Comprehensive study on the effects of fluid dynamics of air curtain and geometry, on infiltration rate of open refrigerated cavities

To date, almost all the studies regarding the improvement of efficiency in open refrigerated display cases by improving the performance of air curtains have been limited to individual cases, which are usually specific to certain designs by certain manufacturers. This study targets the most important variables that can affect the infiltration associated with the entrainment and penetration of outside air into the system, and attempts to identify the relation between each of those variables and infiltration. Variables are defined in non-dimensional forms to make the problem independent from specific design, while each investigated variable covers a wide range of values. The refrigeration system has been eliminated and instead, a tracer gas technique has been employed for the measurement of infiltration. Infiltration results demonstrated a strong and direct relationship with the jet exit Reynolds number and offset angle. Although the relationship between infiltration and the other variables i.e. throw angle, height of the opening, and flow rate ratio, is very significant, the effect of each variable is better pictured in combination of the other variables. ► Infiltration rate of open refrigerated display cases is investigated. ► We identify potential variables affecting air curtain performance and infiltration. ► Infiltration rates are measured by tracer gas. ► We quantify the dependency of infiltration on geometry and flow velocity and ratio.