Large eddy simulations of reacting and non-reacting transcritical fuel sprays using multiphase thermodynamics
Fathi, M., Hickel, S., Roekaerts, D. (2022)
Physics of Fluids 34: 085131. doi: 10.1063/5.0099154
We present a novel framework for high-fidelity simulations of inert and reacting sprays with highly accurate and computationally efficient models for complex real-gas effects in high-pressure environments, especially for the hybrid subcritical/supercritical mode of evaporation during the mixing of fuel and oxidizer at transcritical conditions.
Rapid multi-component phase-split calculations using volume functions and reduction methods
Fathi, M., Hickel, S. (2021)
AIChE Journal 67: e17174. doi: 10.1002/aic.17174
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.
Multi-component vapor-liquid equilibrium model for LES of high-pressure fuel injection and application to ECN Spray A
Matheis, J., Hickel, S. (2018)
International Journal of Multiphase Flow 99: 294-311. doi: 10.1016/j.ijmultiphaseflow.2017.11.001
We present and evaluate a two-phase model for Eulerian large-eddy simulations (LES) of liquid-fuel injection and mixing at high pressure. The model is based on cubic equations of state and vapor-liquid equilibrium calculations and can represent the coexistence of supercritical states and multi-component subcritical two-phase states via a homogeneous mixture approach.
Multi-component vapor-liquid equilibrium model for LES and application to ECN Spray A
Matheis, J., Hickel, S. (2016)
Proceedings of the 2016 Summer Program, Center for Turbulence Research, Stanford University. (also available online on arXiv:1609.08533)
We present and evaluate a detailed multi-species two-phase thermodynamic equilibrium model for large-eddy simulations (LES) of liquid-fuel injection and mixing at high pressure. The model can represent the coexistence of supercritical states and multi-component subcritical two-phase states.
Large-eddy simulation of nitrogen injection at trans- and supercritical conditions
Müller, H., Niedermeier, C., Matheis, J., Pfitzner, M., Hickel, S. (2016)
Physics of Fluids 28: 015102. doi: 10.1063/1.4937948
Large-eddy simulations (LES) of cryogenic nitrogen injection into a warm environment at supercritical pressure are performed and real-gas thermodynamics models and subgrid-scale (SGS) turbulence models are evaluated. The comparison of different SGS models — the Smagorinsky model, the Vreman model, and the adaptive local deconvolution method — shows that the representation of turbulence on the resolved scales has a notable effect on the location of jet break-up, whereas the particular modeling of unresolved scales is less important for the overall mean flow field evolution. More important are the models for the fluid’s thermodynamic state.
Volume translation methods for real-gas computational fluid dynamics simulations
Matheis, J., Müller, H., Lenz, C., Pfitzner, M., Hickel, S. (2016)
Journal of Supercritical Fluids 107: 422-432. doi: 10.1016/j.supflu.2015.10.004
We report on recent developments within the field of real gas thermodynamics models with particular emphasis on volume translation methods for cubic equations of state. On the basis of the generalized form of a cubic equation of state, a mathematical framework for applying volume translations is provided, allowing for an unified and thermodynamically consistent formulation in the context of computational fluid dynamics simulations.
Large-eddy simulation of coaxial LN2/GH2 injection at trans- and supercritical conditions
Müller, H., Pfitzner, M., Matheis, J., Hickel, S. (2015)
Journal of Propulsion and Power 32: 46-56. doi: 10.2514/1.B35827
Large-eddy simulations are carried out for the coaxial injection of liquid nitrogen and preheated hydrogen at supercritical pressures. A novel volume-translation method on the basis of the cubic Peng–Robinson equation of state is introduced for the use in multispecies large-eddy simulations and is tested for both trans- and supercritical injection conditions.