Three-dimensional effects of an air curtain used to restrict cold room infiltration

Abstract

The aim of this study was to compare the measured effectiveness of an air curtain device at different jet velocities against a three-dimensional (3-D) computational fluid dynamics (CFD) model. The air curtain device was not as wide as the entrance and had a geometry that encouraged 3-D flow. By carefully setting up the air curtain an effectiveness of 0.71 was achieved compared to the initial value of only 0.31 as set by the air curtain device installer. The 3-D CFD model predicted the infiltration through the entrance with no air curtain to an accuracy of within 20-32%. The predicted effectiveness, E, of the air curtain at different jet velocities was 0.10-0.15 lower than measured. The shape of the effectiveness curve against jet velocity was well predicted. CFD has shown that the flow from this air curtain cannot be considered as 2-D. The central part of the jet is deflected away from the cold store by the Coanda effect caused by the air curtain device's fan body. The edges of the jet are deflected into the cold store by the stack pressures and turn into the void caused by the deflected central jet. (c) 2006 Elsevier Inc. All rights reserved

Heat Transfer Through Vertically Downward-Blowing Single-Jet Air Curtains for Cold Rooms

“…This is due to the higher amount of mixing at higher jet velocities. Similar results were also presented in literature [2,10,15].…”

“…Foster et al [15] however showed that 3D effects can have a severe impact on the air curtain effectiveness and suggested therefore to use at least an air curtain over the entire width of the door.…”

“…The air flow rate through the curtain was measured with a tracer gas decay method [12,15,16,23,24]. A concentration of CO 2 tracer gas was released in the cooled room while the door was closed.…”

The Simulation and Research of Fiber Cloth Duct System

“…With the actual physical model, constructing the reasonable mathematical model, and the analogue simulation, we can obtain the result which is similar to the experimental research, and can change the condition flexibly, save a lot of time and cost. At present, CFD has been used in all aspects of cold storage research, involving the temperature field, gas flow field, humidity field, pressure field [11,12,13,14], etc. There are some precedents that CFD was used to simulate the airflow in the air space in an air supply duct system [15].…”

Effects of Switch Door on Temperature Field in Cold Storage Based on Numerical Simulation

“…However, there still exist many problems in the designing of the cold storage. For example, unreasonable design can result in heterogeneous distribution of flow field and energy loss [1][2][3][4][5][6][7], especially when you open or close the door of cold storage, for there is relatively huge temperature difference inside and outside of the cold storage, which may generate various problems, such as frosting, increasing temperature in the cold storage, etc [8].In order to solve these problems, air curtains have been installed at the doors of many cold storages. However, no matter what measures will be applied, It is necessary to understand the flow field near the door of the cold storage so as to make the measures more effective.…”