Assessment of varying primary/secondary breakup mechanism of diesel spray on performance characteristics of HSDI engine

Fuel spraying process and hydrodynamic interaction of fuel jet-air plays a crucial role in the mixture formation pattern. A baseline diesel engine is considered and based on the operational values of the experimental engine, the geometric and spraying model is designed and meshed. The values of the primary and secondary breakup coefficients are adjustable according to the tested engine. By fixing the geometrical features, different atomization models with related tuning constants are selected to determine the effect of these factors on the spray quality and engine output in terms of combustion and emissions, and to provide a general framework for model performance for the users. In the present study, both the primary breakup and atomization models, as well as the secondary breakup model are considered emphasizing the modification and identification of the functions of these parameters. In the second breakup of the WAVE model is adopted and the C2 coefficient or constant in the range of 10-60 in the 10 steps is launched by the software for each mode, then in the secondary breakup model, KH-RT with a coefficient of C2 = 12 is investigated. In the next step, the primary breakup model of "Core Injection" is evaluated with C1 coefficients between 10 and 50, and its C2 coefficient will be analyzed for the values 15, 25, and 35. It has been understood that there is a linear correlation between equivalence ratio and C2 of secondary breakup with the determination coefficient of R2 = 0.954. Increasing C2 of WAVE results in deceleration in spray droplet strip (dR/dt) such that C2 = 60 gives the biggest SMD, the lowest pressure, heat release rate, and soot amount.