【摘要】 讨论了块石路堤、护坡试样在表面温度周期波动时自然对流产生的条件,分析了开放系统和封闭系统块石试样内部的热传输机理,以说明其热扩散系数和导热系数的确定方法。指出开放系统的试样由于传热形式不单一而不利于热扩散系数和导热系统的精确测定,而封闭系统试样内部的传热形式以热传导为主。结果表明,可用封闭系统的细长圆柱试样来测试路堤、护坡块石的热扩散系数和导热系数。更多还原

【Abstract】 Conditions of occurring natural convection in the ballast specimens under cyclically fluctuating surfaceairtemperature were discussed. The heat transfer mechanisms in the porous ballast specimens for tighttest and opentest were studied. And the approach of determing thermal diffusivity and conductivity was discussed. It was presented that the specimen for opentest is not favorable for accurately measuring thermal diffusivity and conductivity due to multiform heat transfer, and for tighttest the thermal conduction is predominant. The results show that for tighttest the thermal diffusivity parameter and conductivity parameter can be determined by using slenderly cylindrical specimen.更多还原