Structural design and flow characteristics of conical gas laminar flow element

doi:10.11949/0438-1157.20241377

Abstract

Abstract:

A laminar flow element with a guide cone and annular cross-section was designed to solve the problem of poor linearity in traditional laminar flow meters (LFM), and pressure-measurement position was directly put in the laminar flow section for further improving the linearity between pressure difference and flow rate. Using computational fluid dynamics (CFD) simulation technology to determine a reasonable guide cone angle is 30°. Analysis of the channel size reveals that it has a significant impact on the pressure difference in the measurement section, and the flow error decreases with the increase of the channel size. The applicability of laminar flow elements to different gases was explored using air, N₂ and CO₂ as working fluids, and the flow errors of the three were all less than 2%. By using CFD simulation technology to simulate the new laminar flow meter, detailed data on pressure loss along the flow channel and internal flow field can be obtained, which can provide useful flow details, feasible design ideas, and improve experimental efficiency.

Key words: laminar, cone laminar flow element, optimal design, CFD, flow characteristic

摘要：

为解决常规层流流量计（laminar flow meter，LFM）线性度不佳的问题，设计了一款内有导锥、环形截面的层流元件，并且通过将引压孔设置在层流段的方式进一步提高了压差-流量线性度。采用计算流体力学（computational fluid dynamics，CFD）仿真技术确定了合理的导锥角度为30°，对流道尺寸分析发现，流道大小对测量段压差影响较大，流量误差随流道的增大而减小。以空气、N₂、CO₂气体为工质，探究了层流元件对不同气体的适用性，三者的流量误差均小于2%。借助CFD仿真技术对新型层流流量计进行模拟计算能够得到流道沿程压力损失和内部流场的详细数据，可以为实验提供有用的流动细节、可行的设计思路，从而提高实验效率。

关键词: 层流, 锥形层流元件, 优化设计, 计算流体力学, 流动特性

CLC Number:

TH 814

Xiaofeng CAO, Huahai ZHANG, Jiangyun WANG, Limin WANG. Structural design and flow characteristics of conical gas laminar flow element[J]. CIESC Journal, 2025, 76(9): 4440-4448.

曹潇风, 张华海, 王江云, 王利民. 锥形气体层流元件结构设计及流动特性研究[J]. 化工学报, 2025, 76(9): 4440-4448.

Figures/Tables 19

References 30

[1]	Suga S, Okajima M, Fujiwara K, et al. “Cation flow” method: a new approach to conventional and combinatorial organic syntheses using electrochemical microflow systems[J]. Journal of the American Chemical Society, 2001, 123(32): 7941-7942.
[2]	Sagi H, Zhao Y B, Wereley S T. Wide range flow sensor—Vacuum through viscous flow conditions[J]. Journal of Vacuum Science & Technology A-Vacuum, Surfaces, and Films, 2004, 22(5): 1992-1999.
[3]	Wang B, Zhang N, Cao Q W, et al. Evaluation approach to dynamic characteristic of turbine flowmeters considering calibration system response[J]. Flow Measurement and Instrumentation, 2018, 64: 126-132.
[4]	贺登辉, 陈森林, 白博峰. 基于Chisholm模型的V锥流量计气液分层流测量新模型[J]. 化工学报, 2018, 69(8): 3428-3435.
	He D H, Chen S L, Bai B F. New model for measuring stratified gas-liquid flow by Chisholm-model-based V-cone flowmeter[J]. CIESC Journal, 2018, 69(8): 3428-3435.
[5]	Zhang Z Z, Ding D W, Zhang Z G. Research on fine chemical process and equipment detection and computer monitoring technology[J]. Journal of Physics: Conference Series, 2021, 1992(2): 022152.
[6]	娄锋炎, 尹佳滨, 段笑南, 等. 连续微反应加氢技术在脱保护反应中的应用[J]. 化工学报, 2021, 72(2): 761-771.
	Lou F Y, Yin J B, Duan X N, et al. Application of continuous micro-reactor hydrogenation technology in deprotection reaction[J]. CIESC Journal, 2021, 72(2): 761-771.
[7]	于海鹏, 陈来夫. 精对苯二甲酸装置中空气流量测量的研究与优化[J]. 石油化工自动化, 2024, 60(3): 96-97, 102.
	Yu H P, Chen L F. Researgh and optimization of air flow measurement in a purified terephthalic acid plant[J]. Automation in Petro-Chemical Industry, 2024, 60(3): 96-97, 102.
[8]	Wang Z X, Xu Y, Liu T J, et al. Development of a measurement device for micro gas flowrate based on laminar flow element with micro-curved surface[J]. Micromachines, 2024, 15(5): 660.
[9]	Dong S S, Huang H Q, Peng H D, et al. Development of the pressure potential differential type laminar flow transducer for gas flow measurement[J]. Journal of Electronic Measurement and Instrumentation, 2023, 35(10): 130-136.
[10]	Priestman G H, Boucher R F. The biased laminar by-pass fluidic flowmeter[J]. Journal of Fluids Engineering, 2005, 127(6): 1199-1204.
[11]	Wang Q Q, Dong S S, Li G Z, et al. Numerical simulation of the laminar flow sensing element of pressure potential differential type[J]. Chinese Journal of Sensors and Actuators, 2020, 33(11): 1587-1593.
[12]	王伯年, 王荣杰, 王利民, 等. 层流流量计设计参数的选择与确定[J]. 仪器仪表学报, 2000, 21(5): 474-476.
	Wang B N, Wang R J, Wang L M, et al. On the choice and determination of design parameters for laminar flow meters[J]. Chinese Journal of Scientific Instrument, 2000, 21(5): 474-476.
[13]	Wang X L, Zhao Y J, Yu H C, et al. Research on dynamic characteristics of laminar flow meter[J]. Flow Measurement and Instrumentation, 2024, 97: 102619.
[14]	Robert F B, John D W, Michael R M. Modeling laminar flow meters for process gases[J]. Proceedings of Flomeco, 2010, 8: 13-15.
[15]	Song J, Xie D L, Xu Y, et al. Gas micro and small flow measurement based on conical laminar flow element[J]. Chemical Engineering of Oil and Gas, 2023, 52(6): 110-116.
[16]	Wright J D, Cobu T, Berg R F, et al. Calibration of laminar flow meters for process gases[J]. Flow Measurement and Instrumentation, 2012, 25: 8-14.
[17]	Feng C C, Lin W T, Yang C T. Laminar flow meter with straight glass capillary[J]. MAPAN, 2011, 26(3): 237-245.
[18]	Berg R F. Simple flow meter and viscometer of high accuracy for gases[J]. Metrologia, 2005, 42(1): 11-23.
[19]	Nishimura R, Kawashima K, Kagawa T. Analysis of laminar flow meter with flute-type cross section laminar elements[C]//2008 Asia Simulation Conference-7th International Conference on System Simulation and Scientific Computing. Beijing, China. IEEE, 2008:1110-1114.
[20]	张嘉祥. 层流流量计计算数学模型和标定方法的研究[J]. 中国测试, 2009, 35(5): 14-17.
	Zhang J X. Research on flow calculation mathematic model and calibration of laminar flow meter[J]. China Measurement & Test, 2009, 35(5): 14-17.
[21]	Nuszkowski J, Schwamb J, Esposito J. A novel gas divider using nonlinear laminar flow[J]. Flow Measurement and Instrumentation, 2016, 52: 255-260.
[22]	Wang X L, Chen Y C, Jiang Y X, et al. Rectangle-gap-type laminar flow meter with inward pressure taps[J]. Flow Measurement and Instrumentation, 2021, 79: 101893.
[23]	Pena F L, Diaz A D, Lema M R, et al. A new approach to laminar flowmeters[J]. Sensors, 2010, 10(12): 10560-10570.
[24]	王剪, 豆峰, 赵晓东, 等. 差分式层流流量传感技术研究[J]. 传感技术学报, 2019, 32(12): 1790-1794, 1829.
	Wang J, Dou F, Zhao X D, et al. Research on the differential type laminar flow sensor[J]. Chinese Journal of Sensors and Actuators, 2019, 32(12): 1790-1794, 1829.
[25]	黄浩钦. 压力位差式气体层流流量计研究[D]. 杭州: 中国计量大学, 2021.
	Huang H Q. Study on pressure differential gas laminar flow meter[D]. Hangzhou: China Jiliang University, 2021.
[26]	Pedro A, Morgado T, Navas H. An uncertainties simulation model applied to an automated laminar flowmeter[J]. Applied Sciences, 2020, 10: 888.
[27]	张家庆, 刘朝晖, 李宇, 等. 碳氢燃料JP-10高温液态黏度测量和推算模型构建方法研究[J]. 化工学报, 2022, 73(1): 153-161.
	Zhang J Q, Liu Z H, Li Y, et al. Viscosity measurements and prediction model construction for liquid JP-10 at high-temperature conditions[J]. CIESC Journal, 2022, 73(1): 153-161.
[28]	陈雨萱, 谢代梁, 崔骊水, 等. 环形间隙式层流元件设计及流量特性研究[J]. 电子测量与仪器学报, 2024, 38(4): 195-201.
	Chen Y X, Xie D L, Cui L S, et al. Design and flow characterization of annular gap laminar flow elements[J]. Journal of Electronic Measurement and Instrumentation, 2024, 38(4): 195-201.
[29]	Wojtkowiak J, Popiel C O. Inherently linear annular-duct-type laminar flowmeter[J]. Journal of Fluids Engineering, 2006, 128(1): 196-198.
[30]	Hoff D. The zero-Mach limit of compressible flows[J]. Communications in Mathematical Physics, 1998, 192(3): 543-554.

r₁/mm	r₂/mm	L/mm	L_e/mm
8.0	7.7	180.0	20.0
8.0	7.8	180.0	15.0
8.0	7.9	180.0	10.0

r₁/mm	r₂/mm	L/mm	L_e/mm
8.0	7.7	180.0	20.0
8.0	7.8	180.0	15.0
8.0	7.9	180.0	10.0

配置	计算时间/s	加速比
16 CPU	5.040	—
1 GPU	0.400	12.60
2 GPU	0.275	18.32
3 GPU	0.250	20.00
4 GPU	0.250	20.00
5 GPU	0.255	19.76
6 GPU	0.290	17.38

配置	计算时间/s	加速比
16 CPU	5.040	—
1 GPU	0.400	12.60
2 GPU	0.275	18.32
3 GPU	0.250	20.00
4 GPU	0.250	20.00
5 GPU	0.255	19.76
6 GPU	0.290	17.38

ΔP/Pa	q_r/(L/min)	q_t/(L/min)	δ/%
0	0	0	0
854.10	0.2	0.20	0.50
2987.80	0.7	0.70	0.55
42354.14	10	9.87	1.31
84711.21	20	19.74	1.31
127050.22	30	29.60	1.32
169448.27	40	39.48	1.30
211814.38	50	49.35	1.29
232998.74	55	54.29	1.29