Research of Small Sheet-Type Laminar Flow Meter

小型片式层流流量计研究

School of Power and Energy, Northwestern Polytechnical University, Xi'an 710072, China

Received: 14 October 2019

Abstract

A small sheet-type LFM is proposed to solve the problems of leakage and deformation in the design of traditional sheet-type LFM. The pressure tap is set in the middle of the laminar flow channel to extract pressure from the fully developed laminar flow. The design value Re_max·d_e/l is 5.81, which is much higher than the 2~2.5 required by the traditional design. Experimental results show that the linearity factor ξ_L of small sheet-type LFM can reach 0.81% and the accuracy is up to 1%, which shows that the present design can effectively overcome the nonlinear effects caused by sudden expansion and contraction. In addition, when the flow rate is above 20% designed maximum valve, the calculation error of pressure drop can be controlled below 5.42%.

摘要

为解决片式LFM在设计上存在的泄漏、变形等问题，提出了一种小型片式LFM构型。该小型片式LFM将引压孔设置在层流流道中间，从充分发展的层流中引压，Re_max·d_e/l=5.81，远大于传统LFM设计时要求的2~2.5。试验结果显示，小型片式LFM的线性度ξ_L可达0.81%，满足精度1%所需，说明此设计可有效克服突扩突缩带来的非线性影响。此外，试验流量在设计最大流量20%以上时，压差的计算误差可以控制在5.42%以下。