Abstract Jet impingement heat transfer is an enhanced heat transfer technique.This article reports results on the local heat transfer coefficients for confined impinging air jet.A transient thermochromatic liquid crystals technique is used to visualize and record isotherms on an impingement surface. Quantitative temperature measurement using thermochromatic liquid crystals is a field temperature measurement technique. It utilizes the feature that TLCs change their reflex light colors with variation of temperature and apply an image capturing and processing system to calibrate the characteristic curve of TLCs colour-temperature,and then use it to measure the distribution of surface temperature. Therefore , it can solve some problem that cannot be solved by traditional point Temperature measuring methods in heat transfer field. The main object of this articale is to set up a temperature measurement system of transient thermochromatic liquid crystals. Furthermore, an experimental is carried out in the present study to investigate the characteristics of heat transfer resulting from a low speed air jet impinging onto a horizontal circular disk confined in a vertical adiabatic cylindrical chamber. Experiments are conducted at low nozzle-to-disc spacing (0.5<H/D <3.5) and Reynolds number in the range of500 to 1500 for two different injection pips. The results show that the effects of Reynolds number and nozzle-to-disc spacing on the local heat-transfer coefficient are reported and compared with different diameter of injection pipes.Finally , empirical equations are proposed to correlate the effect of Reynolds number and nozzle-to-disc spacing .

Chemical vapor deposition is an important thin film process for the fabrication of TFT-LCD(Thin-Film-Transistor Liquid Crystal Display), the heat transfer coefficient on the substrate is the important influence parameter in the manufacturing process. For this reason, the main object of this thesis is to set up a temperature measurement system of transient thermochromatic liquid crystals. Furthermore, an experimental is carried out in the present study to investigate the characteristics of heat transfer resulting from a low speed air jet impinging onto a rectangular substrate confined in a vertical rectangular chamber. Finally, empirical equations are proposed to correlate the effect of Reynolds number¡BSeparation distances and Ratio of outlet.