两种堰流计算公式下平底闸闸门净宽不同的原因分析

Different Net Width Analysis of Flat Bottomed Sluice by Two Weir Flow Formulas Calculation

在计算平底闸闸门净宽时,当水闸过流为堰流时,一般采用堰流计算公式确定闸门净宽,同时现行规范亦规定当堰流处于高淹没度(hs/H0≥0.9)时,亦可采用高淹没度计算公式确定闸门净宽。理论上,当设计流量、闸上下水位、闸底板高程确定时,闸门的净宽也应是唯一定值,但在实际计算时,两者计算的水闸净宽相差较大,需明确造成两者计算结果不一致的原因。研究发现,两者计算结果不同主要由淹没系数σ值引起。因此在工程设计时,当水闸堰流处于高淹没度工况,采用常见堰流计算公式计算水闸净宽时,需修正堰流的淹没系数σ。

According to the regulation of net width of flat bottomed sluice,the net width of sluice can be determined using weir flow calculation formula when the overflow is weir flow.Meanwhile,according to current norms,it also can be determined by high submergence degree calculation formula when the weir flow is in high flooding(hs/H0≥0.9).Theoretically,when the designed flow rate,the upper and lower water levels of the sluice and the elevation of sluice bottom are determined,the net width of sluice should be constant.However,the results calculated through the two formulas vary great actually.It is necessary to clarify the reasons for the inconsistent results.We find that the difference results should mainly be attributed to the submerged coefficient of weir flow.In actual engineering design,the submerged coefficient of the weir flow should be corrected when adopting common submerged discharge formula to calculate net width of sluice under the working condition of high submergence degree.