基于兰姆波的罐体液位检测方法研究
摘要
罐体液位检测广泛应用于石油、化工等领域，对液位检测新方法、新原理的研究是近年来该领域的一个研究热点。根据兰姆波中某些模态的特定参数(如衰减因子)对液体存在敏感的特性，提出一种基于兰姆波的罐体液位检测方法，搭建试验系统，并对影响罐体液位检测试验结果的各种主要因素进行试验研究。主要工作内容如下：
(1)基于超声导波理论，对能量速度的求解公式进行推导，并指出能量速度和群速度的区别和联系；对单面液体负载薄板中的兰姆波的特征方程进行求解；并对漏兰姆波和兰姆波、周向导波和兰姆波、纵向导波和兰姆波之间的关系进行理论分析和试验验证。
(2)对厚度不同板中的兰姆波的各模态的传播特性(主要是衰减因子对液体存在的敏感特性)进行了研究，并对影响液位检测试验结果的主要因素(包括激励信号的周期数，激励信号所加的窗函数，模态的频散特性和衰减因子，传感器的工作频率和入射角度等)进行了试验研究。
(3)研制了工作频率为2.5MHz、入射角为50°的超声纵波斜探头和其夹具，实现对壁厚3mm，直径600mm罐体的液位定点和连续检测，并给出液位高度与接收信号幅值之间的拟合曲线。
(4)利用Labview语言编写罐体液位检测软件，实现了罐体液位的定点检测以及实时报警。
Liquid level detection of tanks is widely used in petroleum, chemical and otherfields. Research on new methods and new principles about liquid level detectionhave become hot interests in these fields. A new method detecting the liquid levelwas presented and implemented, based on the sensitivity of the characteristicparameters, such as, attenuation factor, of some Lamb wave modes to the presenceof liquid. Besides, different kinds of factors influencing the liquid level detectionresults were analysed and verified experimentally. The main contents are as follows:
(1) Based on ultrasonic guided wave theory, the energy velocity formula wasderived; The relationship between group velocity and energy velocity was alsoanalysed; The characteristic equations of Lamb waves in solid plate with liquid loadon single side was derived; the relationship among Lamb waves and leak Lambwaves, circumferential guided waves and Lamb waves, longitudinal guided wavesand Lamb waves were also analysed theoretically and verified experimentally.
(2) Propagation characteristics of different modes in different-thickness plateswere analysed. Besides, different kinds of factors (cycle number of excitation signal,window function, mode dispersion and attenuation factor, working frequency andincidence angle of transducer, etc.) influencing the liquid level detection results wereanalysed experimentally.
(3) The transducer with working frequency 2.5MHz, incident angle 50°andtransducer clamp were developed to implement fixed liquid level detection andliquid level measurement of the tank with 600mm-outer-diameter and3mm-thickness-wall, the fitting curve between liquid level and received signalamplitude was obtained.
(4) Programmed real-time liquid level detection software using LabVIEW toimplement fixed liquid level detection and real-time alarm.
(1)基于超声导波理论，对能量速度的求解公式进行推导，并指出能量速度和群速度的区别和联系；对单面液体负载薄板中的兰姆波的特征方程进行求解；并对漏兰姆波和兰姆波、周向导波和兰姆波、纵向导波和兰姆波之间的关系进行理论分析和试验验证。
(2)对厚度不同板中的兰姆波的各模态的传播特性(主要是衰减因子对液体存在的敏感特性)进行了研究，并对影响液位检测试验结果的主要因素(包括激励信号的周期数，激励信号所加的窗函数，模态的频散特性和衰减因子，传感器的工作频率和入射角度等)进行了试验研究。
(3)研制了工作频率为2.5MHz、入射角为50°的超声纵波斜探头和其夹具，实现对壁厚3mm，直径600mm罐体的液位定点和连续检测，并给出液位高度与接收信号幅值之间的拟合曲线。
(4)利用Labview语言编写罐体液位检测软件，实现了罐体液位的定点检测以及实时报警。
Liquid level detection of tanks is widely used in petroleum, chemical and otherfields. Research on new methods and new principles about liquid level detectionhave become hot interests in these fields. A new method detecting the liquid levelwas presented and implemented, based on the sensitivity of the characteristicparameters, such as, attenuation factor, of some Lamb wave modes to the presenceof liquid. Besides, different kinds of factors influencing the liquid level detectionresults were analysed and verified experimentally. The main contents are as follows:
(1) Based on ultrasonic guided wave theory, the energy velocity formula wasderived; The relationship between group velocity and energy velocity was alsoanalysed; The characteristic equations of Lamb waves in solid plate with liquid loadon single side was derived; the relationship among Lamb waves and leak Lambwaves, circumferential guided waves and Lamb waves, longitudinal guided wavesand Lamb waves were also analysed theoretically and verified experimentally.
(2) Propagation characteristics of different modes in different-thickness plateswere analysed. Besides, different kinds of factors (cycle number of excitation signal,window function, mode dispersion and attenuation factor, working frequency andincidence angle of transducer, etc.) influencing the liquid level detection results wereanalysed experimentally.
(3) The transducer with working frequency 2.5MHz, incident angle 50°andtransducer clamp were developed to implement fixed liquid level detection andliquid level measurement of the tank with 600mm-outer-diameter and3mm-thickness-wall, the fitting curve between liquid level and received signalamplitude was obtained.
(4) Programmed real-time liquid level detection software using LabVIEW toimplement fixed liquid level detection and real-time alarm.
引文
1 张金林．罐区自动计量技术国内外发展综述．浙江化工．2004，6：28-30
2 李冬梅，高建华．罐区自动计量技术国内外发展综述．第四届全国冶金、电力、石油和化工行业自动化技术交流演示会论文集—石油化工自动化．2002：134-137
3 张战良．液位测量方式的选择．西部煤化工．2005，1：44-47
4 任开春，涂亚庆．20余种测量方法分析．工业仪表与自动化装置．2003，5：12-16
5 王海峰，唐得刚，高瑞泽．浅析大罐液位在线检测的几种方法．中国仪器仪表．2004，6：27-30
6 李冬梅．国内外液位计量仪表技术发展动向．仪器仪表用户．2002，9(3)：5-7
7 Ka Lok Jimmy Fong. A study of curvature effects on guided elastic waves. PhD thesis in Imperial College London. 2005:180-187
8 Lamb wave inspection of large structures using permanently attached transducers. PhD thesis in university of London. 1998:30-36
9 王维利，王瑞．外测式液位计在球罐液位测量中的应用．第3届“佑利”杯氯碱论文竞赛入选作品集．2002：226
10 周三林．外测式液位仪的使用体会．第20届全国氯碱行业技术年会论文集．2002：225
11 庞启强．ELL外测液位计．川化．2005，2：27-28
12 马志敏，郝毫毫，鲁立中．超声波壁外透射衰减式定点液位测量方法研究．研究与开发．2003，9：45-49
13 马志敏，王敏，刘珍秧．大型压力容器定点液位的超声非介入式检测．无损检测．2003，25(2)：626-637
14 马志敏，赵小红，鲁立中．容器壁中超声余振信号的透射衰减特性及其应用．声学技术．2003，22(4)：223-225
15 Ma Zhi Min, Wang Mina, Hu Ji Caib,Zhao Xiao Honga. A new non-touching ultrasonic measuring method of fixed liquid level for pressure containers. Fifth International Symposium on Instrumentation and Control Technology. 2003: 292-295
16 V.E. Sakharov, S.A.Kuznetsov, BD.Zaitsev. Liquid level sensor using ultrasonic Lamb waves. Ultrasonics. 2003, 41:319-322
17 Yi Liu, L. C. Lynnworth. Flexural wave sidewall sensor for noninvasive measurement of discrete liquid level in large storage tanks. 1993 Ultrasonics symposium, L.C.Lynnworth: 385-390
18 ThomaJs. Matula, Philiph. Marston. Energy branching of a subsonic flexural wave on a plate at an air-water interface.I. Observation of the wave field near the interface and near the plate. Acoustica society of America. 1995, 97(4): 1389-1398
19 J.D.N. Cheeke, K. Shannon, Z. Wang. Loading effects on A0 Lamb-like waves in full and partially filled thin-walled tubes. Sensors and Actuators. 1999, 59B:180-183
20 K. Shannon, X. Li, Z. Wang, J.D.N. Cheeke. Mode conversion and the path of acoustic energy in a partially water-filled aluminum tube. Ultrasonics. 1999, 37:303-307
21 Xing Li. Ultrasonic Circumferential Waves in Empty and Water-filled Tubes. phd thesis in Concordia University.2001
22 J. D. N. Cheeke, X. Li, and Z. Wang. Observation of flexural Lamb waves (AO mode) on water-filled cylindrical shells. Acoustical Society of America. 1998, 104(6):3678-3680
23 J.D.N. Cheeke, X. Li,Z. Wang. Characteristics of Circumferential Waves in Thin Walled Tube Acoustic Devices. Ultrasonics symposium. 1995:441-444
24 何存富，李隆涛，吴斌．周向超声导波在薄壁管道中的传播研究．实验力学．2002，17(4)：419-424
25 李隆涛，何存富，吴斌．周向超声导波对管道纵向缺陷检测的研究．声学学报．2005，30(4)：343-347
26 David N. Alleyne. The non-destructive testing of plates using ultrasonic Lamb waves, phd thesis in Imperial College London. 1991:25-35
27 Joseph L. Rose. Ultrasonic Waves In Solid Media. Cambridge University Press. 1999:83
28 James F.doyle. Wave propagation in structures. Springer-Verlag New York Berlin Heidelberg. 1997:67
29 何存富，吴斌，范晋伟．超声柱面导波技术及其应用研究进展．力学进展．2001，3(2)：203～214
30 D. Alleyne, P. Cawley. A two-dimensional Fourier transform method for the measurement of propagating multimode signals. Journal of the Axoustical Society of America. 1991, 89(3): 1159-1168
31 刘镇清，他得安．用二维傅里叶变换识别兰姆波模式的研究．声学技术．2001，19(4)：212-219
32 李风民．希尔伯特变换及其应用研究．中国无线电．2006，7：53-54
33 徐春林，江志农，肖英．基于Hilbert变换的包络分析及其在机械故障诊断中的应用．机电工程技术．2004，33(7)：114-115
34 张绪省，朱贻盛，成晓雄等．信号包络提取方法—从希尔伯特变换到小波变换．电子科学学刊．1997，19(1)：120-123
35 Elvira-Segura L. Acoustic wave dispersion in a cylindrical elastic tube with a viscous liquid. Ultrasonics. 2000, 37(8):537～547
36 C. Aristegui, M. Lowe, P. Cawley. Guided waves in fluid filled pipes surrounded by different fluids. Ultrasonics. 2001, 39(5):367～375
37 B.Zhao, O.A.Basir, GS.Mittal. Estimation of ultrasound attenuation and dispersi-on using short time Fourier transform. Ultrasonics. 2005, 4(3):375-381
38 张海燕，吕东辉，刘镇清．二维傅立叶变换在Lamb波模式识别研究中的应用．振动、测试与诊断．2004，24(1)：23-26
39 他得安，刘镇清．超声无损检测中的二维快速Fourier变换及Wigner-Ville变换．无损检测．2001，23(7)：313-316
40 赵学智，符红羽，陈文戈等．小波分析在信号包络提取中的应用．广东工业大学学报．2000，17(3)：36-39
41 杨慧娟，曲喜强，韩焱．基于小波变换的声波信号包络提取．华北工学院学报．2005，25(4)：300-302
42 Boualem Boashash, Peter J. Black. An Efficient Real-time Implementation of the Wigner-Ville Distribution. IEEE Trans. Acoust., Speech, Signal Processing. 1987, ASSP-35:1611-1618
43 M. A. Rodriguez, J. L. San Emeterio, J. C. Lazaro, A. Ramos. Ultrasonic Flaw Detection in NDE of Highly Scattering Materials Using Wavelet and Wigner-Ville Transform Processing. Ultrasonics. 2004, 42:847-851
44 刘崇春，裘正定．一种基于Morlet小波的振动信号包络提取方法．电路与系统学报．2000，5(3)：68-71
45 刘彬，戴桂平，林洪彬．一种改进的基于小波变换的包络提取算法研究．仪器仪表学报．2006，27(1)：34-37
46 李隽．基于超声波及虚拟仪器的油罐液位检测系统研究．燕山大学工学硕士学位论文．2005：22
2 李冬梅，高建华．罐区自动计量技术国内外发展综述．第四届全国冶金、电力、石油和化工行业自动化技术交流演示会论文集—石油化工自动化．2002：134-137
3 张战良．液位测量方式的选择．西部煤化工．2005，1：44-47
4 任开春，涂亚庆．20余种测量方法分析．工业仪表与自动化装置．2003，5：12-16
5 王海峰，唐得刚，高瑞泽．浅析大罐液位在线检测的几种方法．中国仪器仪表．2004，6：27-30
6 李冬梅．国内外液位计量仪表技术发展动向．仪器仪表用户．2002，9(3)：5-7
7 Ka Lok Jimmy Fong. A study of curvature effects on guided elastic waves. PhD thesis in Imperial College London. 2005:180-187
8 Lamb wave inspection of large structures using permanently attached transducers. PhD thesis in university of London. 1998:30-36
9 王维利，王瑞．外测式液位计在球罐液位测量中的应用．第3届“佑利”杯氯碱论文竞赛入选作品集．2002：226
10 周三林．外测式液位仪的使用体会．第20届全国氯碱行业技术年会论文集．2002：225
11 庞启强．ELL外测液位计．川化．2005，2：27-28
12 马志敏，郝毫毫，鲁立中．超声波壁外透射衰减式定点液位测量方法研究．研究与开发．2003，9：45-49
13 马志敏，王敏，刘珍秧．大型压力容器定点液位的超声非介入式检测．无损检测．2003，25(2)：626-637
14 马志敏，赵小红，鲁立中．容器壁中超声余振信号的透射衰减特性及其应用．声学技术．2003，22(4)：223-225
15 Ma Zhi Min, Wang Mina, Hu Ji Caib,Zhao Xiao Honga. A new non-touching ultrasonic measuring method of fixed liquid level for pressure containers. Fifth International Symposium on Instrumentation and Control Technology. 2003: 292-295
16 V.E. Sakharov, S.A.Kuznetsov, BD.Zaitsev. Liquid level sensor using ultrasonic Lamb waves. Ultrasonics. 2003, 41:319-322
17 Yi Liu, L. C. Lynnworth. Flexural wave sidewall sensor for noninvasive measurement of discrete liquid level in large storage tanks. 1993 Ultrasonics symposium, L.C.Lynnworth: 385-390
18 ThomaJs. Matula, Philiph. Marston. Energy branching of a subsonic flexural wave on a plate at an air-water interface.I. Observation of the wave field near the interface and near the plate. Acoustica society of America. 1995, 97(4): 1389-1398
19 J.D.N. Cheeke, K. Shannon, Z. Wang. Loading effects on A0 Lamb-like waves in full and partially filled thin-walled tubes. Sensors and Actuators. 1999, 59B:180-183
20 K. Shannon, X. Li, Z. Wang, J.D.N. Cheeke. Mode conversion and the path of acoustic energy in a partially water-filled aluminum tube. Ultrasonics. 1999, 37:303-307
21 Xing Li. Ultrasonic Circumferential Waves in Empty and Water-filled Tubes. phd thesis in Concordia University.2001
22 J. D. N. Cheeke, X. Li, and Z. Wang. Observation of flexural Lamb waves (AO mode) on water-filled cylindrical shells. Acoustical Society of America. 1998, 104(6):3678-3680
23 J.D.N. Cheeke, X. Li,Z. Wang. Characteristics of Circumferential Waves in Thin Walled Tube Acoustic Devices. Ultrasonics symposium. 1995:441-444
24 何存富，李隆涛，吴斌．周向超声导波在薄壁管道中的传播研究．实验力学．2002，17(4)：419-424
25 李隆涛，何存富，吴斌．周向超声导波对管道纵向缺陷检测的研究．声学学报．2005，30(4)：343-347
26 David N. Alleyne. The non-destructive testing of plates using ultrasonic Lamb waves, phd thesis in Imperial College London. 1991:25-35
27 Joseph L. Rose. Ultrasonic Waves In Solid Media. Cambridge University Press. 1999:83
28 James F.doyle. Wave propagation in structures. Springer-Verlag New York Berlin Heidelberg. 1997:67
29 何存富，吴斌，范晋伟．超声柱面导波技术及其应用研究进展．力学进展．2001，3(2)：203～214
30 D. Alleyne, P. Cawley. A two-dimensional Fourier transform method for the measurement of propagating multimode signals. Journal of the Axoustical Society of America. 1991, 89(3): 1159-1168
31 刘镇清，他得安．用二维傅里叶变换识别兰姆波模式的研究．声学技术．2001，19(4)：212-219
32 李风民．希尔伯特变换及其应用研究．中国无线电．2006，7：53-54
33 徐春林，江志农，肖英．基于Hilbert变换的包络分析及其在机械故障诊断中的应用．机电工程技术．2004，33(7)：114-115
34 张绪省，朱贻盛，成晓雄等．信号包络提取方法—从希尔伯特变换到小波变换．电子科学学刊．1997，19(1)：120-123
35 Elvira-Segura L. Acoustic wave dispersion in a cylindrical elastic tube with a viscous liquid. Ultrasonics. 2000, 37(8):537～547
36 C. Aristegui, M. Lowe, P. Cawley. Guided waves in fluid filled pipes surrounded by different fluids. Ultrasonics. 2001, 39(5):367～375
37 B.Zhao, O.A.Basir, GS.Mittal. Estimation of ultrasound attenuation and dispersi-on using short time Fourier transform. Ultrasonics. 2005, 4(3):375-381
38 张海燕，吕东辉，刘镇清．二维傅立叶变换在Lamb波模式识别研究中的应用．振动、测试与诊断．2004，24(1)：23-26
39 他得安，刘镇清．超声无损检测中的二维快速Fourier变换及Wigner-Ville变换．无损检测．2001，23(7)：313-316
40 赵学智，符红羽，陈文戈等．小波分析在信号包络提取中的应用．广东工业大学学报．2000，17(3)：36-39
41 杨慧娟，曲喜强，韩焱．基于小波变换的声波信号包络提取．华北工学院学报．2005，25(4)：300-302
42 Boualem Boashash, Peter J. Black. An Efficient Real-time Implementation of the Wigner-Ville Distribution. IEEE Trans. Acoust., Speech, Signal Processing. 1987, ASSP-35:1611-1618
43 M. A. Rodriguez, J. L. San Emeterio, J. C. Lazaro, A. Ramos. Ultrasonic Flaw Detection in NDE of Highly Scattering Materials Using Wavelet and Wigner-Ville Transform Processing. Ultrasonics. 2004, 42:847-851
44 刘崇春，裘正定．一种基于Morlet小波的振动信号包络提取方法．电路与系统学报．2000，5(3)：68-71
45 刘彬，戴桂平，林洪彬．一种改进的基于小波变换的包络提取算法研究．仪器仪表学报．2006，27(1)：34-37
46 李隽．基于超声波及虚拟仪器的油罐液位检测系统研究．燕山大学工学硕士学位论文．2005：22