Abstract: The grille is a key component affecting the performance of the duct. For increasing the efficiency of the duct and decreasing the noise, it is studied by simulation that the influence of the performance of the different ducts. The research shows that the air volume of flat grille is larger than that of tubercle grille. After the flat grid is adopted, the air volume is increased by 34 % at the same speed, and the noise decreases significantly at the same air volume. Compared with the tubercle grille, the larger the vertical distance from the blade tip of the plane grid to the flow guides surface, the less the vortex near the fan motor is, and the more flow field is uniformed.

Key words: The cylinder top air condition, The tubercle grille, The flat grille, Simulation