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- 2015
U形渠道圆头量水柱水力性能影响因素研究
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Abstract:
【目的】基于临界流原理，研究不同因素对U形渠道圆头量水柱水力性能的影响，为其在我国北方灌区的推广应用提供参考。【方法】对U形渠道上6种喉口收缩比（ε=0.75，0.70，0.63，0.56，0.50，0.44）的圆头量水柱在5种流量（Q=0.015，0.025，0.035，0.045，0.055 m3/s）、4种渠道比降（i=1/1 000，1/2 000，1/3 000，1/5 000）下的测流公式、适宜喉口收缩比、水头损失、临界淹没度、测流精度等水力性能进行试验研究。【结果】圆头量水柱的驻点水深与流量间存在良好的指数相关关系，相关系数达0.997。根据试验数据回归分析得到了4种渠道比降的流量计算公式，公式符合量纲和谐原理，满足了测流精度的要求，实测流量与计算流量之间最大误差为6.79%；圆头量水柱的适宜喉口收缩比为0.50～0.70时，上游壅水高度和水头损失均较小，且临界淹没度较高，可达0.90。【结论】圆头量水柱具有结构简单、抗淤堵等优点，适合在我国北方多泥沙水源的渠道中应用。
【Objective】This paper studied the factors affecting hydraulic performance of water-measuring pillar with round head based on the principle of critical flow to improve its application in irrigation areas of North China.【Method】The hydraulic performance on flow measurement formula,proper throat contraction ratio,head loss,critical submergence degree,and flow measurement precision of water-measuring pillar with round head with six contraction ratios (ε=0.75,0.70,0.63,0.56,0.50,and 0.44) in U-shaped channel was tested based on five discharge rates (Q=0.015,0.025,0.035,0.045,and 0.055 m3/s) and four channel slopes (i=1/1 000,1/2 000,1/3 000,and 1/5 000).【Result】There existed a good exponential correlation between the stagnation point depth of the water measuring pillar with round head and the discharge with coefficient of correlation of 0.997.Discharge formulas of four channel slopes were obtained through the regression analysis of experiment data,the fitted discharge formula which was in line with the dimension concordant principle met the flow measurement accuracy,and the maximum error between the measured discharge and the calculated discharge was 6.79%.When the proper throat contraction ratio was within 0.50 to 0.70 and the upstream backwater as well as the water head loss was small,it had a high critical submergence degree of up to 0.90.【Conclusion】The water-measuring pillar with round head has a simple structure and can resist sludge plugging, which suits the channels with sediment carried water in North China
