Helium-filled Soap Bubbles as a Plume Tracer

For the zoning room air conditioning strategy to work properly, it is essential that the supply air is delivered in such a way that it does not block the plumes' way from the lower zone to the upper. The parameter measuring the fulfilment of this condition is the plume penetration. This kind of parameter could be measured by releasing tracer gas into the heat source and measuring the response elsewhere. This was done in our research also, but the tracer gas experiment was supplemented by an alternative method, utilizing small helium-filled soap bubbles instead of gas. This paper describes the bubble method and its application in the case of an industrial grille air inlet.