Real Gas Equation Of State Research Articles

Numerical study on the effect of complex structural barrier walls on high-pressure hydrogen horizontal jet flames

Hydrogen has the potential to produce energy with no emissions, and therefore offers a strategic opportunity for rapid development of renewable energy storage. However, jet flames caused by the leakage of high-pressure hydrogen may cause casualties and damage equipment, so the safety issues associated with hydrogen incidents are a key issue restricting its development. Barrier walls can be an important mitigative action to reduce the hazard of hydrogen jet flames. Previous studies have evaluated the protective effect of different vertical or inclined arrangements of a single barrier wall in the vertical direction. However, in the vertical direction, a single barrier wall is not sufficient to reduce the hazards associated with high-pressure hydrogen jet flames. In this paper, a two-dimensional CFD model of high-pressure hydrogen jet flames are established. A simplified form of the hydrogen real gas equation of state is used to describe the complex behavior of high-pressure hydrogen. This CFD study employs the standard k-ε turbulence model, the eddy dissipation concept (EDC) model, and the discrete ordinate (DO) radiation model. The results display good agreement with the experimentally obtained flame shape and thermal radiation values, which confirms the applicability of the model. Based on this model, the characteristics of high-pressure jet flames are systematically studied under different forms of barrier walls and different pressures of hydrogen storage. Compared with the vertical barrier wall, barrier walls with complex structures can block the flames in front of the wall more effectively. This is proven through a remarkable decline in the vertical flame length and a reduction in the high temperature area. Comparing the five barrier wall patterns for their combined flame shape and flame temperature, it is more preferred to choose 60° Plate. The results of this study will help to better analyze the consequences of hydrogen jet flames and provide guidance for better design of barrier walls for mitigation.

Discontinuity in cubic equations of state: Impact of attraction term mixing rule on combustion simulation

High-pressure or cryogenic conditions relevant to hydrogen applications introduce non-idealities in the property of fluid, which requires using real gas equations of state in numerical simulation. However, intrinsic but non-physical discontinuities exist in the partial derivatives with respect to temperature of the molecular attraction term of popular cubic equations of state. This feature is related to the van der Waals mixing rule and results in non-physical discontinuities in the thermodynamic functions and simulation results. Thermodynamic properties of dry air were used to illustrate the impact of discontinuities on the thermodynamic functions whereas steady detonation simulation and constant volume reactor simulation were performed to discuss the impact of the discontinuities on combustion modeling. We show that the accuracy of the solution can be decreased by up to several percents. In addition, an increase of computation cost is induced in the vicinity of the discontinuities when adaptive time-stepping is adopted in the simulation. A correlation previously proposed in the literature to remove the discontinuity issue was tested and proved efficient to limit the decrease of the time-step.

High-pressure supersonic carbon dioxide (CO2) separation benefiting carbon capture, utilisation and storage (CCUS) technology

Carbon capture, utilisation and storage (CCUS) is of unique significance for building a green and resilient energy system, and it is also a key solution to tackle the climate challenge. The concept of supersonic decarburization, a joint product of non-equilibrium condensation and swirling separation, can contribute to CCUS technology in a clean way. In this paper, a numerical model is established and validated to investigate the complex physical phenomena of supersonic decarbonization in a high-pressure environment based on the real gas equation of state. The model is compatible with the pure CO2 model and CH4-CO2 model. Through the simulation of the supersonic nozzle and supersonic separator, the condensation and separation performance of supersonic decarbonization technology was evaluated. For the condensation performance of carbon dioxide, the results show that higher pressure makes it much easier to achieve the condensation process. When the pressure is supercritical, the decrease of inlet temperature or the increase of inlet mole fraction of CO2 leads to a higher liquid fraction. For separation performance, when the mass concentration of inlet heterogeneous droplets increases from 0.1 kg/m3 to 7.5 kg/m3, the carbon separation amount increases from 3.33 ton/h to 4.43 ton/h, while the exergy loss of condensed CO2 drops from 436.57 kJ/kg to 329.56 kJ/kg. It demonstrates that the decarburization process is easier, and exergy required for condensation decreases when the concentration of the foreign core is larger. This new concept is beneficial to CCUS technology and can be applied to carbon capture in offshore natural gas processing.

Numerical investigation of the influence of supersonic flow on muzzle combustion

To further understand a muzzle combustion mechanism in high-altitude firing, the influence of supersonic flow on a muzzle combustion phenomenon is investigated. The set of internal ballistic equations is employed, providing accurate velocity and pressure when the projectile moves to the muzzle. Multispecies transport Navier–Stokes equations with complex chemical reactions are solved by coupling a real gas equation of state, the Soave–Redlich–Kwong model, and a detailed chemical reaction kinetic model. The development of muzzle flow with chemical reaction is simulated. The interaction of chemical reactions with the muzzle flow field is obtained by numerical simulation in order to explain the muzzle combustion phenomenon of fire at supersonic flight. The mechanism of muzzle combustion influenced by supersonic incoming flow is analyzed in detail. It is demonstrated from the results that the shock wave and the expansion of the jet are restrained so that the combustion is compressed behind the projectile, at the same time generating a second region of combustion behind the muzzle under the influence of supersonic incoming flow.

Lumped Parameter Modeling of SAE J2601 Hydrogen Fueling Tests

The safety of hydrogen storage is essential for the development of fuel cell vehicles. A mathematical model for a compressed hydrogen storage tank is established based on the mass conservation equation, the energy conservation equation and the real gas equation of state. Using the Matlab/Simulink platform, a dual-zone lumped parameter model, which divides the tank into a hydrogen gas zone and a tank wall zone, is established. The initial conditions of the MC Default method hydrogen filling from SAE J2601 are utilized in the lumped parameter model for numerical simulation. Five cases are studied, including two different tanks. One case used the Lookup table for hydrogen refueling, and four cases used the MC Default method for fueling. The hydrogen gas temperature, wall temperature, pressure in the tank and state of charge are obtained during the fueling process. The simulated results show that the dual-zone lumped parameter model can well predict the temperature, pressure and state of charge (SOC) for Type IV tanks with volumes of 249 L and 117 L during refueling. By using the averaged heat transfer coefficient (80 W/(m2·K)) between gas and wall, and the constant heat transfer coefficient (20 W/(m2·K)) between wall and environment, the gas temperature and pressure of our dual-zone lumped parameter model show good agreement with the experiment. The maximum difference between simulated and experimental wall temperatures for five cases is around 2 °C. The experimental wall temperatures were measured on the external surface of the tank, while the simulated wall temperature of the dual-zone lumped parameter model is representative of a mean temperature averaged alone with the radial direction.

A relaxation model for the non-isothermal Navier-Stokes-Korteweg equations in confined domains

The Navier-Stokes-Korteweg (NSK) system is a classical diffuse interface model which is based on van der Waals' theory of capillarity. Diffuse interface methods have gained much interest to model two-phase flow in porous media. However, for the numerical solution of the NSK equations two major challenges have to be faced. First, an extended numerical stencil is required due to a third-order term in the linear momentum and the total energy equations. In addition, the dispersive contribution in the linear momentum equations prevents the straightforward use of contact angle boundary conditions. Secondly, any real gas equation of state is based on a non-convex Helmholtz free energy potential which may cause the eigenvalues of the Jacobian of the first-order fluxes to become imaginary numbers inside the spinodal region.In this work, a thermodynamically consistent relaxation model is presented which is used to approximate the NSK equations. The model is complimented by thermodynamically consistent non-equilibrium boundary conditions which take contact angle effects into account. Due to the relaxation approach, the contribution of the Korteweg tensor in the linear momentum and total energy equations can be reduced to first-order terms which enables a straightforward implementation of contact angle boundary conditions in a numerical scheme. Moreover, the definition of a modified pressure function enables to formulate first-order fluxes which remain strictly hyperbolic in the entire spinodal region. The present work is a generalization of a previously presented parabolic relaxation model for the isothermal NSK equations.A high-order discontinuous Galerkin spectral element method which supports curved elements and hanging nodes is employed to discretize the system. The relaxation model and its corresponding boundary conditions are validated using solutions of the original NSK model and analytical results for one-, two- and three-dimensional test cases. The simulation of a spinodal decomposition in a three-dimensional porous structure underlines the capability of the presented approach.

Numerical study of real gas effects during bubble collapse using a disequilibrium multiphase model

An explicit density-based solver of the Euler equations for inviscid and immiscible gas–liquid flow media is coupled with real-fluid thermodynamic equations of state supporting mild dissociation and calibrated with shock tube data up to 5000 K and 28 GPa. The present work expands the original 6-equation disequilibrium method by generalising the numerical approach required for estimating the equilibrium pressure in computational cells where both gas and liquid phases co-exist while enforcing energy conservation for all media. An iterative numerical procedure is suggested for taking into account the properties of the gas content as derived from highly non-linear real gas equations of state and implemented in a tabulated form during the numerical solution. The developed method is subsequently used to investigate gaseous bubble collapse cases considering both spherical and 2D asymmetric arrangements as induced by the presence of a rigid wall. It is demonstrated that the predicted maximum temperatures are strongly influenced by the equations of state used; the real gas model predicts a temperature reduction in the bubble interior up to 41% space-averaged and 50% locally during the collapse phase compared to the predictions obtained with the aid of the widely used ideal gas approximation.

Numerical investigations of thermodynamic states formed near a reacting, supercritical CH[formula omitted]/O[formula omitted] flame

The identification of the correct thermodynamic states forming in supercritical mixing and combustion is an important area of research in engineering. When a multi-component mixture evolves at pressures that are higher than the critical pressures of each individual component, a real-gas (RG) equation of state (EoS) must be used in order to achieve superior accuracy in the predictions. However, this may not be enough when the complex non-linear mixing allows the formation of multi-phase states. The physics and the modeling of multi-phase states occurring at supercritical conditions is the subject of many research efforts and it has already been shown to play in important role when coupled with fluid-mechanics. In this situation, the RG EoS needs to be augmented with a multi-phase model that can predict the formation of pockets of liquid and vapor in a certain region, therefore the presence of “pseudo” phases, commonly discussed in supercritical thermodynamics no longer applies. Currently, the concept of vapor-liquid equilibrium (VLE) seems to be one viable approach to describe this physics. In this paper, we focus the attention on the thermodynamic states formed in the vicinity of a supercritical CH4/O2 flame. In particular, we investigate the occurrence of multi-phase conditions that require state-of-the-art modeling in RG thermodynamics. We provide emphasis about the numerical issues that may occur when inverse thermodynamic problems are solved in presence of VLE (as for example obtaining temperature and pressure out of internal energy, density and overall mixture composition) and how they can be avoided. The VLE model is compared with the corresponding single phase (no VLE) counterpart and the results are analyzed and explained. Finally, we provide an a-posteriori method to explain the role of each component in the formation of VLE states and compare it with zero-dimensional, conventional mixing models. The idea behind this work is to establish the effect of VLE in a relatively simple, canonical configuration, as well as describe a method that helps to understand how these states are formed and how they can be predicted before-hand.

Study on hydrogen dispersion in confined space with complex air supply and exhaust system

The safety issue involving unplanned H2 leakage has retarded promotion of Hydrogen fuel cell vehicles (HFCVs). When an accidental leakage occurs in a relatively closed space, H2 tends to accumulate. It is necessary to obtain a better understanding of the H2 dispersion characteristics in a relatively closed space. Most studies focus on the dispersion features in a small garage, whereas few consider large underground garages with complex ventilation systems. Herein, H2 released from a pressurized tank in a real large underground garage was investigated by a two-stage computational fluid dynamics (CFD) study. An isentropic expansion model with a real gas equation of state was employed in stage (1) to estimate the source strength which can be used as inlet boundary conditions for stage (2), the dispersion stage. The CFD models were validated against the experimental results. The concentration field and flammability envelope were focused. This study provides a feasible method for assessing the risks associated with HFCVs.

Numerical Analysis of the Condensing Steam Flow by Means of ANSYS Fluent and in-House Academic Codes With Respect to the Capacity for Thermodynamic Assessment

In this paper numerical analysis of the condensing steam flow in a converging-diverging nozzle is investigated. The ANSYS Fluent results are compared with the results of the in-house academic Computational fluid dynamics code with respect to the capacity for thermodynamic assessment. The “local” real gas equation of state is used as a mathematical complement of flow governing equations in the in-house code. In the Fluent code, the thermodynamic functions as well as the steam and water physical properties are calculated based on the IAPWS formulation with the use of the UDF. The condensation model with the Fuchs and Sutigin correction of the droplet growth equation and nucleation rate with the Kantrowitz correction is implemented in both CFD codes. The CFD results are compared with the obtained experimental data. The experiment was carried out using an in-house steam facility with a transonic steam tunnel. The investigated geometry is a converging-diverging nozzle as adopted under the International Wet Steam Experimental Project with the diverging section expansion rate of 3,000 s−1 and the total throat height of 40 mm.

Transient mathematical prediction and experimental verification of the charging characteristics of subsea accumulators

This study is focused on the charging characteristics of the subsea accumulators used to provide power for safety on a subsea well. The charging time and storage volume are strictly limited according to API specification for a subsea accumulator system. Long hydraulic lines must be used to cope with the depth of seawater, which will significantly increase the charging time and cause a large pressure drop. In addition, the pressure in hydraulic pump and subsea accumulators used also varies with charging. A transient flow will occur during the charging of the system. In this paper, a systematic transient mathematical model (STMM) of the subsea accumulator charge system is established. The STMM includes three main parts: the air driven liquid pump, the long hydraulic pipeline, and the subsea accumulator. A double-coefficient unsteady friction model based on instantaneous acceleration is applied in the long pipeline model. The Redlich–Kwong real gas state equation is used to calculate the gas in the accumulator. A series of charging experiments for two rated working pressure of 10,000 psi and 15,000 psi on the ground were carried out. The results of the experiment showed very consistently with those of the STMM. The liquid pressure in the accumulator is divided into three stages during charging: rapidly increasing stage, slowly increasing stage, and maintaining constant stage. Moreover, an engineering proposal was presented to reduce the design pressure requirements of the system. Furthermore, the charging time will increase significantly as the length of the pipe increases, but decreases as the inner diameter of the pipe increases. The paper outlines a direction for the design theory and engineering practice of the subsea accumulator charge system.

Numerical simulation of nanosecond laser ablation and plasma characteristics considering a real gas equation of state

Based on the governing equations which include the heat conduction equation in the target and the fluid equations of the vapor plasma, a two-dimensional axisymmetric model for ns-laser ablation considering the Knudsen layer and plasma shielding effect is developed. The equations of state of the plasma are described by a real gas approximation, which divides the internal energy into the thermal energy of atoms, ions and electrons, ionization energy and the excitation energy of atoms and ions. The dynamic evolution of the silicon target and plasma during laser ablation is studied by using this model, and the distributions of the temperature, plasma density, Mach number related to the evaporation/condensation of the target surface, laser transmissivity as well as internal energy of the plasma are given. It is found that the evolution of the target surface during laser ablation can be divided into three stages: (1) the target surface temperature increases continuously; (2) the sonic and subsonic evaporation; and (3) the subsonic condensation. The result of the internal energy distribution indicates that the ionization and excitation energy plays an important role in the internal energy of the plasma during laser ablation. This model is suitable for the case that the temperature of the target surface is lower than the critical temperature.

Turbulent chemical-species mixing in the Venus lower atmosphere at different altitudes: a direct numerical simulation study relevant to understanding species spatial distribution

To evaluate a recent hypothesis of species stratification in the Venus lower atmosphere, a time-dependent, three-dimensional model is proposed for studying turbulent mixing of many species in the Venus lower atmosphere. This model is based on fundamental physics embedding non-equilibrium thermodynamics, the Onsager classical relationship between fluxes and forces, high-pressure transport property calculation and a real-gas equation of state. The conservation equations are self-contained, with no need for coefficients based on parametrizations to match Venus observations. The rationale for solving these equations in relatively small spatial domains at different altitudes in the Venus lower atmosphere is presented. The equations are solved in a temporal mixing layer configuration that is eminently suited to investigate turbulent mixing between two streams of different composition. The adopted simulation method is Direct Numerical Simulation (DNS). A substantial database of DNS realizations is generated for mixtures of two and seven species, with different levels of initial stratification, and at the realistic conditions of pressures and temperatures in the Venus lower atmosphere at three altitudes. High density-gradient magnitude regions (HDGM) are shown to form under initial high stratification conditions, with larger gradient values obtained at low altitudes where supercritical conditions occur. Independent of the altitude lower than 50 km, under low stratification conditions, mixing produces a more uniform spatial distribution of the density than at higher initial stratification. Under low initial stratification conditions, the influence of the minor species on the global behavior of the flow seems to be negligible. At high initial stratification conditions, differences in diffusion of various species play an important role in determining the mixture characteristics. The hypothesis of chemical species separation is discussed in the light of the present results which do not support the existence of stable species separation in the lower Venus atmosphere, independent of the number of species or the altitude.

Flow computation inside a scroll compressor based on open-source code

Computational fluid dynamics (CFD) is an essential tool for improving the performance of positive displacement machines, which are commonly adopted in vapour compression applications. The numerical analysis of such machines is characterized by several modelling challenges. Firstly, the relative motion of the wraps and the presence of particularly small gap sizes need to be considered during the implementation of a reliable meshing strategy. In addition to that, the operating conditions are close to the saturated-vapour line, requiring a real gas equation of state for the determination of fluid thermophysical properties.In this work, a commercial scroll compressor has been simulated at three different operating conditions. The geometrical modelling, meshing strategy and compression process have been obtained thanks to a set of libraries built in OpenFOAM-v2006. The results have been compared with experimental data of the pressure evolution in the compression chambers. Furthermore, a complete fluid flow analysis is presented to assess the capabilities of the developed tool when applied to a compressor operating with R410a.

A comparative investigation of thermodynamic performance and flow field structure of a modified Collins cycle-based helium turboexpander system

The optimum design of radial expansion turbine and nozzle (turboexpander) have a remarkable effect on the thermophysical performance of gas liquefaction cycles. The present study proposes a new mean-line design, sensitivity analysis, and optimization method to develop three turboexpander systems for a modified Collins cycle-based helium liquefaction system. The proposed method deals with the real gas equation of state to determine the turboexpander configurations and their performance at off-design conditions. The mean-line design approach integrated with different loss correlations has been performed using an in-house code in Matlab® environment. Furthermore, sensitivity analysis and artificial neural network-based optimization process of thirteen design coefficients and non-dimensional variables has been carried out which improves the off-design performance of the turboexpander up to 4.43%, 12.57%, and 16.36% for total-to-static efficiency, total losses, and power output respectively. Applying the aforementioned procedure, three turboexpanders have been designed. After that, a three-dimensional transient blade-row turbulent flow simulations have been carried out to stimulate the rotor-stator interaction at different operating conditions (25 bar & 80 K, 7 bar & 50 K, and 25 bar & 30 K) and rotational speeds (2.84 × 105, 1.61 × 105, and 2.75 × 105 rpm) using k-ω shear stress transport turbulence model. The commercial Navier-Stokes finite volume solver ANSYS CFX® has been used to study a comparative thermodynamic performance and flow field structures at different streamwise and spanwise directions of the entire flow passage. Additionally, the present numerical results have been validated with available experimental and computational data in the open literature. The present design, optimization, and numerical procedure presented herein will be advantageous for the future development of efficient small-scale turboexpander systems subjected to wide operating ranges.

Cavitation modelling using real gas state equation: A conceptual study

The prediction of the onset of cavitation to allow investigations of the flow in off-design conditions during design is unavoidable for a variety of applications. Numerical modeling of the cavitation phenomena is however computationally challenging due to the nature of the phenomena. High density ratios, steep pressure gradients, the presence of multiple phase including phase change and hence to occurrence of real gas thermophysical behavior would cause a computational effort unmanageable during design. Today’s models are therefore greatly simplified representations of the reality. Conservation equations are usually solved using a mixture approach with flow properties being a volume fraction weighted average of two incompressible fluids thus neglecting real gas effects. The source term from the phase exchange however usually poses significant stability problems. In this article we will therefore present an approach for cavitation modeling using high-order polynomial real-gas state equations to accurately predict the properties of water at any state. Computational performance is improved by the use of structured tabulation using high order interpolation methods. The numerical results are then compared against measurement data and conventional cavitation model results.

Carnot Engine: A New Look with Different Real Gas Equations

The efficiency of Carnot engine, an important machine in classical thermodynamics, depends only on the temperatures of source and sink reservoirs and is independent of the nature of the working substance. There are several real gas equations which may be used to verify this statement. Here we choose three real gas equations viz. Van der Waal’s, Berthelot’s and Clausius’s real gas equation of state for simplicity for this verification.

Gas–water two-phase productivity model for fractured horizontal wells in volcanic gas reservoirs with natural fractures

ABSTRACT Volcanic gas reservoirs, as new exploration and development fields, are rich in resources and have broad exploration and development prospects. However, compared with the conventional sandstone gas reservoirs, volcanic gas reservoirs have more complex storage and permeability mode, with multiple media including pores, caves and fractures, which determines the strong heterogeneity, complicated seepage mechanisms, and difficult development of volcanic gas reservoirs. To further improve the prediction accuracy of fractured horizontal well productivity in volcanic gas reservoirs, Xushen low-permeability volcanic gas reservoirs are presented as examples herein using the equation of motion based on the principle of equal flow. Considering the stress-sensitive effect, starting pressure gradient, high-speed turbulence effect, and dual porous medium structure, as well as combining the nature of gas and real gas state equations, a gas–water two-phase productivity model is established for a matrix-natural fracture-artificial fracture-wellbore volcanic gas reservoir fractured horizontal well. In addition, factors affecting production are studied. Results indicate that stress-sensitivity coefficient of different media has different effects on the production. The natural-fracture stress-sensitive coefficient has the greatest influence on production. With the increase of the natural-fracture stress-sensitive coefficient, the gas production decreases and the reduction amplitude changes little, which is almost uniform. When natural-fracture stress-sensitive coefficient is 0.08, gas well production decreases by 14.24%. The second is the artificial main fracture stress-sensitivity coefficient. With the increase of the artificial main fracture stress-sensitivity coefficient, the decrease of gas production becomes larger. When artificial main fracture stress-sensitivity coefficient is 0.1, gas well production decreases by 6.6%. The matrix stress-sensitivity coefficient on production is the least, almost zero. The high-speed nonlinear coefficient significantly affected the production. With the increase of the high-speed nonlinear coefficient, the gas well production decreases, and the decrease rate is faster and faster. When the high-speed nonlinear coefficient increases to 10000 m−1, gas well production decreases by 45.65%. However, the starting pressure gradient had little effect on production. Finally, the model is verified by the actual production data of Xushen1-H2 well. The average errors of the gas production, water production, and pressure calculations are 9.65%, 9.63%, and 9.8%, respectively. This study contributes positively to the productivity prediction of fractured horizontal wells in low-permeability volcanic gas reservoirs.

Pore-scale study of non-ideal gas dynamics under tight confinement considering rarefaction, denseness and molecular interactions

Non-ideal gas flow behaviors are investigated by an Enskog-Vlasov type kinetic model considering the simultaneous effects of gas molecule size (volume exclusion) and long-range intermolecular attractions at the molecular level, which corresponds to the real gas equation of state at the macroscopic level. The Knudsen minimum is captured and a local Knudsen maximum may appear if gas molecule sizes or intermolecular attractive forces are considered. Although the Boltzmann equation is applicable to all the flow regimes in rarefied gas dynamics, it is invalid for a dense gas system, such as a tight or a shale gas reservoir. The Boltzmann-BGK model and the Enskog-BGK model overestimate and underestimate the mass flow rate of real gases, respectively, while Guo's model is more accurate to investigate real gas dynamics under tight confinements from a physical perspective. As the channel width increases or the solid fraction decreases, the impact of intermolecular interactions reduces. An anomalous slip regime occurs if both the volume exclusion and long-range intermolecular attraction are considered. Although the rarefaction effect is more prominent at larger Knudsen numbers, the flow at a smaller Knudsen number (a larger solid fraction or channel width) contributes to more practical gas production. The effect of long-range intermolecular attractions on gas dynamics decreases with temperature for real gases. This paper provides a novel insight into the real gas flow characteristics in a dense gas system, such as tight and shale gas reservoirs, from molecular natures of fluids.

Numerical simulation of nanodroplet generation of water vapour in high-pressure supersonic flows for the potential of clean natural gas dehydration

The present study evaluates the potential of clean natural gas dehydration using nonequilibrium condensations in high-pressure supersonic flows. A computational fluid dynamics model is developed to study the formation of massive nanodroplets due to the phase change process. The impact of thermodynamic models on nonequilibrium condensations in supersonic flows is analysed based on the ideal gas and real gas equations of state. The sensitivity of high-pressure supersonic separations under different inlet temperatures is discussed in detail, including the influences on gas processing capacities and nonequilibrium condensation processes. The results show that an ideal gas modelling not only predicts the earlier onset of nonequilibrium condensations but also under-predicts the liquid fraction by 61% compared to the real gas model. The decreasing inlet temperatures improve gas processing capacities and predict the earlier condensing onset inside high-pressure supersonic flows. The liquid fraction can be enhanced by 21% with a decrease of 10 K inlet temperature from 593 K and 583 K. It suggests that the decreasing inlet temperature could improve high-pressure supersonic separations from the view of the processing capacity and separation performance.