| 倪 洁,季建辉,李国占,张东飞,张洪军.PPD 气体层流元件设计和使用中几种情况分析[J].电子测量与仪器学报,2023,37(8):194-203 |
| 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 |
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| DOI： |
| 中文关键词: 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 |
| 英文关键词:PPD laminar flow sensor gas flow numerical simulation non ideal situation impedance characteristic |
| 基金项目:浙江省尖兵领雁项目(2023C01247)资助 |
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| 中文摘要: |
| 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。 |
| 英文摘要: |
| 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. |
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