DIN EN ISO 9300-2005 用文杜利临界流量喷嘴测量气体流量

标准号：DIN EN ISO 9300-2005
中文标准名称：用文杜利临界流量喷嘴测量气体流量
英文标准名称：Measurement of gas flow by means of critical flow Venturi nozzles (ISO 9300:2005); English version of DIN EN ISO 9300
标准类型：A42
发布日期：1999/12/31 12:00:00
实施日期：1999/12/31 12:00:00
中国标准分类号：A42
国际标准分类号：17.120.10
适用范围：This International Standard specifies the geometry and method of use (installation in a system and operatingconditions) of critical flow Venturi nozzles (CFVN) used to determine the mass flow-rate of a gas flowingthrough a system. It also gives the information necessary for calculating the flow-rate and its associateduncertainty.It is applicable to Venturi nozzles in which the gas flow accelerates to the critical velocity at the throat (thisbeing equal to the Focal sonic velocity), and only where there is steady flow of single-phase gases. At thecritical velocity, the mass flow-rate of the gas flowing through the Venturi nozzle is the maximum possible forthe existing upstream conditions while CFVN can only be used within specified limits, e.g. limits for the nozzlethroat to inlet diameter ratio and throat Reynolds number. This International Standard deals with CFVN forwhich direct calibration experiments have been made in sufficient number to enable the resulting coefficientsto be used with certain predictable limits of uncertainty.Information is given for cases where the pipeline upstream of the CFVN is of circular cross-section, or it canbe assumed that there is a large space upstream of the CFVN or upstream of a set of CFVN mounted in acluster. The cluster configuration offers the possibility of installing CFVN in parallel, thereby achieving highflow-rates.For high-accuracy measurement, accurately machined Venturi nozzles are described for Iow Reynoldsnumber applications.