Air velocity distribution analysis in the air duct of a display cabinet by PIV technique

This work is aimed at presenting an analysis, by stereoscopic Particle Image Velocimetry (PIV) technique, of the air speed distribution inside the cooling duct of a display cabinet and its effect on the heat exchange efficiency. Two configurations of the duct, in which the air is forced through the evaporator by one and two fans, respectively, are tested. 3D flow fields, upstream and downstream the evaporator, are determined by PIV performed on three planes containing the mainstream velocity vectors and placed at different heights. Measurements are carried out at the maximum fan rotation rate. The analysis of the air flow distribution at the inlet and outlet of the evaporator shows the capabilities of the PIV technique to highlight insufficiently loaded sections of the evaporator and to estimate the energy transfer efficiency. These results are compared with those of an ideal configuration, in which the air flow rate is uniformly distributed at the evaporator entrance.

► Air speed distribution was analysed inside the cooling duct of a display cabinet.
► Air velocity was measured by Stereo PIV technique.
► Measurements performed on 3 planes allowed a volumetric air speed reconstruction.
► Two configuration with 1 and 2 fans were studied.
► Local heat exchange coefficients allowed to assess effects of flow maldistribution.