Research On Flow Fields And Experimentation Of Supersonic Gas Separator With Hybrid Drainage Structure

As a new type dewatering technology in recent years,the supersonic separator cools down by gas expansion,condenses the components with higher condensation points in the gas into droplets and separates it by the strong centrifugal force.The technology simplifies the system process,has the advantages of low investment,no rotating parts,and high isentropic efficiency.Therefore,the supersonic separator has wide application prospects in the gas process.In the separation process of the conventional supersonic separator,the shockwave easily occurs in the nozzle expanding section before the cyclone,the low temperature section is short.And because of the airflow passes through the drainage structure at high speed,the short residence time makes the discharge of the condensate difficult.Based on this,this paper aims to the structure improvement of the supersonic separator,which helps to improve the refrigeration performance and separation efficiency of the separator.The main research work and conclusion are as follows:?1?The design methods of the key parts was studied?the area ratio of throat?swirl generator and throat transition segment?.The numerical simulation method was used to compare and analyze the Laval nozzle throat transition segment of different curved profiles.The results indicate that the exponential function transition curve has a slightly smaller centrifugal acceleration than the other two transition forms,but has a higher Mach number,a lower temperature,and a smaller shock loss.Therefore,this paper uses the exponential function curve transition structure.?2?The three-dimensional numerical simulation model of the two-stage drainage supersonic separator was established,and the optimization effect of the new drainage structure on the flow field was studied.The other key structural parameters and operating parameters were studied for the continuous flow field of the separator.The influence of pressure,temperature,Mach number and other parameters were obtained and the optimal structural parameters and operating parameters were determined.The results show that the two-stage supersonic separator has the optima l flow characteristics when the pressure ratio is1.75 and the area ratio is 1.424.And the shock position is greatly shifted back?718mm?,and the minimum Mach number of the nozzle condensation section is reached to 1.34,the static temperature is constant at around 220K.?3?Combined with the discrete phase model?DPM?,the motion of the particles inside the two-stage drainage supersonic separator and the different structural parameters,operating parameters?pressure and particle concentration?and separation efficiency under the drainage structure were studied.The results show that the separator has a good separation effect for droplets above 5?m.Compared with the traditional drainage structure,the new two-stage drainage structure can significantly improve the separation efficiency of the separator.?4?A supersonic separator with the new hybrid drainage structure is set up to investigate the separation performance of the supersonic gas separator under different operating and structural parameters,especially with different drainage structures.The experimental results show that with the increase of the pressure ratio,the separation efficiency increases first and then decreases.When the pressure ratio is fixed,the separation efficiency increases first and then decreases with the increasing of the area ratio.And the separation efficiency also has a similar trend with the blade exit angle,and both increase first and then decrease.The two-stage drainage supersonic separator has improved separation efficiency compared with the traditional drainage structure.The separation efficiency reaches the maximum when the pressure ratio is 1.75?the area ratio is 1.424,and the cyclone exit angle of 55°.The ethanol removal rate?_ETHTH reaches to 53.14%,which is 1.62 times higher than the traditional drainage structure.