Edge Heat Research Articles

23—THE TRANSMISSION OF HEAT THROUGH TEXTILE FABRICS. PART III. A NEW THERMAL-TRANSMISSION APPARATUS

Details are given of a new thermal-transmission apparatus which is automatic in operation, which does not depend on the measurement of a heat flux, and which requires no guard plates to eliminate edge heat losses. The apparatus works on the principle that for conductors in series with respect to direction of heat flow, the ratio of the temperature drop across them equals the ratio of their thermal resistances, and the only measurements involved are those of temperature in the equilibrium state. The apparatus is suitable for testing the thermal-transmission properties of textile materials up to at least 1 in. thick. Data are presented for the thermal-transmission properties of timber and of plate glass determined with the new apparatus.

23—THE TRANSMISSION OF HEAT THROUGH TEXTILE FABRICS. PART III. A NEW THERMAL-TRANSMISSION APPARATUS

Details are given of a new thermal-transmission apparatus which is automatic in operation, which does not depend on the measurement of a heat flux, and which requires no guard plates to eliminate edge heat losses. The apparatus works on the principle that for conductors in series with respect to direction of heat flow, the ratio of the temperature drop across them equals the ratio of their thermal resistances, and the only measurements involved are those of temperature in the equilibrium state. The apparatus is suitable for testing the thermal-transmission properties of textile materials up to at least 1 in. thick. Data are presented for the thermal-transmission properties of timber and of plate glass determined with the new apparatus.

A Correlation of Leading Edge Transition and Heat Transfer on Swept Cylinders in Supersonic Flow

Summary:—It is shown that stagnation line heating rates for laminar, transitional and turbulent boundary layers measured on swept cylinders at supersonic speeds, can be correlated in terms of a Reynolds number based on the spanwise momentum thickness at the stagnation line.A critical Reynolds number for transition along the stagnation line is determined and experimental results show evidence of transition up to M= 10.

Analysis of error due to edge heat loss in measuring thermal conductivity by the hot plate method

An analysis is made of the error due to edge heat loss in the steady-state determination of thermal conductivity using a hot plate as recommended in British Standard 874: 1956. The solution obtained applies to a rectangular hot plate with or without a guard ring and takes account of heat exchange at the exposed edges of the test specimen in a more precise way than existing solutions. It is therefore less restricted in its application to practical tests.