整流罩和排水立管长度对雨水斗排水性能影响的研究

Study on the effect of anti-vortex cover and length of vertical standpipe on drainage performance of roof outlet

选取市场上某品牌虹吸式雨水斗(无集水斗),通过改变整流罩的有无及排水立管长度(3m、1.5m)来组成4种工况条件,分别进行流量与斗前水深试验。对无整流罩试验水面起伏不定的原因进行了简要分析,并通过对比整流罩的有无所对应的流量与斗前水深关系曲线,总结出适当降低整流罩高度,扩大整流罩罩径,可尽早实现整流罩的隔气作用,减小斗前水深,提高雨水斗的排水性能。通过对比3m和1.5m排水立管时的流量与斗前水深关系曲线和进一步的理论计算,总结出当管内最大负压控制在-1atm(-101.325kPa)以内时,排水立管越长,雨水斗的泄流量就越大,管内最大负压也就越大。同时推算出固定长度排水立管内,距离雨水斗出水口越远,压强越大,管道初始端负压最大。

This paper describes a flow versus depth test on a certain brand of siphonic roof outlet without sink under four working conditions with different vertical standpipe length and with or without cover.The reasons for varying water level without cover were analyzed.Based on the comparison of the flow rates before outlet with and without cover,it was concluded that lowering the anti-vortex cover and extending its diameter appropriately could isolate gas earlier,lower the water level before outlet and improve the drainage performance of roof outlet.Through the comparison of the curves of flow rate-water head relationship between the standpipe of 3mand 1.5mas well as further theoretical calculation,it showed that when the minimum pressure was controlled in less than a negative atmospheric pressure the longer the standpipe,the larger the flow rate and also the minimum pressure would be low.The calculation also proved that in a fixed length of standpipe,the farther the location was away from the roof outlet,the higher the pressure would be.The minimum pressure appeared at the beginning of the standpipe.