(英汉双语)流体力学第十章两相流动理论基础

1、1 Fluid Mechanics 2 3 Chapter 10 Fundamentals of two-phase flow 10-1 Introduction 102 Summary of two-phase flow 10-3 Resistance of mobile 10-4 Sedimentation velocity of particle 10-5 Hydraulic transport transport of material 10-6 Pneumatic transport of material Exercises of Chapter 10 4 第十章第十章 两相流动理

2、论基础两相流动理论基础 10-1 引引 言言 102 两相流动概述两相流动概述 10-3 运动物体的阻力运动物体的阻力 10-4 颗粒的沉降速度颗粒的沉降速度 10-5 物料的水力输送物料的水力输送 10-6 物料的气力输送物料的气力输送 第十章第十章 习习 题题 5 10-1 Introduction This chapter introduce basic concepts, equation and some methods. Whereas the complexity,diversity and levity,advanced analysis relate to extensive

3、 knowledge, here only introduce common two-phase flow phenomenon and some simple method deciding important parameter. It established the theory base for studying advanced two-phase flow. 6 10-1 引言引言 本章介绍两相流动的基本概念、基本方程及一些处理方法。 鉴于两相流动的复杂性、多样性和多变性，深入分析所涉及的知 识十分广泛，这里仅介绍常见的两相流动现象及确定一些重要参 数的简单方法，为进一步深入分析研

4、究两相流动奠定基本的理论 基础。 7 So called “phase”is existing form for matter. Generally, there are three phases solid,liquid and gas. Mixed flow of any two or more phases infusible matter called multiphase flow. Multiphase flow is common phenomenon in nature,daily life and many project.Such as cloud,fog, rain an

5、d snow phenomenon;dirt in atmosphere,sand in river blood flow in organism; engine,burning in boiler, generate electricity, refrigerate, vaporize in distil ; flow in congeal cycle, oil, mine and transportation of natural gas，matter flowed in all kinds of stove , pagoda in chemical production; mill ru

6、n in mining industry, removing dirt in environment defense and so on. 10-2 Summary of two-phase flow 8 所谓“相”是指物质存在的形态。通常有固、液、气三 相。任何两相或两相以上不相溶物质的混合流动，统称为多 相流动。多相流动是自然界、人类日常生活和许多工程中常 见的流动现象。如自然界的云、雾、雨、雪现象，大气中的 烟尘、水流中的泥沙、生物体内的血液流动、发动机、锅炉 中的燃烧、发电、制冷和蒸馏过程中的蒸发、凝结循环系统 中的流动，石油、天然气的开采和输送，化工生产中各种炉 、塔中物质的流化，采

7、矿工业中的选矿，环保工业中的除尘 等等。 10-2 10-2 两相流动概述两相流动概述 9 Two-phase flow may be plotted three class according to matter state: gas-solid two-phase flow;liquid-solid two-phase flow;gas- solid two-phase flow; As a result of much thermodynamics in gas -liquid , the emphases in this chapter is correlative knowledge

8、 about liquid-solid two-phase flow and gas-solid two-phase flow. 10 两相流动根据物质的状态可分为三类：气液两相流； 液固两相流；气固两相流；由于气液两相流涉及热力 学较多的知识，故本章重点介绍液固两相流和气固两相 流的相关知识。 11 1.Character of solid material Two-phase flow often involves physical and geometrical character of solid. 1.1 Main physical character of solid materi

9、al. Main physical character of solid material is mass (rs), specific weight（gs）and specific gravity 。 2.2 Main geometrical character of solid material 2.2.1 Particle diameter. In fact the shape of solid material is anomalistic. Adopt equal volume particle diameter express its size (taking particle a

10、s sphere with equal volume ): 1)(10 ) 6 () 6 ( 3/13/1 s s GV d g 10-3 Resistance of mobile 12 一、固体物料的性质 两相流中常涉及的是固体的物理性质和几何性质。 1、固体物料的主要物理性质 固体物料的主要物理性质有质量（rs）,重度（gs）和比重 。应注意比重是无因次物理量，与重度的物理概念不同。 2、固体物料的几何性质 （1）粒径 实际固体物料的形状一般是不规则的，可采用 等体积粒径来表示颗粒的大小，即把颗粒看作等体积球体， 可得等体积粒径为： 1)(10 ) 6 () 6 ( 3/13/1 s s

11、GV d g 10-3 10-3 运动物体的阻力运动物体的阻力 13 2.2.2 Shape of particle:Get sphere as standard;scaling different shape but same particle and specific weight, called shape coefficient f (102) where surface area of cylinder; surface area of particle pb pb fb fb S S S S f： Because surface area of sphere is least, s

12、o 0 f 1 。 2. Basic type of resistance of mobile When a object moves in liquid, force that liquid act to object is component of forces plumb with speed, P (ascending force)and component of forces adverse with speed R （resistance）,as in 101. Moreover R is made of friction resistance Rm produced by she

13、ar stress and press resistance Rp produced by press: R Rm Rp P F R Fig.101 Object streamline chart 14 （2）颗粒的形状 取球形作标准，衡量颗粒和重度相同但形 状不同的颗粒，称作球形度或形状系数，用f表示 颗粒的表面积。圆柱体的表面积；式中： fbpb fb pb SS S S 2)(10 f 由于球形表面积最小，故其它形状颗粒球形度 0 f1 。 二、运动物体阻力的基本类型 当一物体在流体中运动时，流体对 物体的作用力可分为与速度垂直的分力 P （简称为升力）和与速度相反的分力 R （称为阻力

14、），如图101所示。而阻力 R 又分为由切应力产生的摩擦阻力 Rm 和 由压力产生的压力阻力 Rp ，即 R Rm Rp P F R 图101 物体的流线谱 15 When object moves in fluid, action force law is connected with Renault. When Renault is great,it means inertia force is far large than viscosity force; in reverse ,viscosity is larger than inertia force. 3. Resistance

15、of spherical object with great Reynolds number When Renault is great，object with bad streamline will produce vortex resistance as attached layer separating. Resistance account formula get by modifying the Newton-Reutlingen resistance formula, it is suitable as 500Re105 . 3)-(10 16 22u dRr 4. Resista

16、nce of spherical object with minor Reynolds number In many practical project,particle diameter is very small,moving speed is slow,mostly resistance produced is friction resistance, belong to generic laminar flow movement. Translate formula（103）into generic resistance formula: 16 当物体在流体中运动时，作用力的规律与雷诺

17、数有关， 雷诺数很大时，表示惯性力远大于粘性力，反之则粘性力大 于惯性力。 三、大雷诺数时圆球形物体的阻力 在大雷诺数时，圆球等流线形不好的物体在发生附面层分 离时会产生压差阻力（旋涡阻力）。阻力计算公式是在牛顿 雷廷根阻力公式基础上加以修正得到的，适用与 500Re105 的 情况下。 3)-(10 16 22u dRr 四、小雷诺数时圆球形物体的阻力 在许多实际工程中，颗粒直径很小，运动速度慢，即运 动为小雷诺数时，产生的阻力主要是摩擦阻力，属于一般的 层流绕流运动。 将（103）式写成阻力公式的一般形式： 17 2 222 1 (10-4) 42 where resistance coe

18、fficient connect with Reynolds and object shape u Rcdd u c rr ：， ， When pellet moves slowly,roll flow has no separating phenomenon, neglecting mass force, deducing resistance coefficient 24 , c and Re Substituting into104obtain Re 3 (10-5) ud c v Rud （ ） formula（105）is pellet resistance formula when

19、 Reynolds number is minor（Re1）,called Stokes formula. In Re=25500 ,the spherical object resistance can be calculated with A-Lian empirical formula: 6)-(10 Re4 5 22u dRr Besides above three applicable region,others still need study incessantly. 18 2 222 1 (10-4) 42 u Rcdd u c rr 式中：， 阻力系数，与雷诺数和物体形状有关

20、 在圆球作缓慢运动，绕流无分离现象时，可忽略质量力， 可导出阻力系数 5)-(10 3 410 Re , Re 24 udR v ud c c ）式得代入（和将 （105）式就是小雷诺数（Re1）时圆球阻力公式，称斯 托克斯公式。 在 Re=25500 这个流动范围内，可用阿连经验公式计算 圆球形物体的阻力，该式为： 6)-(10 Re4 5 22u dRr 在上述三个公式适用范围以外的区域，还有待不断的研究解决。 19 1. Free sedimentation velocity of spherical particle in static fluid Free sedimentation

21、 velocity has direct connect with resistance of particle in medium. There are lots of particle sedimentation problems in mill run, material transport, operation of flow state,get rid of dirt by ventilating and water pollution father and so on technology field. So, Free sedimentation velocity of part

22、icle is one of important theories basis in two-phase flow. There are two forms in sedimentation of particle , namely, free sedimentation and hindered sedimentation. 10-4 Sedimentation velocity of particle Free sedimentation occurs when single particle sediments in infinite flow space.There is no ser

23、ious interface between low thickness particle , it can be disposed as free sedimentation . Hindered sedimentation is that particles sediment in finite space, besides gravity and resistance come into play , it also concluded force between particles, particle and implement wall. 20 一、圆球形颗粒在静止流体中的自由沉降速

24、度 沉降速度的大小与颗粒在介质中的阻力有着直接的关系 。在选矿、物料输送、流态化操作、通风除尘、水污染治理 等工业技术领域均有大量颗粒沉降问题。因此，颗粒沉降速 度是两相流动中重要的理论基础之一。 颗粒的沉降分自由沉降与干涉沉降两种形式。自由沉降 指单个颗粒在无限流体空间内的沉降，当颗粒间无严重干扰 的低浓度颗粒沉降也可按自由沉降处理。干涉沉降是颗粒群 在有限空间内的沉降，颗粒除受重力、阻力作用外，还有颗 粒间，颗粒与器壁间的作用力。 10-4 10-4 颗粒的沉降速度 21 1.1 Free sedimentation terminal velocity When spherical par

25、ticle sediments in resting liquid, the forces act to it are: 3 3 22 33 22 gravity: 6 buoyancy: 6 resistance: then the kinetic equation of grain , substituting into above three force formula then () 66 s s s b s b ss sss d W d W Rd u du WWRm dt dd d u g g r rrrr 2 0 , 6 (10-7) r (10-7a) s sss R du dt

26、 duu g dtd du oga dt rrr rr 22 1、自由沉降末速 球形颗粒在静止流体中沉降时，所受到的作用力有： 7a)-(10 7)-(10 6 , 6 )( 6 , 6 6 0 2 3 22 3 22 3 3 R sss s s s ss s b s s b s s ag dt du d u g dt du dt dud ud d dt du mRWW udR d W d W 或简写为 则 得 代入三个力的表达式则颗粒的运动方程为 阻力 浮力 重力 r r r rr r rrr r g g 23 0 where gravity acceleration , only conn

27、ect with density; resistance acceleration ,connect with density and dimension, direct ratio with rate square R g a ： When particle starts to sediment, velocity and resistance are zero, acceleration is max; as sedimentation velocity augmenting, the resistance acceleration increasing,after some time,t

28、he outside forces acted to particle attain balance, particle sediment velocity invariable, this velocity is called sediment terminal velocity, express with ut Using Eq.（107）we have ut )0( dt du 8)-(10 6 )( g d u ss t r rr For spherical particle , resistance coefficient changing along with Re ,due to

29、（103）,（105）,（106）,obtain , substituting into （108）, then 24 且与速度平方成正比。 尺寸均有关系，阻力加速度，与密度和 与密度有关；颗粒的重力加速度，只式中： 0 R a g 颗粒开始下降时，速度为零，阻力亦为零，加速度为最 大值，随着下降速度增大，阻力加速度增大，经一定时间， 作用在颗粒上的外力达到平衡，颗粒等速下降，这个速度称 之为沉降末速，以 ut 表示。 由式（107）可解得 ut )0( dt du 8)-(10 6 )( g d u ss t r rr 对于球形颗粒，阻力系数随 Re 变化，由（103），（105）， （10

30、6）三式中，解出 值，代入（108）式中，则分别得： 25 For Re 1 , Stokes sediment terminal velocity formula 9)-(10 18 )( 2 rr ss t dg u For Re=25500 , A-Lian sediment terminal velocity formula 10)-(10 )g 15 2 ( 33 2 s r r rr st du For Re=500104 ,Newton- Reutlingen sediment terminal velocity formula 11)-(10 )( 3 8 gdu s st r

31、 rr 26 适用于 Re 1 时的斯托克斯沉降末速公式 2 g() (10-9) 18 ss t d u rr 适用于 Re=25500 时的阿连沉降末速公式 10)-(10 )g 15 2 ( 33 2 s r r rr st du 适用于 Re=500104 的牛顿雷廷根沉降末速公式 11)-(10 )( 3 8 gdu s st r rr 27 According to Reynolds spectrum of sedimentation terminal velocity formula, we can obtain corresponding granularity spectru

32、m of formula, namely boundary granularity,expressing with dB , Substituting into（109）,（1010）,（1011） and take into boundary value of Re ,then obtain boundary granularity: s t d u r Re 2 3 22 33 ForRe1, Stokesformula 18 (10-12) g() ForRe2 300, A-Lian formula 0.28 3.4 (10-13) ()() B s B ss d d rr r rr

33、rrr r 28 根据沉降末速公式的雷诺数范围也可求出各公式相应的 粒度范围，并称之为边界粒度，用 dB 表示，将 代入 （109），（1010），（1011）三式，并代入 Re 的边 界值，即可解得边界粒度为： s t d u r Re 13)-(10 )( 4 . 3 )( 28. 0 3002Re 12)-(10 )( 18 1Re 3 2 3 2 3 2 rrr rrr rrr ss B s B d g d 的阿连公式适于 时的斯托克斯公式适于 29 2 3 For 1000,Newton- Reutlingen formula 9.12 (10-14) () B s R d rr r

34、 Example 101 One spherical particle , particle diameter ds=0.09 mm ,density rs=3.3103 kg/m3 , free sediment in water,density of water r=1000 kg/m3 ，viscosity coefficient 0.001 Pa s , find（1） sedimentation terminal velocity of particle ？（2）If sedimentation in atmosphere 1.82105Pas, r1.2kg/m3 , find s

35、edimentation terminal velocity？ Solution：There are three formula according to spectrum of Re , so, applying test method: (1) For free sediment in water ,applying(Re1)formula to check m/s 0102. 0 001. 018 81. 9)10003300()1009. 0( 18 )( 232 rrgd u ss t 30 14)-(10 )( 12. 9 1000 3 2 rrr s B d R雷廷根公式时的牛顿

36、适用于 例题101 一圆球形颗粒，粒径ds=0.09 mm ,密度 rs=3.3103 kg/m3 ,在水中自由沉降，水的密度 r=1000 kg/m3 ，粘性系数 0.001 Pa s , 求（1）颗粒的沉降末速为多少？（2）若在 1.82105Pas, r1.2kg/m3 的空气中自由沉降，其沉降末速又为 多少？ 解：在计算沉降末速时，有三个公式按 Re 范围选用，因此应 采用试算法。 （1）在水中自由沉降按层流（Re rs1 ,due to ut1= ut2 ,so dE1 dE2 ,then equal sedimentation ratio 1 2 1 0 E E d d e （1）

37、When Reynolds number is minor due to 22111 21 tttt uuuuff ff Substituting into Stokes formula of ut1 and ut2 （109） solution15)-(10 )()( 5 . 0 1 2 5 . 0 1 2 2 1 0 rr rr f f s s E E d d e （2）When Reynolds number is large Substituting into Newton- Reutlingen formula（1011） solution It reflects relation

38、between light and heavy particle and difficult extent in making lay according to specific gravity, it is important parameter in classification product according to density. 16)-(10 )( 1 2 2 1 2 2 1 0 rr rr f f s s E E d d e 36 设有两个等降颗粒，其粒度及密度分别为dE1 ,rs1 和dE2 ,rs2 ， 设rs2 rs1 ，由ut1= ut2 知 dE1 dE2 ，则等降

39、比 1 2 1 0 E E d d e （1）小雷诺数时颗粒的等降比 由 22111 21 tttt uuuuff ff 代入 ut1和ut2 的斯托克斯计算公式（109） 解得15)-(10 )()( 5 . 0 1 2 5 . 0 1 2 2 1 0 rr rr f f s s E E d d e （2）大雷诺数时的颗粒等降比 同上方法，代入牛顿雷廷根计算公式（1011） 解得 等降比反映了产品分级中轻重颗粒的关系及按比重分 层的难易程度，是利用不同密度进行分级产品技术中的重 要参数。 16)-(10 )( 1 2 2 1 2 2 1 0 rr rr f f s s E E d d e 3

40、7 Swanson deduced a single sedimentation equation in 1967,it is applicable to any shape particles in spectrum of Reynolds number.In 1975, he amended it : 2 3/2 4 g() 3 (10-17) g (248) 3 ss t s s d u d rr r r practice.in important ist )1710(by determined particle, oft coefficien surface attachment di

41、ameter; particlemean h i dere s ， ： 38 斯瓦恩松（Swanson）在1967年导出一个单一的沉降方程， 可在广泛的雷诺数范围内用于任何形状的颗粒。1975年，他又在 原方程基础上作了改进，其形式如下： 义。用中具有重要的实际意 和使分级机，浓缩机的设计在水力确定，这个公式 ）式沉降实验数据和（颗粒的附面层系数，由， 筛分和测定；平均颗粒直径，取决于式中： 1710 s d 2 3/2 4 g() 3 (10-17) g (248) 3 ss t s s d u d rr r r 39 1.3 Effect of thickness to sedimenta

42、tion terminal velocity When thickness of particle is large, the hinder is serious between each other,come into hindered sedimentation.The effect of thickness is connected with coarse extent of particle. It is spread when coarse particles sediment,liquid viscosity invariable . Due to up-current and t

43、urbulence stirred by particle sedimentation, it is important effect that the augment of mixed liquid specific weight made virtual gravity small. All these factors make sedimentation terminal velocity smaller than low thickness. The factor of sedimentation particle is complex .First thin particle is

44、larger than surface area,produce flocculation phenomenon easily, make sedimentation terminal velocity larger. Flocculation is connected with water quality and thickness.Secondly, effect of thickness shows in change of mixed liquid viscosity coefficient.Thinner as the particle diameter, more bigger a

45、s thickness and viscosity coefficient. For effect of thickness,people summarize some empirical formulas through doing a lot of experiment ,but these formulas has some restrict and mismatch.Especially,different particles produces different revised formulas or coefficient,so ,in practice, we should re

46、fer to literature.。 40 3、浓度对沉降末速的影响 当颗粒浓度较大时，其相互干扰渐趋严重，成为干涉沉降。 浓度的影响与颗粒的粗细程度关系密切。 粗颗粒下沉时呈分散状态，流体粘性不变化，只是由于颗粒 下沉时诱发的向上水流和激起的紊动造成的影响，混合液重度增 大而引起颗粒有效重力减小也有重要影响。这些因素都趋向于使 沉降末速比低浓度时下降。 细颗粒下降时的影响因素比较复杂。首先细颗粒比表面积大 ，易产生絮凝现象，使沉降末速加大。絮凝作用与水质有关，也 与浓度有关，也就是浓度的影响是和水质的影响结合在一起通过 絮凝起作用的。其次，浓度的影响还表现在混合液粘性系数的变 化上。浓度愈

47、大粒径愈细，混合液的粘性系数愈大。 对于浓度的影响，许多人做过大量实验而总结出一些经验公 式，但这些公式都有一定的条件限制和误差，特别是沉降颗粒的 不同会有不同的修正公式或修正系数，而且这些公式还在不断地 研究和完善之中，因此在实际计算时，应查阅最新相关文献，在 此不对这些公式作详细介绍。 41 2. Calculation of sedimentation terminal velocity of transition state In transition state between laminar flow and turbulent flow, viscous force and tu

48、rbulent force come into synchronously. In this transition region, sedimentation terminal velocity can be calculated with Dou-guorens formula. 2 () (10-18) 6 here resistance coefficient in transition state. 4311.2 ()(1 cos )sin (10 Re428 s ts ugd rr r ： -19) where lg4Re , its applicable spectrum is R

49、e0.25350 , normal temperature 0.2 2 mm d 。 42 二、过渡状态颗粒沉降末速的计算 在从层流到紊流之间的过渡状态，粘性力和紊流阻力同 时起作用。在这个过渡区颗粒沉降末速可采用南京水利科学 研究所窦国仁的计算公式。 。 常温下该式的适用范围是其中 由下式计算：过渡状态阻力系数，可式中： mm 22 . 0 , 3500.25Re , lg4Re 19)-(10 sin 8 2 . 1 )cos1 ( 2 1 ) 4 3 Re 4 ( 18)-(10 6 )( 2 d gdu s s t r rr 43 3. Particle sedimentation i

50、n gas-solid two-phase plane flow In mill run technology,using different sedimentation velocity of particle , taking them separate into class of some granularity spectrum, called classification, there are wind power and water power 3.1 Work principle of sedimentation trunk Multiplex movement of gas f

51、low velocity u and sedimentation velocity ut come into play when solid particle come l u vt u Fig.102 work principle of trunk classification based on liquid used.It often uses sedimentation trunk in gas-solid two phase plane flow classification. into sedimentation trunk. Particle moves in trunk with

52、 absolute velocity v, sediment after some distance,as Fig.102. 3.2 Throughput capacity of sedimentation of trunk Assume width of trunk is b ,high is H ,length is l ， sedimentation time along with H is t ， time of gas flow pass trunk is t , then u l t u H t t , 44 三、气固两相水平流中颗粒的沉降 在选矿技术中，常利用颗粒的沉降速度不同，

53、将其分成 若干粒度范围的粒级，称之为分级，根据所用流体分为风力 分级和水力分级。气固两相水平流分级常用沉降箱。 1、沉降箱工作原理 固体颗粒进入沉降箱后组成 气流速度 u 和沉降速度 ut 的复合 运动。颗粒以绝对速度 v在箱中 运动，在一定距离沉降下来，如 图102所示。 l u vt u 图 102 沉降箱工作原理2、沉降箱生产能力 设箱宽为 b ，高为 H ，长为 l ，沿高度 H 的沉降时间为 t ，气 流通过沉降箱时间 t , 则 u l t u H t t , 45 max sedimentation condition is , throughput express with v

54、olume discharge () , ,is maxium, substituting t yielding maxium throughput ( )() (10-20) (10-20) t tt tt l QbHubHas tt Q t ul QbHbHbluAu tH is suitable to laminar flow. In turbulence flow,pluse velocity will damage particle steady sedimentation condition. 3.3 Terminal particle diameter in sedimentat

55、ion trunk Diameter that corresponding to sedimentation terminal velocity is called terminal diameter.Particle with diameter larger than terminal diameter can sediment into trunk.Substituting ut in (10-20) into formula（108）and yielding terminal diameter: 21)-(10 )()( 6 2 2 gbl Q d s s rr r 46 降条件。 粒平

56、稳下时，脉动速度将破坏颗式适于层流流动。紊流 最大生产能力 得最大，代入时， 表示，生产能力用体积流量沉降条件为 20)-(10 20)-(10 )()( , )( , maxtt t Aublu H u bH t l bHQ tQtt t l bHbHuQ Qtt 3、沉降箱中颗粒的临界粒径 对应沉降末速的粒径称临界粒径。大于临界粒径的颗粒才能 降落箱中。将（1020）式中 ut 用一般公式（108）代入并解 出临界粒径为： 21)-(10 )()( 6 2 2 gbl Q d s s rr r 47 Example 102 When throughput of sedimentation

57、trunk is 18000 m3/h ,density of solid particle is 3500 Kg/m3 , atmosphere viscosity coefficient =18.210-6 PaS atmosphere density r1.2 kg/m3 ,what size of sedimentation trunk when terminal diameter is 50 m ? Solution： 2 () 0.262 m/s , take 0.27 m/s . 18 gas flow velocity u=0.8 m/s , assume heigth of

58、trunk 2m , through , yielding 3.1 m , 6 m ks tt t dg uu take H QuH QbHubl Huu rr 4. Particle sedimentation in liquid-solid two-phase plane flow The equipment that utilizing surface velocity of plane flow to separate liquid-solid is called sedimentation groove or pyramid grader,as 103, as analysis in

59、 sedimentation, as t=t is terminal particle condition, then u l u h t 48 例题102 沉降箱生产量为18000 m3/h 时，固体颗粒密度为 3500 Kg/m3 , 空气粘性系数 =18.210-6 PaS 空气密度 r1.2 kg/m3 , 求临 界粒度为 50 m 时，沉降箱尺寸为多少？ 解： m 6 , m 1 . 3 , , m2 , m/s 8 . 0 m/s 27. 0 , m/s 262. 0 18 )( 2 t t sk t u uH l Hu Q bbHuQ Hu u gd u 得由 设沉降箱高度取沉降

60、箱中气流速度 。取 rr 四、液固两相水平流中颗粒的沉降 利用水平流的表面流速进行液固分离的设备称沉降槽 或角锥分级机，如图103所示。如沉降箱中分析，t=t时为临 界粒度的条件，则有 u l u h t 49 designed. be can sizethe defined, is throughput and diameter terminal ,contrarily ;calculated be can diameter terminal defined, is equipment of throughput and size when ,tionclassifica plane gca