减少柴油机暖机阶段HC排放的控制策略研究

柴油机在起动后的暖机过程中排出大量含有未燃碳氢(HC)的蓝烟，给人类健康和社会环境都带来极大的危害。本研究提出降低柴油机暖机阶段未燃HC排放的控制策略，并在试验基础上对不同转速与负荷时柴油机的HC排放浓度和HC排放总量进行了比较与分析，找到一种HC排放浓度和HC排放总量都较小的工况作为柴油机的暖机工况，证实了优化控制的可行性。     

燃烧室参数对小型柴油机突增负荷工况燃烧及HC排放的影响

应用自行开发的柴油机瞬态工况控制系统及排气采集装置，对小型柴油机突增负荷工况下的燃烧及HC排放特性进行了实验研究，利用气相色谱仪分析了HC排放成分，设计了不同参数的燃烧室，研究了不同压缩比（13～19）和燃烧室形状对柴油机燃烧及HC排放的影响，研究结果表明，同一燃烧室在突增负荷工况，燃油开始增加后，THC排放量急剧增加，最大值达到稳态工况的100倍，随循环数的增加，滞燃期缩短，HC排放逐渐减少，HC排放成分中LHC占有很大比例，其中乙烯和丙烯最多，随压缩比的降低，滞燃期延长，HC排放明显增加，压缩比相同时适当缩小燃烧室直径，有助于降低HC排放。     

汽油机排放性能连续测量研究

使用AVL4000型五气分析仪连续测量了492QBW车用汽油机在多种稳定工况和启动工况下排气中有害成分CO，HC和NO的量。稳定工况试验结果表明：汽油机的转速和负荷都对CO，HC，NO排放产生影响，负荷变化对排放浓度变化的影响大于转速变化带来的影响；同时工况稳定情况下连续测量的一段时间内，各排气成分会产生一定波动，尤其是HC排放波动最大。冷启动、热启动试验结果显示，在启动过程中汽油机的CO和HC排放较高，尤其是冷启动时CO和HC排放出现峰值。     

分层进气二冲程汽油机排放的试验研究

介绍分层进气二冲程汽油机排放的试验研究结果，讨论了汽油机的空燃比、浓混合气进气比例值对HC和CO排放浓度的影响，以及HC和CO随功率、转速的变化关系，分析了分层燃烧的排放效果。结果表明，分层进气二冲程汽油机可以较大幅度地改善废气排放。     

点火系统使用因素对发动机HC及CO排放影响规律研究

通过对点火系统使用因素的改变，在特定的工况及运行条件下测试其发动机HC及CO排放变化，指出了点火使用因素对发动机HC排放有很大的影响，而对CO排放影响基本不大，不同使用因素对HC排放影响显著性不同，并且同一使用因素对HC排放影响在不同的工况下表现程度又有所不一致，即存在故障特征工况。     

EGR/EGC技术结合系统降低柴油机排放的研究

对柴油机的排放尾气NOx，CO，HC和PM等进行全面分析，探索设计了一套由EGR（废气再循环技术）和EGC（发动机机外废气净化技术）结合的系统，EGR技术可以有效降低NOx的排放，机外废气净化技术技术可以在有效除去PM的同时降低HC，CO的排放，该系统能在较宽的转速和负荷范围内有效降低废气排放，解决同时降低NOx与PM排放的矛盾，废气排放全面降低。     

进气预热降低汽油机冷起动排放的研究

研究了不同进气温度、加热方式和蓄热箱容积对发动机冷起动排放的影响规律。结果表明，提高进气温度有利于减少冷起动阶段的HC、CO排放。最初参与缸内燃烧的新鲜空气的温度对冷起动HC排放有重要影响，对发动机进气歧管内的冷空气进行加热可以大幅度降低HC排放。蓄热箱容积一定时（30L），存在一个进气温度（70℃）可以使HC、CO排放改善得到最佳效果（分别降低36％和13％）。较强的蓄热能力，可以在较大温度范围内减少排放。     

燃料挥发性对柴油机性能及排放的影响

针对不同的发动机热状态及压缩比，试验研究了燃料物化特性对柴油机稳态及过渡工况下性能、排放的影响规律。应用自行开发的柴油机过渡工况控制系统及排气采集装置，模拟车用柴油机实际工作时的加速状态，对具有相同十六烷值但有不同挥发性能燃料的HC排放特性进行了研究，利用气相色谱仪对HC排放成分进行了分析。研究结果表明，采用挥发性好的燃料，可有效降低排气烟度，提高有效热效率，在发动机热状态不好及压缩比较低等燃烧条件恶劣、HC排放高的情况下，可有效地降低HC排放。     

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。     

灰关联对汽油机排放性能的分析

使用AVIA000型五气分析仪连续测量了492QBW车用汽油机在多种稳定工况下排气中有害成分CO，HC和NO的量。并且运用灰色关联理论对汽油机排放性能试验结果进行了处理和分析，结果显示，发动机的转速对汽油机的CO，HC排放关联度最高，而扭矩对NO排放的关联度最大。     

The effect of cloud layer plane albedo on global and diffuse insolation

The effect of the cloud layer plane albedo is overlooked in correlations of diffuse and global components of insolation. We calculate diffuse and global insolation for cloud-free conditions. These are used in conjunction with observations to determine the effect of the cloud albedo. With this effect removed we then derive relationships for the global and diffuse insolation, as fractions of the cloud-free global radiation, as functions of the average daily cloud cover.     

Effect of interface on the thermal conductivity of carbon nanotube composites

This paper presents the effect of interface on the equivalent thermal conductivity of the carbon nanotube composites. The element free Galerkin method has been utilized as a numerical tool to evaluate the thermal conductivity of the composites. The numerical results have been obtained using continuum mechanics approach for a model composite problem, and it was found that the interface has a major effect on the thermal conductivity of the composites. The effect of interface on the effective conductivity of the composite is small for short nanotubes as compared to long nanotubes. Interface thickness also plays an important role on the effective thermal conductivity of the composite. Nanotube anisotropy has got a small effect on effective thermal conductivity of the composites. Transverse thermal conductivity of the composite has got nearly linear variation with nanotube length.     

Effect of nitrogen-addition on the absorption and diffusivity of hydrogen in a stable austenitic stainless steel

An austenitic stainless steel (SUS316L) was prepared with and without addition of solute nitrogen. The effect of cold-working and nitrogen addition on hydrogen solubility and hydrogen diffusion were investigated. High-pressure hydrogen gas and thermal desorption techniques were used. Increasing dislocation densities were related to a higher hydrogen content and higher nitrogen content related to a lower hydrogen content. Both dislocations and nitrogen had a negligible effect on hydrogen diffusion. The different hydrogen contents in the dislocations and the metal lattice, as well as trapping and diffusion activation energies explained the lack of effect of dislocations on hydrogen solubility.     

Computer modeling and parametric study of a double effect generation absorption refrigeration cycle

This paper presents as assessment based on steady-state thermodynamic analysis and computer modeling of a double effect generation absorption refrigeration cycle for solar air-conditioning. The system consists of a second effect generator between the generator and condenser of the single effect absorption cycle and two solution heat exchangers between the absorber and the two generators. A numerical computer modeling of a water LiBr system based on the solution of simultaneous heat, mass and material balance equations for various components of the system has been carried out. The influences of component temperatures and heat exchanger effectiveness on the cooling coefficients of performance and component heat transfer rates have been investigated to obtain optimum operating conditions for the proposed air-conditioning system. Further, the single and double effect absorption cycles are compared with each other as well as with an ideal absorption cycle operating over the same range of temperatures.     

Co-gasification reactivity of petroleum coke with coal and coal liquefaction residue

In this work, experimental study on co-gasification of petroleum coke with coal and coal liquefaction residue (CLR) under CO₂ atmosphere was investigated in a temperature-programmed reactor. The effect of ashes from coal/CLR and metallic oxide on gasification reactivity of petroleum coke was also investigated. The calculated and experimental gasification conversion was compared to analysis the synergetic effect during co-gasification. The results indicated that the petroleum coke has a much lower reactivity than that of coal/CLR chars, while it can be greatly improved by co-gasifying with coal/CLR. The synergetic effect on co-gasification of petroleum coke with coal/CLR was presented as the progress of co-gasification reaction. It was found that the synergetic effect can be enhanced with increasing coal proportion. However, as the increase of coal rank, the synergetic effect gradually weakened during the co-gasification process. In the selected coal/CLR samples, the low rank coal and CLR exhibited a better effect when co-gasifying with petroleum coke. The difference of synergetic effect was probably attributed to the catalytic effect of mineral matters in different coal/CLR. According to composition analyses of various ashes and the co-gasification reactivity of samples, it can be concluded that high content of active components such as Ca- and Fe-in coal/CLR was beneficial to co-gasifying with petroleum coke, while high content of inert Si- and Al- components in coal tended to resist the reaction.     

Influence of strength differential effect on material effort of a turbine guide vane based on thermoelastoplastic analysis

The strength differential (SD) effect has been observed in many iron-based metals such as 4310, 4330, maraging steel, and HY80 steels as well as titanium, aluminium 2024-T351, magnesium, and nickel-based super alloys such as aged Inconel 718. Moreover, the SD effect increases with temperature. The Huber–Mises–Hencky (HMH) J₂ yield condition is insu?cient to simulate the response of metals that exhibit the SD effect. Our work demonstrates the importance of taking into account the SD effect during strength analysis of turbine components. Two yield conditions are considered: the HMH condition and the SD-dependent Burzynski condition. The equivalent stresses produced by these conditions in the elastic state are compared. Plastic zone areas and effective strain values predicted by the two conditions are compared. Our investigation was performed based on thermal-fluid-structure interaction (FSI) analysis of a turbine guide vane made of a nickel-based super alloy that exhibits the SD effect. Conjugate heat transfer analysis was performed, and then elastoplastic stress analysis was performed with boundary conditions obtained from the computational fluid dynamics (CFD) analysis. The paraboloid Burzynski yield condition was implemented in an FE code. Implementation was based on the Euler backward method with consistency tangent moduli evaluated in the explicit form.     

Effect of LDH composition on the catalytic activity of Ru/LDH for the hydrolytic dehydrogenation of ammonia borane

The hydrolytic dehydrogenation of ammonia borane (NH₃-BH₃, AB for short) in the presence of catalysts has been identified to be a safe and efficient way for hydrogen release. Understanding the dehydrogenation mechanism of AB is helpful and important to design efficient catalysts. So far, although the effects of various factors on dehydrogenation of AB have been studied, such as the noble metal particle size effect, crystal-phase effect and the support crystal plane effect, the effect of support composition on dehydrogenation of AB has rarely been reported yet. In this study, we choose composition-adjustable layered double hydroxide (MgAl-LDHs) as support for Ru nanoparticles, and use the as-prepared catalysts for comparing their catalytic activity towards the dehydrogenation of AB. The catalytic results demonstrate the catalytic activity of Ru/MgAl-LDHs is related to MgAl-LDHs composition, exhibiting a support-composition effect in the hydrolytic dehydrogenation of AB. Combining various characterizations, the different composition of MgAl-LDHs has an effect on the interaction between Ru nanoparticles and MgAl-LDHs, which directly affects the catalytic activity for the hydrolysis of AB. This study provides new important fundamental knowledge on the mechanism of AB hydrolysis over practical supported metal catalysts which can be used for a better catalyst design.     

三效蒸发系统第一效冷凝水热量回收利用(火用)经济分析

本文以年净收益最大为目标函数 ,考虑了回收热量的价格及年设备折旧费用 ,针对碳酸钾三效蒸发系统第一效冷凝水热量回收利用的不同方案提出了经济分析 ,确定对第一效冷凝水利用的最佳方案 ,取得显著经济效益     

CFD modeling of a radiant tube heater

This paper reports experimental and Computational Fluid Dynamics (CFD) studies on combustion and radiation heat transfer from a real radiant tube heater. The temperature along the radiant tube as well as at different positions in a test room has been measured. A good agreement between the experimental and predicted results has been found. Based on this validation, the effect of excess air, presented by Air Factor (AF) on efficiency of heater has been studied, theoretically. Moreover, the effect of inlet air preheating on heater efficiency has been examined. The results show that the higher values of excess air can reduce the heater efficiency. The air preheating temperature caused positive effect on heater efficiency. In addition, the results show at higher preheating temperature the effect of AF value on heater efficiency is negligible.     

基于灰色关联度TOPSIS法的市级供电企业安全投入产出效果评价

电力企业进行安全投入会给企业带来经济效益及社会效益,对电力企业的安全投入产出进行评价,可为电力企业下一步的安全投入进行指导。基于市级供电企业的实际情况,从电力企业安全投入产出的减损效果、成本降低效果、投资收益效果等3方面选取了6个指标,采用灰色关联度改进的TOPSIS法建立了市级供电企业安全投入产出效果评价模型,并通过对西南某省9个地州市供电企业的安全投入产出效果进行评价,验证了模型的有效性。