Wu Zhixiang, Chen Lingen, Feng Huijun
Institute of Thermal Science and Power Engineering, Naval University of Engineering, Wuhan 430033, China.
Military Key Laboratory for Naval Ship Power Engineering, Naval University of Engineering, Wuhan 430033, China.
Entropy (Basel). 2018 Mar 5;20(3):165. doi: 10.3390/e20030165.
Power output ( P ), thermal efficiency ( η ) and ecological function ( E ) characteristics of an endoreversible Dual-Miller cycle (DMC) with finite speed of the piston and finite rate of heat transfer are investigated by applying finite time thermodynamic (FTT) theory. The parameter expressions of the non-dimensional power output ( P ¯ ), η and non-dimensional ecological function ( E ¯ ) are derived. The relationships between P ¯ and cut-off ratio ( ρ ), between P ¯ and η , as well as between E ¯ and ρ are demonstrated. The influences of ρ and piston speeds in different processes on P ¯ , η and E ¯ are investigated. The results show that P ¯ and E ¯ first increase and then start to decrease with increasing ρ . The optimal cut-off ratio ρ o p t will increase if piston speeds increase in heat addition processes and heat rejection processes. As piston speeds in different processes increase, the maximum values of P ¯ and E ¯ increase. The results include the performance characteristics of various simplified cycles of DMC, such as Otto cycle, Diesel cycle, Dual cycle, Otto-Atkinson cycle, Diesel-Atkinson cycle, Dual-Atkinson cycle, Otto-Miller cycle and Diesel-Miller cycle. Comparing performance characteristics of the DMC with different optimization objectives, when choosing E ¯ as optimization objective, η improves 26.4% compared to choosing P ¯ as optimization objective, while P ¯ improves 74.3% compared to choosing η as optimization objective. Thus, optimizing E is the best compromise between optimizing P and optimizing η . The results obtained can provide theoretical guidance to design practical DMC engines.
应用有限时间热力学（FTT）理论，研究了活塞速度有限且传热速率有限的内可逆双米勒循环（DMC）的功率输出（P）、热效率（η）和生态函数（E）特性。推导了无量纲功率输出（P¯）、η和无量纲生态函数（E¯）的参数表达式。论证了P¯与截止比（ρ）之间、P¯与η之间以及E¯与ρ之间的关系。研究了ρ和不同过程中的活塞速度对P¯、η和E¯的影响。结果表明，P¯和E¯随ρ的增加先增大后减小。如果在加热过程和放热过程中活塞速度增加，最佳截止比ρopt将增大。随着不同过程中活塞速度的增加，P¯和E¯的最大值增大。研究结果包括DMC各种简化循环的性能特性，如奥托循环、柴油循环、双循环、奥托 - 阿特金森循环、柴油 - 阿特金森循环、双 - 阿特金森循环、奥托 - 米勒循环和柴油 - 米勒循环。比较具有不同优化目标的DMC的性能特性，当选择E¯作为优化目标时，与选择P¯作为优化目标相比，η提高了26.4%，而与选择η作为优化目标相比，P¯提高了74.3%°因此，优化E是优化P和优化η之间的最佳折衷方案。所得结果可为实际DMC发动机的设计提供理论指导。
