Parametric study on the performance of an air curtain based on CFD simulations - New proposal for automatic operation

This paper presents a parametric study on the performance of an air curtain installed over an access door of a refrigerated room. The aim of this work is to quantify, in an integrated way, the influence of the following geometrical and dynamic parameters: door height; temperature difference between rooms, nozzle thickness; initial orientation angle; jet discharge velocity. A numerical model was used to simulate the turbulent non-isothermal 3D airflow generated in the transient period after the door is opened, with the air curtain device turned on or off. Turbulence effects were taken into account with the k-ω SST model. Results show that the optimum discharge velocity of the air curtain increases with the door height, as well as with the temperature difference between both sides of the air curtain. It was also possible to find an optimum jet nozzle width corresponding to maximum sealing efficiency and lower jet airflow rate. A proposal is made for an empirical correlation to predict the optimum jet discharge velocity as function of the variables used in the parametric study. Additionally, to ensure that the air curtain operates near the optimum conditions, the appropriate air curtain settings are discussed and a new strategy is suggested. •Optimum discharge jet velocity of ACD increases with the door height, as well as with the temperature difference between both sides ACD.•The optimum jet nozzle width corresponding to maximum sealing efficiency was identified.•An empirical correlation to predict the optimum ACD jet discharge velocity is proposed.•The inclusion of an electronic automatic adjustment of the jet velocity is suggested.•Increased discharge nozzle thickness is advisable.