3.5FullyDevelopedHeatTransfer(FDHT)inCircularTubes3.5.1 IntroductiontoFDHTintubesandducts3.5.2 Physical andMathematicalModels3.5.3 Governing equations and their non dimensional forms3.5.4 Conditionsfor uniquesolution3.5.5Numericalsolutionmethod3.5.6Treatmentofnumericalresults3.5.7Discussiononnumericalresults16/58
16/58 3.5 Fully Developed Heat Transfer(FDHT) in Circular Tubes 3.5.2 Physical and Mathematical Models 3.5.3 Governing equations and their non dimensional forms 3.5.4 Conditions for unique solution 3.5.5 Numerical solution method 3.5.6 Treatment of numerical results 3.5.7 Discussion on numerical results 3.5.1 Introduction to FDHT in tubes and ducts
3.5 Fully Developed HT in Circular Tubes3.5.1 IntroductiontoFDHT in tubesand ducts1. Simple fully developed heat transferPhysically: Velocity components normal to flowdirection equal zero, Fluid dimensionless temperaturedistribution is independent on（无关）the position inthe flowdirectionMathematically: Both dimensionless momentum andenergy equations are of diffusion typePresent chapter is limited to the simple cases17/58
17/58 3.5.1 Introduction to FDHT in tubes and ducts 1. Simple fully developed heat transfer Physically：Velocity components normal to flow direction equal zero; Fluid dimensionless temperature distribution is independent on (无关）the position in the flow direction Mathematically：Both dimensionless momentum and energy equations are of diffusion type. Present chapter is limited to the simple cases. 3.5 Fully Developed HT in Circular Tubes
FDHT in straight duct is an example of simple casesaTyw.m-0axFwhereTwmis the circumferential（圆周的）averagewalltemperature2. Complicated FDHTIn the cross section normal to flow direction there exist velocitycomponents,and thedimensionlesstemperature depends on the axialposition,often exhibits periodic（周期的）character.ThefullNavier-Stokes equations must be solvedThis subject is discussed in Chapter 11 of the textbook.18/58
18/58 FDHT in straight duct is an example of simple cases. 2. Complicated FDHT In the cross section normal to flow direction there exist velocity components , and the dimensionless temperature depends on the axial position, often exhibits periodic (周期的）character. The full NavierStokes equations must be solved . This subject is discussed in Chapter 11 of the textbook. , , ( ) 0 w m w m b T T T x T where T w,m is the circumferential (圆周的）average wall temperature
Examples of complicated FDHTTubebundle（bank）（管束）议Fin-and-tubeLouverfin（百叶窗翅片）heatexchanger19/58
19/58 Examples of complicated FDHT Tube bundle (bank) (管束） Fin-and-tube heat exchanger Louver fin (百叶窗翅片)