EXPERIMENTAL STUDIES OF HEAT-TRANSFER AND FLUID-FLOW ACROSS CORRUGATED-UNDULATED HEAT-EXCHANGER SURFACES

True-colour image processing of liquid crystal (LC) images has been es tablished as a new powerful experimental technique to yield full-field measurements of temperature and heat transfer coefficient distributio ns. In this study the LC technique was developed successfully and appl ied to a study of six element-shapes of rotary air heat preheaters are used extensively in power stations. A complete mapping of temperature , heat transfer coefficient and pressure drop was obtained for all of them at every angle and Reynolds number required. The measuring techni que comprising the use of LC flexible sheets and true-colour processin g may also be used for a great variety of applications and should be o f considerable use in improving the design of all types of compact hea t exchanger. (C) 1997 Elsevier Science Ltd.