基于Duffing-Holmes混沌振子的气液两相流参数检测新方法研究

Gas-liquid two-phase flows are a typical type of difficult-to-measure fluids that vary intricately. So far effective approaches to obtain their parameters are quite inadequate. Devoloping new methods and devices based on novle principles are always one of the focuses in the field of gas-liquid two-phase flow study. In this project, chaotic oscillators are employed to measure several important gas-liquid two-phase flow parameters, using the extreme sensitivity of chaotic oscillators to weak disturbance. The oscillating differential pressure behind a bluff body in gas-liquid two-phase flow are added to the periodic driving force as disturbance, and then are both input into a Duffing-Holmes chaotic oscillator which is abundant in nonlinear dynamical behavior. The variation degree of phase trajectory is monitored and discerned to reveal the state of the gas-liquid two-phase flow, and the chaotic features are extracted from the oscillating differential pressure. The correlation and measurement model are established between variation of phase trajectory, chaotic features and flow parameters, by using various advanced signal processing and data mining techniques. Ultimately, flow pattern, phase holdup and flow rate/velocity are realized to be obtained with high sensitivity, accuracy and reliability. This study can provide a new gas-liquid two-phase flow measurement method for flow mechanism investigations and practical applications; therefore it has significant academic value and wide application prospect.

气液两相流是典型的复杂多变的难测流体，目前行之有效的检测手段还相当缺乏，运用新原理发展参数检测新方法和新装置一直以来都是气液两相流领域的研究热点之一。本项目提出利用混沌振子对外加微小扰动极其敏感的特性实现气液两相流多个重要参数的集成检测。将气液两相流钝体尾迹振荡差压信号以外加扰动形式并入周期策动力之中，输入非线性动力学形态丰富的Duffing-Holmes混沌振子，监测和判别系统的相轨迹演变情况及程度，据此反映和辨识气液两相流的流动状况，提取振荡差压信号的混沌特性参数，运用各种先进信号处理技术与数据挖掘方法，建立相轨迹演变、混沌特性参数与气液两相流参数之间的关联关系与测量模型，进而实现对流型、分相含率、流量/流速等关键参数的高灵敏度、高准确度和高可靠性测量。本项目研究可为气液两相流机理研究和工程应用提供有效的参数检测新方法，具有重要的学术价值和广泛的应用前景。

气液两相流广泛存在于自然界和现代工业生产之中，许多生产过程中都涉及气液两相流工况。掌握其流动与传递过程基本规律，对于存在气液两相流的工业设备和生产过程的运行管理与优化控制意义重大。本项目提出将准周期的气液两相流钝体尾迹振荡并入特征丰富的Duffing-Holmes混沌振子，利用振子系统相轨迹在同宿轨道、周期分岔、混沌、大尺度周期等动力学形态之间的演变区分不同流型，提取与气液两相流流动特性密切相关的同频准周期信号特征，研究同频准周期信号特征与流型、分相含率、流量/流速等待测参数之间的关联关系，实现基于Duffing-Holmes混沌振子的高灵敏度、高准确度和高可靠性的气液两相流参数检测。.采用数值模拟方法对表面凸起钝体绕流旋涡脱落流场进行分析，得到不同凸起高度和凸起数量时钝体尾迹流场和换热性能，探讨凸起结构对钝体表面压力分布和边界层分离的影响，发现凸顶和凹槽对换热起相反的作用。研究气液两相流尾迹壁面差压测试与处理方法，提出气液两相流能量比，建立其与体积含气率、两相雷诺数、两相体积流量的关系，实现单相水、泡状流、塞状流、弹状流的流型区分。提出基于混沌特征的气液两相流流型方法，通过对时间序列进行重构相空间得到关联积分，再计算出对应的关联维数，将关联维数与表观速度组合构造新型气液流型图，采用多元非线性拟合建立适用于不同流型各流动参数之间相关性的关联式，用时频熵表征将钝体尾迹波动差压信号并入混沌振子后在时频分布上的差异，发现不同流态下分解得到的固有模态函数的局部性质差异较大，其中对应大周期成分的体现也不尽相同。.本项目研究可为气液两相流机理研究和工程应用提供有效的参数检测新方法，具有重要的学术价值和广泛的应用前景。基于本项目的研究工作，项目组已在国内外刊物上发表论文20篇，其中SCI收录10篇，EI收录20篇；申请或授权发明专利4项、实用新型专利1项；培养硕士研究生10人，其中7人已顺利毕业，1篇硕士论文被评为湖南省优秀硕士学位论文。