CAJ | 학술논문

利用约束热源入口及出口温度的热力学模型，将循环热效率及净输出功统一为一个参数，计算41种工质在473.15K 废热烟气驱动的跨临界有机朗肯循环中的热力学表现，分析蒸发器内窄点温差及工质物性对循环性能的影响。结果表明，临界温度低于烟气出口温度的工质，及高于0.88倍烟气入口温度的工质，临界温度是循环效率的主要影响因素；临界温度在上述范围之间的工质，干湿性对循环效率影响显著，湿工质效率明显高于干工质。所有循环中，该临界温度范围内的湿工质热效率最高。临界温度高于0.88倍烟气入口温度的工质，窄点温差可能出现在蒸发过程中或蒸发器出口，从热力性能角度看，窄点出现在蒸发过程中的循环明显优于窄点出现在蒸发器出口的循环。改变热源入口及出口温度不会影响上述结论。
이용약속열원입구급출구온도적열역학모형，장순배열효솔급정수출공통일위일개삼수，계산41충공질재473.15K 폐열연기구동적과림계유궤랑긍순배중적열역학표현，분석증발기내착점온차급공질물성대순배성능적영향。결과표명，림계온도저우연기출구온도적공질，급고우0.88배연기입구온도적공질，림계온도시순배효솔적주요영향인소；림계온도재상술범위지간적공질，간습성대순배효솔영향현저，습공질효솔명현고우간공질。소유순배중，해림계온도범위내적습공질열효솔최고。림계온도고우0.88배연기입구온도적공질，착점온차가능출현재증발과정중혹증발기출구，종열력성능각도간，착점출현재증발과정중적순배명현우우착점출현재증발기출구적순배。개변열원입구급출구온도불회영향상술결론。
Thermal performance values of 41 working fluids in a trans-critical organic Rankine cycle (ORC) driven by waste heat flue gas of 473.15 K were calculated by means of a theoretical model in which the inlet and outlet temperatures of flue gas were fixed and therefore the thermal efficiency and net work output were unified into one parameter as long as the heat absorbed was given. The influences of pinch point temperature difference (PPTD) in the evaporator and working fluid properties on cycle performance were analyzed. Calculation results showed that for fluids with critical temperatureTc<Tgas,out, and fluids withTc>0.88Tgas,in,Tc had dominant influence on thermal efficiency. For fluids withTc betweenTgas,outand 0.88Tgas,in, fluid dryness had significant influence on cycle performance, and wet fluids outperformed dry fluids apparently. Wet fluids withTc between Tgas,outand 0.88Tgas,in exhibited the highest thermal efficiency. For fluids withTc>0.88Tgas,in, PPTD might lie either inside the evaporator or at the outlet. Thermal performance values of the cycle with PPTD inside the evaporator outperformed that with PPTD at the outlet. Application of such conclusions was confirmed through sensitivity analysis for flue gas inlet and outlet temperatures.