Hydrodynamic Analysis Of Turntable In Rotary Energy Recovery Device

At present,reverse osmosis desalination technology has become one of the most widely used technology in the field of desalination.The energy recovery device plays a key role in reducing the energy loss in the process of the reverse osmosis desalination,but the energy recovery device technology has not yet been fully localized.The rotary energy recovery device is a new device designed to break the patent monopoly and achieve localization,The author of this paper participated in the structural design and optimization process of the device.The principle used in the rotary energy recovery device is the international mainstream positive displacement principle.Fresh seawater and high-pressure concentrated salt water directly contact in the internal flow passage of the hydraulic cylinder and exchange pressure energy,and the process of pressure energy exchange is controlled by the turntable.The turntable of the rotary energy recovery device is self-balancing and rotating under the action of hydrodynamic forces,so that the pressure exchange is continuously performed,and no additional energy input and control system is required.In order to optimize the structural design and predict the engineering application performance of the device,this paper studies the hydrodynamic characteristics of the turntable based on three aspects:fluid mechanics theory,numerical simulation and related experiment.The specific research content includes the following aspects:(1)Theoretically analyze the relationship between the important performance of the device and the rotation speed of the turntable,and focus on the relationship between the mixing ratio of the device and the efficiency of energy recovery under the influence of rotation speed.And present goals and requirements for controlling the turntable speed.(2)Theoretically analyze the hydrodynamic mechanism of the rotary disk high-pressure runner driving the turntable rotation and derive the mathematical model of the rotary drive torque.By changing the cross-sectional area of the high-pressure annular flow passage of the turntable,the outer diameter of the turntable and the rotational speed of the turntable,the CFD simulation is carried out to investigate the characteristics and laws of the driving torque of the turntable.(3)Analyze the generation mode and location of the rotary resistance torque of the turntable and use the Newton internal friction theory as the theoretical basis to derive the mathematical model of the rotational resistance torque in the laminar flow state.The influencing factors and influence laws of the inertia resistance torque of the inner flow passage of the rotary table and the frictional resistance torque of the clearance flow passage are calculated by CFD simulation.(4)Calculate the driving torque characteristics and resistance torque characteristics of the turntable under different flow conditions by CFD simulation and predict the rotation speed of the turntable to obtain the relationship between the rotation speed and the flow condition.Verify the accuracy of the experimental data by comparing the experimental data with the simulated rotational speed.