摘要
为了解决传统层流流量计(LFM)线性度不佳、长径比较大、加工使用不便和结构易受流体影响等诸多问题,受双锥流量计的启发,提出了一种环形间隙式层流元件结构,介绍了测量原理和流道内非线性压力损失来源。保持该结构外套筒体和圆柱锥体同轴心,其流道截面为同心圆环,通过CFD仿真确定了锥形导流结构的合理锥形角度,确定了层流元件的尺寸参数。将取压孔设置在流道中充分发展的层流段,理论上消除了传统毛细管式LFM进出口处流动局部损失和层流发展段的动能损失。制作3种不同间隙大小的试件并进行试验,结果显示,当测量流量值小于53 mL/min时,层流元件的测量误差在3%以内;当测量流量值在(130~6189)mL/min时,测量误差在±2%以内;层流元件的压差和流量之间具有优秀的线性关系。说明环形间隙式层流元件结构可有效克服传统LFM的非线性影响,同时测量流量范围可随间隙大小变化而改变。
To address various challenges associated with conventional laminar flowmeters(LFM),such as inadequate linearity,significant length-diameter,inconvenient processing and use,and susceptibility to fluid-induced effects,a novel annular-gap laminar element structure is proposed,drawing inspiration from the double-cone flowmeter.This innovative design is accompanied by a comprehensive elucidation of its measurement principles and an analysis of the sources contributing to non-linear pressure losses within the flow conduit.Central to this design is the maintenance of coaxial alignment between the outer jacket cylinder and the cone and circular cylindrical,resulting in a flow channel characterized by concentric circular annual.Computational fluid dynamics(CFD)simulations were leveraged to ascertain the optimal cone angle of the conical guiding structure and establish the dimensional parameters of the laminar element.Furthermore,pressure taps were strategically positioned within the fully developed laminar segment of the flow channel,thereby theoretically mitigating localized losses at the inlet and outlet typical of conventional capillary-type LFM,as well as kinetic energy dissipation within the laminar development region.Experimental validation involved the fabrication of three distinct test specimens with varying gap dimensions,followed by rigorous testing.Results revealed that for flow rates below 53 mL/min,the measurement error of the laminar element remained within an acceptable margin of 3%.Likewise,within the flow rate range at(130~6189)mL/min,the measurement error was constrained within the range of±2%.Notably,a robust linear relationship between pressure drop and flow rate was observed,affirming the efficacy of the proposed design in circumventing the non-linear influences inherent in traditional LFM.The elucidation asserts the structural efficacy of annular gap laminar flow elements in effectively mitigating the nonlinear influences characteristic of traditional LFM.Simultaneously,it highlights the adaptability of the measured flow range,which can vary with alterations in gap size.
作者
陈雨萱
谢代梁
崔骊水
徐雅
黄震威
刘铁军
Chen Yuxuan;Xie Dailiang;Cui Lishui;Xu Ya;Huang Zhenwei;Liu Tiejun(Key Lab.of Flow Measurement Technology of Zhejiang Province,College of Metrology Measurement and Instrument,China Jiliang University,Hangzhou 310018,China;National Institute of Metrology,Beijing 100029,China)
出处
《电子测量与仪器学报》
CSCD
北大核心
2024年第4期195-201,共7页
Journal of Electronic Measurement and Instrumentation
关键词
层流流量计
微小气体流量
环形间隙式
数值模拟
流量测量
laminar flow meter
micro gas flow
annular gap type
numerical simulation
flow measurement
