We visualize air flow

News, 09/08/2022

The modern equipment of the Bustěhrad CTU UCEEB laboratories enables analysis and visualization of air flow using PIV anemometry, which is more accurate than calculation methods. The obtained data are then used to propose steps to improve the conditions of the indoor environment in buildings.

Particle laser (PIV) anemometry is a precise method for visualizing the flow of air and other liquids. Thanks to this, it has a wide range of applications from aviation to the automotive industry to medicine. In our laboratories, we perform it mainly as part of the optimalizace podmínek vnitřního prostředí v budovách service, which also includes analysis of thermal comfort, assessment of air quality and lighting. With its help, we are also able to determine the flow pattern in the individual parts of the air handling units, in pipes, fittings and around the outlets.

The method is based on the optical tracking of the movement of marker particles dispersed in the measured environment. To highlight and define the measured area, the marking particles are illuminated by a laser plane with a width of approx. 2 to 8 mm. A laser-synchronized camera is placed perpendicular to the plane, which is capable of recording two images (double-frame) with a time interval of the order of a few microseconds. Individual particles carried by the air stream can then be recognized on the dual images from the camera, their path and direction of movement can be determined, and the resulting vector field based on the flow velocity can be determined based on time measurement.