文丘里法管道煤粉流量测量的实验研究

通过实验确定了文丘里法测量煤粉流量的可行性。首先根据实验数据,得出了3种不同管型参数、固气比Z和气体速度u与差压Δp1m、Δp2m的关系,从物理意义上分析了上述关系的合理性,并进一步分析了气固两相流流经文丘里管产生压力损失的机理。然后从测量精度、重复性和压力损失等方面对3种不同的文丘里管进行了比较研究,得到了设计文丘里流量计的基本方法。最后,在实验基础上,标定了3种文丘里流量计的系数。实验表明,管径比为0.71的文丘里管测量煤粉流量的最大误差不超过5%。     

用于管道煤粉流量测量的文丘里管型设计及优化

为准确测量电站管道煤粉流量,设计了一种基于文丘里法的煤粉流量计。首先采用气固两相流数值模拟的方法,研究不同管型参数对文丘里法测量管道煤粉流量的影响,发现管型参数是影响稀相气固两相流测量结果的关键因素,并由此提出了文丘里管型设计的优化原则。然后从提高测量精度和保证测量稳定性两方面出发,对文丘里流量计进行了设计优化,获得了3种文丘里管的管型参数,可为管道煤粉流量测量的试验研究提供参考。     

用于管道煤粉流量测量的文丘里管型设计及优化

为准确测量电站管道煤粉流量,设计了一种基于文丘里(V en turi)法的煤粉流量计。首先采用气固两相流数值模拟的方法,研究不同管型参数对文丘里法测量管道煤粉流量的影响,发现管型参数是影响稀相气固两相流测量结果的关键因素,并由此提出了文丘里管型设计的优化原则。然后从提高测量精度和保证测量稳定性2方面出发,对文丘里流量计进行了设计优化,获得了3种文丘里管的管型参数,可为管道煤粉流量测量的试验研究提供参考。     

基于长喉径文丘里管的双差压湿气流量测量

为实现湿气气液两相流量的在线非分离测量,提出一种基于长喉径单文丘里管的双差压湿气流量测量方法．通过理论分析和实验研究,揭示了湿气液气质量比和气相流速与长喉径文丘里管收缩段差压、扩张段差压之间存在一定的内在变化规律及物理本质．为有效提高测量精度,针对传统虚高模型的缺陷,提出了虚高模型的优化原则．建立了基于单文丘里管的气液两相测量模型,并通过迭代运算实现了气液两相流量的分相测量,对于压力P为0．10—0．16MPa,气相弗劳德数0．4～0．7,液气质量比0～1范围内,气相流量测量的相对误差优于±3％,液相流量测量的满度误差小于±10％．     

4种常用流量计性能的对比试验研究与分析

利用π定理推导出孔板、文丘里、电磁及涡轮流量计水力特性.将4种流量计串联组成测试装置进行试验研究,利用软件采集各流量计测试数据,与称重法测量数据进行对比.用Origin软件绘出流量曲线,分析在不同流量条件下各种流量计的准确度和误差率,以期为流量计的选型和应用提供有价值的参考依据.     

一种计量稠油中油气水三相流的方法和装置研究

油田现场稠油井黏度大、流动性差,传统的分离计量方法很难对其准确计量;另外,稠油油井的流量范围较宽,每天产油量可以从几桶到1 000多桶,可以从不含气到含气率高达80%,一般计量设备难以覆盖这样的井况条件。为了解决这些难题,研究了一种计量稠油中油气水三相流的方法,可以适应较宽的油井产量范围,该方法包含一个文丘里流量计、双能伽马传感器和配备差压传感器的小型分离器。当稠油多相流流量较高处于文丘里流量计的计量范围内时,采用文丘里流量计和双能伽马传感器来测量稠油中的油气水流量,同时考虑低雷诺数流动条件下对文丘里流出系数的实时动态计算,建立了适当的模型。当稠油多相流流量处于文丘里流量计的下限或呈间歇流时,利用小型分离器内累积的液相差压对液相进行称重式计量,结合伽马传感器测得的相分率,可得油气水流量。该方法利用伽马射线技术测量稠油的相分率,使得稠油的相分率计量更精确,不受稠油形态的影响;同时,结合准确的称重计量原理,真正实现了对稠油进行油气水三相的在线实时计量。实验结果表明,液相流量、含水率、气流量标准偏差分别为4.2%、1.5%、6.3%。     

涡街流量计在我厂氧气计量中的应用

流量计量技术是一门综合性学科,它集流体力学、仪表技术、计算机技术、电子电路、通讯技术及现场工艺状况于一体,具有较深的理论研究价值,而流量计量是公司一项极其重要的工作,和生产操作、成本核算直接关联,可以说流量计量工作是影响我公司生产与效益的重要因素之一。在我厂动力量厂际流量计量中常用的流量计主要有以下几种:孔板(配差压变送器、流量计算仪)、涡街流量计、金属转子流量计、文丘里管、威力巴等。它们分别有着不同的测量原理及特点因而适用范围(对象)也有所不同。其中涡街流量计在我厂的氧气计量中取得了比较好的测量效果。下面结合实例阐述涡街流量计的使用方法及在使用中的注意事项。     

单支管中气固两相流质量流量测量的新方法

提出了一种采用电容传感器与文丘里管相结合测量单支管中气固两相流质量流量的新方法·通过电容传感器对固相浓度的测量,可以求出气固两相流的固气比,结合文丘里管上的差压信号,可以计算出相应气体单独流经文丘里管时所产生的差压,由此可以求得气体的质量流量,进而得出固相的质量流量·实测结果显示,测量误差小于３３％·此方法不直接测量管道中气体的质量流量,而是通过测量浓度和差压信号来求得气固两相的流量值·此方法特别适用于不能直接测量气体流量的场合支管流量的测量·     

文丘里洗涤器压力损失计算模型

准确预测文丘里洗涤器的压力损失并加以合理利用,是设备优化设计和节能的关键．由实验可知,文丘里洗涤器的扩散段可回收相当大一部分能量,不能简单地认为它与摩擦压力损失可互相抵消．通过理论分析,在考虑气体摩擦压力损失和扩散段液滴减速压力回收的基础上,推导出了1个简单、准确的文丘里洗涤器压力损失模型．该模型的理论预测值和实验值一致,并在实验基础上将该模型和修正的Calvert模型及Yung模型进行了对比．     

弯管流量计测量高温气冷反应堆一回路流量的可行性研究

为保证高温气冷堆发电系统的安全运行,弯管流量计被设计在系统一回路中对氦气循环流量进行测量。在循环流动过程中,氦气会分流到镜像对称分布的14根上升管路,再汇总流入汇流箱中,通过压气机返回反应堆。根据系统设计要求测量4根上升管路上的支路流量进而实现对于全部14根上升管路总流量的高精度测量。为保证上升管路支路流量测量与全部14根上升管总流量的准确对应关系,通过实验和数值模拟相结合的方式研究了一回路14根上升管的流量分布规律。实验系统是根据流动相似准则,针对14根上升管结构设计并建立了一套与真实系统几何相似的1：5尺寸实验模型。并在每根上升管路上安装高精度弯管流量计对分支流量进行测量。根据统计实验分析得到,合计14根弯管流量计测量的总流量与流量真值能够在1%的精度水平上一致。数值模拟分析上升管各支路的流量分布特性表明：在严格控制装置各个环节的对应关系时,上升管各支路流量与流量平均值分布在±1%精度范围,因此通过选择4根支路作为弯管流量计的测量支路实现测量全部14根上升管流量的设计是可行的。     

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.     

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.     

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.     

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.     

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.     

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-