Research On The Operation Characteristics Of Self-Driven Rotary Energy Recovery Device

There are many technical routes for the energy recovery device of seawater reverse osmosis system,the self-driven rotary energy recovery device stands out among many technical routes because of its stable and efficient characteristics.Based on the principle of positive displacement,the device drives the rotor to rotate through fluid to complete the energy transfer between high-pressure brine and low-pressure seawater in the rotor channel of the device.The energy recovery efficiency is up to 98%,and the market share is increasing year by year.But since rotary displacement energy recovery device patent technology has been firmly in control in the western developed countries represented by ERI company of the enterprise,and costly,in the increasingly fierce competition in the international and global shortage of fresh water resources today,since the localization process of rotary displacement energy recovery device for seawater desalination project in our country’s strategic security very positive meaning.A self-driven rotary energy recovery device is taken as the research object in this paper,using the combination of theoretical analysis and numerical simulation to predict the rotor speed characteristics of the device;According to the speed characteristic curve obtained from the prediction analysis,the fluid flow and pressure pulsation inside the device are simulated to explore the general law of energy dissipation of the device.Finally the energy recovery efficiency of the device for the device efficiency of fluid mechanics and fluid mixing rate of the product,based on the above research results,using component transport model,the internal fluid mixing characteristics of the rotor channel simulation analysis,to explore the rotor of the pore fluid mixed characteristics and the changing rule of the blending ratio In this paper,specific work contents and results are as follows:(1)According to the research results of the existing energy recovery device,a 3D model of the flow components including the rotor sleeve of the upper and lower end disks was constructed.The model was meshed by ICEM-CFD,and the grid-independence was verified.(2)This paper creatively put forward by intercepting the dish among average tangential velocity and the rotor radius linear velocity is the same as the foundation,and by using the FLUENT 6DOF model simulation calculation on rotor characteristics,the theoretical analysis and numerical simulation method of combining the preliminary forecast rotor speed characteristic curve,a new prediction method is given for the displacement energy recovery device speed,and the physical parameters of solid rotor were loaded into FLUENT software in the way defined by UDF.By comparing the speed characteristic curves obtained from theoretical analysis and numerical simulation,it is concluded that the speed characteristic curves predicted bytheoretical analysis and numerical simulation have a high degree of coincidence,and the relative error of the two curves is the largest at the condition of small flow,reaching 14.9%.The maximum rotor speed is proportional to the flow rate of the device,and the device rotor has speed adaptability.(3)Based on theoretical analysis and FLUENT 6DOF model prediction analysis speed characteristic curve,the simulation analysis was carried out on the flow field of measurement under the rated conditions,analysis the reasons of rotary displacement energy recovery device energy loss,it is concluded that the rotary displacement energy recovery device since hydraulic characteristics and pressure fluctuation characteristics,combined with the experimental data validated the reliability of predictions of speed characteristic curve.(4)Based on the rotational speed characteristic curve obtained from theoretical analysis and FLUENT 6DOF model prediction analysis,the fluid mixing model in the rotor passage of the self-driven energy recovery device was established by using the component transport model.NACL mass fraction of the inlet of high-pressure brine and the inlet of low-pressure seawater was set as 6% and 3.5% respectively.The results show that the mixing rate is proportional to the flow rate at a certain speed.Under a certain flow rate,the mixing rate of the device is inversely proportional to the rotational speed,and the mixing rate of the self-driven rotary energy recovery device is adaptive.