On the Measurement of Thermal Conductivity by the Unsteady Heat Flow

Rapid measurement of thermal conductivity of unknown material of which all thermophysical properties are unknown and dimensions are given, is accomplished, applying unsteady heat conduction. In this paper, the thermal conductivity λ〔kcal/mh°c〕is calculated by the following equation, λ=(Qr_0)/(2・Δ_0)log e(t_2)/(t_1) where, Q stands for the heat supplied, r_0 for the inside radius of the material tested and Δ_0 for the difference between the temperatures, at the point of M shown in Fig. 1,measured at the test times of t_2 and t_1. By this method, λ is found rapidly and simply.