Huang C., Lin Y., Li B., Gou J., Wang W., Chen K., Yang X., Zhou H., 2020, Experimental Study on the Drag Reduction of Surfactant and Microgrooves, Chemical Engineering Transactions, 81, 1261-1266.
In the drag-reducing surfactant solution, the scale of near-wall vortices could be enlarged, and the drag reduction mechanism of longitudinal microgrooves was related to the scale of near-wall streamwise vortices. The drag reduction mechanisms of surfactant and microgroove might be complementary. In this study, the collaborative drag-reducing performance of surfactant and microgroove was verified by experiment. The collaborative drag-reducing performances of 0.16 - 0.47 mmol/L CTAC/NaSal surfactant solution in two longitudinal microgroove channels at different temperature were investigated. It is found that the drag reduction effect of surfactant solution can be enhanced by microgrooves at 20 °C, and compared with the smooth channel. The maximum drag reduction rate was increased by 5 % for G1 channel and 8 % for G2 channel for 0.22 mmol/L CTAC solution. The critical temperature Tc and critical Reynolds number Rec of drag-reducing surfactant solution in G1 channel are lower than that in G2 channel, but they are almost the same for G2 channel and smooth channel. The drag-reducing size of microgroove could be enlarged in the drag-reducing surfactant solutions. The collaborative drag-reducing mechanism between surfactant and microgroove might be that the scale of near-wall vortices was enlarged in surfactant solutions, resulting in that microgrooves could restrict more near-wall streamwise vortices and maintain the drag reduction performance in higher Reynolds number.
