发动机实时模拟系统中的发动机模型及其应用

计算机实时模拟技术在发动机电控系统的开发工作中受到越来越广泛的重视，而计算机实时模拟系统的核心是发动机模型。本文介绍了发动机实时模拟系统中几种主要的发动机模型，并给出了运用发动机模型建立实时模拟系统的实例。     

二冲程发动机油

二冲程发动机油１前言二冲程发动机和四冲程发动机不同，因为没有气门机构，所以发动机可以小型化、低成本、升功率高等。然而，二冲程发动机因润滑油与燃油混合，在被稀释的状态下进入曲轴箱，且大部分继续进入燃烧室，故曲轴箱内保留的少量润滑油必须维持发动机的润滑性...     

燃煤发动机

美国能源部认为,用煤作柴油机燃料在技术和经济上都是可行的。以煤作燃料的发动机造成的污染比现有柴油机小。柴油机厂的试验表明:燃煤发动机产生的氮氧化物(NO~x)比柴油机少一半。氮氧化物是柴油机排放的主要污染物,它与二氧化硫一起引起酸雨。美国能源部的SO_2计划要求用煤粉或煤水混合液作为发动机燃料。这种燃煤发动机的方案包括发动机、涡轮增压器、余热回收装置、尤其是能减少NO_x、SO_2和燃煤产生烟灰的排放控制系统。用煤代替柴油作燃料就能显著减少发动机产生的NO_x 量。然而,二氧化硫的控制比较困     

新世纪的发动机——没有运动件的发动机热声斯特林发动机简介

1979年Ceperley首先提出热声斯特林发动机的设想,但是他做的模型未能运转。其后的热声发动机(又称热声热机)采用不可逆驻波热声循环,热效率较低。1999年5月,“NATURE”刊载美国能源部LosAlamos国家试验室科学家S.Backhaus和G.Swift的文章:“热声斯特林热发动机(AthermoacousticStirlingHeatEngine)”,采用可逆斯特林循环热声热机,使热效率大大提高。热声斯特林发动机被认为是21世纪的发动机,将有可能替代传统的发动机——内燃机。国外许多刊物的“未来的发动机”、“没有运动件的发动机”、“无活塞热气机——热声发展的方向”等为题…     

煤粉发动机

[美《科学文摘》报道] 美国通用公司的发动机工程研究所的专家理查德·斯台特劳实验研制成一种用劣等燃料——煤粉——燃烧来驱动的新发动机。工程过程是:将燃料箱中的煤粉输送进同时也充满压缩空气的燃烧室内,点火燃烧后产生的高压热空气放出来驱动燃气涡轮发动机工作。斯台特劳预示这种功率较大的燃气涡轮发动机将首先应用于大型载重卡车和机车以及燃     

发动机振动控制技术研究

我们简述了发动机产生振动的原理,分析了发动机对车身振动的传递特性。以某型号直列四缸发动机为例,建立了发动机悬置振动系统模型,通过研究降低发动机对车身振动最有效的措施是调整车身联结点的刚度。为实现对发动机振动的控制,建立了发动机振动控制系统模型,研究表明主动控制技术可以较好地抑制发动机对车身的振动。     

塑料发动机

美国一家研究公司最近采用注射成型塑料来制造发动机部件,这种部件可使发动机的总质量减小一半以上。     

二冲程发动机

广泛应用在汽车上的曲轴箱扫气二冲程发动机,与四冲程发动机相比较,在气口配气正时、进气扫气和排气的方法等方面都有明显的差别。正因为这样,二冲程发动机有它很大的特点。本文就设计上应该注意之点等作有关阐述。     

发动机失火实例分析

失火是发动机常见的故障,当发动机发生失火时不但使发动机的经济性和动力性下降,同时发动机的排放也大大恶化,尤其以HC排放增多最为明显。此外更为严重的是由失火引起的后燃会导致三元催化器温度过高而烧毁,进入排气管中未充分燃烧的油气混合物吸附在催化器和氧传感器上使之中毒而失效,对发动机造成巨大伤害。因此如何及时的找出发动机失火的原因对于降低发动机的损伤至关重要,我们结合实例分析了发动机失火的主要原因。     

地热发动机

莫斯科的一位革新能手普列斯尼亚科夫研制出一种新的地热发动机,它可以直接把地热变为机械运动。据《汽笛报》报道,这种发动机的转子     

525t/h CFB锅炉旋风分离器制造工艺简介

大型循环流化床锅炉中的管式旋风分离器的制造所涉及的工艺复杂,装配难度高。以525t/hCFB旋风分离器的制造工艺为例,描述了分片出厂的大型旋风分离器在厂内分片制造、试拼装的工艺方案,分析了制造中重要的工艺难点,诸如大弯曲半径的圆弧形、锥体形管排的成形及组装等,并提出相应的工艺解决方案,重点在于保证旋风分离器的对口装配上。为今后同类大型CFB锅炉的制造,确保产品质量、简化工艺装备设计、加快制造进度提供了工艺措施,积累了经验。     

The method Heliosat-2 for deriving shortwave solar radiation from satellite images

This article presents the method Heliosat-2 that converts observations made by geostationary meteorological satellites into estimates of the global irradiation at ground level. This new version integrates the knowledge gained by various exploitations of the original method Heliosat and its varieties in a coherent and thorough way. It is based upon the same physical principles but the inputs to the method are calibrated radiances, instead of the digital counts output from the sensor. This change opens the possibilities of using known models of the physical processes in atmospheric optics, thus removing the need for empirically defined parameters and of pyranometric measurements to tune them. The ESRA models are used for modeling the clear-sky irradiation. The assessment of the ground albedo and the cloud albedo is based upon explicit formulations of the path radiance and the transmittance of the atmosphere. The method Heliosat-2 is applied to Meteosat images of Europe for the months of January 1995, April 1995 and July 1994. Pyranometric measurements performed by thirty-five meteorological stations are used to assess the performances that are close to those of Heliosat-1 found in the literature. Possible improvements are discussed.     

利用工程热力学原理对商品价值量进行分析、计算的探讨

热力学是研究一个体系的热、能量等量的科学,整个社会的劳动人员、物资、生产设备等一起构成了一个经济整体,从热力学的角度,这个整体是一个体系。在这个体系中不可避免地涉及有关能量之类的问题,比如劳动人员的劳动付出,实质就是一个做功和能量转移的过程,因此有理由认为热力学的一些基本定律也适用于经济体系。本文的主要思想是用热力学原理来分析和解决经济管理问题。首先作者从思考马克思的科学社会主义的热力学依据出发,得出“社会生产力不断进步的热力学本质是经济体系的熵（即无序程度）在减小“这一结论;然后又对商品的价值量的热力学本质进行思考,认为商品价值量的实质是该商品相对于原料的有效程度的增加,在热力学上就是从原料到生产产品的过程中,由劳动者向商品中转移的熵流的大小。     

降低原油沉降脱水热能消耗的研究

提高沉降脱水温度,可以加快原油沉降脱水速度,缩短流程;增加设备和延长处理流程,利用长时间的沉降,也可以达到原油脱水的目的。提高脱水温度,加热能耗增加;长时间沉降中热量散失,需要加热来保持温度,也消耗能量,在设计和运行中还没有优化脱水温度和沉降时间以获得最佳运行状态的方法。本文通过对常规原油沉降脱水数据的分析,得到了脱水效果相同的沉降时间与沉降温度间的等效关系。利用等效关系,提出了原油沉降脱水热能消耗的计算方法,并且对加热量、散热量和总的热量消耗进行了计算,结果表明延长脱水的时间,降低脱水温度,有利于降低脱水热能消耗。     

热电厂叶片断裂事故分析

对叶片裂纹、断裂进行了分析，该叶片材质为2Cr13钢，叶片的成分、组织、性能均符合标准要求，断口的宏观和微观分析表明，叶片的断裂起源于叶片机械加工遗留的刀痕、磕碰形成的缺口和尖锐的圆孔边缘，工艺缺陷降低了叶片的使用寿命。裂纹源在交变应力作用下不断扩展，导致叶片发生疲劳断裂。     

Prof. S. Shcheklein – One of the founders of the scientific and methodical school of energy saving,increasing energy efficiency and hydrogen energy in the Urals

The article gives the main results of scientific and educational activities of a prominent and well-known scientist in the field of energy saving and energy efficiency improvement, hydrogen energy, development of methods and technologies for the use of renewable energy sources, environmentally efficient projects, head of the Department of Nuclear Power Plants and Renewable Energy Sources of Ural Federal University (UrFU), Honored Power Engineer of Russia, Full Member of the International Energy Academy, Dr. Tech. Sciences, Professor Sergei Shcheklein. It is shown the achievements of the Ural Scientific and Methodological School in this area of knowledge, as well as the history of the creation of the first in Russia Department of Energy Saving at UrFU, the Center for the Training and Certification of Specialists in the Field of Energy Saving, the Regional Educational and Methodological Center for Energy Saving. The results of the work of the Interuniversity Coordination Council on Energy Saving in educational institutions of the Ural Region under the Regional Energy Commission of the Government of the Sverdlovsk Region on the implementation of the Energy Saving Program of the Ministry of Education of the Russian Federation in 1999–2005 are described. The article expounds twenty years of experience in organizing and holding all-Russian, and recently – international student olympiads, youth scientific and practical conferences, exhibitions of scientific and technical creativity of students, graduate students and young scientists on energy and resource saving, renewable energy sources and nuclear energy. We have presented some results of scientific research of the laboratory “Eurasian Center for Renewable Energy and Energy Saving”, created and operated under the guidance of prof. Sergei Shcheklein and described briefly the textbooks published in recent years in the field of hydrogen energy, on the safe use of nuclear energy at modern and promising nuclear power plants, the development of a methodology for calculating complex energy systems based on the use of renewable energy sources, the classification of renewable energy clusters, performed in collaboration and under the guidance of prof. Sergei Shcheklein. Moreover, references to the main federal and regional regulatory documents, scientific publications and educational publications related to the scientist's many years of work in this area, scientometric indicators are given.     

直接测力俯仰振荡翼型动态气动性能研究

在西北工业大学NF-3低速风洞二元实验段开展翼型俯仰振荡运动动态气动性能深入研究。实验模型为展向三段式测力模型,测力仅在模型中段进行以减小风洞侧壁干扰的影响。实验中采集模型的转动瞬态迎角、计算模型中段的惯性力和惯性力矩、并从天平采集数据中扣除以修正模型惯性对结果的影响。结果表明,迎角超过正向或负向静态失速迎角是升力系数和俯仰力矩系数产生大的迟滞环的必要条件。随着振荡缩减频率增大,动态失速会推迟,升力系数迟滞环增大,阻力系数增大,最大迎角附近的俯仰力矩系数减小。在迎角小于静态失速迎角或超过不大的迎角范围,随着缩减频率的增大,翼型振荡运动俯仰力矩系数上行时减小,下行时增大。随着振荡振幅的增大,翼型振荡运动动态升力系数和俯仰力矩系数的迟滞环增大。随着平均迎角的增大,翼型迎角更多地进入正向失速区,升力系数迟滞环增大,俯仰力矩系数最小值变小。雷诺数对升力系数、阻力系数和俯仰力矩系数迟滞环无明显影响;但是,在翼型模型下行过程,随着雷诺数的增大,升力恢复提前,同时迟滞环随雷诺数增大而减小。     

Hysteresis behavior of electrical resistance in Pd thin films during the process of absorption and desorption of hydrogen gas

We report the fabrication of a novel hydrogen sensor that utilizes the electrical resistance changes in the palladium thin films with nanometer thicknesses. The sensing mechanism is based on transitory absorption of hydrogen atoms into the palladium layer, which leads to the reversible alteration of the electrical resistance. In concentrated hydrogen ambient, the excess hydrogen absorption process leads to mechanical deformation on the surface of the palladium films, corresponding to the phase transition from α-phase to β-phase. The reversible sensing process results in a hysteresis curve for resistive properties, of which the height (sensitivity) could be controlled by manipulating the thickness of the palladium layers. The peel-off phenomena on the surface of the palladium film were suppressed by decreasing the thickness of the film. At the thickness of 20 nm, a hysteresis curve of resistance was obtained without any structural change in the palladium thin film. These results provide a significant insight to the fundamental understanding of the relationship between the electrical sensitivity of pure Pd thin films and related structural deformation, which is essential to develop robust H-sensors with high sensibility.     

Structural integrity analysis of axially cracked pipelines using conventional and constraint-modified failure assessment diagrams

This study explores applications of the failure assessment diagram (FAD) methodology to predict the failure behaviour for high pressure pipelines with planar defects having different geometries (i.e., crack depth and crack length). One purpose of this investigation is to assess the capability of FAD procedures in integrity analyses of high pressure pipelines with varying crack configurations. Another purpose is to address the effectiveness of constraint-based FADs to predict burst pressure of low-constraint cracked pipelines. Full scale burst testing of end-capped pipe specimens with axial surface flaws provide the data needed to compare the failure predictions derived from the FAD procedures. The analyses reveal that the degree of agreement between predicted pressures and experimentally measured values depends rather markedly on the crack size for the tested pipes. Moreover, the analyses also show a possible weak dependence of the predicted pressures on the constraint-based correction scheme. Overall, the results validate the use of FAD-based methodologies for defect assessments of axially cracked pipelines.