圆管突然扩大与突然缩小的局部水头损失系数的研究

采用RNG k-ε紊流模型,对Re4 400时圆管中突然扩大和突然缩小的局部水头损失进行数值模拟;并与实验值进行比较。结果表明:模拟得到的测压管水头差与实测值吻合较好,局部水头损失系数的相对误差较经验值的相对误差小;圆管突扩与突缩的局部水头损失系数与雷诺数的对数呈良好的线性关系。随雷诺数的增大,局部水头损失和突扩局部水头损失系数逐渐增大;而突缩局部水头损失系数呈减小的趋势。对工程实践中水利工程的设计有重要的指导意义。

Study on local head loss coefficient of suden expanded and shrunken tube

Using RNG k-e turbulent model, local head loss of suden expanded and shrunken tube was simulated when Re was more than 4400, and compared them with the experimental value. Results show that the simulated of piezometric head deviation agreed well with measured value, the relative error of simulated local head loss coefficient is smaller than relative error of empirical value; sudden expanded and shrunken local head loss coefficient is in good linear with logarithm of Reynolds number, Along with the increase of Reynolds number, the local head loss and the sudden expanded local head loss coefficient increased gradually, but the sudden shrunken local head loss coefficient went down. And the study is very important in the design of hydraulic engineering,