共查询到20条相似文献,搜索用时 62 毫秒
1.
2.
3.
4.
应用有限时间热力学方法,探索有限热源、热阻和回热损失的斯特林热机的优化性能,得到一些新的性能参数,所得结论可为斯特林热机的研制和优化设计提供些新理论指导。 相似文献
5.
6.
刘会珍 《内燃机与动力装置》2012,(5):1-4,7
一般就四缸发动机而言,由于进排气门重叠开启,会出现排气废气倒流现象,影响发动机的进气充量,导致发动机性能偏低。本文从排气歧管结构对进气充量影响进行分析,得出导致倒流可能存在的原因,同时就分析结果提出优化方案对排气歧管结构进行优化,进行试验验证,确定最终的排气歧管结构,有效地提高发动机性能。 相似文献
7.
本文基于一台压缩比可变的单缸热力学发动机,使用自主开发的空气辅助喷射系统,在全负荷条件下,开展了活塞式航空煤油发动机性能优化及爆震抑制的试验研究。探究了采用双点火、降低压缩比以及使用CO2辅助喷射对航空煤油发动机的性能及爆震抑制的影响研究。结果表明,采用双点火可以有效提高航空煤油火焰传播速率,提高燃烧相位,降低循环波动,并且有抑制爆震的作用;通过降低压缩比有效实现了爆震抑制,解决在较高压缩比下航空煤油发动机只能运行在小负荷区间的难题,压缩比降至6,发动机实现全负荷运行,动力性、经济性较好,且不易发生爆震;采用CO2辅助航空煤油喷射时,随着CO2脉宽的增加,同一点火时刻下,发动机的动力性经济性下降,但由于CO2的抑制爆震的作用,MBT点火时刻最大可提前至14 °CA BTDC,使得燃烧相位提前,发动机燃烧效率提高。 相似文献
8.
首先叙述了煤油在航空领域的应用背景和前景,概述了活塞式发动机燃烧煤油的意义.综述了国内外活塞式煤油发动机所采取的技术方案和获得的研究结论.以课题背景,论述了活塞式发动机燃烧煤油所需面对的问题和关键技术.以小型二冲程发动机为研究对象,通过对汽油和煤油燃料的缸压示功图、扭矩输出和缸盖温度进行对比,结果表明两种燃料的相应的性能差别不大. 相似文献
9.
10.
11.
Zhuming Huang Feng Wu Lingen Chen Chih Wu Fangzhong GuoDepartment of Physics Heat Engineering Wuhan Institute of Chemical Technology Wuhan China E-mail: wufeng@mail.whict.edu.cn Faculty Naval Academy of Engineering Wuhan 《热科学学报(英文版)》2002,11(3):193-197
The purpose of this paper is to study the optimal performance for an irreversible quantum Stirling cooler with heat leak and other irreversible losses. The relationship between the optimal cooling load and the coefficient of performance (COP) for the quantum Stirling cooler is derived. The maximum cooling load and the corresponding COP, as well as the maximum coefficient of performance and the corresponding cooling load are obtained. The experimental observation for the optimal region is provided. 相似文献
12.
对内燃机混合加热循环的特性做了进一步的分析与研究,使得对该循环的分析结果与内燃机实际热力过程的不可逆性充分接近,对内燃机的设计和理论研究工作具有重要意义;并运用有限时间热力学的方法,对135柴油机Dual循环进行了有限时间特性分析,得出了应用该方法对内燃机缸内热力过程不可逆性进行研究具有重要实际意义的结论。 相似文献
13.
14.
The quantum mechanics model of a magnetic Stirling cooler is established. The optimal relation between the cooling load and the coefficient of performance (COP) is obtained. The maximum cooling load and corresponding COP as well as the maximum COP and the corresponding cooling load are derived. The optimization criteria for a magnetic Stirling cooler are determined. The results obtained here will be useful for the further understanding and the selection of the optimal operating conditions for a magnetic Stirling cooler. Published in 2002 by John Wiley & Sons, Ltd. 相似文献
15.
16.
17.
内燃机有限时间内不可逆循环热力学分析 总被引:8,自引:0,他引:8
本文讨论了内燃机循环在逐步考虑各种主要不可逆因素后所构成的一系列新的热力学模型下有限时间热力学分析,重点寻找出在规定的模型下其循环最大输出功率与对应的热效率之间的关系,给出了有限时间热力学意义下内燃机循环新的性能界限,它们对实际内燃机性能的评估及改进有一定的指导意义。 相似文献
18.
19.
Optimization of Output Power and Thermal Efficiency of Solar‐Dish Stirling Engine Using Finite Time Thermodynamic Analysis 下载免费PDF全文
This paper presents an investigation on finite time thermodynamic (FTT) evaluation of a solar‐dish Stirling heat engine. FTTs has been applied to determine the output power and the corresponding thermal efficiency, exergetic efficiency, and the rate of entropy generation of a solar Stirling system with a finite rate of heat transfer, regenerative heat loss, conductive thermal bridging loss, and finite regeneration process time. Further imperfect performance of the dish collector and convective/radiative heat transfer mechanisms in the hot end as well as the convective heat transfer in the heat sink of the engine are considered in the developed model. The output power of the engine is maximized while the highest temperature of the engine is considered as a design parameter. In addition, thermal efficiency, exergetic efficiency, and the rate of entropy generation corresponding to the optimum value of the output power is evaluated. Results imply that the optimized absorber temperature is some where between 850 K and 1000 K. Sensitivity of results against variations of the system parameters are studied in detail. The present analysis provides a good theoretical guidance for the designing of dish collectors and operating the Stirling heat engine system. 相似文献