喷嘴式空气流量测量不确定度分析与评定  

Analysis and evaluation of measurement uncertainty of air flowrate with nozzle

作　　者：徐卫荣[1] 杜垲[1] 

机构地区：[1]东南大学

出　　处：《制冷与空调》2009年第5期13-16,41,共5页Refrigeration and Air-Conditioning

基　　金：国家自然科学基金资助项目(50876020);"十一五"国家科技支撑计划重点项目(2008BAJ12B02)

摘　　要：为了解可直接测量参数对喷嘴式空气流量测量结果准确性及可靠程度的影响，找出对测试结果影响较大的环节以进行提高测量准确度的改进，建立喷嘴式空气流量测量数学模型，分别对测试喷嘴处空气比容和测试喷嘴前后气体静压差引入的不确定度进行分析，对喷嘴式空气流量测量进行合成标准不确定度评定和扩展不确定度评定。结果表明：测试空气质量流量为0．119kg／s时，合成标准不确定度为2．396×10kg／s，扩展不确定度为1．433×10^-3kg／s，测试相对误差为1．20％，其中测试喷嘴前后气体静压差引入的不确定度较大，提出选用量程为0～500Pa的差压变送器较为适宜。To understand the influerce of parameters measured directly on the accuracy and reliable degree of measuring air flow with nozzle, finds out the links affecting great on the test results in order to improve measure accuracy, builds mathematical model of measuring air flow with nozzle. Analyzes uncertainty caused by air specific volume at nozzle and static pressure difference pre and post nozzle. Evaluates combined standard uncertainty and expanded uncertainty of measuring air flow. The results show that when the air mass flow measured is 0. 119 kg/s, the combined standard uncertainty is 2. 396×10^-3 kg/ s. And the expanded uncertainty is 1. 433× 10^-3 kg/s. The relative error of the measuring system is 1.2%. Uncertainty caused by air specific volume at nozzle is greater. And puts forward selecting differential pressure transmitter with the range of 0-500 Pa.

关 键 词：喷嘴 空气流量 误差分析 不确定度 压差 

分 类 号：TG801[金属学及工艺—公差测量技术]