Measurement and visualization of diffuser flow fields using liquid crystal sheets

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:33323

Kirkpatrick, A T; Stetz, M ^[1]; Engel, J A ^[2]

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1. Colorado State Univ., Fort Collins, CO (United States). Dept. of Mechanical Engineering
2. Westinghouse, Hanford, WA (United States)

This paper describes the development and application of a novel imaging technique for determining at air temperatures and flow fields from heating, ventilating, and air conditioning (HVAC) diffusers. This technique uses a temperature-sensitive liquid-crystal-coated sheet to produce a two-dimensional color image of the air temperature field. Due to their molecular structure, liquid crystals reflect visible light of a particular wavelength depending upon their temperature. Two mixtures of liquid crystals were used in this study-one visible in the range of 40 F to 75 F and the other visible in the range of 54 C to 68 C, changing color from red to blue as their temperature increased. These liquid crystals were applied to acetate sheets, which were then placed into the cold airstream and observed. Image processing equipment consisting of a color video camera and computer, a frame grabber, and appropriate software was used to acquire and analyze the resulting color changes. Image-processing software was used to extract the true color of the crystals at every location on the sheet. This color was then correlated to temperature and provided a rapid means of observing the temperature field of the cold jet. Visualization of the flow field from various diffuser types was performed. The effect of the sheet on the airflow and the difference between the sheet temperature and the room temperature were also examined.

• OSTI ID: 33323
• Report Number(s): CONF-9406105--
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
AIR FLOW
DIFFUSERS
FLOW VISUALIZATION
IMAGE PROCESSING
SPACE HVAC SYSTEMS