喷射器优化设计新理论及方法探索

Ejectors are effective device for low-grade heat recovery and new energies exploitation. They are widely used in process industries such as chemical industry, power industry, oil and gas industries, sugar industry, paper industry, light industry, food industry, and the utilization of renewable energies. But up to now the design of ejectors still depends on the classical methods established several decades ago, hence many new problems appear in practical applications. This project would systematically arrange and analyse the existing classical ejector design theories and further elucidate their internal relations, differences and respective applicable conditions. Then this project, employing the knowledges of fluid dynamics, thermodynamics and heat and mass transfer, advanced computing technologies as well as experimental and actual engineering data, tries to investigate the quantitative relationships between ejector structure parameters, operation parameters and working fluid thermodynamic and transport properties so that the rules and mechanisms of interrelationships and constraints for those three aspects are discovered. Finally, the project strives to establish a new design theory or method for ejectors according to real gas models, which can calculate non-sectional dimensions and is suitable for various working fluids. On the one hand, this project should comprehensively and profoundly contribute to the understanding of advantages and disadvantages of existing classical ejector design methods, furthermore, improve and develop the design theories for ejectors. On the other hand, it can effectively and reliably provide technical support for the applications of ejectors in energy intensive process industries and new energies industry.

喷射器是低品位热能回收与新能源开发利用的有效设备，广泛应用在化工、电力、石油天然气、制糖、造纸、轻工食品、可再生能源利用等过程工业。但迄今，喷射器的设计大多仍采用沿袭了几十年的传统方法，在实际应用中出现了许多新问题。本项目将系统梳理和分析当前经典的喷射器设计理论，进而阐明它们的内在联系与区别、及各自的适用条件；在此基础上，运用流体力学、热力学和传热传质学知识及先进计算技术，并结合实验与工程实践数据，探讨喷射器结构参数、工作参数和工质物性参数之间的定量关系，揭示它们相互影响的规律和制约机理；最终建立基于实际气体模型、可理论计算非截面尺寸、适用工质种类广泛的喷射器设计新理论和方法。通过本项目的研究，一方面有助于全面而深刻地认识当前喷射器经典设计方法的优缺点，进而完善和发展喷射器设计理论；另一方面，为喷射器在高能耗过程工业及新能源产业的应用提供有效而可靠的技术支持。

喷射器是当前低品位热能回收及新能源开发利用的有效设备之一，广泛应用在化工、电力、石油天然气、可再生能源利用、制糖、造纸、轻工食品等流程工业。随着喷射器应用范围越来越广、应用要求越来越多，设计理论与实际应用的矛盾日益凸显；再者，发展相对滞后的喷射器理论未能有效指导在用喷射器的性能优化及结构改进。. 本项目深入分析了常用喷射器设计方法的共性与特色，归纳、辨析了它们的适用参数域，提出了等喷射系数压缩比和等喷射系数参数线（参数区）等概念并以它们来确定圆柱形和圆锥形混合室的选用原则。通过研究喷射器内流体流动的特殊规律及探寻喷射器结构（包括结构变换）、性能及工质物性之间相互影响的定量关系；提出了一种基于激波波长的最佳喷嘴距计算公式，明确了混合室长度设计的理论依据及扩压室出口直径与混合室直径的定量关联；进而设计了一种内壁结构可调节的喷射器。从结构决定性能和性能反演结构两条路径切入，建立了基于实际气体模型、可理论计算非截面尺寸且适用工质种类广泛的喷射器优化设计新方法，其特点是准确、快捷；该方法计算的喷射系数与实验值吻合较好，误差在±17%内；更进一步，尝试了一种不需判别混合室结构即可设计最优喷射器结构的设计方法。研发了喷射器优化设计及性能分析一体化软件，利用实际工程数据进行检验发现该软件计算结果的偏差范围为2.71%-11.45%，具有较好的可靠性。此外，还研究了喷射器在丙烯腈生产工艺低品位能量回收中的应用、喷射器结合努森泵（压缩机）的新型真空系统及制冷系统。. 通过本项目的研究，一方面有助于完善和发展喷射器理论和设计方法，另一方面为喷射器在相关领域的应用提供有效且可靠的技术支持。