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恒热流准稳态法于五十年代中期起就用于测试含湿材料热物性,但在原理上及边界条件的实现上存在着理论误差。本文论证了理论误差的来源,并对理想的和最差的两类极端条件进行了计算。表明:在以试材本身作端面绝热层的极端情况下,如果控制傅利叶数F_0在0.4至0.5时,则理论误差小于3％;若加上修正平面热源的热容的误差,那么理论误差为3.5％。——这可作为本方法存在的理论误差的极限。南工Ⅱ型导热装置克服了把本方法用于深冷测试时的困难,比较满意地解决了工程材料低温热物性的快速简易测试问题。文中还介绍了测试装置、记录曲线和对聚氨脂的测试结果。即使用了普通的记录式电位差计,最大可能的综合误差仍小于±8％。
The constant heat flow quasi-steady state method was used to test the thermophysical properties of moisture-containing materials since the mid-1950s. However, there are theoretical errors in principle and the realization of the boundary conditions. This article demonstrates the sources of theoretical errors and calculates the ideal and worst extremes. The theoretical error is less than 3% if the control Fourier number F_0 is 0.4 to 0.5. If the error of the heat capacity of the planar heat source is corrected, the theoretical error is 3.5%. This can be used as the theoretical error that exists in this method. Nankong Ⅱ thermal conductivity device to overcome the method used in cryogenic testing difficulties, more satisfied with the engineering materials to solve the low temperature thermophysical properties of quick and easy test. The article also introduces the test device, record the curve and test results of polyurethane. Even with an ordinary record-type potentiometer, the maximum possible combined error is still less than ± 8%.