燃气引射器工况研究与优化设计

本文在对燃气引进器进行热力学分析的基础上建立了引射器特性方程；分析了引射器在混气系统中的工况；给出了引射器的优化设计计算方法，全面地论述了燃气引射器的问题。     

壁挂式家用燃气灶L型引射器性能研究

介绍一种新型的壁挂式家用燃气灶及L型引射器。对L型引射器进行实验测试及数值仿真,结果表明同等条件下,L型引射器引射的空气量小于常规的文丘里管引射器,通过增加L型引射器的空气吸入口面积,可使其引射的空气量满足设计要求;L型引射器出口断面燃气—空气的混合均匀程度优于常规的文丘里管引射器。     

液化石油气混空气中压引射器的理论分析与计算

根据动量守恒原理,对液化石油气混空气中压引射器进行热力学分析,并建立了最佳结构条件下中压燃气引射器特性方程,通过实例计算及引射器能量有效利用的分析,了解渐缩喷嘴的使用范围及判定方法。合理使用“拉伐尔”喷嘴,则液化石油气混空气中压引射器对小区供气是可行的。     

燃气比例阀的控制方案分析

燃气、空气混合比例调节对于维持良好的全预混燃烧工况至关重要。针对燃气、空气混合比例控制,论述了引射器与燃气调压器相结合的燃气比例阀的两种不同控制方案,比较了优缺点。     

喷嘴位置对引射器性能影响的数值模拟

采用FLUENT软件对大气式燃气燃烧器的引射器进行数值模拟,得出喷嘴位置与一次空气系数的关系。     

低氮氧化物燃气燃烧器的CFD研究

文章综述了燃气燃烧NOx生成理论与计算公式，利用计算流体力学(CFD)软件对浓淡式燃气燃烧器进行了燃烧模拟研究，形成温度场、各组分浓度场等状态参数，提出了设计NOx燃气燃烧器的方法，达到了降低氮氧化物排放的目的。     

液化石油气混空气中压引射器实验研究

本文在对中压引射器实验研究的基础上论述了引射器结构尺寸的确定问题。对实验结果进行分析，指出喷嘴轴向位置，混合管长度对引射器特性的影响。引射器实验特性曲线与计算特性曲线基本一致。引射器特性曲线具有体积混合比常数段。论述了混气系统工况调节方法。     

《燃气应用理论与实践》(第1版)介绍

金志刚主编的《燃气应用理论与实践》(第1版),于2011年8月,由中国建筑工业出版社(http://www.cabp.com.cn)出版发行,定价70.00元。该书共分7篇,燃气燃烧特性和分类(第1篇):燃气燃烧特性(第1章)、燃气互换性和燃气分类(第2章);燃气灶具和热水器(第2篇):燃气灶具(第1章);热水器(第2章);燃气采暖(第3篇);燃气燃烧器的设计(第4篇):AGA大气式燃气燃烧器设计方法(第1章)、引射器设计与计算(第2章)、燃气空气比例调     

关于膜式燃气表现场检定规程修订的几个问题

燃气表现场检定规程的实施，对于规范现场检定，解决燃气销售公司与燃气消费者之间的计量争议，维护计量的公平、公正等起到了十分重要的作用。本文就燃气表现场检定规程的修订及修订中的有关主要技术指标、不确定度评定、能力验证几个主要问题向大家作介绍。     

大气式浓淡燃烧器低压引射器的设计与研究

通过数值模拟方法对一款家用浓淡燃烧器灶具4组不同的2型低压引射器进行了设计与分析,对比了不同工况下引射器的引射系数。研究结果显示引射器引射性能的主要影响因素包括引射器喉部直径、引射器出口压力及喷嘴距离等,其引射系数随着引射器出口压力的减小而增大,且受引射器喉部直径和喷嘴直径的相对大小影响。     

杭带锡田合江口锡钨矿床流体包裹体和稳定同位素特征

合江口锡钨多金属矿为钦杭缝合带上锡田矿田中的岩浆热液型矿床。为探讨矿床的成矿流体性质、演化及成因机制,文章分别研究了3个成矿期中流体包裹体的特征,并重点对第Ⅱ期的流体特征进行了分阶段剖析。发现第Ⅰ期为L+V型包裹体,成矿流体为中高温、中盐度H_2O-CO_2-Na Cl体系,流体不混溶作用不明显;第Ⅱ期有L+V、Cl、Cl+Cv、Aq+Cl+Cv和S型几类包裹体,初始成矿流体为高温、中盐度的H_2S-N_2-CO_2-H_2O-Na Cl体系,本期不仅新发现了大量的N_2包裹体,还见到了萤石子矿物,同时检出了大量的CO_2、H_2S、CH_4、N_2、CO、F、Cl等挥发分,挥发分对矿质的析出、溶解和搬运起了重要作用,温度-盐度的降低、挥发分逃逸、流体不混溶作用、还原至氧化环境的改变、大气水的参与是导致矿质沉淀的重要机制,本期的成矿深度约为4. 5 km,N_2的检出为幔源流体参与成矿提供了证据。第Ⅲ期主要为L+V型包裹体,流体为高温、中—高盐度的H_2O-NaCl体系。稳定同位素研究表明第Ⅰ期流体以壳源为主,第Ⅱ期为壳幔混合源,初始成矿流体主要源自岩浆水,后期有大气水混入。     

Assessment of an equivalent porous medium for coupled stress and fluid flow in fractured rock

The equivalent porous medium (EPM) for coupled stress and fluid flow in fractured rock was assessed. The assessment was focused on the contributions of the seepage-induced force to the system's equilibrium and deformation as well as fluid flux through the fractures, with the special emphasis on the inter-relations among these three aspects. Seepage-induced average stress was calculated for the EPM. And it was proved, with respect to the fluid flow system (FFS) proposed by Long et al. [Long JCS, Remer JC, Wilson CR, Witherspoon PA. Porous medium equivalents for networks of discontinuous fractures. Water Resour Res 1982;18:645–658], that the equivalence of the equilibrium contribution of the seepage-induced force is unconditionally satisfied in the EPM. The equivalence of fluid flux and seepage-induced deformation was evaluated using numerical techniques based on the FFS, in which the seepage-induced deformation was considered as ‘tensile’ deformation under fluid pressures. The numerical simulation results of the two cases suggest that the EPM established in terms of fluid flux based on the FFS guarantees equivalence of coupled stress and fluid flow. Also, the numerical simulation results indicate that the percolation theory can not be applied to a system with fractures of remarkably different size and hydraulic conductivity.     

Performance of radiator by using SiO2 nano fluids

ABSTRACT

This article reports a study on heat transfer and flow characteristics of nano fluid consisting of water and ethylene glycol as base fluid with different concentrations of SiO₂as nanoparticles (0.1% and 0.15%) are flowing in a shell and tube exchanger. The SiO₂ nanoparticles of about 15 nm diameter are used in this study. The results showed that the heat transfer coefficient of nano fluid was slightly higher than that of the base fluid at the same inlet temperature and at the same mass flow rate. It was observed that heat transfer coefficient of nano fluid was increased with an increased mass flow rate. Heat transfer coefficient was noticed to increase with the increase of the volumetric concentration of the SiO₂. But increasing the volume concentration caused the increase in the viscosity of the nano fluid resulted in an increase in friction factor.     

基于流体力学理论的风场数值模拟

利用流体力学理论对自然风进行描述,对风场进行数值模拟.运用基于特征线理论的分离变量算法(Char-acteristic-Based Split,CBS)求解流体域,推导了CBS算法的有限元方程.并利用自主开发的AADS中的流体计算模块对稳态风场进行数值模拟,给出了建筑物表面的风压分布规律,为进一步研究提供基础.     

采用粘滞流体阻尼器的工程结构减振设计研究

本文在对不同结构构造的粘滞流体阻尼器的耗能原理进行分析研究的基础上,研制了一种性能良好的阻尼器──双出杆型粘滞流体阻尼器(专利号ZL00219648.4)。试验研究表明,研制的流体阻尼器是一种无刚度的速度相关型阻尼器,阻尼器的阻尼力与活塞的运动速度近似呈线性关系。介绍了工程结构采用粘滞流体阻尼器的减振设计原理,对一栋框架结构建筑进行了减振计算。计算表明,流体阻尼器可有效地降低结构的振动反应,是一种性能良好的消能减振装置。     

The aerodynamic forces acting on groups of two and three circular cylinders when subject to a cross-flow

The fluid drag and lift forces in the in-flow and cross-flow directions, respectively, have been measured on one cylinder in a group of either two or three cylinders, when the group was subject to a uniform cross-flow. This was done for a variety of geometrical patterns, and the effect of static cylinder displacements on the fluid forces investigated. The cross-flow spacing between cylinders was varied from 0.75 to 2.0 cylinder diameters and the in-flow spacing from 1.5 to 5.0 cylinder diameters. In general it was found that the effect of cylinder displacement on the fluid forces for one cylinder in a group of three is very similar to that obtained with one cylinder in a group of two. This led to an attempt to use a superposition principle to determine the fluid forces in the former arrangement from a knowledge of the fluid forces in the latter arrangement. Remarkable success was obtained using this superposition for the above range of cylinder spacings.     

非饱和土受压变形的简化计算研究

非饱和土的固结问题是岩土工程研究中非常复杂的热门课题。本文拟将非饱和土受压后的固结过程简单地分为压密和固结两个阶段。在压密过程中,与饱和土固结不同是,由于非饱和土的孔隙水、气来不及排出,与骨架共同承担荷载,产生了超孔隙气压和超孔隙水压,这个阶段土体变形主要是压缩孔隙气产生的压缩变形;固结阶段,土体在恒定荷载作用下,超孔隙气压和超孔隙水压逐渐消散而固结。对于饱和度较高的地基土,将水、气可看作混合流体,并考虑残留混合流体的压缩性,建立平衡微分方程和混合流体的连续方程,求出有效应力和混合流体压力;土体中水压力可通过水连续方程求出,继而求出气压力、吸力等。最后算例表明:加载过程中,有效应力、混合流体压力、水压力不断增大,吸力不断减小;竣工后,混合流体压力、水压力还在增长;由加载产生变形以荷载压密变形为主,之后变形增量逐渐减小。这与路堤填筑过程中的监测结果相一致,说明本文的简化方法是合理的。因此本文的非饱和土固结研究对于促进了非饱和土固结变形计算走向实用化,具有重要的工程意义。     

Coupled hydro-thermo-mechanical modeling of hydraulic fracturing in quasi-brittle rocks using BPM-DEM

This paper presents an improved understanding of coupled hydro-thermo-mechanical(HTM) hydraulic fracturing of quasi-brittle rock using the bonded particle model(BPM) within the discrete element method(DEM). BPM has been recently extended by the authors to account for coupled convective econductive heat flow and transport, and to enable full hydro-thermal fluidesolid coupled modeling.The application of the work is on enhanced geothermal systems(EGSs), and hydraulic fracturing of hot dry rock(HDR) is studied in terms of the impact of temperature difference between rock and a flowing fracturing fluid. Micro-mechanical investigation of temperature and fracturing fluid effects on hydraulic fracturing damage in rocks is presented. It was found that fracture is shorter with pronounced secondary microcracking along the main fracture for the case when the convectiveeconductive thermal heat exchange is considered. First, the convection heat exchange during low-viscosity fluid infiltration in permeable rock around the wellbore causes significant rock cooling, where a finger-like fluid infiltration was observed. Second, fluid infiltration inhibits pressure rise during pumping and delays fracture initiation and propagation. Additionally, thermal damage occurs in the whole area around the wellbore due to rock cooling and cold fluid infiltration. The size of a damaged area around the wellbore increases with decreasing fluid dynamic viscosity. Fluid and rock compressibility ratio was found to have significant effect on the fracture propagation velocity.     

设置非线性粘滞阻尼器结构地震响应的时程分析

本文基于国内外现有的粘滞阻尼器性能试验和计算研究,提出单自由度非线性粘滞阻尼器的计算方法。文中给出了粘滞阻尼器非线性运动方程的解法,并运用该方法进行了大量的比较计算,研究了单自由度非线性粘滞阻尼器的动力响应特性。     

地质流体与成矿作用浅析

地质流体是在一定地质条件下、通过一定地质作用(包括构造活动、岩浆作用、变质作用、沉积作用、成矿作用、地表作用等)而形成的天然流体。不同特征的地质流体记录了其形成地质环境条件,并代表了特定的地质作用事件和过程。同时,地质流体是地质作用中不可缺少的介质,它几乎参与所有的地质作用,而其中相关的成矿作用是本文关心的内容。