双层交错布置多孔喷嘴燃烧排放性能试验研究

在某单缸柴油机上搭建高压共轨系统整机试验台架,研究双层交错布置多孔喷嘴结构对柴油机燃烧和排放性能的影响规律。试验结果表明:相同几何流通面积的双层交错布置多孔喷嘴相比于传统单层喷嘴经济性提高,NOx排放和碳烟排放改善;孔径较小的双层交错布置多孔喷嘴方案燃油消耗率较高,NOx排放较低,碳烟排放较高;下层喷孔喷射夹角小的双层交错布置多孔喷嘴方案缸内平均压力和温度高,油耗和排温降低,NOx排放较多,碳烟排放较少。     

柴油机TR燃烧系统实现低温预混合燃烧的研究

为了验证TR燃烧系统降低发动机排放、实现低温预混合燃烧的能力,在一台经过改造的单缸135柴油机上进行了降低压缩比、燃用柴油-乙醇混合燃料和推迟供油的试验研究.结果表明,压缩比ε降低后,着火推迟,最大放热率增加,缸内最高压力和最高温度降低,NOx排放也降低.但是中高负荷时燃烧速率降低,有效油耗率增加.当燃用乙醇体积含量20%的乙醇-柴油混合燃料时,与燃用柴油燃料相比,着火延迟期延长,烟度大幅度降低.小负荷时缸内最高压力、最高温度、最大放热率和燃烧速率都降低,NOx降低较多;中高负荷时最大放热率高于后者,燃烧速率提高,NOx降低得较少.当供油定时从15°CA BT-DC推迟到13°CA BTDC后,烟度基本不变.     

优化进气道改善高强化柴油机燃烧与性能的试验研究

基于提高流量系数和降低涡流比的方式对某高强化柴油机进气道进行优化,并在单缸试验测试平台开展了燃烧和性能的试验研究,结果表明:在保持功率一定的前提下,进气道的新方案使得发动机的进气量增加,缸内最高燃烧压力降低,燃烧相位推迟,最大压力升高率明显下降,燃烧持续期显著缩短;发动机燃油消耗率降低,烟度下降,排气温度降低。     

热EGR氢内燃机的动力性和排放

基于进气道燃料喷射(port fuel injection,PFI)氢内燃机试验系统,研究了带热废气再循环(exhaust gas recirculation,EGR)系统氢内燃机的燃烧和排放特性。试验结果表明:采用热EGR能增大氢内燃机的滞燃期和燃烧持续期,显著降低缸内最高压力和温度;EGR率增大时平均有效指示压力和循环变动的变化并不显著,对整机的功率输出和平顺工作几乎没有影响,中高负荷时需要采用很大的EGR率才能大幅度降低NOx排放,在高负荷时控制排放所需的EGR率不大,高负荷时过大的EGR率可能造成燃料经济性和动力性的大幅度下降。     

直喷式柴油机燃用二甲基醚(DME)试验研究

介绍了在1100单缸直喷式柴油机上燃用DME的发动机试验研究结果。研究表明：通过增加循环供油量可使柴油机燃用DME后恢复到原机略低，同时缸内最大爆发压力降低，发动机碳烟排放为零，HC和CO排放比原机略高，NOx排放比原柴油机降低约50%以上，供油提前角减少，缺内最大爆发压力降低，NOx排放可进一步大幅度降低，但HC排放略有升高；加大喷孔直径，缸内爆发压力升高，NOx排放升高，HC和CO排放在中低负荷相差不大，但在大负荷工况有所升高。     

TBD620柴油机缸内工作过程仿真研究

利用PRO／E建立TBD620柴油机的进气道和燃烧室三维模型;并在FIRE软件中对进气、压缩和燃烧过程进行仿真计算。分析了TBD620柴油机双进气道可控涡流系统对缸内涡流、油气混合和燃烧排放特性的影响。结果表明,低负荷工况时关闭双进气道可控涡流系统的进气控制阀能显著改善缸内混合气的形成,提高柴油机燃烧及排放性能。     

汽油和乙醇预混对柴油机燃烧与排放影响的试验

基于一台单缸柴油机,分别采用进气道喷射汽油和乙醇的预混方式,通过调节不同负荷下喷射汽油/柴油和乙醇/柴油燃料比例,以研究其对发动机燃烧与排放的影响.结果表明,低负荷下采用汽油或者乙醇预混,缸内最高燃烧压力降低,实现较为缓和的燃烧放热,均可以同时降低碳烟(Soot)和NOx,但HC和CO排放增加.较高负荷下随着预混比例增大,放热更加剧烈,缸内最大爆压升高.滞燃期随燃油预混比例增大而增大,但增大幅度随负荷增大而逐渐减小.与汽油预混方式相比,采用乙醇预混的方式滞燃期增大更加明显,且燃烧温度较低,在较高负荷下仍能实现较为缓和的燃烧放热,表明采用乙醇预混的方式有利于向高负荷拓展.     

缸内温度对柴油均质燃烧NOx排放影响的试验研究

采用在进气上止点附近进行燃油喷射,通过缸内高温残余废气促进燃油蒸发混合的方法,在单缸135柴油机上实现了柴油燃料的均质压燃(HCCI).对HCCI燃烧的燃烧特性和排放特性进行了测试分析,根据实测示功图计算了HCCI燃烧缸内温度,分析了其对NOx排放的影响,当缸内温度超过1700K时,将使HCCI燃烧的NOx排放显著增长.     

柴油发动机预混汽油对排放物的影响研究

利用一台单缸柴油发动机进行了进气道预混合汽油压燃的试验研究。通过安装在进气道的电控喷油器喷射汽油,实现汽油和空气的预混合。汽油和空气的混合气在缸内经过压缩之后,由少量的直喷柴油引燃。研究不同的汽油比例对燃烧参数和排放特性的影响。研究结果表明,随着汽油比例的提高,指示热效率降低,HC,CO增加,NOx与SOOT降低;在小负荷下,随着汽油比例的增加,缸内最大爆压降低;而在大负荷下,随着汽油比例的增加,缸内最高压力增加。     

用在线乳化技术实现柴油机低温燃烧的研究

使用自制在线乳化装置,在单缸135型试验机上进行了在线乳化台架试验,探索出不同负荷下掺水比对燃烧特性、燃油耗率、NOx及碳烟排放的影响;在相同掺水比下进行了与乳化油柴油、进气道喷水方式的性能对比试验。研究表明：在线乳化具有与乳化柴油方式的同样效果,并且可获得燃油耗率、NOx和碳烟排放同时降低的综合性能。     

小型锅炉烟尘测试时锅炉出力的计算

锅炉烟尘测试时,必须对锅炉出力进行测试。但监测中,许多小型锅炉往往不具备相关的计量装置和仪表,为解决这一问题,文章提出了用烟气量和空气过剩系数来计算锅炉的出力的公式,在实际使用中,该方法简单易行,其结果和实测值具有很好的一致怀。     

Unerroric of control of mutual compliance of the efficiency of hydrogen engines of unmanned vehicles in the conditions of mass production

The issues related to the reliability of hydrogen engines of unmanned vehicles and increasing the efficiency of using hydrogen as fuel when using the method of its production during the decomposition of hydrogen-containing molecules of liquid-phase organic compounds in a plasma discharge under the action of intense ultrasonic exposure are considered. Experiments have shown that as a result of decomposition in the acoustoplasma discharge of liquid hydrocarbons, solid-phase carbon-containing products are formed, chemical transformations occur in the liquid phase and hydrogen-containing combustible gas is formed. Hydrogen-containing gas can be used as fuel immediately after synthesis, i.e. it does not require separation, since in addition to hydrogen it contains only impurities of CO₂ and water vapor. The purpose of the study is to formalize the basic conditions for tightening the control of mutual compliance with the efficiency of hydrogen engines of the same series in the conditions of their mass production. Methods of mathematical statistics and hardware-software modeling were used in the study. The term “unerroric of quality mutual compliance control” is introduced to describe a set of hardware and software tools for such control. The principle of in-depth testing of the technical condition of such engines of one series is described in a multidimensional formulation of the quality control problem for three of their operating parameters at once. The conditions for increasing the mutual correspondence of the measured values of such parameters in the conditions of serial production of hydrogen engines are formalized.     

中国煤炭地下气化技术的发展

本文综述了煤炭地下汽化技术的国内外发展现状,对我国“长通道、大断面”煤炭地下气化新工艺给予了技术经济评述,并提出了发展煤炭地下汽化技术的政策建议。     

Review of theory of distortion and disintegration of liquid streams

Linear and nonlinear analyses of the instabilities and distortion of liquid streams injected into a gaseous media are discussed. The various fundamental mechanisms and the predictive capabilities for the distortions are emphasized. Round jets, planar sheets, annular sheets, and conical sheets are discussed in detail. The balance between capillary and inertial forces is primarily examined. The method for simplifying the analyses in the case of thin liquid sheets is discussed. The capabilities for representing the droplet size distribution that follows the stream disintegration are outlined.     

机车车轮多轴疲劳强度安全评定的研究

使用ANSYS8.0软件对高速列车车轮进行了三维有限元分析,计算出车轮在直线、曲线和道岔条件下牵引、制动共6种工况时孔边薄弱部位的应力,分别通过Mises等效平均应力方法、Sines平均主应力方法和应力分量中考虑平均应力方法计算出应力在极值位置时的等效应力幅、等效平均应力,从而进一步算出车轮的安全系数,对其疲劳强度进行评定,并对3种方法进行了比较研究。     

Constructal optimization of the geometry of an array of micro-channels

This paper documents the geometric optimization of an array of circular and non-circular ducts. The optimization was carried out numerically using finite volume method. As optimal dimensions were independent of the array configuration, the numerical simulation was performed on a unit cell. Numerical optimization for circular, square and isosceles right triangle cross-sections of channels was performed. Based on the results of this investigation, some correlations were proposed to predict the optimal hydraulic diameter and dimensionless heat transfer per unit volume. In addition to examining the effect of pressure drop on these parameters, it was showed that among the different geometries of this study, square cross-section has the most efficiency for a given volume. The numerical results of the present study were compared with approximate results reported in the literature which a good agreement was observed.     

MgO膨胀剂细度对MgO水化和水泥浆体膨胀的影响

基于《水工混凝土掺用氧化镁技术规范》中的Ⅰ型氧化镁（MgO）,研究了该型MgO膨胀剂（MEA）细度对掺粉煤灰水泥浆体膨胀性能的影响。即采用X射线衍射分析(XRD)及同步热分析（TG DSC）分析了掺MEA水泥浆体中MgO的水化性。结果表明,养护温度相同时,MEA的细度对水泥浆体内MEA中MgO的水化和水泥浆体的膨胀无显著影响,产生的膨胀均能补偿水泥浆体的收缩;MEA的细度可从试验设计采用的45 μm筛筛余15%左右增加到30%左右,这将有利于MEA生产企业的节能降耗。     

固体热辐射Yong性能分析

本文对漫灰均温物体在常物性条件下对外辐射传热的Ｙｏｎｇ值计算建立了数学模型。通过与物体内能Ｙｏｎｇ公式的数值计算比较,得出了辐射能量的Ｙｏｎｇ值不大于内能Ｙｏｎｇ值的结论。从初步的热射Ｙｏｎｇ值计算公式发现。Ｙｏｎｇ与物体表面辐射率有关。     

Measurements of concentration distribution of hydrogen jet using deflection of center of the laser spot

The main purpose of this work is to propose a new method to evaluate the concentration distribution of the hydrogen jet by using a He–Ne laser through the jet. This research attempts to apply the expression of concentration Gaussian distribution, the refraction formula of inhomogeneous refractive index medium, and the concentration inversion function to disclose the displacement of the center of the laser spot at different heights in the gas jet. The spot images of the laser beam passing through the gas jet at three vertical heights z = 10d, 20d, 30d, and different radial positions are obtained. The radial spatial asymmetry of the gas jet is also found in the experiment. Finally, the calculated concentration distribution curve and the fluent simulation curve, it is found that the two results are very similar. Our findings show that the error between the concentration distribution of this method and the simulated concentration distribution reaches 2.43%.     

汽轮机零件防锈性能的改善

介绍了汽轮机零件的封存特点、防锈要求及防锈油性能对比试验的方法,通过对试验结果的对比分析,客观验证了各种防锈油的性能。试验表明,只有选择了合适的防锈油,才能保证汽轮机零件长期封存的质量。