Thermal and Stress Analyses of Ignition Plug During Fuel Droplet Impingement Using Smoothed Particle Hydrodynamics With Multilevel Resolution

Abstract

Abstract. To enable robust ignition of heavy fuels and the operation of compression-ignition (CI) engines at altitude, the use of ignition-assistant (IA) devices, such as glow plugs, is essential. However, this requires using the glow plugs outside of the conditions for which they were originally designed, often with fuel impinging directly on the hot surface. It is important to evaluate the temperature distribution and resulting thermal stress on the ignition plug during fuel injection to ensure its reliability and performance. This work uses a computational approach based on the smoothed particle hydrodynamics (SPH) method; this method is extended to conduct integrated simulations of heat conduction in solids, drop-wall interaction, and resulting heat transfer. Furthermore, a multilevel resolution SPH framework is developed to simulate fuel droplet impingement on a glow plug, capturing the thermal responses with high accuracy and computational efficiency. The model is validated against experimental data for droplet dynamics using F-24 and n-decane for various Weber numbers. A series of parametric studies are then conducted to investigate the influence of droplet loading, droplet diameter, and impact parameter on glow plug surface temperature and localized thermal stresses. Results indicate that higher droplet loading and impact parameters intensify cooling and stress levels, while smaller droplets are more effective in heat extraction from the glow plug. This study highlights the critical role of spray characteristics in thermal performance and provides a simulation tool for designing reliable ignition-assistant devices under demanding conditions.