CAJ | 학술논문

建立了考虑外部有限速率传热过程和热源间热漏的不可逆半导体固态热离子制冷器模型，基于非平衡热力学和有限时间热力学理论导出了热离子制冷器的制冷率和制冷系数的表达式；对比分析了不可逆热离子制冷器与可逆热离子制冷器的发射电流密度特性、电极温度特性以及制冷系数特性；研究了不可逆系统的制冷率与制冷系数最优性能，得到了制冷率和制冷系数的最优运行区间；通过数值计算，详细讨论了外部传热以及内部导热、热源间热漏损失、热源温度、外加电压、半导体材料势垒等设计参数对热离子装置性能的影响。在总传热面积一定的条件下，进一步优化了高、低温侧换热器的面积分配以获得最佳的制冷率和制冷系数特性。结果表明，由于存在内部和外部的不可逆性，热离子装置的发射电流密度及制冷系数都会明显降低；不可逆半导体固态热离子制冷器的制冷率与制冷系数特性呈扭叶型；合理地选外加电压、势垒等参数，可以使制冷器设计于最大制冷率或最大制冷系数的状态。
건립료고필외부유한속솔전열과정화열원간열루적불가역반도체고태열리자제랭기모형，기우비평형열역학화유한시간열역학이론도출료열리자제랭기적제랭솔화제랭계수적표체식；대비분석료불가역열리자제랭기여가역열리자제랭기적발사전류밀도특성、전겁온도특성이급제랭계수특성；연구료불가역계통적제랭솔여제랭계수최우성능，득도료제랭솔화제랭계수적최우운행구간；통과수치계산，상세토론료외부전열이급내부도열、열원간열루손실、열원온도、외가전압、반도체재료세루등설계삼수대열리자장치성능적영향。재총전열면적일정적조건하，진일보우화료고、저온측환열기적면적분배이획득최가적제랭솔화제랭계수특성。결과표명，유우존재내부화외부적불가역성，열리자장치적발사전류밀도급제랭계수도회명현강저；불가역반도체고태열리자제랭기적제랭솔여제랭계수특성정뉴협형；합리지선외가전압、세루등삼수，가이사제랭기설계우최대제랭솔혹최대제랭계수적상태。
A model of an irreversible semiconductor solid-state thermionic refrigerator considering external finite rate heat transfer and the heat leakage between two heat reservoirs is established.The general expressions for cooling load and coefficient of performance (COP ) of the thermionic refrigerator were derived based on the theory of finite time thermodynamics and non-equilibrium thermodynamics.Performance characteristics of emitted current density,electrode temperature and COP for the irreversible thermionic refrigerator were compared with those for an idealized endoreversible thermionic refrigerator.The cooling load and COP performance were optimized and the optimum regions of cooling load and COP were determined.The influences of external heat transfer and design parameters such as internal heat conduction, heat leakage between reservoirs, heat reservoir temperature,applied voltage and potential barrier on the performance of the thermionic refrigerator were analyzed by detailed numerical calculations.Moreover,for the fixed total heat transfer surface area of two heat exchangers,the ratios of the heat transfer surface area of the hot side heat exchanger to the total heat transfer surface area of the heat exchangers were optimized for maximizing the cooling load and COP of the refrigerator,respectively.It is found that both the emitted current density and COP of the device are reduced due to the internal and external irreversibilities.The characteristic curves of cooling load versus COP are loop-shaped ones.By properly choosing the values of the design parameters such as applied voltage and potential barrier, the irreversible thermionic refrigerator can be designed to operate at maximum cooling load or maximum COP point.