Transcritical real-fluid effects on dual-fuel combustion of methane and n-dodecane
M. Fathi, D. Roekaerts, S. Hickel (2025)
Applications in Energy and Combustion Science 24: 100398. doi: 10.1016/j.jaecs.2025.100398
A comprehensive unified framework of high-fidelity physical models and numerical simulation techniques for transcritical dual-fuel combustion systems is presented and applied for the analysis of three configurations, each involving injection of an n-dodecane jet into a 6 MPa, 1000 K environment. The cases differ in ambient composition: (1) a single-fuel baseline consisting of air mixed with combustion products, and (2–3) two dual-fuel cases with either methane or a 90:10 (by volume) methane/ethane blend added to the ambient.
Effects of intense strain on flame structure and NOx generation in turbulent counterflow lean-premixed hydrogen flames
M. Fathi, S. Hickel, N.A.K. Doan, I. Langella (2025)
Combustion and Flame 282: 114459. doi: 10.1016/j.combustflame.2025.114459
This work examines for the first time in detail the coupled effects of strain and turbulence in hydrogen flames, for various conditions spanning different signs of the Markstein length and increasing applied strain levels. In particular, it clarifies the different roles of applied strain, turbulence-driven strain, and curvature on both flame structure and NOx generation. Results show for the first time that both in-flame and post-flame NOx can be suppressed at high strain levels under turbulent combustor-relevant conditions by straining the flame.
Large eddy simulations of transcritical e-fuel sprays using real-fluid multiphase flamelet-based modeling
M. Fathi, S. Hickel, D. Roekaerts (2025)
Combustion and Flame 281: 114360. doi: 10.1016/j.combustflame.2025.114360
This work introduces a modeling technique for the use of transcritical counterflow flames in flamelet modeling, expanding the capabilities of large-eddy simulations with multiphase thermodynamics (LES-MT) to accurately modeling transcritical combustion. By incorporating real-fluid effects and two-phase interactions, the transcritical flamelet library provides a high-fidelity representation of the complex behaviors in high-pressure multiphase autoignition scenarios. This calibration-free approach can significantly improve our understanding of the transcritical combustion of emerging fuels such as OME3 or their combination with traditional fuels such as n-dodecane.
Dynamic multi-level load balancing for scalable simulations of reacting multiphase flows
G. van den Oord, V. Azizi, M. Fathi, S. Hickel (2025)
Int. J. of High Performance Computing Applications 39: 519-531. doi: 10.1177/10943420251329199
We have addressed the uneven computational load arising from chemical reactions and multiphase thermodynamics in INCA by dynamically offloading work to underutilized cores. The implementation is highly abstract, enabling the use of independent dynamic load balancers for the chemistry and thermodynamics components within INCA.
Numerical simulation of transcritical multiphase combustion using real-fluid thermochemical and transport properties
M. Fathi, D. Roekaerts, S. Hickel (2025)
Combustion and Flame 275: 114055. doi: 10.1016/j.combustflame.2025.114055
Large eddy simulations of reacting and non-reacting transcritical fuel sprays using multiphase thermodynamics
M. Fathi, S. Hickel, D. Roekaerts (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
M. Fathi, S. Hickel (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.
Three-dimensional reacting shock-bubble interaction
F. Diegelmann, S. Hickel, N.A. Adams (2017)
Combustion and Flame 181: 1339-1351. doi: 10.1016/j.combustflame.2017.03.026
We investigate a reacting shock–bubble interaction through three-dimensional numerical simulations with detailed chemistry. The convex shape of the bubble focuses the shock and generates regions of high pressure and temperature, which are sufficient to ignite the diluted stoichiometric H2-O2 gas mixture inside the bubble. We study the interaction between hydrodynamic instabilities and shock-induced reaction waves at a shock Mach number of Ma = 2.83.
Shock Mach number influence on reaction wave types and mixing in reactive shock-bubble interaction
F. Diegelmann, S. Hickel, N.A. Adams (2016)
Combustion and Flame 174: 85-99. doi: 10.1016/j.combustflame.2016.09.014
We present numerical simulations for a reactive shock–bubble interaction with detailed chemistry. The convex shape of the bubble leads to shock focusing, which generates spots of high pressure and temperature. Pressure and temperature levels are sufficient to ignite the stoichiometric H2–O2 gas mixture. Shock Mach numbers between Ma = 2.13 and Ma = 2.90 induce different reaction wave types (deflagration and detonation).
On the pressure dependence of ignition and mixing in two-dimensional reactive shock-bubble interaction
F. Diegelmann, V. Tritschler, S. Hickel, N.A. Adams (2016)
Combustion and Flame 163:414-426. doi: 10.1016/j.combustflame.2015.10.016
We analyse results of numerical simulations of reactive shock-bubble interaction with detailed chemistry. The interaction of the Richtmyer–Meshkov instability and shock-induced ignition of a stoichiometric H2-O2 gas mixture is investigated. Different types of ignition (deflagration and detonation) are observed at the same shock Mach number of Ma = 2.30 upon varying initial pressure.