【作者】 杨杰；

【导师】 曲志刚；

【作者基本信息】 天津科技大学 ， 控制理论与控制工程， 2019， 硕士

【摘要】 管道在输送流体方面具有很大优势,在经济和社会发展中都起着十分重要的作用。管道内的结垢是石油、天然气、食品和许多其他相关行业普遍关注的一个问题。它迫使相关行业定期清除结垢,甚至更换管道。如果除垢操作不及时或操作不当,可能会导致管道变形、泄漏甚至爆裂。和传统除垢方法相比,超声导波除垢方法因其传播远、覆盖广和不停工等优势被广泛关注。根据上述问题,本文提出了一种基于超声导波的环保型管道除垢方法。论文提出的基于FPGA的超声导波管道除垢技术,其不仅保留了传统除垢方式的优点,而且还具有在不影响正常生产下大范围去除结垢的优势。在进行大范围除垢工作的同时,可最大程度地节省时间和资源,实现高效、快速、安全的除垢目的。本文对基于FPGA的超声导波管道除垢技术进行理论分析和实验研究。首先通过FPGA开发平台和Verilog HDL编程语言设计了基于FPGA的信号源发生器,作为除垢系统的一部分可产生满足后续除垢环节的换能器驱动信号。其次,通过有限元仿真软件COMSOL建立了基于超声导波的充液管道除垢模型并进行了两种情形的对比研究,即单件传感器和传感器阵列。经过扫描式激光测振仪挑选波形信号的最优激励频率,仿真结果表明声压呈正压和负压交替分布,且传感器阵列的声压和应力幅值较大且更均匀。最后详细介绍了 CaCO3除垢实验方案并进行相关除垢实验,通过分析电镜和能谱分析实验的数据,实验结果表明:压电超声换能器激发的超声导波可有效去除充液管道内CaCO3结垢且传感器阵列除垢效果更清洁,管道均无明显伤害。因而可得出基于FPGA的超声导波管道除垢技术可以安全有效地去除充液管道内壁CaCO3结垢的结论。更多还原

【Abstract】 Pipelines have great advantages in transporting fluids,which play an important role in the rise of the economy and social development.Fouling in pipelines is a common issue that may be paid attention to by the oil and gas,food and many other industries.It forces related industries to regularly remove fouling and even replace pipes.If the descaling operation is not timely or improper,it may also lead to deformation,leakage or even burst.Compared with the traditional descaling method,ultrasonic guided waves have been widely concerned because of their advantages of long transmission,wide coverage and non-stopping.According to the above problems,this paper proposes an environmentally friendly pipeline descaling method based on ultrasonic guided waves.The technology on fouling removing in pipelines of ultrasonic guided waves based on FPGA not only retains the advantages of the traditional descaling method,but also has the advantage of extensively descaling without affecting normal production.During a wide range of cleaning,this method not only saves time and resources,but also achieves efficient,fast,safe descaling target.In this paper,the theoretical analysis and practical research on the fouling removing technology in pipelines of ultrasonic guided waves based on FPGA is carried out.Firstly,FPGA-based signal source generator is designed by FPGA development platform and Verilog HDL code.As a part of the descaling system,it can generate the transducer drive signal to meet the subsequent descaling part.Secondly,descaling model of liquid-filled pipeline based on ultrasonic guided waves is established by finite element simulation software COMSOL.Two descaling scenarios,single sensor case and the sensor array one,are studied.The optimal excitation frequency of waveform signal is selected by the scanning laser vibrometer.The simulation shows that the sound pressure is alternately distributed with positive pressure and negative pressure.The sound pressure and stress amplitude of the array sensor is larger and more uniform.Finally,the design of the CaCO3 descaling scheme and the related descaling experiment are introduced in detail.The data of the electron microscopy and energy spectrum analysis experiments were analyzed,and the experimental results show that the ultrasonic guided waves excited by the piezoelectric ultrasonic transducers can remove the CaCO3 fouling in the liquid-filled pipelines effectively and the descaling effect of the latter case is cleaner than the former one.Moreover,the pipelines have no obvious damage,so it can be concluded that the descaling technology in pipelines of ultrasonic guided waves based on FPGA can safely and effectively remove the CaCO3 fouling on the inner wall of the liquid-filled pipelines.更多还原