连续燃烧分缸工作型发动机理论热力循环分析

doi:10.12382/bgxb.2022.0121

摘要/Abstract

摘要：

连续燃烧分缸工作型发动机因其热效率及功率密度高,振动及噪声小,未来将在小型无人机及鱼雷上具有很好的应用前景。该型发动机将压缩、燃烧和膨胀过程分缸进行,同时使用进气掺水、不等缸径、回热器和连续外燃技术,被认为具有极高的热功转换潜力,但目前缺乏对其热力循环的研究,导致在发动机设计过程中缺乏理论指导。将发动机各工作阶段等效为定温压缩、定容加热、定熵膨胀、排气放热与回热共5个工作过程,构建出新型理论热力循环并推导出指示热效率公式。研究结果表明:指示热效率主要由工质热物性、压缩比、膨胀比和回热率决定,增大压缩比或降低膨胀比均可提升指示热效率;应用定温压缩后可扩大回热温差,提升指示热效率,同时还可保持较低的缸内温度和压力;该型发动机热效率及可靠性较传统汽油机、柴油机具有显著优势,发动机指示热效率可达65%以上。

关键词: 连续燃烧分缸工作型发动机, 理论热力循环, 指示热效率, 定温压缩

Abstract:

The continuous combustion multi-cylinder engine has promising application prospects in mini unmanned aerial vehicles and torpedoes because of its high thermal efficiency and power density, and low vibration and noise. The engine works with separate cylinders for the compression, combustion and expansion processes. The technologies of water induction, unequal bore size, recuperator and continuous external combustion are also adopted. It is considered to have high potential in heat-work conversion. However, the lack of research on its thermodynamic cycle means the lack of theoretical guidance for the design of the engine. The engine working stages can be equivalent to 5 processes: isothermal compression, constant volume combustion, isentropic expansion, exhaust heat release and recuperation. A new theoretical thermodynamic cycle is constructed and the equation of its indicated thermal efficiency is derived. It is found that: the indicated thermal efficiency is mainly determined by the working medium’s thermo-physical property, compression ratio, expansion ratio and recuperation ratio; with the increase of compression ratio and the reduction of expansion ratio, the indicated thermal efficiency is improved; especially, isothermal compression can enlarge the recuperative temperature difference which leads to a significant increase of indicated thermal efficiency; meanwhile, the temperature and pressure in the cylinder is not increased; this engine is proved to have higher thermal efficiency and operation reliability than traditional gasoline and diesel engines; the calculation results show that the indicated thermal efficiency of the engine can reach more than 65%.

Key words: continuous combustion multi-cylinder engine, theoretical thermodynamic cycle, indicated thermal efficiency, isothermal compression

中图分类号:

TK123

吴晗, 张泽宇, 孙柏刚, 李向荣. 连续燃烧分缸工作型发动机理论热力循环分析[J]. 兵工学报, 2023, 44(1): 74-83.

WU Han, ZHANG Zeyu, SUN Baigang, LI Xiangrong. Theoretical Thermodynamic Cycle Analysis of Continuous Combustion Multi-Cylinder Engine[J]. Acta Armamentarii, 2023, 44(1): 74-83.

图/表 8

图1 连续燃烧分缸工作型发动机工作过程示意图

Fig.1 Working processes of continuous combustion multi-cylinder engine

图2 连续燃烧分缸工作型发动机理论热力循环 p-v图和T-s图

Fig.2 p-v and T-s theoretical thermodynamic cycle of continuous combustion multi-cylinder engine

图3 不同压缩比下的进气掺水质量比例

Fig.3 Mass proportion of water mixed with intake air under different compression ratios

图4 压缩比对能量分配及指示热效率的影响规律

Fig.4 Effect of compression ratio on energy distribution and indicated thermal efficiency

图5 膨胀比对能量分配及指示热效率的影响规律

Fig.5 Effect of expansion ratio on energy distribution and indicated thermal efficiency

图6 定温压缩与定熵压缩缸内能量分配及指示热效率对比

Fig.6 Comparison of energy distribution in the cylinder and indicated thermal efficiency between isothermal and isentropic compression conditions

图7 定温压缩与定熵压缩缸外能量分配对比

Fig.7 Comparison of energy distribution outside the cylinder between isothermal and isentropic compression conditions

图8 定温压缩与定熵压缩最高燃烧压力与温度对比

Fig.8 Comparison of maximum pressure and temperature of thermal cycle between isothermal and isentropic compression conditions

参考文献 22

[1]	徐勤超, 李善军, 练永庆, 等. 新型凸轮发动机活塞强度分析及结构改进[J]. 武汉大学学报, 2019, 52(3):270-276.
	XU Q C, LI S J, LIAN Y Q, et al. Strength analysis and structure improvement of piston for a new type cam engine[J]. Engineering Journal of Wuhan University, 2019, 52(3):270-276. (in Chinese)
[2]	叶莹, 赵振峰, 符代桥, 等. 对置活塞轴向发动机同步运动机构空间圆柱凸轮的设计与优化[J]. 兵工学报, 2017, 38(5):852-858. doi: 10.3969/j.issn.1000-1093.2017.05.003
	YE Y, ZHAO Z F, FU D Q, et al. Design and optimization of spatial cylindrical cam of synchronous movement mechanism of opposed-piston axial cylinder engine[J]. Acta Armamentarii, 2017, 38(5):852-858. (in Chinese) doi: 10.3969/j.issn.1000-1093.2017.05.003
[3]	徐勤超, 李善军, 练永庆, 等. 新型大功率凸轮活塞发动机结构设计与试验[J]. 兵工学报, 2018, 39(10):1979-1987. doi: 10.3969/j.issn.1000-1093.2018.10.014
	XU Q C, LI S J, LIAN Y Q, et al. Structural design and test of a new high power cam piston engine[J]. Acta Armamentarii, 2018, 39(10):1979-1987. (in Chinese)
[4]	练永庆, 王树宗, 陈宜辉, 等. 鱼雷滚轮斜置式凸轮发动机分析[J]. 鱼雷技术, 2005, 13(4):13-16.
	LIAN Y Q, WANG S Z, CHEN Y H, et al. Analysis of torpedo cam engine with inclining rollers[J]. Torpedo Technology, 2005, 13(4):13-16. (in Chinese)
[5]	徐勤超, 王树宗, 练永庆. 轻型水下航行器大功率凸轮发动机设计[J]. 深圳大学学报理工版, 2012, 29(6):498-503.
	XU Q C, WANG S Z, LIAN Y Q. Design of high power cam engine for lightweight underwater vehicle[J]. Journal of Shenzhen University(Science & Engineering), 2012, 29(6):498-503. (in Chinese)
[6]	EASTOP T D, MCCOMKEY A. Applied thermodynamics for engineering technologists[M]. UK: Dorling Kindersley Pvt.Ltd., 2009:155-161.
[7]	王建昕, 帅石金. 汽车发动机原理[M]. 北京: 清华大学出版社, 2011:59-61.
	WANG J X, SHUAI S J. Automotive engine fundamentals[M]. Beijing: Tsinghua University Press, 2011:59-61. (in Chinese)
[8]	DUMBOCK O, SCHUTTING E, EICHLSEDER H. Extended expansion linkage engine: a concept to increase the efficiency[J]. Automotive and Engine Technology, 2018, 3:83-92. doi: 10.1007/s41104-018-0029-9 URL
[9]	ZHAO J X. Research and application of over-expansion cycle (Atkinson and Miller) engines-a review[J]. Applied energy, 2017, 185:300-319. doi: 10.1016/j.apenergy.2016.10.063 URL
[10]	张惠. 机械式低压缩比、高膨胀比发动机研究[D]. 长春: 吉林大学, 2016.
	ZHANG H. Mechanical low compression ratio,high expansion ratio engine research[D]. Changchun: Jilin University, 2016. (in Chinese)
[11]	WU C, PUZINAUSKAS P V, TSAI J S. Performance analysis and optimization of a supercharged Miller cycle Otto engine[J]. Applied Thermal Engineering, 2003, 23:511-521. doi: 10.1016/S1359-4311(02)00239-9 URL
[12]	THOMBARE D G, VERMA S K. Technological development in the Stirling cycle engines[J]. Renewable & Sustainable Energy Reviews, 2018, 12:1-38.
[13]	ULRICH R, DIETER V. Axialkolbenmotor mit einer innerenkontinuierlichen Verbrennung:EP2846029A2[P]. 2010-07-26.
[14]	李建锋, 吕俊复, 杨海瑞, 等. 基于大小气缸与大小活塞的新型发动机系统性能预测分析[J]. 机械工程学报, 2008, 44(11):186-191.
	LI J F, LÜ J F, YANG H R, et al. Performance prediction of new engine system with big and small air cylinders and big and small pistons[J]. Chinese Journal of Mechanical Engineering, 2008, 44(11):186-191. (in Chinese)
[15]	刘龙, 唐元亨, 安琛, 等. 一种基于分缸式热力学循环的自由活塞发动机:CN113047951A[P]. 2021-06-29.
	LIU L, TANG Y H, AN C, et al. A free-piston engine based on separated-cylinder thermodynamic cycle:CN113047951A[P]. 2021-06-29. (in Chinese)
[16]	范亚东, 吴天宝, 李雪松, 等. 汽油机缸内喷水技术研究现状与进展[J]. 车用发动机, 2020(2):1-8.
	FAN Y D, WU T B, LI X S, et al. Research status and progress of water injection technology in gasoline engine[J]. Vehicle Engine, 2020(2):1-8. (in Chinese)
[17]	秦静, 张启锐, 裴毅强, 等. 进气道喷水量对GDI汽油机燃烧和排放特性的影响[J]. 天津大学学报, 2020, 53(11):1167-1174.
	QIN J, ZHANG Q R, PEI Y Q, et al. Effects of intake manifold water injection mass on combustion and emission characteristics of GDI engine[J]. Journal of Tianjin University, 2020, 53(11):1167-1174. (in Chinese)
[18]	陈二锋, 王志标, 张早校, 等. 活塞压缩机喷水内冷却过程的性能分析[J]. 压缩机技术, 2005(2):1-5.
	CHEN E F, WANG Z B, ZHANG Z J, et al. Performance analysis of water-injection internal cooling in the reciprocating compressor[J]. Compressor Technology, 2005(2):1-5. (in Chinese)
[19]	何子伟, 罗马吉, 涂正凯. 等温压缩空气储能系统喷水量研究[J]. 西安交通大学学报, 2018, 52(1):33-39.
	HE Z W, LUO M J, TU Z K. Research on the water spraying rate for an energy storage system of isothermal compressed air[J]. Journal of Xi’an Jiaotong University, 2018, 52(1):33-39. (in Chinese)
[20]	贾冠伟, 许未晴, 郑海务, 等. 低品质余热蒸发雾滴冷却空气压缩方法[J]. 液压与气动, 2021, 45(7):58-64.
	JIA G W, XU W Q, ZHENG H W, et al. Air compression cooling method with low grade waste heat evaporation sprays[J]. Chinese Hydraulics & Pneumatics, 2021, 45(7):58-64. (in Chinese)
[21]	刘喜岳, 张靖周, 李刚团, 等. 串列双U型管束换热器压降与回热效率模型实验[J]. 航空学报, 2017, 38(3):106-114.
	LIU X Y, ZHANG J Z, LI G T, et al. Model experiment on pressure drop and thermal recovery efficiency of tandem double-U-shaped-tube heat exchangers[J]. Acta Aeronautica et Astronautica Sinica, 2017, 38(3):106-114. (in Chinese)
[22]	薄冲, 袁春, 赵翔, 等. 外燃式微型燃气轮机循环[J]. 燃气轮机技术, 2008, 21(4):15-17.
	BO C, YUAN C, ZHAO X, et al. Externally fired cycle of microturbine[J]. Gas Turbine Technology, 2008, 21(4):15-17. (in Chinese)