Modern automobiles are dependent on complex networks of electronic sensors and controls for efficient and safe operation. These electronic modules are tested for stringent environmental load conditions where product validation consists of one or a combination of loads such as Vibration, Mechanical Shock, Temperature, Water, Humidity, Dust, Chemicals, and Radiation. Exposure of electronics to water leads to many harmful effects resulting in the failure of electronic systems. Previously published technical paper [1] SAE 2023-01-0157 described a methodology to estimate risk in a humid environment, where water is dispersed in air as a gas phase. The present paper extends the scope of virtual validation using Computational Fluid Dynamics (CFD) simulation tools to an environment with water in the liquid phase.
In this paper, a non-sealed automotive electronic module subjected to a water drip test is evaluated using the CFD model. A transient 3D multiphase simulation is performed using the Volume of Fluid method (VOF) to simulate water droplets falling on a module mounted as per the test set-up described in ISO 20653. The study focuses on issues related to the simulation of the IPx2 test set-up at a ‘product level’. Computational challenges of performing such assessment are described with emphasis on rapid evaluation of design concepts along with necessary simplification in model and test set-up. ISO standard does not describe the pass/fail criterion objectively hence practical considerations of evaluation criterion are briefly outlined.