Simulation of air curtains for vertical display cases with a two-fluid model

• Published in: Applied thermal engineering Vol. 27; no. 14; pp. 2583 - 2591
• Main Authors: Yu, Ke-zhi, Ding, Guo-liang, Chen, Tian-ji
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.10.2007; Elsevier
• Subjects: Air curtain; Applied sciences; Display case; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Heat transfer; Temperature field; Theoretical studies. Data and constants. Metering; Two-fluid model; Velocity field; Air curtain; Temperature field; Display case; Velocity field; Two-fluid model; Temperature distribution; Turbulence; Empirical relation; Stored food product; Thermal stratification; Simulation; K epsilon model; Comparative study
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2007.01.027

In a vertical open display case, air curtains are used to weaken the influence of ambient air on the store. The flow and heat transfer characteristics of air curtains in a vertical display case are simulated with a two-fluid turbulence model in this paper, which takes the fluid in the space to be simulated as a mixture of turbulent fluid and non-turbulent fluid. The air curtains are taken as a turbulent fluid and described by the conventional k– ε turbulence model. The ambient air outside the display case is considered as a non-turbulent fluid and calculated by a laminar model. The exchanges of mass, momentum and energy between the turbulent and the non-turbulent fluids are expressed by empirical relations. The simulation results based on the two-fluid model are compared not only with experimental data, but also with the simulation results when the k– ε model is used for the whole simulated space. The comparisons indicate that the two-fluid model enables to predict thermal stratification phenomenon more accurately and shows better agreement with the measured values than the k– ε model.