Numerical study on the influence of geometrical parameters on natural convection cooling effect of the crushed-rock revetment

作     者：ZHANG MingYi CHENG GuoDong LI ShuangYang 

作者机构：State Key Laboratory of Frozen Soil EngineeringCold and Arid Regions Environmental and Engineering Research InstituteChinese Academy of SciencesLanzhou 730000China 

出 版 物：《Science China(Technological Sciences)》 (中国科学（技术科学英文版）)

年 卷 期：2009年第52卷第2期

页      面：539-545页

核心收录：

学科分类：0810[工学-信息与通信工程] 081401[工学-岩土工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0814[工学-土木工程] 0702[理学-物理学] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

基　　金：Supported by the National Natural Science Foundation of China (Grant Nos.40601023 and 40730736) the Special Funding for "Prize for Excellent Student" (to Dr. ZHANG Mingyi),awarded by the President of the Chinese Academy of Sciences the Western Program of the Chinese Academy of Sciences (Grant No.KZCX2-XB2-10) 

主　　题：crushed-rock revetment geometrical parameter Nu number convection pattern cooling effect 

摘      要：The crushed-rock revetment, considered as a highly porous medium, is often applied to embankment slope to protect the underlying permafrost and ensure the thermal stability of roadway in permafrost regions. In this paper, in order to increase and optimize the cooling capacity of crushed-rock revetment in cold regions roadway engineering, based on the thermal convection theories, the practical geometry and the temperature characteristics of in-situ crushed-rock revetment, convective pattern and cooling effect of crushed-rock revetment are numerically studied, with a thickness of 1.0 m under different geometrical parameters, e.g. sloped angle and aspect ratio. The results indicate that, with a thickness of 1.0 m and a temperature difference of 10.0 °C between top and bottom boundaries, due to the existence of natural convection, the effective thermal conductivity of crushed-rock revetment can be increased and the thermal “semi-conductor characteristics are endowed. However, the convective pattern changes with the variation of the sloped angle, namely, with the increase of the sloped angle, the convection cell number decreases; furthermore, when the flow changes from various cells to a single cell at a sloped angle, the Nu number is the smallest and the cooling effect is the worst, therefore, the corresponding sloped angle is considered as the worst cooling sloped angle. Besides, with the increase of the aspect ratio, the worst cooling sloped angle increases and tends to 32°, also approaching to the in-situ crushed-rock revetment angle 33.7°. Therefore, when the crushed-rock revetment embankment is too high, that is to say, the aspect ratio of the sloped crushed-rock revetment is too large, some measures should be taken to enhance its cooling effect, which have been researched and discussed in this paper. It is hoped that some scientific references can be supplied to the design and maintenance of the crushed-rock revetment embankment in cold regions.