基于锥形层流元件的气体微小流量测量研究

Gas micro and small flow measurement based on conical laminar flow element

关键词:  锥形层流元件  差压  质量流量  层流传感技术  流量测量  气体微小流量 

Key words:  conical laminar flow element  differential pressure  mass flow  laminar flow sensing technology  flow measurement  gas micro and small flow

摘要:

目的 常规毛细管层流流量测量技术因层流传感元件结构而存在进出口压损等非线性问题。因此,须改进层流传感元件,解决非线性问题。方法 提出了一种锥形结构的层流元件,利用在层流充分发展段直接取压的优势,有效解决层流起始段非线性压损问题,能直接反映流量与差压之间的线性关系。设计并加工了3种不同间隙的锥形层流元件,搭建了空气微小流量测量系统。结果 在0.015 0~2.348 1 kg/h气体流量范围内,3套装置的测量误差均小于±2%,其中,基于间隙为0.7 mm的锥形层流元件装置的测量误差最小,小于±1%。结论 锥形层流元件用于天然气等气体微小流量测量方面具有良好性能。 

Abstract:

Objective Conventional capillary laminar flow measurement technology has nonlinear problems such as inlet and outlet pressure loss due to the structure of laminar flow sensing element. Therefore, it is necessary to improve the laminar flow sensor to solve the nonlinear problem. Methods A conical laminar flow element was proposed, which could effectively solve the nonlinear pressure loss problem in the initial stage of laminar flow by taking advantage of direct pressure extraction in the fully developed stage of laminar flow and directly reflect the linear relationship between flow and differential pressure. Three kinds of conical laminar flow elements with different gaps were designed and manufactured, and the gas micro and small flow measurement system was built. Results Within the flow range of 0.015 0-2.348 1 kg/h, the measurement errors of the three sets of devices are in the range of ±2%, and the measurement error of the conical laminar flow element device based on the gap of 0.7 mm is the smallest, in the range of ±1%. Conclusion It is proved that the conical laminar flow element has good performance in measuring small and micro natural gas and other gas flow.