华工流体力学复习提纲.ppt

1、Chapter 2 Fluid flow 流体流动fluid statics and its application,Nature of fluids Density 密度 Incompressible fluid 不可压缩流体 Compressible fluid 可压缩流体 Pressure 压强(压力) Independent of direction Unit SI制：N/m2或Pa， mmHg， mH2O Pg = Pabs Patm Pv = Patm - Pabs,Hydrostatic equilibrium 静力学方程,hydrostatic equation applica

2、tion 应用 U tube manometer U形压差计的计算式,Limitation: 适用：静止、连续的同种不可压缩性流体； Incompressible fluid、 Continuous fluid,压力形式,能量形式,Solution: 图(a) p=Rg(m-)； 图(b) p=Rg(m-空)=Rgm； 图(c) p=Rg(m-E) 图(d) p=Rgm-hg。,Chapter3 Fluid-flow phenomena 流体的流动现象,Ideal fluid 理想流体 Has zero viscosity Potential flow has two characterist

3、ics: Irrigational flow There is no friction loss,Newtonian fluid 牛顿型流体,the proportionality constant For gas, it increases with temperature For liquid, it decreases with temperature 1PaS =10 P（泊） =1000 cP ( 厘 泊),一、 牛顿粘性定律,Laminar flow 层流/滞流 fluid flows in parallel straight lines. without lateral mixi

4、ng,Laminar and turbulent flow 滞流和湍流,Turbulent flow 湍流 fluid moves erratically in form of crosscurrents and eddies,Reynolds number 雷诺准数, Re 2100, flow is laminar flow 滞流 Re 4000, flow is turbulence 湍流, 2100 Re4000 , a transition flow 过渡流,Flow in boundary layers 边界层定义,Laminar and turbulent flow in bou

5、ndary layers,Boundary-layer formation in straight tubes 流体在管内边界层的发展,Boundary-layer separation and wake formation 边界层的分离,Chapter 4basic equations of fluid flow 流体动力学,Mass balance 连续性方程,incompressible fluid, flow through the station a and b,Mechanical energy balance 柏努力方程,J/kg,m,pa,应用范围,For incompress

6、ible flow (不可压缩流体.) 2. Without friction loss 3. For unit,Chap5 Incompressible flow in pipes and channels 流体流动阻力, =4f,Shear stress and skin friction in pipes 直管阻力,直管阻力通式（范宁公式,Flow in noncircular channel非圆形管内的流动阻力,当量直径直径 de 代替非圆形管 d,Velocity distribution in a pipe 流体在圆管内速度分布,层流流动时，平均速度与最大速度的关系：u=0.5um

7、ax 湍流流动时，平均速度与最大速度的关系：u=0.87umax,Hagen-Poiseuille equation 哈根一泊谡叶公式,Turbulent flow in pipes 湍流流动,Laminar flow in pipes 层流流动,friction factor and friction coefficient chart 莫狄（Moody）摩擦因数图,Friction from changes in velocity or direction 局部阻力计算,Friction loss from sudden expansion of cross section Frictio

8、n loss from sudden contraction of cross section Effect of fittings and valves,u-小管平均流速,Pipe Flow Systems 管路计算,Single Pipes 简单管路,Multiple Pipes Systems 复杂管路,Chapter 6flow past immersed bodies 非均相物系分离,Terminal velocity,laminar 层流区(Stokes区) ：,Rep1,Transition (过渡区)：Allen law,turbulent (湍流区) ：Newton law,

9、Separation equipments Gravity settling processes gravity settling chamber Centrifugal settling processes,cyclone separator,Critical diameter,Filtration discontinuous pressure filters Principles of cake filtration Constant-pressure filtration,【7-66】,Filtration equation of constant pressure,【7-70】,Con

10、tinuous filtration,【7-74】,Washing filter cakes,Chapter8 transportation and metering of fluids,Developed head Power requirement power supplied to the pump drive from an external source,Suction lift and cavitation no liquid can be drawn when cavitation occurs air bound,Suction lift,To avoid cavitation

11、, the pressure in station 2 must,Centrifugal pump theory,Effects of speed and impeller size change,Characteristic curves; head-capacity relation,characteristic curve,Centrifugal-pump characteristics,characteristic curve,System head curve,system curve,Operating point,system curve,Operating point chan

12、ge,Operational point,Operation in parallel and in series of centrifugal pump in parallel in series,Measurement of flowing fluids,Venturi meter,(8-34),Orifice meter,Area meters: Rot meters Calibration Installation Direction of flow through modification,Picot tube measure the local velocity,(8-48),Cha

13、pter 10 Heat Transfer,Conduction,(10-2),Direction of heat flow conductivity,Convection Newtons law of cooling,Coefficient depends on the flow patterns the thermal properties of the fluid,Radiation,The energy emitted is proportional to the fourth power of the absolute temperature.,Steady-state conduc

14、tion heat transfer through flat slab heat transfer through cylinder,Compound resistance in series,overall thermal resistance,total temperature drop,Chap11 Principles of heat flow in fluids,Countercurrent and parallel-current flows,parallel,Single-pass shell-and-tube condenser,t2,Energy balances,Over

15、all heat-transfer coefficient,Special cases of the overall coefficient,Average temperature of fluid stream,Where,Chap12 Heat transfer to fluids without phase change,Heat transfer by forced convection in turbulent flow,(12-30),Chap13Heat transfer to fluids with phase change,Heat transfer from condensing vapors Dropwise and film-type condensation,(13-14),vertical tubes,Horizontal tubes,noncondensing gas,Pool boiling of saturated liquid,natural