Z形薄壁堰过流能力试验

鉴于Z形堰的水流特性及过流能力尚未见到相关报道,为研究Z形堰的过流能力,采用概化水工模型,进行了6个堰型方案、12组流量的水工模型试验。结果表明,Z形堰的过流能力大于直线堰,且Z形堰的展宽比越大,流量扩大倍数越大;Z形堰的流量计算可采用通用的堰流公式,其综合流量系数与堰上水深、堰高、展长、前堰宽、后堰宽等因素有关,展宽比、前后堰宽比越大,流量系数越大;堰上水深与堰高之比越大,流量系数越小。利用试验数据给出了考虑堰上水深与堰高之比、展宽比、前后堰宽比等因素的Z形堰流量系数估算公式。

Experiments on discharge coefficient of Z-shape weirs

There is still no research reports on the hydraulic characteristics and discharge capacities of Z-shape weirs. To study the hydraulic characteristics of Z-shape weirs, six schemes of weir shapes and twelve groups of different flow discharges were carried out by model tests, and the experimental data was analyzed. The results show that, the discharge capacity of Z-shape weirsis proved to be stronger than that of linear-type weirs. Furthermore, the ratio of flow discharge of Z-shape weirs to that of linear-shape weirs(in the same channel)increases with the larger ratio of the crest length to the channel width. In addition, the flow discharge of Z-shape weirs can be calculated by the general weir formulas, and the integrated discharge coefficient is related to the water height on the crest(H), the height of weir(P), the crest length, the width of the front and back weir. The discharge coefficient has a positive relation with the ratio of crest length to channel width and the ratio of the front weir width to the back weir width while it had an inverse relation with H/P. A novel experimental formula is established in the consideration of H/P, the ratio of the crest length to the channel width and the ratio of the front weir width to the back weir width, which can estimate the discharge coefficient of Z-shape weirs.