偏离水力最佳断面渠道运行效益分析计算

Operating benefit analysis and calculation of the channel with deviation of the best hydraulic cross section

根据矩形和梯形断面的水力最佳断面条件,在保持过水断面面积、渠道底坡、边壁粗糙系数不变的情况下,推导出偏离水力最佳断面的矩形渠道和梯形渠道运行效率计算公式,绘出偏离量与效率的变化关系曲线,分析了偏离程度、过水断面面积、运行效率之间的相互变化关系,提出了由于偏离而影响运行效益的一般计算方法,并给出了算例。该方法在渠道设计方案选择时能快速、准确地计算出各方案的运行效益影响值。该方法也可对已建渠道进行评价。

Based on the best hydraulic cross section condition of a rectangular section and trapezoid section, and holding the channel bottom slope, the wetted area and the roughness coefficient constant, the calculation formula for the operatinal benefit of rectangular and trapezoid channels with deviation of the best hydraulic cross section is deduced. The relationship between deviation extent, water through the sectional area, and operational benefit are analyzed. Meanwhile, the common method for calculating operational benefit affected by deviation is put forward, and an example is given. This method can calculate the operational benefit＇s influence value quickly and exactly during design scheme selection. The method can also be used to evaluate channels that have been built.