Subgrid Scale Modeling of the Equation of State for Turbulent Flows under Supercritical Conditions

Unnikrishnan, Umesh; Wang, Xingjian; Yang, Suo; Yang, Vigor

doi:10.2514/6.2017-4855

Cited by 16 publications

(4 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Matheis and Hickel 24 used a combined VLE-LES model to study inert mixing of dodecane and nitrogen. For most of the multidimensional numerical simulations carried out in the literature so far, 19,22,[24][25][26][27][28][29][30] a diffuse interface method is used where surface tension effects are neglected.…”

Section: Introductionmentioning

confidence: 99%

Phase separation analysis in supercritical injection using large-eddy-simulation and vapor-liquid-equilibrium

Banuti¹,

Peter²,

Ihme³

2017

53rd AIAA/SAE/ASEE Joint Propulsion Conference

View full text Add to dashboard Cite

Injection at pressures exceeding the propellant critical pressures is typically considered a diffuse interface mixing process rather than a sharp interface break-up. However, this is not necessarily the case in mixtures where the local mixture critical pressure may exceed the value of the pure components. So far, there is no canonical theoretical or computational model to analyze local phase separation under these conditions. In the present paper, we propose to separate the problem into two aspects: determination of local mixture temperature and composition, and analysis of the local thermochemical state. We calculate transport of mass, momentum, energy, and species using a large-eddy simulation (LES) method to obtain an accurate local state. This local state is then assessed via a vapor-liquid equilibrium solution using the Peng-Robinson equation of state. We apply this methodology to three technically relevant mixing problems at propellant supercritical pressures: inert nitrogen/n-dodecane injection, an inert liquid oxygen/gaseous hydrogen shear layer, and a reacting liquid oxygen/gaseous hydrogen shear layer. The last case represents the first phase analysis of a reacting case; we show that it can be reduced to the binary mixing of oxygen and water. Counterintuitively, the reacting LOX/GH2 shear layer is more susceptible to phase separation than the inert mixing case, despite the high temperatures reached in the flame. Finally, we compare the mixture critical loci obtained from the canonical computational fluid dynamics mixing rules with results obtained from vapor liquid equilibrium calculations, and show that both are fundamentally, qualitatively different.

show abstract

Section: Introductionmentioning

confidence: 99%

Phase separation analysis in supercritical injection using large-eddy-simulation and vapor-liquid-equilibrium

Banuti¹,

Peter²,

Ihme³

2017

53rd AIAA/SAE/ASEE Joint Propulsion Conference

View full text Add to dashboard Cite

show abstract

“…DNS model is the most natural approach, where almost 100% of the turbulence flows are resolved, additionally does not require turbulence closure or modeling as RANS. Unfortunate, the DNS is inappropriate for most flows, due to its high computational cost, where the domain of computation must be large enough to capture large scales and the mesh or grid must be sufficiently accurate to capture the smallest scales or eddies (Unnikrishnan et al, 2017). Moreover, the time step should be short to capture the quick time scales related to the smallest eddies.…”

Section: Turbulent Modelsmentioning

confidence: 99%

Comparison among the Turbulence Models to Simulate Flow Pattern over ogee Spillway Case Study (Mandali dam in Iraq)

.¹,

.²

2022

IJCE

View full text Add to dashboard Cite

The spillway is an important structure in the dams, used to pass the flood wave to the downstream safely. In the past decades, Computational fluid dynamics (CFD) has evolved. Research findings have shown the CFD models are a great alternative for laboratory models. According to it, the flow pattern over ogee spillways can be studied in a short time and without paying high expenses. Because the flow over the ogee spillway is turbulent and has a free surface, its properties are complex and often difficult to predict. Therefore, the present paper focuses on the study of turbulence closure models including the standard k-ε, RNG k-ε, k-ω, also, the large-eddy simulation (LES) models, to assess their performance to simulate flow over the spillway. The Flow-3d software with the volume-of-fluid (VOF) algorithm is applied to obtain the free surface for each turbulence model. The results of the analysis show that the LES model yielded better results when compared with laboratory results, while the turbulence closure models result of Reynold average Navier Stocks equations (RANS) was more stable, especially standard k-ɛ and RNG models.

show abstract

“…To study transcritical flows numerically, diffused interface methods have been widely used and different numerical schemes have been adopted [19,20,21,22,23,24,25,26,27,28]. The surface tension force is typically not considered in these solvers.…”

Section: Introductionmentioning

confidence: 99%

Numerical analysis on mixing processes for transcritical real-fluid simulations

Peter

Banuti

et al. 2018

2018 AIAA Aerospace Sciences Meeting

View full text Add to dashboard Cite

The accurate and robust simulation of transcritical real-fluid flows is crucial for many engineering applications. Diffused interface methods are frequently employed and several numerical schemes have been developed for simulating transcritical flows. These schemes can be categorized into two types, namely fully conservative and quasi-conservative schemes. An adaptive scheme which is a hybrid of the two is developed in this study. By considering several numerical test cases, it is shown that different schemes predict distinctly different mixing behaviors. It is shown that the mixing processes follow the isobaric-adiabatic and isobaric-isochoric mixing models for fully and quasi-conservative schemes, respectively, and the adaptive scheme yields a mixing behavior that spans both models. The distinct mixing behaviors are a consequence of numerical diffusion instead of physical diffusion and can be attributed to insufficient numerical spatial resolution. This work provides a better understanding on the interpretation of numerical simulation results and the mixing models that are commonly used to study transcritical flows.

show abstract

Subgrid Scale Modeling of the Equation of State for Turbulent Flows under Supercritical Conditions

Cited by 16 publications

References 34 publications

Phase separation analysis in supercritical injection using large-eddy-simulation and vapor-liquid-equilibrium

Phase separation analysis in supercritical injection using large-eddy-simulation and vapor-liquid-equilibrium

Comparison among the Turbulence Models to Simulate Flow Pattern over ogee Spillway Case Study (Mandali dam in Iraq)

Numerical analysis on mixing processes for transcritical real-fluid simulations

Contact Info

Product

Resources

About