Particle Image Velocimetry and Thermometry Using Thermochromic Liquid Crystals

In recent years Thermochromic Liquid Crystals (TLCs) have been successfully used in non-intrusive heat transfer and fluid mechanics studies. Application of TLC tracers allows instantaneous measurement of the temperature and velocity fields for two-dimensional cross-section of flow. Here we present the review of the development of techniques for visualising and analysing flow images with TLC tracers we used over past 15 years for studying natural convection in small enclosures. Using digital acquisition technique and image analysis methods, fully automatic quantification of temperature and velocity can be performed. The method combines computerised true-colour analysis of digital images for temperature measurements and modified Particle Image Velocimetry used to obtain the flow field velocity. Examples given for flow field measurements demonstrate advantages of the method and the importance of this full field experimental technique for the validation of numerical codes.