Development of a wall jet model dedicated to 1D combustion modelling for CI engines Alejandro Aljure Osorio , Xavier Tauzia and Alain Maiboom Abstract Diesel engines are becoming smaller as technology advances, which means that the fuel spray (or jet) interacts with the cylinder walls before combustion starts. Most fuel injection 1D models (especially for diesel fuel) do not consider this interaction. Therefore, a wall-jet sub-model was created on an Eulerian 1D diesel spray model. It was calibrated using data from the literature and validated with experimental data from a fuel spray impacting a plate in a constant volume combustion chamber. Results show that the spray moving along the wall has a higher mixing rate but less penetration as an equivalent free jet, therefore they show a similar volume. Spray-wall interaction creates a stagnation zone right before the impact with the wall, and friction of the jet with the wall is relatively low. All these phenomena are well cap- tured by the wall-jet sub-model. Keywords 1D model, diesel spray, wall jet interaction, IC engine, CI combustion 1. Introduction Diesel Engines are widely used all over the world, either for heavy-duty applications such as truck or marine propulsion, off-road and power generation, or for light-duty automotive propulsion. Due to Diesel-gate the share of Diesel car has dropped but was still at 30% in Europe in 2020. 1 In the medium term Diesel engines appear as promising solutions for heavy duty applications since they can be easily decar- bonized if they use biofuels or synthetic fuels. 2,3 However, in this context, a further increase in engine efficiency and keeping pollutant emission (mainly NOx and particles) under control is even more challenging. 4,5 Therefore, it is of major importance for engine design and calibration to have simulation tools available which combine good accur- acy and limited computational effort so that a lot of options can be tested. In particular the modelling of the spray is crit- ical. 6 In the past years, the authors have developed a 1D combustion model that was successfully validated against measurement in bombs with free Diesel jets. 7–10 However, combustion chambers of Diesel engines are quite confined so that the jet interacts with the wall well before the end of combustion. Consequently, the develop- ment of a wall jet model was undertaken and is presented in this paper. In a first section, a literature review is per- formed to analyse existing studies on wall/jet interaction. Then, after a short description of 1D combustion model pre- viously developed by the authors, the wall/jet model is detailed, with main assumptions, equations and calibration process. Finally, results are discussed and compared with experiments. 2. Literature Review 2.1. Early Works When a fluid jet impacts (or impinges on) a surface, the outward flow is termed a “wall jet” (Figure 1). This term was first introduced by Glauert in 1956, 11 and later used (with variations such as “partially open jet”, “surface jet” and “submerged jet) by Poreh 12 and others. Neglecting compressibility, Glauert divided the wall jet section profile in two overlapping parts: an inner part (in contact with the wall) and an outer part (in contact with the sur- rounding environment), as seen in Figure 2. The inner part is dominated by friction forces with the wall (like an ordinary boundary layer flow) and the outer part is domi- nated by free mixing with the surrounding media (like a free jet). The solutions for the velocity of both parts were Ecole Centrale de Nantes, LHEEA, BP 92101, 44321 Nantes Cedex 3 Corresponding author: Xavier Tauzia, Ecole Centrale de Nantes, LHEEA, 1 rue de la noe, 44321 Nantes Cedex 3, France. Email: xavier.tauzia@ec-nantes.fr Original Research Article International Journal of Spray and Combustion Dynamics 2021, Vol. 13(2–3) 146–163 © The Author(s) 2021 Article reuse guidelines: sagepub.com/journals-permissions DOI: 10.1177/17568277211059073 journals.sagepub.com/home/scd