裂解气压缩机吸入压力高的原因分析及对策

对裂解气压缩机GB-201吸入压力高的原因进行了分析,找出了原因,通过采取措施,提高了乙烯产量,取得了明显经济效益。     

微型计算机在高层建筑消防控制系统中的应用及实现方法

消防控制系统是高层建筑保证安全防火的必要设备。本文以高层建筑自动消防为主要目标,讨论了一种实用的微机消防控制系统方案在设计时所涉及到的一些问题及其实现方法。     

Novel synthesis of metastable HCP nickel by water quenching

It is shown for the first time that water quenching from 1100 °C could yield the metastable HCP Ni phase. The lattice parameters of HCP Ni obtained by water quenching are surprisingly smaller than those reported for either Ni₃C, NiCl₂ or Ni synthesized by chemical routes. Our current findings may partially clarify discrepancies around stability of HCP Ni. In addition, NiO was not formed when quenching from 1100 °C but only when quenching from 950 °C. It is therefore logical to assume that the metastable Ni HCP phase is less prone to oxygen attack as compared to the expanded FCC phase.     

A thermal formulation for single-wall quenching of transient laminar flames

Improving our knowledge of flame-wall interaction is of relevance to performing near-wall combustion calculations. Quenching distance is to be determined accordingly, as a major parameter of flame quenching. For this purpose, an equation describing the behavior of single-wall flame quenching has been derived from a simplified model of laminar flame-wall interaction. It allows evaluating quenching distance from wall heat flux and mixture properties; a significant advantage of this formula is the absence of any empirical coefficient. To assess its reliability, the results computed with this equation have been compared to experimental data concerning laminar flame-wall interaction. For this purpose, single-wall quenching parameters have been recorded in both head-on and sidewall configurations. Quenching distance and wall heat flux have been measured simultaneously, during the combustion of quiescent methane-air mixtures in a constant-volume vessel. Quenching distance is determined through direct visualization, whereas wall heat flux is processed from the time evolution of wall surface temperature. The equation has been verified over the pressure range 0.05-0.35 MPa in stoichiometric and lean mixtures. It shows good agreement with experimental data at first order, with less than 20% variation.     

Controlled synthesis of alumina nanoparticles using inductively coupled thermal plasma with enhanced quenching

Synthesis of alumina nanoparticles in an Ar-O₂ inductively coupled radio frequency (rf) plasma controlled by axial quench gas injection was investigated. The flow and temperature fields for various quench gas flow rates in the plasma reactor, as well as the corresponding quench rates, were predicted using a renormalization group (RNG) k-ε turbulence model. Nanosize alumina particles were synthesized from the vapor phase by oxidation of aluminum in the plasma. The collected products were characterized by means of field emission scanning electron microscopy (FE-SEM), dynamic light scattering (DLS), and BET surface area analysis. The dependences of particle size and shape on the injection position and the flow rate of the quench gas were discussed.     

激光淬火吸光层技术的发展及在内燃机工业中的应用评述

综述了激光淬火及吸光层技术在国内外的应用和发展过程。比较了不同吸光层的性能特点，介绍了新型吸光层技术在内燃机激光淬火中的应用及发展趋势。     

Effect of Different Surface Treatment Methods on the Friction and Wear Behavior of AISI 4140 Steel

In this study,the effects of various surface treatments on the friction and wear behavior of AISI 4140 steel have been evaluated.Sample surfaces of AISI 4140 steel were treated by quenching,carburizing,boronizing and plasma transferred arc (PTA) modification.The microstructural characteristics of surface treated steel samples were examined by optical microscopy and scanning electron microscopy (SEM).The mechanical properties of the samples including the surface roughness,microhardness,and abrasive and adhesive wear characteristics were also evaluated.Wear tests were applied by using a block-on-disc configuration under dry sliding conditions.The wear behavior and friction characteristics of the samples were determined as a function of sliding distance.Each sample group was compared with the other sample groups,and it was observed that the carburized samples demonstrated the lowest weight losses;however,PTA-treated samples demonstrated the lowest coefficient of friction in comparison to the other sample groups at the same sliding distance.     

Syngas formation in methane flames and carbon monoxide release during quenching

Following a recent investigation into chemi-ionization and chemiluminescence during gradual aeration of small, laminar methane flames, we proposed that partial oxidation products, or syngas constituents, formed in the pre-flame zone well below the luminous region, were responsible for the observed effects. We therefore map temperature, CO, and H₂ for geometries and conditions relevant to burners in domestic boiler systems, to assess the potential hazard of CO release into the ambient atmosphere, should any partial quenching occur. CO concentrations peaks of 5.5 volume % are recorded in the core surrounding the axis. Appreciable CO concentrations are also found in the absence of added air. Experiments on various burner port geometries and temperatures suggest that this is not due to air entrainment at the flame base but to diffusion from zones closer to the flame. Next, quenching surfaces such as grids, perforated plates and flame trap matrices of different metals are progressively lowered into the flame. To avoid flow line distortion, suction aspirates the quenched products. The highest emission rate occurs with the quenching plane some 4 mm above the burner; further lowering of the quenching surface causes flame extinction. The maximum CO release is close to converting 10% of the CH₄ feed, with some variation with quenching material. Expressing this potential release in terms of, e.g. boiler power, predicts a potentially serious hazard. Results of numerical simulations adequately parallel the experimental sampling profiles and provide insights into local concentrations, as well as the spatially resolved CO flux, which is calculated for a parabolic inlet flow profile. Integration across the stream implies, on the basis of the simulation, a possible tripling of the experimental CO release, were quenching simply to release the local gas composition into the atmosphere. Comparison with experiment suggests some chemical interaction with the quenching surface.     

高效、节能的新型铝合金淬火炉

为国优高速齿轮泵的铝合金壳体设计制造的新型淬火炉,其加热元件和炉衬采用红外新技术,加强了辐射传热,并采用强迫空气循环,高精控温仪表,底卸式机构,快速入水,达到了炉温稳定和均匀,且节能显著．     

Application of quenching to create highly triaxial residual stresses in type 316H stainless steels

It has been proposed that highly triaxial residual stress fields may be sufficient to promote creep damage in thermally aged components, even in the absence of in-service loads. To test this proposal, it is necessary to create test specimens containing highly triaxial residual stress fields over a significant volume of the specimen. This paper presents results from an experimental and numerical study on the generation of triaxial residual stresses in stainless steel test specimens. Spray water quenching was used to generate residual stress fields in solid cylinders and spheres made from type 316H stainless steel. A series of finite element simulations and measurements were carried out to determine how process conditions and specimen dimensions influenced the resulting residual stress distributions. The results showed that highly compressive residual stresses occurred around the surfaces of the cylinders and spheres and tensile residual stresses occurred near the centre. Surface residual stresses were measured using the incremental centre hole-drilling technique, while internal residual stresses were measured using neutron diffraction. Overall there was good agreement between the predicted and measured residual stresses. The level of triaxiality was found to be very sensitive to the heat transfer coefficient, and could be controlled by adjusting the cooling conditions and changing the dimensions of the steel samples. This differed from other processes, such as welding and shot-peening, where the magnitudes and distributions of residual stresses are ill-defined and the volume of material subjected to a triaxial residual stress state is relatively small.