Numerical and experimental investigations on the use of mist flow process in refrigerated display cabinets

Abstract This study concerns the use of mist flow whereby fine water droplets are injected into the air curtain to improve the performance of Refrigerated Display Cabinets (RDCs). The deposition and evaporation of droplets on the surface of products partially compensate the radiative heat gained by the products by removing from it the amount of latent heat of the evaporated droplets. The experiments were carried out on an actual display cabinet. Numerical modelling was performed using Fluent Computational Fluid Dynamics (CFD) software. In two-phase flow, an Euler–Lagrange approach was adopted to predict the transport of droplets by the air curtain and their spatial distribution on the product surface of the RDC. An original numerical procedure was built in the CFD model in order to compute the deposited droplets while taking into account the evaporative flux of droplets on the product surface. The two-phase flow model was used to analyse the performance of the mist cooling process in terms of surface temperature decrease and the homogeneity of droplet deposition on the product surface of the RDC as a function of inlet droplet injection configurations.

[1]  B. A. Kader.  Temperature and concentration profiles in fully turbulent boundary layers , 1981 .

[2]  S. A. Morsi,et al.  An investigation of particle trajectories in two-phase flow systems , 1972, Journal of Fluid Mechanics.

[3]  Jiyuan Tu,et al.  On the numerical study of contaminant particle concentration in indoor airflow , 2006 .

[4]  B. Launder,et al.  The numerical computation of turbulent flows , 1990 .

[5]  Hyung Jin Sung,et al.  A nonlinear low-Reynolds-number κ-ε model for turbulent separated and reattaching flows—I. Flow field computations , 1995 .

[6]  B. Launder,et al.  Ground effects on pressure fluctuations in the atmospheric boundary layer , 1978, Journal of Fluid Mechanics.

[7]  Judith Evans,et al.  The use of CFD to improve the performance of a chilled multi-deck retail display cabinet , 2005 .

[8]  Stephen James,et al.  Humidification of chilled fruit and vegetables on retail display using an ultrasonic fogging system with water/air ozonation , 2004 .

[9]  N. V. Nirmalan,et al.  An Experimental Study of Turbine Vane Heat Transfer With Water–Air Cooling , 1998 .

[10]  M. Ozisik.  Heat Transfer: A Basic Approach , 1984 .

[11]  Shengwei Wang,et al.  Application of CFD in evaluation and energy-efficient design of air curtains for horizontal refrigerated display cases , 2004 .

[12]  Xianchang Li,et al.  Mist/steam heat transfer of multiple rows of impinging jets , 2005 .

[13]  Refrigerating.  ASHRAE handbook and product directory /published by the American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc , 1977 .

[14]  Wei Sun,et al.  Dispersion and settling characteristics of evaporating droplets in ventilated room , 2007 .

[15]  Giovanni Cortella,et al.  cfd-aided retail cabinets design , 2002 .

[16]  S. Orszag,et al.  Renormalization group analysis of turbulence. I. Basic theory , 1986 .

[17]  R. Kinnersley,et al.  A computational and wind tunnel study of particle dry deposition in complex topography , 2004 .

[18]  G. Alvarez,et al.  Analysis of heat transfer during mist chilling of a packed bed of spheres simulating foodstuffs , 2001 .

[19]  Refrigerating.  ASHRAE handbook of fundamentals , 1967 .

[20]  R. A. Holley,et al.  The temperatures and ages of packs of beef displayed in multi-shelf retail cabinets , 2003 .

[21]  Brenda S. Henderson,et al.  Jet entrainment rate in air curtain of open refrigerated display cases , 2005 .

[22]  M. Wolfshtein.  The velocity and temperature distribution in one-dimensional flow with turbulence augmentation and pressure gradient , 1969 .

[23]  Application of low Reynolds number k–ε turbulence models to the study of turbulent wall jets , 2004 .

[24]  Gamal H. Moustafa,et al.  Experimental investigation of high-speed twin jets , 1994 .

[25]  Wolfgang Rodi,et al.  Calculation of Turbulent Wall Jets With an Algebraic Reynolds Stress Model , 1980 .

[26]  Sergio A. Giner,et al.  Generalized model for the simulation of food refrigeration. Development and validation of the predictive numerical method , 2002 .

[27]  Yun-Guang Chen,et al.  Experimental study of the performance of single-band air curtains for a multi-deck refrigerated display cabinet , 2005 .

[28]  Jean-Dominique Daudin,et al.  Modelling of temperature and weight loss kinetics during meat chilling for time-variable conditions using an analytical-based method — II. Calculations versus measurements on wet plaster cylinders and cast , 1996 .

[29]  Goodarz Ahmadi,et al.  Transport and deposition of particles near a building model , 2006 .

[30]  Francisco J. Trujillo,et al.  A computational fluid dynamic model of the heat and moisture transfer during beef chilling , 2006 .

[31]  Y. Buyevich,et al.  Cooling of a superheated surface with a jet mist flow , 1996 .

[32]  Xianchang Li,et al.  Mist/Steam Cooling by a Row of Impinging Jets , 2001 .