A novel reactor that achieves rapid liquid–liquid mixing via free triple-impinging jets(FTIJs) is developed to improve mixing efficiency at unequal flow rates for liquid–liquid reactions. The flow characteristics of...A novel reactor that achieves rapid liquid–liquid mixing via free triple-impinging jets(FTIJs) is developed to improve mixing efficiency at unequal flow rates for liquid–liquid reactions. The flow characteristics of FTIJs were investigated using particle image velocimetry(PIV). The instantaneous and mean velocities data at different Reynolds numbers(Re) were analyzed to provide insights into the velocity distributions in FTIJs. The effect of jet spacing on the stagnation points, instantaneous velocity, mean velocity, profiles of the x- and ycomponents of mean velocity, and turbulent kinetic energy(TKE) distributions of FTIJs were investigated at Re = 4100 with a volumetric flow rate ratio of 0.5. The characteristics of the turbulent flows are similar for all jet spacings tested. Two stagnation points are observed, which are independent of jet spacing and are not located in the center of the flow field. However, velocity and TKE distributions are strongly dependent on the jet spacing.Decreasing jet spacing increases the expansion angle and the values of TKE, leading to strong turbulence, improving momentum transfer and mixing efficiency in FTIJs. The present study shows that optimization of the operating parameters is helpful for designing FTIJs.展开更多
Experimental tests were conducted to evaluate the hydrodynamic performance of an L-type podded propulsor in straight-ahead motion and off-design conditions using an open-water measuring instrument developed by the aut...Experimental tests were conducted to evaluate the hydrodynamic performance of an L-type podded propulsor in straight-ahead motion and off-design conditions using an open-water measuring instrument developed by the authors for podded propulsors, a ship model towing tank, and under water particle image velocimetry （PIV） measurement systems. Under the three types of conditions, the main parameters of an L-type podded propulsor were measured, including the propeller thrust and torque, as well as the thrust, side force, and moment of the whole pod unit.In addition, the flow field on the section between the propeller and the strut was analyzed. Experimental results demonstrate that the dynamic azimuthing rate and direction and the turning direction affect the forces on the propeller and the whole pod unit. Forces are asymmetrically distributed between the left and right azimuthing directions because of the effect of propeller rotation. The findings of this study provide a foundation for further research on L-type podded propulsors.展开更多
基金Supported by the Graduate Innovation Foundation of Shanxi Province of China(2015BY44)
文摘A novel reactor that achieves rapid liquid–liquid mixing via free triple-impinging jets(FTIJs) is developed to improve mixing efficiency at unequal flow rates for liquid–liquid reactions. The flow characteristics of FTIJs were investigated using particle image velocimetry(PIV). The instantaneous and mean velocities data at different Reynolds numbers(Re) were analyzed to provide insights into the velocity distributions in FTIJs. The effect of jet spacing on the stagnation points, instantaneous velocity, mean velocity, profiles of the x- and ycomponents of mean velocity, and turbulent kinetic energy(TKE) distributions of FTIJs were investigated at Re = 4100 with a volumetric flow rate ratio of 0.5. The characteristics of the turbulent flows are similar for all jet spacings tested. Two stagnation points are observed, which are independent of jet spacing and are not located in the center of the flow field. However, velocity and TKE distributions are strongly dependent on the jet spacing.Decreasing jet spacing increases the expansion angle and the values of TKE, leading to strong turbulence, improving momentum transfer and mixing efficiency in FTIJs. The present study shows that optimization of the operating parameters is helpful for designing FTIJs.
基金Foundation item： Supported by the National Natural Science Foundation of China （Grant Nos. 41176074, 51379043 and 51409063）Acknowledgement This project was supported by the National Natural Science Foundation of China （Grant Nos. 41176074,51379043 and 51409063） and was conducted in response to the great support received from a basic research project entitled ＂Multihull Ship Technology Key Laboratory of Fundamental Science for National Defence＂, which was conducted at Harbin Engineering University. The authors would like to extend their sincere gratitude to their colleagues in the towing tank laboratory.
文摘Experimental tests were conducted to evaluate the hydrodynamic performance of an L-type podded propulsor in straight-ahead motion and off-design conditions using an open-water measuring instrument developed by the authors for podded propulsors, a ship model towing tank, and under water particle image velocimetry （PIV） measurement systems. Under the three types of conditions, the main parameters of an L-type podded propulsor were measured, including the propeller thrust and torque, as well as the thrust, side force, and moment of the whole pod unit.In addition, the flow field on the section between the propeller and the strut was analyzed. Experimental results demonstrate that the dynamic azimuthing rate and direction and the turning direction affect the forces on the propeller and the whole pod unit. Forces are asymmetrically distributed between the left and right azimuthing directions because of the effect of propeller rotation. The findings of this study provide a foundation for further research on L-type podded propulsors.
