【作者】 金弋；

【导师】 刘伟；

【作者基本信息】 华中科技大学 ， 工程热物理， 2004， 硕士

【摘要】 随着多孔介质传热传质理论研究的不断深入,其应用范围也日益广泛。在农业方面,现代农业在“可持续发展的农业”的要求下,人们不但注重产量,同时也注重如何提高资源的利用效率和尽量减小对环境产生尽量小的影响。在REPS系统中,深入研究了热、湿迁移的机理及其影响因素,从连续介质体力学的观点出发,采用局部体积平均方法,建立了描述土壤中热湿迁移的二维圆柱坐标下的数学模型。同时还建立了根系吸水、土面蒸发、叶面蒸腾模型,以更全面的描述REPS系统中的热湿迁移规律。在稳态数值模拟中,原模型中没有考虑植物根系占位及植物根系的物性对计算的影响。在本文中对REPS系统模型进行修正,加入植物根系占位及物性,并对修正后模型计算结果与原模型计算结果进行比较。在对含植物根系土壤床内部热湿迁移的研究中,植物根系构型是影响土壤床内部各物理量场的一个重要因素。由于植物根系生长的不确定性,模拟根系的生长一直比较困难。本文在冬小麦根系生长发育与土壤条件关系研究的基础上,以土壤含水量为主导因子完善了综合考虑土壤环境的根系生长模型;以随机分形布朗运动模型(FBM)为基础,根据根系生长模型,在WINDOWS平台上结合Visual C.NET和OpenGL三维图形库语言开发了冬小麦根系形态的计算机模拟软件。通过根系实测参数,对冬小麦根系生长模拟进行宏观控制,进而真实再显冬小麦地下根系部分的动态生长过程。根据随机模拟的根系形态,判断土壤床中含有冬小麦根系的网格,进一步完善对REPS系统中物理量场数值模拟,研究含植物土壤床中物质与能量的消耗和迁移。本文研究接受国家自然科学基金资助:(1) REPS系统中的热物理问题研究(No.59976010)(2) 土壤次生盐渍化过程的机理研究和模型预报(No.50376015)更多还原

【Abstract】 With the development of the research on heat and mass transfer in porous media, the applied field of the research has being more and more far-ranging. In the field of agriculture, on the demand of “the continuable developing agriculture”, human not only pay attention to the total yield, but also to the efficiency of using resource and to the influence that they bring to the environment as little as they can.In REPS system, lucubrate the mechanism and influence of heat and moisture migration. Starting from continuity-media dynamics, using the technique of local-volume averaging, a mathematical model of describing transfer of heat and moisture in soil on a two-dimensional cylinder coordinate is built. On the same time, the models expressing root water up taking, soil surface evaporation and leaf surface transpiration are built to describe the regulation of heat and moisture migration in RPES system fully. In stably numerical simulation, the influence of root-occupation in soil is not considered in the old model. In this paper, the REPS system model is revised, adding root-occupation and physical character in soil, what’s more, the compare of the revised model and the old model is given.During the research on the heat and moisture migration in vegetation soil bed, the influence of plant roots modality on the physical fields in soil bed is great. For the uncertainty of plant roots’ growing, simulation of plant roots is a difficult. This paper consummates the model of plant roots growing in which the magistral factor is water content in soil bed and soil structure is considered. Based on Fractal Brown Motion (FBM) and the model of plant roots’ growing, on the platform of Windows, a computer simulation and analyzing software system was exploited with the technique of fractal theory and computer graphics. On the data of the field experiment, this software controls macroscopically the model of winter wheat roots growing, and reappears winter wheat roots’ dynamic growing course. According to the modality of the simulated roots, we estimate the griddings that contain winter wheat roots, and consummate the numerical simulation for physical fields in REPS system.更多还原