气波增压强化压力振荡管制冷性能研究

A major disadvantage of GAS-Wave Refrigeration (GWR) is its need to transform pressure energy into low-quality thermal energy. This project proposes a pressure-enhancing GWR mechanism, which utilizes the pressure-enhancing property of gas waves to recycle expansion energy through a compression process. Such process transforms expansion energy, which is usually released and wasted in the form of thermal energy by traditional GWR techniques, into pressure energy. In the proposed pressure-enhancing GWR mechanism, the flow and distribution of gas waves is optimized so that expansion waves are used to produce low-pressure gas, which is then compressed by compression waves generated during the expansion, resulting in an increase in the effective expansion ratio and, consequently, a high refrigeration efficiency. The main research issues of this project include: (1) analyzing the flow field in a pressure-enhancing oscillating tube and establishing quantitative relationships between gas waves to obtain the ideal wave map inside the tube, (2) analyzing the dynamic evolving behaviors of gas waves and the interface to minimize energy dissipation in the intermittent-jetting process, (3) investigating variances of the temperature distributions inside the low-pressure region under different gas waves to optimize the circulation process and develop an optimal cold-outputting method, (4) investigating the effects of condensation, moisture and real gas on wave flow and heating inside the tube to understand the gas-wave refrigeration mechanism when phase change exists, and (5) investigating the effects of structure and operation parameters on wave flow and heating inside an oscillating tube to improve operation conditions of the refrigeration tube. The aim of this project is to investigate and apply the proposed pressure-enhancing mechanism to improve the performance of GWR oscillating tubes for the development of gas-wave refrigeration techniques.

将压力能直接转换为低品位热能是气波制冷技术的主要缺陷。本项目提出气波增压强化气波制冷的方法。该方法利用气波增压特性，提高排出气体压力，实现膨胀压力能的有效回收。通过匹配振荡管内运动波系，在管内形成比出口压力低的内循环低温低压区，增加有效膨胀比，大幅度提高制冷效率。项目主要工作：1.分析气波振荡管内波动流场，获得包含气波膨胀和增压过程的压力振荡管内波系之间定量关系，形成理想波图；2.分析间歇射流在管内生成波系和分界面的渐变过程，探寻减小该过程能量损失有效方法；3.分析气体低温冷凝、带液和真实气体效应对管内的流动和热效应的影响，探索含有相变的气波制冷机理；4.分析结构和操作参数对管内波动和热效应的影响机理，优化振荡管制冷的运行条件；5.分析管内低温低压区的流动特性，确定装置内循环流动和换热方式，获得冷量取出的有效方法。气波增压强化制冷机制可大幅提高气波振荡管制冷效率，促进气波制冷技术发展。

将气体压力能转换为低品位热能是气波制冷技术的主要缺陷。利用双开口振荡管内激波增压特性，将气体膨胀功以压力能的形式进行回收，避免对外输出热量，可以大幅提升制冷效率，避免气体压力能的浪费，拓宽了气波制冷技术的应用范围。（1）分析了双开口振荡管管内激波传递能量效率，得到膨胀制冷压比与激波增压效率曲线，获得自增压气波制冷适用压比范围。（2）建立自增压振荡管制冷的定量理想波图，并以此为基础形成自增压型气波制冷机结构二维设计方法。（3）研究了双开口振荡管内冷热气体分界面形态，及其对带有增压过程的气波制冷性能的影响。提出两种揭示冷热分界面形态的图形表述方法。为自增压型气波制冷机性能提升提供指导。（4）建立自增压气波制冷平台，获得了结构参数以及操作参数对增压气波制冷机性能影响规律，确定自增压性气波制冷机最佳运行条件。（5）扩展自增压气波制冷的应用范围，提出了二次增压气波制冷方法以及气波脱湿增压方法，并搭建制冷平台进行测试，并获得其制冷性能参数。（6）建立了描述非定常膨胀凝结流动过程的数值模型，并以激波管中湿空气的膨胀凝结流动为研究对象，得到了非定常膨胀凝结流动过程中凝结参数的时空分布情况和气体湿度及初始膨胀比等因素对自发凝结的影响规律；针对气波机中的重烃组分凝结蒸发问题，采用SRK真实气体方程计算真实气体模型下辛烷在甲烷中的凝结和蒸发现象。为冷凝波转子的研究提供了理论基础和技术手段。