低速条件下给水管线中余氯衰减模拟研究

目的研究低速条件下给水管线中水质的余氯的衰减变化状况．方法应用有限差分法求解水质模型，用数值模拟给水管线中余氯的衰减变化规律来反映给水管网中的水质状况．结果当给水管线中流速较大，水流处于高雷诺数紊流状态时，氯的随流迁移在组分传输过程中占主导作用，通常忽略扩散项，采用一维水质传输模型数值模拟管线中的余氯变化规律．但在管网末端或者夜晚供水时段，管线中的流速可能较低，忽略扩散作用将给模拟结果带来较大误差．这时需考虑求解包含扩散项的一维水质移流扩散模型．结论给水管线在低速条件下，需求解包含扩散项的一维水质秽流扩散模型来数值模拟余氯的衰减变化规律，以提高模拟结果准确性。从而真实地反映给水管线中水质的变化状况．

Numerical Simulation of Residual Chlorine Decay in Water Supply Pipelines under Low Velocity

Residual chlorine decay reflects the water quality in water distribution systems,so numerical simulation of residual chlorine decay makes significance.When the velocity of water in pipelines is large enough,the advection of chlorine is dominant in the componential transport process.In the circumstances,the one-dimensional water quality transport model without the dispersion term is usually used to simulate residual chlorine decay in pipelines.However,the velocity in pipelines at tail end or at night could be smaller.The paper demonstrates that the water quality transport model that omits the dispersion term can result in a big error.Therefore,numerical simulation of residual chlorine decay needs to make use of the water quality advection-dispersion model including the dispersion item under the circumstances.Finally the paper presents the detailed approach to solving the model by the method of finite difference.