多核并行热声发动机自激振荡演化行为及参数耦合调控研究

The theoretical analysis, experimental test and numerical simulation are combined to investigate the nonlinear evolvement characteristic of self-excited oscillation and coupling-controlling mechanism of complex parameters in thermoacoustic engine with parallel multi-thermoacoustic cores. In the theoretical region, heat transfer model under Low-Mach number flow and physical model of thermoacoustic engine with variable thermal properties, fluid-solid coupling and thermal non-equilibrium will be developed. By investigating the irreversible loss and synergistic effect between multi-thermoacoustic cores, the nonlinear evolvement characteristic of thermoacoustic self-excited oscillation and enhancement mechanism of heat transfer in oscillatory flow will be revealed. The improvement method and evaluation index of heat transfer structure applied in thermoacoustic engine will be enacted. In the experimental region, thermoacoustic engine with parallel multi-thermoacoustic cores and the experimental system of heat transfer characteristic under Low-Mach number flow will be built. Then the synergy of multi-thermoacoustic cores and coupled effect between different parameter will be studied. Based on the multi-objective parameter optimization method, the influence weight of complex parameters on thermal performance of the thermoacoustic engine and its components will be analyzed. Finally, parameter optimization and design of thermoacoustic engine and its components will be achieved, which further improves thermoacoustic transforming efficiency and overcomes the defect for engineering application. This project has wide application background as well as significant academic value.

本项目将从理论分析、实验研究和数值仿真三个方面来揭示多（热声）核并行热声热机中自激振荡非线性演变特性和复杂参数耦合调控机理。理论方面：建立变物性、流固耦合、非平衡热声核物理模型和低Ma数流动传热模型，考察热声核内不可逆损失及核间工作协同性，揭示热声自激振荡非线性演变特性和热声交变传热的强化机制，提出适用热声系统的传热结构改进方法及评价指标。实验方面：搭建多核并行热声热机和低Ma数流动传热特性测试系统，开展多（热声）核协同及参数耦合作用研究，基于多目标优化设计方法，分析复杂变量对系统及传热部件热力性能的影响权重，实现多核并行热声发动机及部件的参数优化配置，进一步提高热声热机转换效率和克服工程应用弊端。该项目不仅具有较广的基础研究应用背景，而且具有重要的学术价值。

热声系统复杂的多学科交叉融合特性，导致对热声自激振荡的触发机制与非线性演变行为以及交变流动传热特性等基础科学问题认识不足，而起振温度较高、能流密度较低、结构不紧凑等应用“瓶颈”问题，也严重制约着热声技术的进一步发展与推广。.本项目首先建立单、多段回热器与多（热声）核流固耦合、非热平衡模型，分析回热器不可逆损失对其性能的影响机理。研究系统结构参数及交互作用对系统性能参数的影响，探讨系统声直流的定量预测方法，分析突变截面处交变流动的涡流特性和非线性效应。基于火用损失方法和多目标优化算法分别研究不同传热结构的结构参数及交互作用对换热和流阻的影响。研究错列平板换热器、丁胞板叠和渐缩板叠结构的传热与压降特性，分析交变流下传热结构的强化机制。构建多（热声）核系统数理模型，分别研究多核驻波和行波热声系统内的自激振荡特性和变温热源下声功转换的机理。基于阻抗匹配的原则，研究结构参数不一致性对多（热声）核系统性能参数的影响，建立高效声功传输系统的优化设计流程。构建斯特林发动机的热-动力学耦合分析模型并搭建相关测试平台，分析热、动力学参数对系统热力性能的影响规律。开展两相脉动流动流型可视化研究，分析流型分布与换热系数增强比和时均压降相关联对其流动换热的影响机制。.本研究揭示热声不可逆损失对自激振荡触发及非线性行为的影响规律，提出复杂热声系统的多目标参数优化方法与配置策略，明晰传热结构的流动换热机理和多参数交互耦合关系，获得各自结构下流动传热与阻力实验关联式，探明热、动力学参数匹配对交变流动的影响，揭示多（热声）核系统高效声功传输与阻抗匹配的协同作用关系。.本项目通过理论、数值模拟和试验相结合的方法，进一步揭示热声系统自激振荡非线性演变特性和复杂参数耦合调控机理，有助于推动强化传热结构在热声热机领域的推广应用，实现多核并行热声发动机及部件的参数优化配置。