矩形渠道分水口水力性能试验研究

Experimental study on hydraulic characteristics of rectangular water-diversion

为了研究矩形渠道含堰坎分水口水力性能,对不同渠宽比下的分水口进行了试验研究,试验选取了5种流量,每个来流量下通过调节下游水深获得不同分流比,总共75组试验,测量了分水口附近的水深等水力因素,获得了分水口附近的水面变化曲线,分析了影响分流比的因素,根据堰流公式,拟合了各渠宽比下流量系数与相对堰上水头之间的关系式.结果表明:分水口处的水面变化在不同流量下变化规律大致相同,随距分水口距离的不同,水面变化也不同;同一渠宽比、流量下,分流比与相对堰上水头呈线性关系,随相对堰上水头的增加而增加,随主渠道上下游傅汝德数的增加而减小;拟合得到的流量系数计算公式精度较高,相关系数大于0.9,满足测流精度要求.该研究对分水口处水力性能进行了初步的研究,以期为灌区量水提供参考依据.

An experimental study was carried out side weir under the different channel width ratios. on the rectangular channel water separation with a Five kinds of flow rates were selected in the experi- ments. Under each flow rate, the different diversion ratios were obtained by adjusting the downstream water depth of the main channel. A total of 75 groups of experiments were carried out. The water depth and other hydraulic factors near the water diversion were measured, and the water surfaces near the wa- ter diversion were obtained. According to the weir flow fommla, the relationship between the discharge coefficient and the head of the relative weir was fitted at each channel width ratio. The results show that the variation of water surfaces at the water-diversion is approximately the same under different flow rates, and the water surface change is different with the distance from water-diversion. Under the same channel width ratio and the flow rate, the diversion ratio is linearly related to the water head on the re- lative weir, and increases with the increase of the relative water head on the weir and decreases with the increase of the Froude number of the main channel upstream and downstream. The accuracy of the calculated formula of the flow coefficient is higher and the COtTelation coefficient is more than 0.9,which meets the accuracy requirement of flow measurement. A preliminaPy study on hydraulic perfor- mance at the water-diversion is carried out, in attempt to provide reference for discharge measurement In litigation areas.