Analysis of Mixed Convection inside an Automotive Headlamp: 3rd Report, Prediction of the Condensation on the Surface of the Parts

In the former study, a method called FSI-DM was developed. This FSI-DM is the method of connecting fluid and solid parts using a discontinuous mesh, and the density of the mesh inside the solid and the fluid can be changeable. The temperature results by CFD were within ±7 degrees ascompared with the experimental results. In the present study, in order to predict a vapor condensation, the analogy was assumed between heat transfer and vapor transfer in the boundary layer formed on the surface of the parts inside a headlamp and transport equations of velocity, temperature and vapor concentration was analyzed. As the results, after turn on the bulb, the moisture was once emitted from plastic parts to fluid inside the headlamp, and moisture concentration of fluid became rise. In such stage, by cooling down the surface of the lens, the fog on the surface of the lens arose.