【作者】 倪志强；

【导师】 张子明；

【作者基本信息】 河海大学 ， 工程力学， 2006， 硕士

【摘要】 在计算大坝运行期的温度场时,需要确定沿坝面的水温分布作为边界条件;另一方面,在水文与环境科学中湖泊、水库的水温分布也是影响许多水质指标的关键因素。因此,研究水库水温的分布规律,不论对于水工建筑物的设计和施工还是水文水质研究及水库的调度和管理使用,都有重要的意义。 本文对水库水温的一维模型,用基于加权余量法的伽辽金有限单元法对水温模型的控制方程进行离散,得到了求解水库水温一维模型的系统方程。根据理论证明和工程实践,库底可取为绝热边界条件,有限单元法可以很方便地处理绝热边界条件;而水面边界须满足考虑辐射、传导和蒸发等热传递过程的热能平衡方程,考虑到水面掺混作用,该方程可化为一个关于水面温度的一元四次方程,则水面为固定边界条件。在此基础上,并考虑了热对流和风吹掺混对水温分布的影响,利用FORTRAN语言编制了预测水库水温的微机程序。 以龙滩工程为例分别用有限单元法和有限差分法对水库水温进行了计算。计算结果表明:用有限单元法和差分法计算水库水温都有较高的可靠性,能基本反映水库水温的变化规律,但是有限单元法能更方便的处理绝热边界条件。 本文还对水库水温的流速分布问题作了探讨。针对出入库水流流速分布的不同假设编制了相应的子程序,并对龙滩工程进行了计算。计算结果表明,不同的出入库水流流速分布对水库水温的影响很小,为今后的进一步研究提供了参考。更多还原

【Abstract】 While the temperature field of dam in running period is being calculated, it needs to confirm the distribution of water temperature along the dam as the boundary condition;on the other hand, the distribution of water temperature is the key factor which influences the quality of water among hydrology and environmental science. Therefore, studying the distribution law of the water temperature of the reservoir, no matter design and construction or research on quality of water and management of reservoir, there are important meanings.In this thesis, based on 1-D model of water temperature, the differential equation by use of Galerkin method of weighted residual method and finite element method is discrete. Therefore, the system equation of 1-D model is deduced. The boundary condition of the bottom is decided to be adiabatic boundary condition according to engineering practice and academic prove. However, Finite element method can easily deal with the adiabatic boundary.The boundary of water surface must satisfy the equation of heat energy balance, which contains solar radiation, conduct and evaporates and so on. This equation can be deduced to an algebraic equation. Then, the boundary of water surface is fixed boundary condition.The program of water temperature of reservoir is made in FORTRAN language and the convection and wind effect is considered.The numerical results of water temperature of reservoir in Longtan engineering by use of finite element method and finite difference method is reliable, because the results basically reflect the rule of distribution of water temperature of reservoir. However, finite element method deals with the adiabatic boundary more convenient than finite difference method.Furthermore, the problem of the speed of flow is discussed. Subprograms are made considering different assumptions of the distribution of the speed of flow and the numerical results of water temperature of reservoir in Longtan engineering by use different assumption show that different assumption of the speed of flow do little to water temperature. These results provide the reference for the next further research.更多还原