浑水条件下水头及流量测量方法探讨  

Discussion on measuring method of head and flow under turbid water conditions

作　　者：陆力[1] 徐洪泉[1] 孟晓超[1] 张海平[1] 张建光[1] 

机构地区：[1]中国水利水电科学研究院,北京100038

出　　处：《水电站机电技术》2017年第5期1-6,共6页Mechanical & Electrical Technique of Hydropower Station

基　　金：国家重大科学仪器设备开发专项"水力机械磨蚀测试系统研制"(2011YQ070049)

摘　　要：从浑水水头的定义入手,提出了以一个压力场和两个速度场为前提的浑水水头表达方式,并在对欧拉数、压力系数、流量系数等相似参数进行细致分析的基础上,进一步确认了两相流条件下浑水水头的相似表达。其次,本文还探讨了泥沙等固体颗粒进入压力测量管路给测量结果带来的不确定性和巨大影响,介绍了浑水水头的正确测量方法,推导了避免泥沙颗粒进入测压管路的浑水水头测量计算公式,提出了通过测量泥沙流量浓度和体积浓度的方式间接测量计算泥沙流速和清水流速的方法。关于固液两相流的流量测量,主要介绍了电磁流量计不受固体颗粒影响并可高精度测量浑水流量的原理,论述了固体颗粒对文透里流量计测试浑水流量的影响,介绍了水轮机蜗壳压差流量计在浑水条件下高低压两侧泥沙浓度的巨大差异,分析了其产生的原因及对流量测试的影响,提出了初步的解决办法。Based on the definition of turbid water head,an expression of turbid water head is proposed on the premise of one pressure field and two velocity fields.Moreover,based on detailed analysis on Euler number,pressure coefficient and flow coefficient,the similarity expression of turbid water head under two-phase flow conditions is further determined.Meanwhile,this paper also discusses uncertainties and great influences on measuring results due to sediment and other solid particles in piezometer tube,introduces a correct measuring method of turbid water head,derives the formula of measuring and calculating turbid water head by avoiding sediment particles entering the piezometer tube,and proposes a method for indirectly measuring the flow velocities of sediment and clear water by measuring the flow concentration and the volume concentration of sediment.In view of solid-liquid two-phase flow measuring,this paper mainly introduces the principle of measuring the turbid water flow by means of an electromagnetic flow meter at a high accuracy without influences from solid particles,discusses the influences of solid particles on measuring turbid water flow using a Venturi flow meter,introduces great difference in sediment concentration between HP and LP sides measured using a differential flowmeter of turbine spiral casing under turbid water conditions,analyzes the cause of such a great difference and corresponding influences on flow measuring,and proposes a preliminary solution.

关 键 词：浑水 两相流 水头 流量 浑水密度 测量不确定度 泥沙流速 

分 类 号：TV149[水利工程—水力学及河流动力学]