Simultaneous Determination of Reference Free-Stream Temperature and Convective Heat Transfer Coefficient
This paper deals with the development of a new method that can obtain heat transfer coefficient and reference free stream temperature simultaneously, The method is based on transient heat transfer experiments using two narrow-band TLCs. The method is validated through error analysis in terms of the random uncertainties in the measured temperatures. It is found that the errors could be reduced more than 2 times less. The general method described in this paper is applicable to many heat transfer models with unknown free stream temperature.
Liquid crystal methods for studying turbulent heat transfer
Abstract Liquid crystals that can accurately measure temperature and are relatively stable are now available. There are exciting new opportunities to apply these liquid crystals to the investigation of important and interesting heat transfer/fluid flow problems. Five methods of using narrow-band liquid crystals for the measurement of local heat transfer coefficients are reviewed in this paper. These methods have been developed and used at the University of California, Davis and include the heated-coating method, three variations of the transient method (preheated-wall transient, duct-insertion technique, and shroud-heating technique), and a uniform coating method. Some examples of applications for these methods are described. The examples include cylinders in cross-flow, pin fins, impinging jets, turbine blades, smooth and ribbed square ducts, and spirally fluted ducts.
Spin label motion in fatty acids.
Spin labels dissolved in highly purified fatty acid systems exhibit nearly identical tumbling rates in liquid and solid phases. Even though the spin labels do not have the same molecular geometry as the lipid matrix the melting point of the matrix can be inferred by measurements of the temperature dependency of molecular motion.