水下平台CO_(2)基混合工质闭式循环温度适应性分析  

Temperature Adaptability Analysis of Closed Cycle Using CO_(2)-Based MixedWorking Fluid for Underwater Platforms

作　　者：冯佳琪 王俊鹏 陈真韬 骆政园[1] 白博峰[1] FENG Jiaqi;WANG Junpeng;CHEN Zhentao;LUO Zhengyuan;BAI Bofeng(State Key Laboratory of Multiphase Flow in Power Engineering,Xi’an Jiaotong University,Xi’an 710049,China)

机构地区：[1]西安交通大学动力工程多相流国家重点实验室,陕西西安710049

出　　处：《水下无人系统学报》2024年第6期1053-1062,共10页Journal of Unmanned Undersea Systems

基　　金：国家重点项目资助(2020-****-ZD).

摘　　要：超临界CO_(2)布雷顿循环系统是水下平台动力技术的重要发展方向,但由于深海低温较远离CO_(2)临界温度,致使循环系统存在温度适应性问题。文中提出了利用CO_(2)基混合工质改善循环温度适应性并进一步优化循环性能的方案,建立了简单回热循环热力学模型,分析了CO_(2)基混合工质临界参数随加入气体种类和质量分数的变化规律,阐明了压缩机入口状态参数对CO_(2)基混合工质闭式循环热力学性能的影响规律,探讨了混合工质拟临界点位置对回热器夹点和热惯性等的影响。结果表明:低临界参数混合工质循环可进一步扩大循环温度范围和压比,以改善循环热力学性能,但仅扩大温度范围而降低压比可能会对其造成不利影响;综合考虑循环热效率、比功、回热器内部夹点及热惯性,CO_(2)+Xe(CO_(2)/Xe:0.5/0.5)-跨临界朗肯循环、CO_(2)+SF_(6)(CO_(2)/SF_(6):0.9/0.1)-跨临界液体布雷顿循环以及CO_(2)+SF_(6)(CO_(2)/SF_(6):0.5/0.5)-跨临界朗肯循环较超临界CO_(2)布雷顿循环热效率最大可提高3.79%,比功最大可提升31.6%,回热器夹点位于冷端并未加剧其热惯性,不会减缓系统响应速度。The supercritical CO_(2) Brayton cycle system is an important development direction of underwater platform power technology.However,due to the low temperature in the deep sea which is far away from the critical temperature of CO_(2),the cycle system has temperature adaptability problems.This paper proposed the plan to use CO_(2)-based mixed working fluid to improve cycle temperature adaptability and further optimize cycle performance.A simple recuperative closed cycle thermodynamic model was established,and the changes in critical parameters of CO_(2)-based mixed working fluid with the type and mass fraction of added gas were analyzed.The influence of the compressor inlet state parameters on the thermodynamic properties of the closed cycle of CO_(2)-based mixed working fluid was clarified.Besides,the influence of the pseudo-critical point position of the mixed working fluid on the pinch point and thermal inertia of the regenerator was discussed.The results show that the mixed working fluid cycle with low critical parameters can further expand the cycle temperature range and pressure ratio to improve the cycle thermodynamic performance.However,only expanding the temperature range and reducing the pressure ratio may have an adverse impact on it.Comprehensive consideration of cycle thermal efficiency,specific power,and pinch point and thermal inertia of regenerator,the maximum thermal efficiency of CO_(2)+Xe(CO_(2)/Xe:0.5/0.5)-transcritical Rankine cycle,CO_(2)+SF_(6)(CO_(2)/SF_(6):0.9/0.1)-transcritical liquid Brayton cycle,CO_(2)+SF_(6)(CO_(2)/SF_(6):0.5/0.5)-transcritical Rankine cycle can be increased by 3.79%than that of the supercritical CO_(2) Breton cycle,and the maximum specific power can be increased by 31.6%.The pinch point of the regenerator is located at the cold end,which does not increase its thermal inertia and does not slow down the system response speed.

关 键 词：水下平台 CO_(2)基混合工质 闭式循环 温度适应性 

分 类 号：TJ630.34[兵器科学与技术—武器系统与运用工程] U674[交通运输工程—船舶及航道工程]