In this study, the main purpose is to analyze the heat and flow characteristics of behavior of dust around the sensor and inside of the sensor by using CFD simulation. We did flow analysis for natural convection caused by high temperature of heater. Lagrangian multiphase analysis was used to simultaneosly analyze the dust particle and air flow. The realizable k-e turbulence model used and discrete element methods (DEM) was used to visualize the movement of dust particles.