地下式水电站调压室交通洞过渡过程中的风速模拟

Simulation of wind speed in the traffic cave of surge tank of underground hydropower station in transient process

在考虑气体可压缩性的基础上,建立了地下式水电站调压室交通洞过渡过程中的气体运动数学模型,依据气体管道瞬变流的特征线法,提出了风速模拟的方法并编制了完整的模拟程序,通过与试验结果的对比验证了所提求解方法与模拟程序的适用性与合理性。然后分析了交通洞的体型(长度、断面积、倾角)对风速发展、分布及波动过程的影响,并从波动叠加的角度揭示了各因素的作用机理。结果表明:对于地下式水电站调压室交通洞在过渡过程中的风速的模拟,考虑气体可压缩性是必要的。交通洞断面的风速波动过程由低频质量波(基波)与高频弹性波(谐波)叠加而成。通气洞长度影响谐波的振幅和周期、断面积影响基波和谐波的振幅、倾角则仅影响谐波的振幅。

This paper presents a mathematical model established for the simulation of gas movement in the traffic cave of surge tank on the basis of considering the compressibility of gas, and proposes a wind speed simulation method and simulation program according to the characteristics line method of the gas tran- sient flow in the pipe. The applicability and rationality of the proposed method and program has been veri- fied by comparing with the experimental results. Then the influences of traffic cave size （length, area, an- gle） on the development, distribution and wave process of wind speed are analyzed, and the mechanism of these factors are revealed from the point of wave superposition. The results show that it is essential to take the compressibility of the gas into consideration on the simulation of wind speed in the traffic cave of surge tank of underground hydropower station in transient process. The wind speed fluctuation is superim- posed by the low frequency mass wave （fundamental wave） and the high frequency elastic wave （harmonic wave）. The length of traffic cave mainly effect amplitude and cycle of harmonic wave, the sectional area of traffic cave affect the amplitudes of fundamental wave and harmonic wave while the dip angle only influenc- es the amplitude of harmonic wave.