects of dimensions on the fluid flow and mass transfer characteristics in wavy-walled tubes for steady flow

Abstract

Flow and mass transfer characteristics in axisymmetric sinusoidal wavy-walled tubes with different dimensions are investigated experimentally. The overall pressure drops are measured with U-manometer, and the measurements of mass transfer rate are performed by the electrochemical method, while the flow patterns are visualized by the aluminum dust method. The results showed that the wavelength and amplitude of the wavy-walled tubes obviously affect the fluid flow and mass transfer characteristics. With the increment of the wave factor Fw, the overall pressure drop increase and thus leads to an earlier shift of transitional flow to turbulence as well as a better mass transfer enhancement. Furthermore, mass transfer enhancement is compared with the corresponding straight-walled tube under equal pumping power condition. It is found that the greater mass transfer enhancement appears at the moderate Reynolds number, and the optimum mass transfer enhancement could be obtained in the wavy-walled tube with Fw = 0.5. Based on the flow visualization results, the characteristics of the flow structures in wavy-walled tube with different dimensions are displayed clearly.