Using ANSYS-FLOTRAN CFD program, the finite element simulation is conducted by a series of procedures, such as three-dimensional model building of airflow inclination sensor, network modifying, loads applying and equation solving. The flow field in three-dimensional hermetic chamber of sensitive element of airflow level posture sensor is calculated, FEM analysis has been obtained. The numerical results show that under the buoyancy lift affecting, the direction of nature convection gas always keeps the vertical upward in two-dimensional enclosure, nature convection gas has the pendulum characteristic, and when the dimensional enclosure is inclined, temperature distribution at the several points in dimensional enclosure will change with the tilt angle. The pendulum characteristic can be utilized to measure the level posture by the airflow level posture sensor.
