基于SSA-BP算法的仿鸮翼形量水槽水力性能

Hydraulic performance of the flow measuring flume of imitating long-eared owl wing based on SSA-BP algorithm

为了设计出构造简单、水力性能优良,同时能满足灌区量水需求的量水槽,该研究根据鸮翼曲线提出了一种仿鸮翼形渠道量水槽。首先,利用基于麻雀搜索算法的BP神经网络(sparrow search algorithm,SSA-BP)优化鸮翼展向比,得到最小水头损失的量水槽线形,并探究了优化后的量水槽在输水渠道的适用性。进一步地,在8种流量工况下,选用6组收缩比开展测流试验,结合FLOW-3D数值模拟分析仿鸮翼形量水槽水头损失、弗劳德数、壅水高度、临界淹没度等水力参数,建立测流公式。试验表明,基于SSA-BP优化的仿鸮翼形量水槽具有良好的测流性能,在建议收缩比0.60~0.66范围内,其水头损失为7.75%~14.21%,临界淹没度为0.81~0.90,上游壅水高度为0.84~3.16 cm,上游弗劳德数均小于0.42,符合灌区量水要求。建立的测流公式,平均测流误差为1.49%,测流精度较高。仿鸮翼形量水槽各项水力性能指标优良,能满足灌区测量精度,针对灌区优化水资源配置、精细化用水具有一定的推广价值。

Water demand of irrigation areas is required for the flow-measuring flume with simple structure and excellent hydraulic performance.Among them,the morphological structure of long-eared owl wings has been proved as the outstanding noise reduction and excellent drag reduction.The impeded state of the flume in the channel flow field is also similar to the air resistance of the long-eared owl during flight.In this study,the flow-measuring facility was proposed to imitate the shape of long-eared owl.The structure of bird wing was used to design a bionic structure flume.Numerical simulations were combined with the experiments to explore the correlation among various factors.The optimal line shape was determined using internal logical connections.Firstly,Sparrow Search-based BP Neural Network(SSA-BP)was utilized to optimize the spanwise location of the owl wing.The optimal flume shape was achieved with the minimal head loss.The suitability of the optimized flume was also investigated in the irrigation channels.Furthermore,a series of flow measurement tests and numerical simulations were conducted to verify the effectiveness of the optimization.The hydraulic trials were carried out in the Laboratory of Hydraulic Engineering and Hydraulics of Northwest A&F University in 2024.The channel was set as a flatslope rectangular channel with the channel length L=10 m,inner width B=0.7 m,and height H=0.4 m.The flow measuring flume was 4.3 m away from the inlet of the channel.The flow measurement experiments were selected as the eight kinds of flow conditions(0.50,0.54,0.58,0.60,0.62 and 0.66),and six sets of contraction ratios(20-55 L/s,each increase of 5 L/s was a flow gradient).FLOW-3D numerical simulation was combined to analyze the hydraulic parameters,such as the head loss percentage,Froude number,backwater height,and critical submergence degree of the flow measuring flume of imitating longeared owl wing.The experiments demonstrated that the flow measuring flume exhibited the excellent flow measurement performance after SSA-BP optimization.Within the recommended contraction ratio range of 0.60 to 0.66,the head loss percentage was ranged from 7.75%to 14.21%,the critical submergence degree was from 0.81 to 0.90,the upstream backwater height was from 0.84 to 3.16 cm,and the upstream Froude number was all less than 0.42,fully meeting the precision requirements of irrigation water measurement.Therefore,the flow measurement formula was then established.The relative error between the calculated and the actual flow was less than 5%,and the average relative error was 1.49%.The accuracy of flow measurement was higher than before.The excellent hydraulic performance was achieved in the flow-measuring flume of imitating long-eared owl wing.The finding can provide a strong reference to optimize the water resource allocation and finetuning water usage in irrigation areas.