Modelling and numerical analysis of the phenomenon of reduction in thermal conductivity in small thickness samples of some selected synthetic materials

摘要

The phenomenon of reduction in thermal conductivity which is observed in thin samples(of some millimetres in thickness)of synthetic materials and the related temperature slip at the cold measure- ment surface of the sample have been studied. Various forms of dependence of the jump-like variation in essential thermal conductivity on the sample thickness have been simulated, their influence on the differential equation of steady-state heat transfer being studied for samples having form of discs of different thickness. Our considerations were not concerned with particular synthetic materials, but the dependence of the essential thermal conductivity on the sample thickness and the temperature differenceΔT = 65 deg. C between the heater and the cooler of the plate apparatus assumed for the consid- erations were closely connected with earlier experimental investigations into the relations mentioned for polymethyl metacrylate and polyamide 6, pure and with soot addition[3,7,9].