铝活塞耐磨镶圈(续篇Ⅱ)

2　耐磨镶圈的设计2 1　单环槽耐磨镶圈的设计(如表1)表1活塞直径(mm)活塞环高度(mm)<2 .5 >2 .5～4.0 >4.0～5 .0 >5 .0～6.5<12 5<12 5 ,<15 02 .02 .5 52 .5 53 .23 .24.04.05 .1C .环槽最大深度K .环槽最大宽度(梯形环槽时取最大值)B .环槽后面厚度,一般取0 .5C ,但最小不得小于2 1mmT .环岸宽度,根据活塞直径及环槽宽度决定A .活塞环岸直径加7.5mmE .台阶直径,A -4 .5 7mmF .耐磨镶圈内径D -2B -2Cα.斜面角度,3°3 0′或7°3 0′G .计算得出H .定位台阶宽度1/ 2 (K +T +T) ,最小2mmR .圆弧角半径,根据环槽后面厚度决定,从2 …     

The Torsional Vibration of Turbo Axis Induced by Unsteady Aerodynamic Force on Rotor blade

INTRoDUCTIONThestructuralfailureofturbotalsbytorsionalvibrationisoneofthemostimPortantproblemsthect-ingthesafetyoftheturbomachineryoperation-Inthepasttime,researchesonthecauseofthetorsionalvibrationofturboaxishavebeenfocusedonelectricalandmechanicalfields(D.Lambrecht,1982.H.DikenandI.G.Tadjbakhsh,1989.IEEEWorkingGroupInterimReport,l982).Butasafluidmachinerystea-mturbinemayexperienceintensetorsionalvibrationin-ducedbyfluid.Thisphenomenonissimilartotheflutterinsofarasbothoftheminvolve…     

Analysis of Evaporation Heat Transfer of Thin Liquid Film in a Capillary of Equilateral Triangular Cross—Section

IntroductionThe study on evaPoration heat transfer in caPillmpbodies is imPOrtant for design and development of higIilyefficient heat transfer equipment, such as heat pipe. P.C.W and Y.K. Kao[i] stUdied the interline heattransfer coefficients of an evaPorating wetting film.L.SoloVyev and S.A. KovalevI2l discussed the mechAnsmabout evaPoration of a liquld film from a porous sdse.A. Schonberg and P.C. Wayner['l developed Shae's(l953)['l evaPoration heat transfer model that based ontem…     

Average Droplet Diameter Measurement and Results for Fuel Aerosol Injected by Certain Types of the Turbojet Burners

INTRODUCTIONMeasurementofthedropletdiameteroffuelaerosolisverydifficult,becauseofthefastchangeofitssize,whichiscausedbyevaporationandassociation.Itisalsoverydifficulttogetaknowledgeofaerosolstreamsinthecourseofconstructionofnewtypeoffuelburn-ersanddiagnosticprocessaswell.Diffractionmethodisoneofthemostusefulmea-suringproceduresinthiscase.Thedropletsizeofmonodispersivemediumiseasytorecognise.Analy-sisofadiffeactionpatternofpolydispersivemediumisconsiderablymoredifficult.Thisworkpresentsam…     

参考文献格式要求

正1.参考文献按正文部分标注的序号依次列出,并在序号中加[]。2.对于常见的各类参考文献标注方法如下:1)著作:作者姓名,题名[M].出版地:出版者,出版年.2)期刊论文:作者姓名.题名[J].期刊名称,年,卷(期):页码.3)会议论文集:作者姓名.题名[C]//论文集名称,会议地点,会议日期.4)学位论文:作者姓名.题名[D].出版地:出版者,出版年.5)专利文献:专利申请者或所有者姓名.专利题名.专利国别.专利号[P].公告日期或公开日期.获取路径.6)电子文献:作者姓名.题名[文献类型标志(含文献载体标志)见其它].出版地:出版者,出版年(更新或修改日期),获取路径.7)报告:作者姓名.题名[R].出版地:出版者,出版年.     

冷凝水及二次蒸汽回收实现节能

一、冷凝水回收与节能 冷凝水在工业生产中具有很大的利用价值:1.冷凝水中包含有大量的热能;2.节省水费;3.节省水处理费;4.节约排水费;5.节约冷却水费.     

英文摘要

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几种参考文献的书写格式

正(其中空格、标点符号、字母照写)连续出版物:[标引序号]作者.文题[J].刊名,年,卷(期):起始页码一终止页码.专著:[标引序号]作者.书名[M].出版地:出版者,出版年.译著:[标引序号]作者.书名[M].译者.出版地:出版者,出版年.论文集:[标引序号]作者.文题[A].编者.文集[C].出版地:出版者,出版年.起始一     

国外节能与环保科学文摘

1.工厂和市场废物合成肥料的原始成分和曝气法研究.G.A.Aydn,etal.Investigationofappropriateinitialcompositionandaerationmethodforco-compostingofyardwastesandmarketwastes.JournalofEnviron-mentalScienceandHealth.partB.2003,838(2):221～231(英文).　　内容提示     

英文摘要

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A fractal resistance model for flow through porous media

A fractal model for resistance of flow through porous media is developed based on the fractal characters of porous media and on the pore–throat model for capillary. The proposed model is expressed as a function of the pore–throat ratio, porosity, property of fluid, pore/capillary and particle sizes, fluid velocity (or Reynolds number) and fractal dimensions of porous media. There is no empirical constant and every parameter has clear physical meaning in the proposed model. The model predictions are compared with experiment data, and good agreement is found between them.     

Numerical simulation of fluid flow and convection heat transfer in sintered porous plate channels

Fluid flow and convective heat transfer of water in sintered bronze porous plate channels was investigated numerically. The numerical simulations assumed a simple cubic structure formed by uniformly sized particles with small contact areas and a finite-thickness wall subject to a constant heat flux at the surface which mirrors the experimental setup. The permeability and inertia coefficient were calculated numerically according to the modified Darcy’s model. The numerical calculation results are in agreement with well-known correlation results. The calculated local heat transfer coefficients on the plate channel surface, which agreed well with the experimental data, increased with mass flow rate and decreased slightly along the axial direction. The convection heat transfer coefficients between the solid particles and the fluid and the volumetric heat transfer coefficients in the porous media predicted by the numerical results increase with mass flow rate and decrease with increasing particle diameter. The numerical results also illustrate the temperature difference between the solid particles and the fluid which indicates the local thermal non-equilibrium in porous media.     

含湿非饱和多孔介质的完全分形传热研究

为了探究在含湿情况下多孔介质有效导热率的变化,基于分形理论,考虑多孔介质在含湿时加热过程中相变的影响,结合加热过程中的热量守恒方程和傅里叶导热定律推导出计算有效导热率的新公式。将该模型相关数据代入进行计算,分析了孔隙率、含湿率、面积分形维数和迂曲分形维数对有效导热率的影响。研究发现,孔隙率与有效导热率呈负相关,含湿率与有效导热率呈正相关,分形维数与有效导热率呈负相关。该研究能够反映多孔介质内的传热进程,对于探究微孔结构物质的传热具有一定的指导意义。     

多孔介质导热的分形模型

多孔介质中热量传递与多孔介质内部的几何结构有密切的关系，讨论了多孔介质的分形结构和相关的分形维数，利用能量方程，导出了分形维数为D的有限尺度多孔介质中的广义热传导方程，在此基础上，假定热量在多孔介质中的传导路线也是一种分形结构，提出了一个筒化的多孔介质并联通道分形导热模型，求出了基于分形理论的多孔介质有效导热系数表达式。     

基于格子Boltzmann方法的饱和土壤渗流与传热数值模拟

本文利用随机多孔介质生成算法重构了与真实土壤外貌相近的多孔介质几何结构。通过引入不可压耦合双分布格子Boltzmann模型（lattice Boltzmann model ,LBM）对孔隙尺度下单相饱和土壤渗流和传热进行了模拟。着重讨论了不同渗流压差、孔隙率、土壤固体颗粒尺寸分布对流动与传热的影响。结果表明：土壤渗流速度与渗流压差呈线性单调递增关系,平均温度随渗流压差增加而增大,但温升速率逐渐减缓;当孔隙率增大时,渗流速度增加,且当孔隙率大于0.58时,对流换热作用迅速增强,土壤温升速率显著加快;对于相同孔隙率,当土壤固相颗粒尺寸较大时,流动出现典型优先流效应;随着土壤固相颗粒尺寸减小,土壤温度变化逐渐趋于平缓,平均温度降低。     

含甲烷水合物的石英砂渗透率实验和分形模型对比研究

含水合物的多孔介质渗透率是影响水合物开采的关键参数,多孔介质渗透率与水合物的饱和度密切相关。定量研究多孔介质渗透率随水合物饱和度的变化,对自然界中天然气水合物藏内渗流场的研究具有重要的理论价值。本文以平均粒径为139.612 μm的石英砂为多孔介质,采用稳态注水法测量在不同甲烷水合物饱和度（0 ~ 28.56%）下的石英砂渗透率,将实验数据与两种不同水合物赋存形式（颗粒包裹、孔隙填充）下的石英砂渗透率二维分形模型进行了对比。结果表明,石英砂渗透率比K_r随甲烷水合物饱和度S_h的增大呈现指数减小的趋势。当水合物饱和度低于11.83%时,渗透率比下降缓慢。而当水合物饱和度高于11.83%时,渗透率比下降迅速;当饱和度指数n = 12时,渗透率分形模型与实验数据吻合良好。通过分形模型与实验数据对比,发现当水合物饱和度低于11.83%时,甲烷水合物的赋存形式为颗粒包裹型。在11.83% ~ 28.56%水合物饱和度范围内,甲烷水合物的赋存形式为孔隙填充型。本研究成果量化了石英砂渗透率与甲烷水合物饱和度的关系,确定了含甲烷水合物的石英砂的渗透率分形模型的参数取值。     

Permeability of fractal porous media by Monte Carlo simulations

The permeability of the fractal porous media is simulated by Monte Carlo technique in this work. Based on the fractal character of pore size distribution in porous media, the probability models for pore diameter and for permeability are derived. Taking the bi-dispersed fractal porous media as examples, the permeability calculations are performed by the present Monte Carlo method. The results show that the present simulations present a good agreement compared with the existing fractal analytical solution in the general interested porosity range. The proposed simulation method may have the potential in prediction of other transport properties (such as thermal conductivity, dispersion conductivity and electrical conductivity) in fractal porous media, both saturated and unsaturated.     

An Investigation on Transport Properties Near the Wall in Porous Media by Fractal Models

A comprehensive investigation on the wall effects on the transport properties, permeability, thermal conductivity, and thermal dispersion conductivity is performed, based on the fractal models for these properties and the porosity variations near the wall in porous media. The results show that the fractal models for transport properties of porous media can provide good agreement with the conventional models in the region near the wall in porous media. This indicates that the fractal models for transport properties of porous media also hold in the region near the wall in porous media if the wall effects are taken into account.     

A fractal model for the coupled heat and mass transfer in porous fibrous media

This paper developed a mathematical model for the coupled heat and mass transfer in porous media based on the fractal characters of the pore size distribution. According to Darcy’s law and Hagen–Poiseuille’s law for liquid flows, the diffusion coefficient of the liquid water, a function of fractal dimension, is obtained theoretically. The liquid flow affected by the surface tension and the gravity, the water vapor sorption/desorption by fibers, the diffusion of the water vapor and the phase changes are all taken into account in this model. With specification of initial and boundary conditions, distributions of water vapor concentration in void spaces, volume fraction of liquid water, distribution of water molecular content in fibers and temperature changes in porous fibrous media are obtained numerically. Effects of porosity of porous fibrous media on heat and mass transfer are analyzed. The theoretical predictions are compared with experimental data and good agreement is observed between the two, indicating that the fractal model is satisfactory.     

Fractal analysis of Herschel–Bulkley fluid flow in porous media

The Herschel–Bulkley (HB) fluid is the representative fluid which may be reduced to the power-law fluid, Bingham and Newtonian fluids in appropriate conditions. In this paper, fractal models for velocity and the starting pressure gradient for HB fluid in porous media are derived based on fractal characteristics of porous media and capillary model. The proposed models are expressed as a function of fractal dimensions, porosity, maximum pore size and representative length of porous media. Every parameter in the proposed expressions has clear physical meaning, and the proposed models relate the flow characteristics of HB fluid to the structural parameters of porous media. The variation trends of fractal velocity and starting pressure gradient versus different impact factors are shown, and the analytical expressions reveal the physical principles for flow velocity and starting pressure gradient in porous media.