A fundamental understanding and simulation of fuel atomization, phase transition, and mixing are among the topics researchers have struggled with for decades. One of the reasons for this is that the accurate, robust, and efficient simulation of fuel jets remains a challenge. In this paper, a tabulated multi-component real-fluid model (RFM) is proposed to overcome most of the limitations and to make real-fluid simulations affordable. Essentially, a fully compressible two-phase flow and a diffuse interface approach are used for the RFM model, which were implemented in the CONVERGE solver. PISO and SIMPLE numerical schemes were modified to account for a highly coupled real-fluid tabulation approach. These new RFM model and numerical schemes were applied to the simulation of different fundamental 1-D, 2-D, and 3-D test cases to better understand the structure of subcritical and transcritical liquid–gas interfaces and to reveal the hydro-thermodynamic characteristics of multicomponent jet mixing. The simulation of a classical cryogenic injection of liquid nitrogen coaxially with a hot hydrogen jet is performed using thermodynamic tables generated by two different equations of state: Peng–Robinson (PR) and Soave–Redlich–Kwong (SRK). The numerical results are finally compared with available experimental data and published numerical studies with satisfactory agreement.

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The substitution of diesel by cleaner renewable fuels such as short-chain alcohols in dual-fuel internal combustion engines is considered an attractive solution to reduce the pollutant emissions from internal combustion engines. In this context, accurate and robust two-phase flow models taking into account the real fuel thermodynamics are required to predict the phase change and mixing processes when various fuels are injected in sub-transcritical conditions. The present study proposes an efficient Real-Fluid model (RFM) based on a two-phase fully compressible four-equation model under mechanical and thermal equilibrium assumptions and closed by a thermodynamic equilibrium tabulation approach. Compared to previous research limited to binary mixtures tabulation, the proposed tabulation approach can further handle ternary mixtures using four-dimensional (4D) tables. In this article, the RFM model has been applied to compare the evaporation and mixing of n-dodecane droplets in single and bi-component ambient. For the single component nitrogen ambient, the numerical results compare well with recent experiments. Finally, n-dodecane droplets evaporation in a bi-component (nitrogen and methanol) ambient relevant to dual-fuel engines have been explored using the Cubic Plus Association (CPA) equation of state. It was found that the initial presence of methanol in the ambient strongly accelerates the mixing process.

Accurate, robust, and fast fully compressible real-fluid simulation of fuel jets is today's one of the highly debated topics in various research laboratories and industries. Indeed, the use of real-fluid equations of state has proved to be computationally very expensive and is one of the current challenges. In this paper, a thermodynamic equilibrium tabulation approach is proposed to overcome most of the limitations and to make real-fluid simulations affordable in the industry. This tabulation approach is implemented in the Converge software as a closure to the fully compressible two-phase and multi-component real-fluid model (RFM). This modeling approach has been applied to the simulation of a classical cryogenic injection of liquid nitrogen (LN2) coaxially with warm hydrogen (H2) jet, in a transcritical regime using thermodynamic tables generated by two different equations of state: Peng-Robinson (PR), and Soave-Redlich-Kwong (SRK). The numerical results are compared to available experiments and published numerical studies. The computational efficiency, accuracy, and robustness of the proposed RFM model are thereby confirmed.