贫燃预混燃烧室混氢燃烧性能研究

为加快实现碳中和，传统化石燃料燃气轮机逐步向含氢气燃料转型，因此需要掌握燃料中氢气对燃气轮机燃烧室性能影响，为燃气轮机燃氢化奠定理论基础。本文以国内某型现役低排放燃气轮机燃烧室参数与结构为例，采用氢气甲烷混合燃料燃烧，研究混氢比例对燃烧室性能影响。研究表明：氢气体积占比低于30%时，燃烧室喷嘴无回火；燃料中氢气占比由0增加至30%，燃烧室总压损失升高11%,NOx排放(@15%O₂干基)升高31%，火焰筒上游区域温度略有升高，燃烧效率升高，出口温度场均匀性几乎无变化。     

波瓣混合器内扩张角对一体化加力燃烧室性能的影响

通过开源场运算和OpenFOAM中二次开发的数值计算程序对某型一体化加力燃烧室进行了数值仿真研究,并基于仿真结果定量分析了波瓣混合器内扩张角对加力燃烧室气动热力性能的影响。结果表明:随着内扩张角的增大,强化了加力燃烧室中流体的混合效果,但同时也导致了较大的总压能损失。在加力燃烧室出口处,相对于基准环形混合器模型,内扩张角25°模型对应的热混合效率提升了16.2%、总压恢复系数相对下降了0.88%。当内扩张角逐渐增加时,缩小了不考虑与考虑辐射换热时热混合效率的差值,即减弱了辐射换热强化热掺混的效果。     

H2O/CO2污染对煤油燃料超声速燃烧影响数值研究

在纯净空气与H₂O/ CO₂污染空气来流对比试验结果基础上,采用数值计算方法和化学动力学方法,研究了H₂O和CO₂污染组分对煤油燃料超声速燃烧的影响,获得了试验手段难以得到的燃烧室流场参数和性能数据。完成了相应的煤油燃料超声速燃烧室二维数值计算,其中匹配了进口总温、总压、马赫数、氧气摩尔分数和工作当量油气比。将数值计算结果与相应试验测量值进行了对比分析,并结合燃烧室流场数据、性能参数分析了H₂O和CO₂污染的动力学影响、以及对燃烧室性能的影响。研究表明:(1)数值计算结果与实验测量值总体上吻合,两种手段均体现了纯净空气来流时不同煤油当量油气比的燃烧室性能,并反映了一致的“污染效应”影响趋势；(2) H₂O污染、H₂O+ CO₂污染的存在降低了煤油燃料超声速燃烧室性能,体现在燃烧诱导压升、燃烧效率、流向冲量增量的下降,而且随着污染组分含量的增加,燃烧室性能下降越加显著。      

纯净空气液态煤油超声速燃烧室性能研究

液态煤油高热值、高密度,还容易储存、便于携带,在飞行Ma数小于8的飞行条件下,煤油是超燃冲压发动机的理想燃料,如何实现煤油在超声速燃烧室中稳定燃烧是关键。本文在西北工业大学电阻加热超燃冲压发动机实验台上,针对给定的燃烧室,对以航空煤油为燃料的超声速燃烧冲压发动机燃烧室性能进行初步试验研究。实验来流空气总温为870-930 K,总压保持在77 kPa左右,燃烧室进口Ma数为2。同时结合CFD模拟,对3个不同油气比下燃烧室性能参数进行了对比分析。研究结果认为:要成功地实验煤油点火并稳定燃烧,成功设计凹槽及分布位置是关键;选择合适的油气比,可在提高燃烧室性能的同时保持隔离段的抗扰动能力。     

联焰稳流器对驻涡燃烧室性能的影响分析

为考察联焰稳流器对驻涡燃烧室的流场和性能的影响,应用高端数字样机系统进行了设计和数值计算。在典型驻涡燃烧室三维模型上添加了联焰稳流器,分析了2个燃烧室模型在不同进口马赫数条件下的冷态流场结构和总压损失。选取进口马赫数为0.2的工况,对2个模型的燃烧流场进行对比,分析了联焰稳流器对燃烧室性能的影响。结果表明:驻涡燃烧室的NOx排放低于普通构型燃烧室;添加联焰稳流器后,驻涡区能更好地实现与主流区的物质交换,避免因主流速度过快,切断驻涡区与主流区的能量传递;燃烧效率从97%提高至99%,出口温度分布系数从0.92降为0.49;2个模型各冷态工况的总压损失也分别增加2%~12%。     

不同燃料超声速燃烧室准一维计算模型

快速高效的准一维计算是超燃冲压发动机设计的重要研究方法。该文发展建立了适用于气态或液态燃料、包含隔离段结构、跨声速工况的准一维通用计算模型。该模型以Euler方程组作为基本控制方程,综合考虑了燃烧室截面面积变化、液态燃料蒸发相变、燃料质量添加、摩擦力项以及隔离段内斜激波串结构对流动的影响等因素。依次以NAL氢燃料发动机实验、气态煤油燃料发动机实验和液态煤油燃料发动机实验等3个不同燃料实验作为验证算例对模型进行考核,计算结果与实验数据均吻合良好,验证了模型的有效性和准确性。该模型可进一步应用于各类燃料的超燃冲压发动机燃烧室结构及工作参数的设计与优化等研究工作。     

分配器式扩压器挡板的试验研究

针对高性能航空发动机燃烧室进口马赫数不断提高以及先进变几何燃烧室燃烧组织特点,设计出一种新型可变几何燃烧室扩压装置—分配器式扩压器。通过试验研究了面积比、马赫数与总压损失的关系。结果表明: 冷却模和燃烧模的总压损失与其开孔面积以及孔形有关;各个模之间的影响与面积百分比有关;卷边孔挡板可以有效减少总压损失。     

JS-1磁流体发电装置的燃烧室

本文叙述了JS—1小型磁流体发电装置中热壁型燃烧室的结构,以及有关的试验条件,燃烧器利用空气作雾化介质。使用轻柴油作燃料,1520～1770°K高温预热空气作氧化剂。主燃烧室散热损失<3％,燃烧效率达到接近完善的程度。进入磁流体发电机之前,相应的燃气温度为2570～2700°K。文中还列出了有关燃气温度、燃气成分分析、散热损失等方面的部份测量数据。     

再生冷却结构参数对煤油流动换热的影响及优化

为揭示冲压发动机燃烧室再生冷却结构参数对煤油流动换热的影响,实现对结构参数的优化,以单根再生冷却通道为研究对象,在通道总数一定的情况下,分别对RP-3航空煤油在不同内壁厚度、肋片厚度及高度的通道中流动换热进行了数值研究,发现薄内壁的通道冷却效果好,流动压力损失稍大;厚肋片的通道冷却效果好,但压力损失随肋片厚度的增大而急剧增大;随着高度增大,冷却效果变差,但流动压力损失急剧减小;3种结构参数对油温的影响都很小。分别对影响机理进行了理论分析,在此基础上,为得到一种对流换热效果尽可能好以及流动压力损失尽可能小的冷却通道,利用Workbench平台的目标驱动优化工具,采用遗传算法对冷却通道进行优化设计,经校验,优化后的通道满足设计目标。     

新型纽扣式涡喷发动机燃烧室数值模拟

为了给超微型燃烧室提供数据参考,对设计的某微型燃烧室的稳态燃烧过程进行数值模拟。采用三维建模,入口参数采用等熵数值计算,考虑了湍流化学反应、热辐射等情况,不仅得到燃烧室稳态工作时的速度场、温度场及各组分浓度分布,而且分析了燃料/空气的流动与回流、燃烧效率以及总压恢复系数的情况,并与实验数据进行对比。计算结果可以较为准确地反映燃烧室的实际燃烧情况。结果表明,燃烧室出口速度约为65m/s,出口温度约1000K,仿真与实验数据契合度高,燃烧室结构设计合理。      

Markedness and its Interpretation in Language Use

Language markedness is a common phenomenon in languages, and is reflected from hearing, vision and sense, i.e. the variation in the three aspects such as phonology, morphology and semantics. This paper focuses on the interpretation of markedness in language use following the three perspectives, i.e. pragmatic interpretation, psychological interpretation and cognitive interpretation, with an aim to define the function of markedness.     

Features of Women's language

Language is a means of verbal communication. People use language to communicate with each other. In the society, no two speakers are exactly alike in the way of speaking. Some differences are due to age, gender, statue and personality. Above all, gender is one of the obvious reasons. The writer of this paper tries to describe the features of women＇s language from these perspectives： pronunciation, intonation, diction, subjects, grammar and discourse. From the discussion of the features of women＇s language, more attention should be paid to language use in social context. What＇s more, the linguistic phenomena in a speaking community can be understood more thoroughly.     

Characterization of Ordovician carbonate reservoirs, southeastern Saskatchewan, Canada

The discovery of the prolific Ordovician Red River reservoirs in 1995 in southeastern Saskatchewan was the catalyst for extensive exploration activity which resulted in the discovery of more than 15 new Red River pools. The best yields of Red River production to date have been from dolomite reservoirs. Understanding the processes of dolomitization is, therefore, crucial for the prediction of the connectivity, spatial distribution and heterogeneity of dolomite reservoirs.The Red River reservoirs in the Midale area consist of 3～4 thin dolomitized zones, with a total thickness of about 20 m, which occur at the top of the Yeoman Formation. Two types of replacement dolomite were recognized in the Red River reservoir: dolomitized burrow infills and dolomitized host matrix. The spatial distribution of dolomite suggests that burrowing organisms played an important role in facilitating the fluid flow in the backfilled sediments. This resulted in penecontemporaneous dolomitization of burrow infills by normal seawater. The dolomite in the host matrix is interpreted as having occurred at shallow burial by evaporitic seawater during precipitation of Lake Almar anhydrite that immediately overlies the Yeoman Formation. However, the low δ18O values of dolomited burrow infills (-5.9‰～ -7.8‰, PDB) and matrix dolomites (-6.6‰～ -8.1‰, avg. -7.4‰ PDB) compared to the estimated values for the late Ordovician marine dolomite could be attributed to modification and alteration of dolomite at higher temperatures during deeper burial, which could also be responsible for its 87Sr/86Sr ratios (0.7084～0.7088) that are higher than suggested for the late Ordovician seawaters (0.7078～0.7080). The trace amounts of saddle dolomite cement in the Red River carbonates are probably related to "cannibalization" of earlier replacement dolomite during the chemical compaction.     

低渗透非均质砂岩油藏启动压力梯度研究

理论推导与室内实验相结合,建立了低渗透非均质砂岩油藏启动压力梯度确定方法。首先借助油藏流场与电场相似的原理,推导了非均质砂岩油藏启动压力梯度计算公式。其次基于稳定流实验方法,建立了非均质砂岩油藏启动压力梯度测试方法。结果表明:低渗透非均质砂岩油藏的启动压力梯度确定遵循两个等效原则。平面非均质油藏的启动压力梯度等于各级渗透率段的启动压力梯度关于长度的加权平均;纵向非均质油藏的启动压力梯度等于各渗透率层的启动压力梯度关于渗透率与渗流面积乘积的加权平均。研究成果可用于有效指导低渗透非均质砂岩油藏的合理井距确定,促进该类油藏的高效开发。     

On Tragic Consciousness In The Works By Ernest Hemingway

As an American modern novelist who were famous in the literary world, Hemingway was not a person who always followed the trend but a sharp observer. At the same time, he was a tragedy maestro, he paid great attention on existence, fate and end-result. The dramatis personae's tragedy of his works was an extreme limit by all means tragedy on the meaning of fearless challenge that failed. The beauty of tragedy was not produced on the destruction of life, but now this kind of value was in the impact activity. They performed for the reader about the tragedy on challenging for the limit and the death.     

A computer generator for randomly layered structures

AcomputergeneratorforrandomlylayeredstructuresYUJia shun1,2,HEZhen hua2(1.TheInstituteofGeologicalandNuclearSciences,NewZealand;2.StateKeyLaboratoryofOilandGasReservoirGeologyandExploitation,ChengduUniversityofTechnology,China)Abstract:Analgorithmisintrod…     

An Index mechanism for multi-scale view in spatial databases

There are numerous geometric objects stored in the spatial databases. An importance function in a spatial database is that users can browse the geometric objects as a map efficiently. Thus the spatial database should display the geometric objects users concern about swiftly onto the display window. This process includes two operations:retrieve data from database and then draw them onto screen. Accordingly, to improve the efficiency, we should try to reduce time of both retrieving object and displaying them. The former can be achieved with the aid of spatial index such as R-tree, the latter require to simplify the objects. Simplification means that objects are shown with sufficient but not with unnecessary detail which depend on the scale of browse. So the major problem is how to retrieve data at different detail level efficiently. This paper introduces the implementation of a multi-scale index in the spatial database SISP (Spatial Information Shared Platform) which is generalized from R-tree. The difference between the generalization and the R-tree lies on two facets: One is that every node and geometric object in the generalization is assigned with a importance value which denote the importance of them, and every vertex in the objects are assigned with a importance value,too. The importance value can be use to decide which data should be retrieve from disk in a query. The other difference is that geometric objects in the generalization are divided into one or more sub-blocks, and vertexes are total ordered by their importance value. With the help of the generalized R-tree, one can easily retrieve data at different detail levels.Some experiments are performed on real-life data to evaluate the performance of solutions that separately use normal spatial index and multi-scale spatial index. The results show that the solution using multi-scale index in SISP is satisfying.     

Jane Eyre——A Feminist In The 19th Century

In the 19th century the society was controlled by men, and women were just appendants of them, they had not any rights and freedom. But Jane was an exception, she showed some characteristics of early feminist. Jane showed her characteristics of feminism in three aspects: rebellion, equality, and independence. These characteristics were helpful to her success, and feminism is the only way out for women of that time.     

Achieving Unusual States of Matter Under High Pressure

正The periodicity of the elements and the non-reactivity of the inner-shell electrons are two related principles of chemistry,rooted in the atomic shell structure.Within compounds,Group I elements,for example,invariably assume the+1 oxidation state,and their chemical properties differ completely from those of the p-block elements.These general rules govern our understanding of chemical structures and reactions.Using first principles calcula-     

Exchange-Correlation and Electronic Excitation Energies from Pairing Matrix Fluctuations

We have developed an adiabatic connection to formulate the ground-state exchange-correlation energy in terms of pairing matrix linear fluctuations.This formulation of the exchange-correlation energy opens a new channel for density functional approximations based on the many-body perturbation theory.We illustrate the potential of such approaches with an approximation based on the particle-particle Random Phase Approximation(pp-RPA).This re-