Analysis of Thermal Stress on Silicon Nitride Surface Caused by Drop-Wall Interaction at Engine Conditions

The phenomenon of drop-wall interaction plays a crucial role in a wide range of industrial applications. When liquid droplets come into contact with a high-temperature surface, it can lead to thermal shock due to rapid temperature fluctuations. This abrupt temperature change can generate thermal stress within the solid wall material. If the thermal stress exceeds the material's strength in that specific stress mode, it can result in material failure. Therefore, it is imperative to delve into the evolving temperature patterns on high-temperature surfaces to optimize material durability. This study focuses on investigating drop-wall interactions within the context of engine environments. To achieve this, the Smoothed Particle Hydrodynamics (SPH) method is employed to simulate the impact of fuel droplets on a silicon nitride wall. The goal is to understand the heat transfer mechanisms, thermal penetration depths, and temperature distributions within the heated wall. Furthermore, this research explores the performance of ceramic materials, specifically silicon nitride, in terms of thermal stress. Thermal stress calculations are derived from temperature gradients and material properties. Results show that the silicon nitride glow plug can operate for infinite engine cycles if it is run under the relevant engine conditions.