Rohsenow W., Hartnett J., Young Cho. Handbook of Heat Transfer (776121), страница 11
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Conversion factors for commonlyTABLE 1.13SI Prefixes (Decimal Multiples and Submultiples in SI Are Formedby Adding the Following Prefixes to the SI Unit)FactorPrefixSymbolFactorPrefix10TM10151012exapetateragigamegakilohectodeka-EPTGMkhda10-1deci-10 -210 -3centimilli-10-610-9micronano-10 -1210 -15picofemto-10-18atto-10 910 610 310210SymbolBASIC CONCEPTS OF HEAT TRANSFERTABLE 1.14Symbols and Names for Units Used in the HandbookSymbolNameSymbolNameABtuC°Ccalcmdegdyn°FftgHhhpinampereBritish thermal unitcoulomb (= A.s)degree Celsiuscaloriecentimeterdegreedynedegree Fahrenheitfootgramhenry (= V.s/A)hourhorsepowerinchjoule (= N.m)kelvin (thermodynamictemperature)kgkgfIbmlbemminmolNPapdl°RradssrTVWkilogram masskilogram forcepound masspound forcemeterminutemolenewtonPascal (= N/m 2)poundaldegree Rankineradian (plane angle)secondsteradian (solid angle)tesla (= V.s/m 2)voltwatt (= J/s)JK1.31used q u a n t i t i e s in h e a t transfer, f r o m SI to English e n g i n e e r i n g units and vice versa, are givenin Table 1.15.C o n v e r s i o n factors for mass, density, pressure, energy, specific energy, specific heat, therm a l conductivity, d y n a m i c viscosity, and k i n e m a t i c viscosity in different s y s t e m s of units arealso given in Chap.
2 (Tables 2.1-2.9).TABLE 1.15Conversion Factors for Commonly Used Quantities in Heat TransferQuantitySI ---)EnglishEnglish ~ SI*Area1 m2= 10.764 ft 2= 1550.0 in 2ft 2 = 0.0929 m 2in 2 = 6.452 x 10-4 m 2Density1 kg/m 3 = 0.06243 lbm/ft3Ibm/ft3 = 16.018 kg/m 3slug/ft 3 = 515.379 kg/m 3Energy t1 J = 9.4787 x 10-4 Btu= 6.242 x 10 TM eVBtu = 1055.056 Jcal = 4.1868 Jlbcft = 1.3558 Jhp.h = 2.685 x 10 6 JEnergy per unit mass1 J/kg = 4.2995 × 10-4 Btu/lbmBtu/lbm = 2326 J/kgForce1 N = 0.22481 lbflbf = 4.448 Npdl = 0.1382 NHeat flux1 W/m 2 = 0.3171 Btu/(h.ft z)Btu/(h'ft 2) = 3.1525 W/m:kcal/(h.m 2) = 1.163 W/m 2cal/(s.cm 2) = 41.870 x 10 3 W / mHeat generation per unit volume1 W/m 3 = 0.09665 Btu/(h.ft 3)Btu/(h'ft 3) = 10.343 W/m 3Heat transfer coefficient1 W/(m2-K)=0.17612 Btu/(h.ft2.°F)Btu/(h.ft 2-°F) = 5.678 W/(ma-K)kcal/(h.m:.°C) = 1.163 W/(m2.K)cal/(s.cm 2.°C) = 41.870 x 103 W/(mR.K)21.32CHAPTER ONETABLE 1.15C o n v e r s i o n Factors for C o m m o n l y U s e d Q u a n t i t i e s in H e a t T r a n s f e rQuantity(Continued)SI ---) E n g l i s hE n g l i s h ---) SI*H e a t t r a n s f e r ratei W = 3.4123 B t u / h1 B t u / h = 0.2931 WLength1 m = 3.2808 ft= 39.370 in11111111ft = 0.3048 min = 2.54 cm = 0.0254 my a r d = 0.9144 ms t a t u t e mile = 1609 mm i l = 0.001 in= 2.54 x 10 -5 mlight-year = 9.46 x 1015 ma n g s t r o m = 10-1° mm i c r o n = 10-6mMassi kg = 2.2046 Ibm1 Ibm = 0.4536 kgi slug = 14.594 kgMass flow rate1 kg/s = 7936.6 lbm/h= 2.2046 lbm/s1 lbm/h = 0.000126 kg/s1 lbm/s = 0.4536 kg/sPower1 W = 3.4123 B t u / h1111B t u / h = 0.2931 WBtu/s = 1055.1 Wlbcft/s = 1.3558 Whp = 745.7 WP r e s s u r e a n d stress*1 N/m2====11111lbJft2 = 47.88 N / m 2lbf/in2 = 6894.8 N / m 2psi = 1 lbJin2 = 6894.8 N / m 2s t a n d a r d a t m o s p h e r e = 1.0133 x 105 N / m 2bar = 1 x 105 N / m 2Specific h e a t1 J / ( k g .
K ) = 2.3886 x 10 -4 Btu/(lbm.°F)1 B t u / ( l b m . ° F ) = 4187 J / ( k g . K )Surface t e n s i o n1 N / m = 0.06852 lbf/ft1 lbf/ft = 14.594 N / m1 d y n / c m = 1 x 10 -3 N / mTemperatureT(K) ===T(°C) =0.020886 l b J f t 21.4504 x 10-4 l b J i n 24.015 x 1 0 -3 in w a t e r2.953 x 10-4 in H gT(°C) + 273.15T(°R)/1.8[T(°F) + 459.67]/1.8[ T ( ° F ) - 32]/1.8T ( ° R ) = 1.8T(K)= T(°F) + 459.67T(°F) = 1.8T(°C) + 32= 1 .
8 [ T ( K ) - 273.15] + 321K=I°C= 1.8°R= 1.8OF1OR = 1OFThermal conductivity1 W / ( m . K ) = 0.57782 B t u / ( h . f t . ° F )1 B t u / ( h - f t - ° F ) = 1.731 W / ( m . K )1 k c a l / ( h . m . ° C ) = 1.163 W / ( m - K )1 c a l / ( s . c m . ° C ) = 418.7 W / ( m . K )T h e r m a l diffusivity1 m2/s -- 10.7639 ft2/s1 ft2/s = 0.0929 m2/s1 ft2/h = 2.581 x 10 -5 m2/sT h e r m a l resistance1 K / W = 0.52750 ° F . h / B t u1 ° F . h / B t u = 1.8958 K / WVelocity1 m/s = 3.2808 ft/s1 ft/s = 0.3048 m/s1 k n o t = 0.5144 rn/sViscosity ( d y n a m i c ) ~1 N.s/m2 = 0.672 lbm/(ft's)1 l b m / ( f t ' s ) = 1.4881 N . s / m 21 c e n t i p o i s e = 10 -2 poise= 1 x 1 0 -3 N .
s / m 2Temperature difference= 2.089 x 10 -2 l b f ' s / f t 2Viscosity ( k i n e m a t i c )I mZ/s = 10.7639 ftZ/s- 1 K/1.8= 1°C/1.81 ft2/s = 0.0929 m2/s = 929 stoke1 m2/s = 10,000 stokeBASIC C O N C E P T S O F H E A T T R A N S F E RTABLE 1.151.33Conversion Factors for Commonly Used Quantities in Heat Transfer (Continued)QuantitySI --+ EnglishEnglish --+ SI*VolumeI m 3 = 35.3134 ft 31 ft 3 = 0.02832 m 31 in 3 = 1.6387 x 10-5 m 31 gal (U.S. liq.) = 0.003785 m 31 gal (U.K.
liq.) = 0.004546 m 31 m 3 = 1000 liter1 gal (U.S. liq.) = 4 quarts= 8 pints= 128 ounces1 quart = 0.946 x 10 -3 m 3Volume flow rate1 m3/s = 35.3134 ft3/s= 1.2713 x 105 ft3/h1 ft3/h = 7.8658 x 10-6 m3/s1 ft3/s = 2.8317 x 10-2 m3/s1 gal (U.S. liq.)/min = 6.309 x10 -5 m3/s = 0.2271 m3/hr* Some units in this column belong to the cgs and mks metric systems., Definition of the units of energy based on thermal phenomena:1 Btu = energy required to raise 1 Ibm of water I°F at 68°F1 cal = energy required to raise 1 g of water I°C at 20°C* The SI unit for the quantity pressure is the pascal (Pa); 1 Pa = 1 N/m 2.Also expressed in equivalent units of kg/(s.m).NOMENCLATURESymbol, Definition, SI Units, English UnitsAheat transfer area: m 2, ft 2aacceleration: m/s 2, ft/s 2as p e e d of sound: m/s, ft/sCmass c o n c e n t r a t i o n of species: kg/m 3, lbm/ft 3cspecific heat: J/(kg.K), Btu/(lbm'°F)Cpspecific heat at constant pressure: J/(kg.K), Btu/(lbm'°F)cvspecific heat at constant volume: J/(kg.K), Btu/(lbrn" °F)Dtube inside diameter, diameter: m, ftDdiffusion coefficient: mE/s, ft2/sEcE c k e r t n u m b e r (see Table 1.10)eemissive power: W / m 2, Btu/(h.ft 2)ebb l a c k b o d y emissive power: W / m 2, Btu/(h.ft 2)Fforce: N, lbfF1-2view factor ( g e o m e t r i c shape factor for radiation f r o m o n e b l a c k b o d y toanother)~1-2real b o d y view factor ( g e o m e t r i c shape and emissivity factor for radiation f r o mo n e gray b o d y to a n o t h e r )ff r e q u e n c y of vibration (see Table 1.10): s -1d e n o t e s function of Eqs.
1.80-1.82 and 1.851.34CHAPTERONEGrgggchhoiitgJJkLMmNuPPrAPqq,,q,,q tp!RthReFrr .tScShStTATtUI1VVVVrVzGrashof number (see Table 1.10)gravitational acceleration: m]s 2, ft/s 2gravitational acceleration (vector): m/s 2, ft/s 2conversion factor (see Table 1.11): lbm'ft/(lbcs 2)heat transfer coefficient: W/(m2.K), Btu/(h.ft 2"°F)mass transfer coefficient: m/s, ft/senthalpy per unit mass: J/kg, Btu/lbmlatent heat of evaporation: J/kg, Btu/lbmheat of formation: J/kg, Btu/lbmmass diffusion flux of species: kg/(s-m2), lbm/(h'ft 2)mass diffusion flux of species (vector): kg/(s.m2), lbm/(h'ft 2)thermal conductivity: W/(m.K), Btu/(h.ft.°F)length: m, ftmass: kg, Ibmmass fraction of species (Eq. 1.63)Nusselt number (see Table 1.10)pressure: Pa (N/m2), lbf/ft 2Prandtl number (see Table 1.10)pressure drop: Pa (N/m2), lbf/ft 2heat transfer rate: W, Btu/hheat flux (vector): W/m 2, Btu/(h.ft 2)heat flux: W/m E, Btu/(h-ft 2)volumetric heat generation: W/m 3, Btu/(h-ft 3)thermal resistance: K/W, h.
°F/BtuReynolds number (see Table 1.10)radial distance in cylindrical or spherical coordinate: m, ftrecovery factor (Eq. 1.19)volumetric generation rate of species: kg/(s.m3), lbm/(h-ft 3)Schmidt number (see Table 1.10)Sherwood number (see Table 1.10)Stanton number (see Table 1.10)temperature: °C, K, °E °Rtemperature difference: °C, °Ftime: svelocity component in the axial direction (x direction) in rectangularcoordinates: m/s, ft/sinternal energy per unit mass: J/kg, Btu/lbmvelocity: m/s, ft/svelocity (vector): m/s, ft/svelocity component in the y direction in rectangular coordinates: m/s, ft/svelocity component in the r direction: m/s, ft/svelocity component in the z direction: m/s, ft/sBASIC CONCEPTS OF H E A T T R A N S F E RVoV~WXyZvelocity component in the 0 direction: m/s, ft/svelocity component in the ¢~direction: m/s, ft/svelocity component in the z direction in rectangular coordinates: m/s, ft/srectangular coordinate: m, ftrectangular coordinate: m, ftrectangular or cylindrical coordinate: m, ftGreek88o8rE.HE.ME.m0gVPthermal diffusivity: m2/s, ft2/scoefficient of thermal expansion: K -1, °R-1hydrodynamic boundary layer thickness: m, ftconcentration boundary layer thickness: m, ftthermal boundary layer thickness: m, ftemissivityeddy diffusivity of heat: m2/s, ft2/seddy diffusivity of momentum: m2/s, ft2/seddy diffusivity of mass: m2/s, ft2/sangle in cylindrical and spherical coordinates: rad, degmolecular mean free path: m, ftdynamic viscosity: Pa-s, lbm/(S-ft)kinematic viscosity: m2/s, ft2/sdensity: kg/m 3, lbm/ft 3surface tension (see Table 1.10): N/m, lbf/ftStefan-Boltzmann radiation constant: W/(m2.K4), Btu/(h.ft 2.°R4)shear stress: N/m:, lbf/ft 2shear stress tensor: N/m R, lbf/ft 2dissipation function (see Table 1.7): s-2angle in spherical coordinate system: rad, degSubscriptsdawcrfgilmrssattwsurroundingsadiabatic wallcriticalfluidgas (vapor)species iliquidmeanradiation (Eq.
1.36)solidsaturationtotalwall1.351.36CHAPTERONExx componentyy componentzz component00 component~ componentMiscellaneous Subscripts1species 1 in binary mixture of I and 2oofree-stream conditionSuperscripts•fluctuating component (for example, X' is the fluctuating component of X)time average (for example, X is the time average of X)Mathematical Operation Symbolsd/dxderivative with respect to x: m -1, ft -1i)/i)tpartial time derivative operator:d/dttotal time derivative operator: s-1 (Eq. 1.37)D/Dtsubstantial time derivative operator: s-1 (Eq. 1.38)Vdel operator (vector): m -i, ft -1V2laplacian operator: m -2, ft -2S -1REFERENCES1.2.3.4.5.6.7.8.9.10.11.12.13.14.15.E Kreith and W. Z.
Black, Basic Heat Transfer, Harper & Row, New York, 1980.J.P. Holman, Heat Transfer, 8th ed., McGraw-Hill, New York, 1997.E E Incropera and D. P. DeWitt, Fundamentals of Heat Transfer, 4th ed., Wiley, New York, 1996.M.N. Ozisik, Basic Heat Transfer, McGraw-Hill, New York, 1977.R.E. Treybal, Mass-Transfer Operations, 3d ed., McGraw-Hill, New York, 1980.W. M. Kays and M. E. Crawford, Convective Heat and Mass Transfer, 2d ed., McGraw-Hill, NewYork, 1980.H. Schlichting, Boundary-Layer Theory, 7th ed., McGraw-Hill, New York, 1979.J.O.
Hinze, Turbulence, 2d ed., McGraw-Hill, New York, 1975.J.H. Lienhard, A Heat Transfer Textbook, Prentice-Hall, Englewood Cliffs, NJ, 1981.R. B. Bird, W. E. Stewart, and E. N. Lightfoot, Transport Phenomena, Wiley, New York, 1960.W. M. Rohsenow and H. Y. Choi, Heat, Mass, and Momentum Transfer, Prentice-Hall, EnglewoodCliffs, NJ, 1961.D. K. Edwards, V. E.
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