高效稳定双罐式液体活塞近等温膨胀过程热力性能研究  

Thermal Performance Study on Efficient and Stable Dual-TankLiquid Piston Near-Isothermal Expansion Process

作　　者：张宇飞 金鹏 王海洋 李向东 王焕然[1] 席光[1] 李瑞雄 ZHANG Yufei;JIN Peng;WANG Haiyang;LI Xiangdong;WANG Huanran;XI Guang;LI Ruixiong(School of Energy and Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安交通大学能源与动力工程学院,西安710049

出　　处：《西安交通大学学报》2024年第7期1-12,共12页Journal of Xi'an Jiaotong University

基　　金：国家自然科学基金资助项目(52106052);陕西省自然科学基础研究计划资助项目(2021JQ-047)。

摘　　要：为确保双罐式液体活塞膨胀过程的连续稳定运行,提出了一种创新的液体活塞近等温膨胀运行方式。该运行方式下,膨胀阶段完成后液体活塞进入膨胀后的吸气阶段,实现罐体水位的下降,从而保证了循环稳定性。通过建立相关的热力学模型,探究了高压空气在近等温膨胀过程中的热力性能变化特性,并揭示了不同运行特征下液体活塞近等温膨胀的释能规律。研究结果显示:该运行方式使系统在第二次循环后进入稳定循环阶段;系统呈现出较好的等温性能,当膨胀比为5时,循环过程中空气最低温度达到282.3 K;空气与液滴换热占比随喷嘴数量的变化较为显著,喷嘴数量由2增加至18时,空气与液滴换热占比由20.2%增加至72.8%;在单个循环周期时长为4 800 s时,液体活塞膨胀释能效率和液体活塞膨胀释能量提升率都达到最大值,分别为84.6%和18.1%;液体活塞运行条件不同情况下,最佳喷淋时刻的无量纲压力存在差异。该研究为提高双罐式液体活塞近等温膨胀过程的稳定性提供了新的方案。To ensure the continuously stable dual-tank liquid piston expansion process,this study introduces an innovative approach for near-isothermal expansion of the liquid piston.In this mode of operation,the liquid piston enters the post-expansion suction stage after the completion of the expansion stage to achieve a drop in the tank water level,thus ensuring the stability of the cycle.By establishing relevant thermodynamic models,the study explores the variations in the thermodynamic performance of high-pressure air during near-isothermal expansion and reveals the energy release patterns of the liquid piston across different operational characteristics.The study findings indicate that this operational approach enables the system’s stable cyclic phase after the second cycle;the system exhibits favorable isothermal performance,with the air temperature dropping to the lowest at 282.3 K during the cycle when the expansion ratio is 5.The ratio of air-to-liquid droplet heat exchange shows notable fluctuations based on the number of nozzles,rising from 20.2%to 72.8%as the number of nozzles increases from 2 to 18.For a single-cycle lasting 4800 s,the efficiency and increase rates of energy release during liquid piston expansion reach maximum values of 84.6%and 18.1%,respectively.Optimal spray timing under different operational conditions exhibits variations in dimensionless pressure.This study proposes a novel approach to enhance the stability of the near-isothermal expansion process of the dual-tank liquid piston.

关 键 词：液体活塞 近等温膨胀 热力性能 喷淋 

分 类 号：TK02[动力工程及工程热物理]