Experimentální stanovení trajektorie neizotermního proudu pomocí interferometrie

Experimental determination of the non-isothermal jet trajectory by means of the interferometry

journal article - other

Czech

V článku je popsáno experimentální stanovení trajektorie neizotermního proudu vzduchu z vyústky pomocí interferometrie. Pro vizulalizaci proudění byl použit Machův-Zehnderův interferometr o průměru zorného pole 200 mm. Zkoumána byla trajektorie neizotermního proudu vzduchu z kruhové a štěrbinové vyústky. Experimenty byly prováděny na měřicí trati umožňující měnit rychlost a teplotu vzduchu proudícího z vyústky. Záznam interferogramů byl prováděn CCD kamerou do počítače a na videokazety. Vyhodnocení interferogramů bylo provedeno pomocí programu INTERFER, který byl vyvinut na odboru termomechaniky a techniky prostředí FSI VUT Brno.

A jet is the most important single type of flow occurring in ventilation, and is defined as the discharge of fluid from an opening into a large body of the same or similar fluid. If the jet temperature is different then an ambient fluid temperature, the jet is called non-isothermal jet. The paper presents experimental determination of the trajectory of non-isothermal jet. Flow visualization by means of the interferometry was employed to fulfill this task The interferometric visualization provides several advantages for the study of fluid flow, in comparison to measurement techniques based on air velocity and temperature sensors. The interferometric visualization enables to obtain flow patterns or temperature fields all at once, and since there are not any sensors, flow patterns or temperature fields are not disrupted. The interferometric visualization has also some disadvantages. The interferogram processing is time-consuming, and determination of local air velocities from the interfero-grams is not possible. The main goal of the research was to determine the trajectory of non-isothermal jet. A Mach-Zehnder interferometer, with the view field diameter of 200 mm, was used for the flow visualization. Interferograms were captured to the PC by a CCD camera. The interferogram processing software INTERFER, which was developed at the Department of Thermodynamics & Environmental Engineering, was employed in the processing of interferograms. The trajectories of round jets as well as plane jets were studied. The interferometric visualization proved itself to be a suitable method for this task. Another area where the interferometric visualization was applied, was the determination of C-values of ventilation outlets.

non-isothermal jet, jet trajectory, flow visualization, interferometry, Mach–Zehnder interferometer, interferogram processing

CHARVÁT, P., PAVELEK, M., JANOTKOVÁ, E.

2002

20. 8. 2001

1210-2717

Inženýrská mechanika - Engineering Mechanics

8

4

Czech Republic

287

294

8