调压井模型试验变态比尺的研究

The study of distorted scale of surge-tank model test

本文对有压非恒定流调压井系统，其中包括调压井，进水隧洞，压力管道三部分的变态模型设计进行了系统的研究．提出了模型比尺的相关性概念，研究表明，仅从涌波方程推导相似条件往往产生顾此失彼问题．文中还提出了变态模型比尺的参数表示法，通过该方法可实现变态模型比尺的优化选择．研究还指出，当调压井的比尺小于１／２５时，整个系统完全正态模型是难以实现的．得出的结论表明，不仅可以，而且应该使变态模型比尺同时满足涌波方程，水锤波方程和压力管道水弹性方程的相似条件．本文还提供了一个实际工程项目的变态模型设计比尺的优化选择．

The design of the distorted model of surge tank system, which includes surge tank, inlet tunnel and penstock, is studied as an inseparable whole and the concept of model scale correlation is proposed in this paper. The study shows that the derivation of similarity condition only by surge equation will attend to one thing and lose sight of another. The parameter method of distorted model scale is also proposed and by using this method the optimum choosing of the scale can be realized.The study also point out that when the scale of surge tank is less than one to twenty-fifth, it is difficult to make the whole system as an absolute normal model. The obtained conclusion shows that the distorted model scale should satisfy the similarity condition of surge equation, water - hammer equation and elastic equation of penstock flow. The optimum choice of distorted model scale for practical engineering project is also proposed.