Study Of The Flow Field And Condensation Characteristics In A Supersonic Cyclone Separator

Methane makes up the majority of natural gas that is produced from oil fields,along with water,heavy hydrocarbons,and other contaminants.Natural gas with free moisture can create hydrates with heavy hydrocarbons,which can obstruct equipment pipes.Natural gas moisture can combine with acidic gases to cause severe financial losses by corroding pipelines and equipment.Therefore,it is necessary for natural gas dehydration process.The goal of gas-liquid separation is achieved via supersonic cyclonic separation technology,which leverages the temperature drop caused by the fluid’s ultra-high speed movement to condense water vapor.Because of its simplistic design and cost-effectiveness,supersonic separation technology,as a new kind of natural gas dewatering technology,supersonic cyclonic separation technology has aroused the interest of many academics,and the scope of its potential applications is steadily growing.Hence,to further enhance the performance of the supersonic cyclone separator,research on the flow field and condensation features law has important considerable theoretical value and practical significance.In this work,using air-water vapor as the fluid medium,the flow field and condensation properties within the supersonic cyclone separator were explored by a combination of numerical simulation and particle image velocimetry（PIV）experiments.The major work and results are as follows:At the input pressure of 1.86×10⁵Pa（A）,the input temperature of 279.6 K,and the input water steam quality score of 5%,the flow fields and condensation characteristics were compared within the steeped,attached,five-curved three separator structures and the control group without the separator structure.The results show that the number of mahs of the ultrasonic spin separator of the ladder separator structure reached 1.51,the minimum pressure is 2.2×10⁴Pa（A）,resulting in a temperature drop of approximately 100 K.The flow field of the ladder structure separator is most conducive to droplet condensation and growth with a maximum nucleation rate of up of 2.23×10²³kg^-1·s^-1,the droplet diameter of 6.64×10^-3μm and the humidity of0.77%.An exhaustive analysis shows that the trapezoidal splitter structure is superior to the other two structural shapes,and its splitting efficiency is also the highest,reaching 85.6%.The effect of different sizes of discharge port gap on the flow field structure and condensation flow inside the supersonic cyclone separator was analyzed used a numerical simulation system.At the input pressure of 1.86×10⁵Pa（A）,the input temperature of 279.6 K,and the input water steam quality score of 5%,the supersonic cyclone separator with a discharge port gap size of δ=0.5D has better overall performance than the other designs,the minimum pressure in the separator is 1.92×10⁴Pa,the lowest temperature was 136.3 K,the nucleation rate and droplet radius reached 3.18×1023 kg^-1·s^-1and 9.96×10^-3μm,the maximum value of humidity is 0.45%,and separation efficiency up to 81.5%.The influence of operating parameters on the flow field distribution and condensation characteristics inside the supersonic cyclone separator was evaluated.In this study,the pressure loss ratio of 0.5,a temperature of 279.6 K and an inlet water vapor mass fraction of 12.5%were found to be most suitable for droplet condensation and growth.The experimental results of PIV in the velocity distribution in the supersonic nozzle are basically consistent with the simulation results,and the numerical simulation results well reflect the flow characteristics in the supersonic cyclone separator.The experimental and numerical simulation results also show that appropriately increasing the mass fraction of steam at the water inlet and increasing the pressure loss ratio are conducive to the condensation and growth of droplets,and the number of droplets in the supersonic nozzle will increase,which is beneficial for improving the separation performance of supersonic cyclones.