On the numerical behavior of diffuse-interface methods for transcritical real-fluids simulations

Peter, Christine; Wu, Hao; Banuti, Daniel T.; Ihme, Matthias

doi:10.1016/j.ijmultiphaseflow.2019.01.015

Cited by 42 publications

(36 citation statements)

References 60 publications

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“…Under super-or transcritical conditions, this is a major challenge for numerical methods and computational performance since the complex thermodynamics have to be modeled precisely. Recent findings by Ma et al [25] showed that adiabatic and isochoric mixing are respective limits of conservative and quasi-conservative schemes that suffer from numerical approximation errors. Based on these discoveries, high resolution methods with low numerical diffusion are needed to resolve physical mixing correctly.…”

Section: Numerical Consideration and Thermodynamic Modelingmentioning

confidence: 99%

“…For example, an adiabatic mixing is generally defined as a thermodynamic process where mixing is controlled solely by convective transport and is not influenced by any diffusive transport of heat or mass from the surrounding. Investigations in the context of super-and transcritical jet injections were performed by Lacaze et al, Ma and Matheis [23,25,27]. For a given pressure and adiabatic conditions, the specific molar enthalpy is a linear function in the molar composition space with…”

Section: Thermodynamic Mixing Processmentioning

confidence: 99%

“…However diffusive or non-equilibrium thermodynamic effects related to, e.g. Fourier, Fickian, Dufour or Soret contributions are not considered in plots presented in [23,25,27] and Fig. 4.…”

Section: Thermodynamic Mixing Processmentioning

confidence: 99%

“…In fact, heat transfer and species diffusion according to Fouriers and Ficks law can already lead to significant deviations. From a numerical point of view, Ma et al [25] found the adiabatic mixing model to be a limiting case for insufficient spatial resolution for conservative methods. Considering this, an extended analysis of the mixing data with regard to the applicability of the adiabatic mixing model is carried out.…”

Section: Introductionmentioning

confidence: 99%

“…The developments and tools mentioned are used to simulate a specific experimental setup proposed in [7]. The numerical results are interpreted in the context of Ma et al [25].…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

On the Consideration of Diffusive Fluxes Within High-Pressure Injections

Föll

Gerber

Munz

et al. 2020

Notes on Numerical Fluid Mechanics and Multidisciplinary Design

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Mixing characteristics of supercritical injection studies were analyzed with regard to the necessity to include diffusive fluxes. Therefore, speed of sound data from mixing jets were investigated using an adiabatic mixing model and compared to an analytic solution. In this work, we show that the generalized application of the adiabatic mixing model may become inappropriate for subsonic submerged jets at high-pressure conditions. Two cases are discussed where thermal and concentration driven fluxes are seen to have significant influence. To which extent the adiabatic mixing model is valid depends on the relative importance of local diffusive fluxes, namely Fourier, Fick and Dufour diffusion. This is inter alia influenced by different time and length scales. The experimental data from a high-pressure n-hexane/nitrogen jet injection were investigated numerically. Finally, based on recent numerical findings, the plausibility of different thermodynamic mixing models for binary mixtures under high pressure conditions is analyzed.

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Section: Numerical Consideration and Thermodynamic Modelingmentioning

confidence: 99%

Section: Thermodynamic Mixing Processmentioning

confidence: 99%

“…However diffusive or non-equilibrium thermodynamic effects related to, e.g. Fourier, Fickian, Dufour or Soret contributions are not considered in plots presented in [23,25,27] and Fig. 4.…”

Section: Thermodynamic Mixing Processmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…The developments and tools mentioned are used to simulate a specific experimental setup proposed in [7]. The numerical results are interpreted in the context of Ma et al [25].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

On the Consideration of Diffusive Fluxes Within High-Pressure Injections

Föll

Gerber

Munz

et al. 2020

Notes on Numerical Fluid Mechanics and Multidisciplinary Design

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Rapid multi‐component phase‐split calculations using volume functions and reduction methods

Fathi

Hickel

2021

AIChE Journal

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We present a new family of fast and robust methods for the calculation of the vapor-liquid equilibrium at isobaric-isothermal (PT-flash), isochoric-isothermal (VT-flash), isenthalpic-isobaric (HP-flash), and isoenergetic-isochoric (UV-flash) conditions. The framework is provided by formulating phase-equilibrium conditions for multi-component mixtures in an effectively reduced space based on the molar specific value of the recently introduced volume function derived from the Helmholtz free energy. The proposed algorithmic implementation can fully exploit the optimum quadratic convergence of a Newton method with the analytical Jacobian matrix. This article provides all required exact analytic expressions for the general cubic equation of state. Computational results demonstrate the effectivity and efficiency of the new methods. Compared to conventional methods, the proposed reduced-space iteration leads to a considerable speed-up as well as to improved robustness and better convergence behavior near the spinodal and coexistence curves of multi-component mixtures, where the preconditioning by the reduction method is most effective.

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Numerical Simulations of Real-Fluid Reacting Sprays at Transcritical Pressures Using Multiphase Thermodynamics

2023

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Transcritical fuel sprays form an indispensable part of high-pressure energy-conversion systems. Modeling the complex real-fluid effects in the highpressure multiphase regime of such sprays accurately, especially the hybrid subcritical-to-supercritical mode of evaporation during mixing fuel and oxidizer, is essential and challenging. This paper represents a novel numerical framework for accurate and efficient simulations of transcritical sprays. The spray is modeled using a diffuse interface method with multiphase thermodynamics, which couples real-fluid state equations with vapor-liquid equilibrium (VLE) calculations to compute thermo-transport properties. A physically consistent turbulence model for large-eddy simulations (LES) is used, with combustion being modeled via real finite-rate chemistry based on the fugacity of the species. The current method is accurate and free from semi-empirical drop break-up/evaporation models. LES results for the Engine Combustion Network (ECN) Spray-A benchmark demonstrate the potential of the proposed method and its advantages over traditional approaches.

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On the numerical behavior of diffuse-interface methods for transcritical real-fluids simulations

Cited by 42 publications

References 60 publications

On the Consideration of Diffusive Fluxes Within High-Pressure Injections

On the Consideration of Diffusive Fluxes Within High-Pressure Injections

Rapid multi‐component phase‐split calculations using volume functions and reduction methods

Numerical Simulations of Real-Fluid Reacting Sprays at Transcritical Pressures Using Multiphase Thermodynamics

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