Multi-component Gas Condensation Peculiarity In Supersonic Flows

To improve supersonic swirl separator liquefying efficiency and reveal multi-component gas condensation peculiarity in supersonic flows,the paper studied core problems for multicomponent gas condensation flow systematically.Systematic theoretical analysis,numerical simulation and experimental investigation have been carried out for our studies based on the theories of the multicomponent equilibrium,gas dynamics,computational fluid dynamics and thermodynamics.The study main results and innovations are as follows:(1)The revised multicomponent gas condensation models are established.Considering that the classical nucleation theory neglects real gas effects,the SRK equation is adopted and fugacity is introduced to calculate the chemical potential and partial pressure.Moreover,the Tolman model is recommended to revise the effect of droplet radius on surface tension.In order to simplify the droplet growth model,the hypothesis that gas is consumed in some proportion is proposed.The deviation between revised model and experimental results is in 1~2 order of magnitude.(2)The completed mathematical models for multicomponent gas in supersonic condensation flow are developed and thermodynamic relations for gas-liquid mixture in supersonic flow are also deduced.The Euler two-fluid model is used in governing equation and the condensation droplet is introduced in equation by source term.To solve equation,the UDF is used in numerical methods.The simulation results fit well with Lamanna's and Pathak's experiment data,proving the accuracy of the mathematical model.(3)An experimental system is set up to test the gas condensation characteristics under supersonic flow condition.The results show that the pressure distribute results are in good agreement with the numerical results.For unitary gas,the Wilson point tested in experiment is in the front of predicting value,while which is in the rear of calculating value for binary gas.As for condensation parameters,the distribution rules of experiment are agreement with simulation results,and the droplet number deviation between experiment and calculation is in-1.37~-1.58 order of magnitude for unitary gas and in-0.26~-1.84 for binary gas.For droplet radius,the testing values and calculating values are in the same magnitude,which is fit well with Pathak's experiment value.All these prove accuracy of the established mathematical model for multi-component gas in supersonic condensation flow.(4)Based on mathematical models,the multi-component gas condensation and phase transition peculiarity in supersonic flows is obtained,the Wilson's point is predicted accurately,and the effect of different inlet parameters,components or back pressure on condensation process is studied systematically.The results show: increasing inlet temperature or pressure or condensable gas the Wilson point will move to throat section,and the maximum nucleation will rise too;Shock waves will emerge and move to throat section with the pressure ratio increasing,causing nucleation condition damaged and nuzzle outlet humidity reduce.For recycling pressure energy as much as possible and undamaging nucleation environment,the maximum pressure ratio should less than 0.5.Comparing with unitary gas,the Wilson point of binary gas is closer to throat,and condensation process of binary is severer.Further analysis reveals that,when binary gas condensing,if the droplet can be soluble with each other,the two gas condensation process can be promote with each other.