Air curtain dust-collecting technology: Influence factors for air curtain performance

Abstract Air curtains are extensively used to isolate and control dust, heat, and smoke. Because of the high airflow velocity, columnar air curtains have several shortcomings, such as the nonuniform distribution of air, deviation from the axis, and the lack of a basis for determining the volume of the air curtain unit. Existing research cannot systematically explain the factors that directly influence these shortcomings. Therefore, this study employed a single factor design for investigating the effects of the spacing between guide vanes in the air curtain unit, cross sectionof the air curtain unit, and angle of the guide vanes on the air curtain uniformity, deviation, and volume of the air curtain unit, as well as the jet attenuation. The results show that the guide vanes can be used for shunting and diverting the airflow mechanically, the guide vanes with smaller spacing exhibit considerable mechanical diversion, which can lead the air flow out of the supply air slot in a timely manner, as well as reduce the downstream air flow and the overall static pressure difference of the air curtain unit to maintain a uniform air velocity. The cross section of the air curtain unit influences the uniformity of the air curtain. A wedge-shaped air curtain unit can ensure that the velocity of the internal airflow remains constant when the flow of air in the duct decreases gradually. This causes a drastic decrease in the pressure gradient in the air curtain unit, and an improvement in the overall uniformity of the air curtain unit. The deflection of the air curtain is affected directed by the angle of the guide vane, and the deflection is determined by the combined velocity direction of the mechanical deflection due to the guide vane and the non-mechanical air flow driven by the static pressure. The angle between the inside and outside of the symmetrically installed guide vane is 136°, and a jet of air curtain with a small inclination (≤8°) can be formed. The attenuation law of the air curtain jet may be approximately represented by a new correlation, and helps in the selection of air curtain velocity and range in different industrial applications.