PPD气体层流元件设计和使用中几种情况分析  

Analysis of several cases in design and application of pressure potential difference gas laminar flow element

作　　者：倪洁 季建辉 李国占 张东飞 张洪军 Ni Jie;Ji Jianhui;Li Guozhan;Zhang Dongfei;Zhang Hongjun(College of Metrology&Measurement Engineering,China Jiliang University,Hangzhou 310018,China;Suzhou Institute of Metrology,Suzhou 215128,China)

机构地区：[1]中国计量大学计量测试工程学院,杭州310018 [2]苏州市计量测试院,苏州215128

出　　处：《电子测量与仪器学报》2023年第8期194-203,共10页Journal of Electronic Measurement and Instrumentation

基　　金：浙江省尖兵领雁项目(2023C01247)资助。

摘　　要：针对PPD层流流量传感元件在设计制作和使用中可能出现的3种非标准设计或非理想情况采用数值模拟进行研究。对于两个支路中毛细管根数不同的非标准结构设计,数值仿真得到的压降曲线、差压-流量关系与标准结构相比差别微小,根据压降计算得到流量与准确流量之间的相对偏差在±0.4%以内;流量测量实验数据也验证了仿真结果,说明PPD原理适用于两通道毛细管数量不同的结构设计。对制作或使用中可能出现的毛细管进出口部分堵塞情况,计算发现,差压会出现非线性偏差,根据不同堵塞位置,可能正偏差也可能负偏差。当两支路中毛细管直径存在偏差时,两支路阻抗特性不再相同,两支路毛细管中流量和流速不同导致进出口局部阻力不能完全抵消,差压-流量曲线将偏离理想曲线。上述研究结果对于PPD层流流量传感技术的实际应用有一定的参考价值。Numerical simulations were conducted to investigate three non-standard design or non-ideal situations that may arise in the design,fabrication,and usage of PPD laminar flow elements.For the non-standard design with different numbers of capillaries in two branches,in which the numerical simulations were conducted,the pressure drop curves and differential pressure-flow relationships obtained showed minimal differences compared to the standard structure.The relative deviation between the calculated flow rate and the accurate flow rate,as determined by the pressure drop calculations,was within±0.4%.Additionally,the experimental data from flow rate measurements confirmed the simulation results,further demonstrating the applicability of the PPD principle to structural designs with varying numbers of capillaries in the two channels.Regarding the potential occurrence of blockages at the capillary inlets or outlets during fabrication or usage,calculations revealed the presence of nonlinear deviations in the differential pressure.Depending on the location of the blockage,either positive or negative deviations may occur.Furthermore,when there is a deviation in the capillary diameter between the two branches,the impedance characteristics of the two branches become dissimilar.This dissimilarity in flow rates and velocities within the capillaries of the two branches leads to incomplete compensation of local resistances at the inlets and outlets,causing the differential pressure-flow curve to deviate from the ideal curve.The aforementioned research findings hold valuable insights for the practical application of PPD laminar flow sensing technology.

关 键 词：PPD层流流量传感元件 气体流量 数值模拟 非理想情况 阻抗特性 

分 类 号：TN06[电子电信—物理电子学]