基于伴随方法的液环泵内非稳态气液两相流动优化研究

Liquid-ring pump is widely used in coal, power, chemical industry, and metallurgy industry due to its characters of structure and hydraulic performance. The complex inner gas-liquid two phase flow and the optimization of the hydraulic performance have attracted the researcher's attention with the expansion of its application. Under the influence of two-phase flow, rotation, the changing of the passage curvature and the changing of sectional area, the unstable free interface and secondary flow would arise in the transient gas-liquid two phase flow in liquid-ring pump.The optimization design of liquid-ring pump is hard to carry out for the complex inner flow constraint. To realize the description of the complex gas-liquid two phase flow in liquid-ring pump with enough accuracy in this research, the affection of the transient behaviour of the free interface and the secondary flow on its hydraulic performance would be analyzed by numerical simulation and experiment investigation. Then, the adjoint method would be introduced to optimize the shape of impeller and pump body. The optimization model of the impeller and pump body with gas-liquid two phase flow constraint would be constructed based on adjoint method. The variation of the objective function, the adjoint equations and its boundary condition would be deduced in detail. The calculation of the flow simulation and the optimization can be fulfilled by CFD software and calculation code. At last the proposed theory and method would be verified by experimental research. Above all，this investigation will provide the theoretical basis for optimization design of liquid-ring pump and optimization for complex gas-liquid two phase flow.

液环泵由于其结构及性能特点被广泛应用于煤矿、化工及冶金等领域，随着液环泵应用领域的拓展，其内部复杂的气液两相流及其性能的优化研究逐渐得到国内外研究者的关注。在气液两相流、叶轮的旋转、流道曲率及面积变化等因素作用下，液环泵内气液两相流动中存在不稳定的气液分界面及复杂的二次流结构，由于复杂的内部流动约束的存在导致液环泵的优化设计难以进行。本研究采用数值模拟与流场测试相结合对液环泵内部气液两相流自由界面形状的变化、二次流结构及其与泵外特性间的关系进行分析，期望实现对液环泵内复杂流动结构的精确描述，并在此基础上引入伴随方法对液环泵叶轮及壳体进行优化研究，建立气液两相流条件下的叶轮及壳体伴随优化模型，推导相关的目标函数变分、伴随方程及其边界条件等，采用CFD软件与程序代码相结合实现叶轮及泵体优化的相关计算，最后由实验验证所提出理论及方法的可行性，为液环泵的性能优化及复杂气液两相流动优化提供理论支撑。

液环泵由于其抽气量大、等温压缩等优点，被广泛应用于煤炭、化工及冶金等领域，特别是在大型煤矿瓦斯的抽放、高超音速多功能风洞及核电站抽凝用大型真空设备等国家重大需求对液环泵的性能要求越来越高，但液环泵内复杂的气液两相流结构导致其性能的优化难以进行。本项目研究首先由数值模拟与实验方法相结合对液环泵内复杂的内部气液两相流结构进行研究，得到了液环泵叶轮、壳体及叶轮轴向间隙内的气液两相流场结构的精确描述。在液环泵内流动及性能优化方面，对液环泵内过压缩特性及排气口单向阀工作机理、基于自由曲面变形方法的离心泵三维叶片反问题方法、基于直接自由曲面变形技术的液环泵壳体优化方法、径向间隙及叶片型线对液环泵性能影响、液环泵轴向叶顶间隙两相泄漏流结构等进行分析；在优化理论及方法方面，提出了基于本征正交分解法的液环泵气液两相流场重构方法、基于本征正交分解与径向基函数（POD-RBF）混合代理模型方法的离心泵叶轮内流场的重构及模态分析、提出了低比转速离心叶轮的POD代理模型优化方法研究。研究成果为液环泵水力性能的提升提供了理论基础。.依托该项目研究发表论文12篇，其中SCI 2篇、EI 收录 6篇, 另有2篇EI源刊录用待出版。发明专利3项（授权1项），出版专著1部；培养博士生2名，硕士生21名，已毕业硕士生9名。