导流隧洞泄流能力预测偏差影响因素分析

为解决导流隧洞泄流能力影响因素及作用机制复杂引起的预测偏差较大问题,采用理论分析、数值模拟及模型试验相结合的研究方法,对导流隧洞泄流能力影响因素进行了识别和分类,剖析了各影响因素对泄流能力的作用机制及影响程度,提出了减小泄流能力预测偏差的方法。结果表明:导致泄流能力预测发生较大偏差的关键因素是糙率模拟偏差和模型水气两相因素缩尺效应引起的洞内明满流流态及流量区间偏差,使得模型洞内明满流转变为满流的分界点提前发生。为解决上述问题,首先需对试验得到的明满流区间范围进行修正,在有压流条件下,糙率模拟偏差可采用原模型糙率偏差值按所介绍的步骤予以修正。

Factors Affecting the Prediction Deviation of Diversion Tunnel's Discharge Capacity

In order to solve the problems of large prediction deviation caused by multiple factors affecting the discharge capacity of the diversion tunnel and the complex action mechanism,we identified and classified the influencing factors of the discharge capacity of diversion tunnel by integrating theoretical analysis,numerical simulation and model test.By analyzing the mechanism and degree of influence of each factor,we proposed the method of reducing the prediction deviation of discharge capacity.Roughness simulation deviation and scale effect of the modeled water-air two-phase flow are key factors that lead to the large deviation of the predicted discharge capacity,resulting in deviations of the open and full flow in cavern and the flow rate interval,which makes the open and full flow transforms to full flow in advance.To reduce the deviation,the range of the open and full flow obtained by test needs to be corrected.Under the condition of pressure flow,the roughness simulation deviation can be calculated by using the roughness deviation value of the original model according to the steps introduced in this paper.