Thermomechanical Analysis of an Ignition-Assistance Device Due to Fuel Spray Impingement Using the Smoothed Particle Hydrodynamics Method

Abstract Accurate prediction of the ignition-assistance device's thermomechanical response during fuel spray impingement is essential for understanding ignition reliability in aviation compression-ignition engines. This work presents a thermomechanical analysis of an ignition-assistance device under transient interaction with F-24 fuel droplets using a smoothed particle hydrodynamics (SPH) framework. The computational model captures liquid–solid heat transfer and droplet dynamics during film boiling at elevated surface temperatures. To accurately represent heat transfer in the film-boiling regime, a novel heat transfer model is incorporated alongside a multilevel resolution strategy that reduces computational cost while preserving local accuracy. A parametric study is performed to evaluate the influence of key injection characteristics, including droplet size, fuel loading, and impact parameter, on the resulting surface temperature and thermal stress evolution. The results show that increasing any of these parameters leads to larger maximum temperature decreases and corresponding increases in the thermal stress levels. Overall, the study provides a physics-based characterization of ignition-assistance device cooling during fuel impingement and establishes a computational foundation for future investigations of ignition-assistance device thermal processes.