Air Flow Characteristic in Scale Models of Room Ventilation

Improvement in methods of air flow pattern scale modelling in large enclosure requires above all, précising the conditions necessary in the model in order to maintain Reynolds number independence of the mean flow, as well as defining ways in which the flow turbulent structure could be simulated. The paper presents the results of experimental analyses of air velocity fields in scale models in the range of Reynolds number 1850 to 98000. The field maps of air velocity mean value were tested. Turbulence energy spectra in the models flows were analysed at the corresponding points of similar systems. The analyses referred to the approximate similarity of air flow fields. Experiment results have been used to identify the threshold Reynolds number, which makes it possible to maintain approximate similarity of mean velocity distribution in the whole area of the flow pattern modelling. The tests show also that it is possible to maintain similarity of turbulence spectrum in scale models when a second threshold Reynolds number is exceeded.