新型气溶性射流喷嘴设计与数值模拟

针对传统高压水射流清洗耗水量大,能耗和运营费用高、清洗后的废液需要处理才能达到环保要求的缺陷,提出了新型射流清洗方式—气溶性射流.对新型气溶性射流喷嘴进行了结构设计,得到了喷嘴混合室直径、喉部直径、出口直径、收缩段长度以及扩张段长度等关键参数,并对新型喷嘴内外气液二相流场进行了深入计算与分析.结果表明,气液二相流雾滴在喷嘴轴线上速率随气流入口压力增大而增大,在喷嘴喉部速率变化率最大,在喷嘴出口处速率达到最大;当扩散角为10°时,射流扩散较慢,内部扰动和摩擦损失较小;当收缩角为30°时,气液二相流流动性较好,能量损失较小;粒径较小雾滴沿轴线方向速率变化较大,当喷射距离为35mm时,气液二相流雾滴速率达到最大值.     

基于Fluent的射流喷嘴结构设计与优化

合理地选择射流喷嘴参数,实现天然气水合物的固态硫化开采,是促进天然气水合物商业化采掘的关键因素之一.利用Fluent软件建立不同结构参数的单喷嘴流场湍流模型,仿真分析了5种不同结构尺寸的喷嘴对水合物射流破碎的影响,并通过正交试验对单喷嘴结构参数进行优化.仿真结果表明:喷嘴出口处带有扩散角时有利于利用水射流的能量,达到良好的射流破碎效果;最优的喷嘴结构参数为,入口直径D=2.0mm,过渡段直径d0=0.8mm,过渡段长度l=4mm,收缩角α1=24°,扩散角α2=10°.     

基于数值模拟的高压磨料射流喷嘴流场分析及结构优化

为得到高压磨料射流喷嘴内部水流和磨料颗粒运动分布的最佳特性,本文基于二相流理论,利用数值模拟方法研究了高压喷嘴内部混合水相的速度及湍流强度分布,重点分析了磨料入口位置对喷嘴出口处磨料颗粒收束性及喷嘴内壁面磨损状况的影响,并提出了减轻壁面磨损的改进措施。结果表明,距喷嘴中心轴线距离越远,喷嘴内部混合水相的湍流强度越低,但由于磨料入口处存在旋涡,混合水相速度则随之先降低后升高。随着磨料入口位置越靠近高压水入口,出口处磨料的收束性呈现先变好后变差的趋势,磨料颗粒则会大量聚集于磨料入口与上壁面交界处,造成喷嘴内壁磨损,此时可通过在后壁面和上下壁面使用圆角过渡来改善射流流向,进而减少聚集处磨料颗粒的体积分数。     

过冷度对喷嘴效率影响的测试研究

为研究流体过冷度对喷嘴工作性能的影响,研制了两相流体混合速度的测试装置.基于动量定理,测定两相流体的质量流量和冲击力,从而得到质量平均的流体混合速度.利用R410A制冷系统实验台,实验研究了制冷剂过冷度对喷嘴出口流体混合速度及喷嘴能量转化效率的影响.实验表明:随着入口制冷剂过冷度的提高,喷嘴的通过质量流量逐渐增加;同时,制冷剂过冷度的提高使喷嘴出口流体混合速度及喷嘴转化效率明显下降;在实验工况下,喷嘴进口为饱和制冷剂时,2#喷嘴出口制冷剂混合速度达到了94.1 m/s,喷嘴转化效率为64.1%;当制冷剂过冷度由饱和状态增至11℃时,2#喷嘴出口流体的混合速度降低35.7%,喷嘴转化效率降低33.9%.     

锥型喷嘴组合射流特性试验研究

对锥型喷嘴组合射流特性进行了实验研究。组合喷嘴射流由初始段、基本段、过渡段和均匀混合段四部分组成。在射流的初始段中,每个喷嘴射流都存在等速核区。在基本段中,每个喷嘴射流的速度分布均有相似性,但其规律彼此不同,文中给出了各自的数学表达式。在过渡段中,各射流之间相互干扰、掺混十分显著,速度分布无相似性。在均匀混合段中,各射流混合的结果变为单一射流,又出现了相似性,本文也给出了其速度分布规律的数学表达式。研究得到的一些规律对进一步研究复杂射流和石油钻井工程中的喷射钻井机理有重要作用。     

气膜抽吸与叶片前缘内部壁面射流的作用机制

为揭示气膜抽吸对壁面射流流动与换热的干涉效应,获得壁面射流冷却通道内的流动特性与换热特性,建立了涡轮叶片前缘带气膜抽吸的单通道壁面射流冷却计算模型。采用RANS方法,结合SST k-ω湍流模型,研究了气膜抽吸、射流雷诺数、气膜孔位置和数量等因素对壁面射流内部冷却特性的影响机制。结果表明：气膜抽吸会大幅提高流动结构的稳定性,气膜孔入口的分离涡则会显著提高孔口附近的换热系数;气膜抽吸引起壁面射流流量的降低不利于靶面下游的冷却,但滞止区和通道内的流动损失降低幅度大于气膜孔内的掺混损失,从而使整体流动损失系数降低了4.5%;射流雷诺数的增加会提高换热强度,但对流动结构几乎没有影响;单孔结构中,在前缘滞止线处开孔能够提供最高的气膜流量比,且对前缘内部靶面的冷却效果良好;多孔结构中,双气膜孔结构的流动损失最大,三气膜孔结构的流动损失和换热强度最为均衡。研究结果可为壁面射流冷却结构的气膜孔布置提供依据,为进一步提高壁面射流冷却结构的冷却效果提供参考。     

水力喷射压裂中环空水力封隔全尺寸实验

多级水力喷射压裂技术依靠水力封隔实现层段间隔离。通过地面全尺寸实验,提出从环空压力变化的角度评估水力封隔效率。实验中对喷射速度、围压、喷嘴直径和射孔入口直径以及环空注液对水力封隔效率的影响进行测试。实验结果表明:射流速度和围压是影响环空压力降低的两个主要因素,环空压力降低的幅度与射流速度呈线性增长关系,与围压呈指数递减关系;水力封隔效率与射流动能和孔道入口直径的比值成正比,可通过增大喷嘴直径和减小孔道入口直径的方法提高水力封隔能力;环空注液降低水力封隔效率。     

有机工质透平膨胀机喷嘴的响应面分析优化

为了提高有机工质膨胀机的性能,建立了喷嘴型线优化设计平台,并以喷嘴叶片损失系数为性能指标、以喷嘴型线5个控制点的距离参数为设计变量进行了有机透平膨胀机喷嘴的试验设计。采用响应面方法分析了叶片损失系数随型线控制点的变化,揭示了叶片损失系数对喷嘴型线变化的敏感性。研究结果表明:叶片压力面后段、叶片压力面中部、叶片吸力面后段均存在最佳型线,使喷嘴的叶片损失系数较小;在喷嘴的设计过程中,减小喷嘴前段和中段的厚度,可以有效降低喷嘴损失系数;叶片吸力面中段型线的改变对叶片损失系数的影响较大,叶片压力面中段型线的变化对喷嘴损失系数的影响最小。相对于原型喷嘴,采用最优喷嘴型线后叶片损失系数下降了10%。该研究不仅获得了使叶片损失系数较小的喷嘴型线,还能揭示影响喷嘴性能指标的关键因素。     

淹没条件下长圆喷嘴流场数值模拟

为了提高径向水平井扩孔效率,将长圆喷嘴引入磨料射流扩孔技术,建立射流流场的流动控制方程,结合Real-izable k-ε模型对方程组进行求解,并将结果与锥形喷嘴射流结果进行对比。结果表明:长圆喷嘴射流具有一定的扩散性,且短轴剖面上的扩散角比长轴剖面上大;喷嘴内射流速度及出口速度随长宽比增大而减小,随出口直径增加而增加;在喷嘴入口速度和出口直径相同的情况下,长圆喷嘴出口速度小于锥形喷嘴;无因次喷距大于11.3时,长圆喷嘴外射流轴线速度大于锥形喷嘴的;射流出口断面宽度随喷距增大而增大,在相同条件下长圆喷嘴扩孔宽度大于锥形喷嘴,且射流具有自模性;数值计算结果与磨料射流扩孔试验结果基本吻合。     

淹没条件下长圆喷嘴流场数值模拟

为了提高径向水平井扩孔效率,将长圆喷嘴引入磨料射流扩孔技术,建立射流流场的流动控制方程,结合Realizable k-ε模型对方程组进行求解,并将结果与锥形喷嘴射流结果进行对比.结果表明:长圆喷嘴射流具有一定的扩散性,且短轴剖面上的扩散角比长轴剖面上大;喷嘴内射流速度及出口速度随长宽比增大而减小,随出口直径增加而增加;在喷嘴入口速度和出口直径相同的情况下,长圆喷嘴出口速度小于锥形喷嘴;无因次喷距大于11.3时,长圆喷嘴外射流轴线速度大于锥形喷嘴的;射流出口断面宽度随喷距增大而增大,在相同条件下长圆喷嘴扩孔宽度大于锥形喷嘴,且射流具有自模性;数值计算结果与磨料射流扩孔试验结果基本吻合.     

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.     

Lower Paleozoic oil relationships within Williston Basin, Canada

The Williston Basin is a significant petroleum province, containing oil production zones that include the Middle Cambrian to Lower Ordovician, Upper Ordovician, Middle Devonian, Upper Devonian and Mississippian and within the Jurassic and Cretaceous. The oils of the Williston Basin exhibit a wide range of geochemical characteristics defined as "oil families", although the geochemical signature of the Cambrian Deadwood Formation and Lower Ordovician Winnipeg reservoired oils does not match any "oil family". Despite their close stratigraphic proximity, it is evident that the oils of the Lower Palaeozoic within the Williston Basin are distinct. This suggests the presence of a new "oil family" within the Williston Basin. Diagnostic geochemical signatures occur in the gasoline range chromatograms, within saturate fraction gas chromatograms and biomarker fingerprints. However, some of the established criteria and cross-plots that are currently used to segregate oils into distinct genetic families within the basin do not always meet with success, particularly when applied to the Lower Palaeozoic oils of the Deadwood and Winnipeg Formation.     

An Analysis of Catherine＇s Character——Wuthering Heights

Wuthering Heights, Emily Bronte＇s only novel, was published in December of 1847 under the pseudonym Ellis Bell. The book did not gain immediate success, but it is now thought one of the finest novels in the English language. Catherine is the key character of this masterpiece, because everybody and everything center on her though she had a short life. We can understand this masterpiece better if we know Catherine well.     

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.     

Design and analysis of generic LBS application developing platform

Location based services is promising due to its novel working style and contents.A software platform is proposed to provide application programs of typical location based services and support new applications developing efficiently. The analysis shows that this scheme is easy implemented, low cost and adapt to all kinds of mobile nework system.     

橡胶颗粒沥青混合料低温抗裂性试验研究

以AC-13级配为基础,将橡胶颗粒代替部分集料掺入混合料中,以低温弯曲试验为评价方法对不同橡胶颗粒掺量下沥青混合料的低温抗裂性进行研究,并引入应变能密度值对混合料的低温抗裂性进行综合评价.试验结果表明:橡胶颗粒沥青混合料试件的破坏微应变均超过2 300,满足冬寒区的技术指标;无论是否掺加橡胶颗粒,随着温度的下降,沥青混合料破坏时的最大弯拉强度增大,弯拉应变降低,劲度模量增大;弯曲应变能密度在胶粒掺量为1%左右时具有较大的弯曲应变能密度值,此时橡胶颗粒沥青混合料具有较好的低温抗裂性.     

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。     

Quantitative trait loci （QTLs） for quality traits related to protein and starch in wheat

Quality traits in wheat （Triticum aestirum L.） were studied by quantitative trait locus （QTL） analysis in a recombinant inbred line （RIL） population, a set of 131 lines derived from Chuan 35050 × Shannong 483 cross （ChSh）. Grains from RILs were assayed for 21 quality traits related to protein and starch. A total of 35 putative QTLs for 19 traits with a single QTL explaining 7.99-40.52% of phenotypic variations were detected on 10 chromosomes, 1D, 2A, 2D, 3B, 3D, 5A, 6A, 6B, 6D, and 7B. The additive effects of 30 QTLs were positive, contributed by Chuan 35050, the remaining 5 QTLs were negative with the additive effect contributed by Shannong 483. For protein traits, 15 QTLs were obtained and most of them were located on chromosomes 1 D, 3B and 6D, while 20 QTLs for starch traits were detected and most of them were located on chromosomes 3D, 6B and 7B. Only 7 QTLs for protein and starch traits were co-located in three regions on chromosomes 1D, 2A and 2D. These protein and starch trait QTLs showed a distinct distribution pattern in certain regions and chromosomes. Twenty-two QTLs were clustered in 6 regions of 5 chromosomes. Two QTL clusters for protein traits were located on chromosomes 1D and 3B, respectively, three clusters for starch traits on chromosomes 3D, 6B and 7B, and one cluster including protein and starch traits on chromosome 1D.     

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.