给水管网三维渗漏计算

Three-dimensional pipe leakage assessment in water distribution system

为了有效地展开管道的漏损控制,充分理解水压力和渗漏速率的关系.提出考虑漏损口周围土体影响的管道三维渗漏量近似计算方法.在假设土体饱和、均质及符合大西定律的前提下,通过将管道漏损口周围土体中的复杂渗流简化为以破损口为点源的球形渗漏模型,结合孔口出流推导漏损口渗漏量计算公式.推导过程中管壁考虑为非渗透性边界.通过实验对计算公式进行验证,实验结果和模型的计算结果吻合较好.结果表明,土体的存在对渗漏量有显著的影响.该模型有效地解释水头压力、土体性质、破损口孔径以及管径对渗漏量的影响,为管网的压力控制提供了理论依据.

An approximate solution for three-dimensional pipe leakage assessment considering the surrounding soil was prescnted in order to control the leakage efficiently and understand the relationship between the leakage flow rate and water pressure.The orifice equation from a circular orifice and the leakage diffusion in the soil were combined to predict the leakage flow rate.When a pipe leakage occurs,the leakage water will diffuse into the soil in the radial direction.The following hypotheses were introduced：soil skeleton was homogenous and stable,the soil around pipe was saturated and the leakage flow was governed by the Darcy-law.An impervious surface formed by the pipe was considered in the analytical model.A series of experiments were conducted out under steady-state conditions to validate the solution.The experimental results agreed well with the derived solution and indicated that the presence of soil would change the leakage flow rate.The new solution gives the effects of the water pressure,soil,the leak diameter and pipe diameter on leakage characteristic,and gives the theory basis for pressure control.