P2.6.2 Ecuacion Diferencial Lineal Homogenea Con Coeficientes Constantes.
Factores de Conversion y Constantes
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Factores de conversion MAGNITUD SISTEMA METRICO SISTEMA METRICO INGLES Aceleracion Area Densidad Energia, calor, trabajo y energia especifica Fuerza Longitud Masa Potencia Presion o esfuerzo, y presion expresada como carga hidrostatica Calor especifico Volumen especifico Temperatura Velocidad , 1 N = 1 kg.m/s2 = 105dlnas 1 kgf = 9.80665 N I 1 kg= 1OOOg 1 tonelada = 1000 kg 1 Pa = 1 N/m2 1 kPa = lo3 Pa = MPa 1 atm = 101.325 kPa = 1.01325 bar = 760 mm Hg a 0°C = 1.03323 kgf/cm2 1 mm Hg = 0.1333 kPa 1 kJ/kg . "C = 1 kJ/kg . K = 1 Jlg . "C 1 m/s2 = 3.2808 ft/s2 1 ft/s2 = 0.3048* m/s2 1 m2 = 1550 in2 = 10.764 ft2 1 ft2 = 144 in2 = 0.09290304* m2 1 g/cm3 = 62.428 Ibm/ft3 = 0.036127 Ibm/in3 1 Ibm/in3 - 1728 Ibm/ft3 1 kg/m3 = 0.062428 Ibm/ft3 1 kJ = 0.94782 Btu 1 Btu = 1.055056 kJ = 5.40395 psia . ft3 = 778.169 Ibf . ft 1 Btullbm = 25,037 ft2/s2 = 2.326* kJ/kg 1 kwh = 3412.14 Btu 1 N = 0.22481 Ibf 1 Ibf = 32.174 Ibrn . ft/s2 - 4.44822 N 1 Ibf - 1 slug.ft/s2 1 m = 39.370 in = 3.2808 ft - 1.0926 yd 1 ft = 12 in = 0.3048* m 1 milla = 5280 ft = 1.6093 km 1 in = 2.54" cm 1 kg = 2.2046226 Ibrn 1 Ibm = 0.45359237* kg 1 onza = 28.3495 g 1 slug = 32.174 Ibrn = 14.5939 kg 1 tonelada corta = 2000 Ibrn = 907.1847 kg 1 kW = 3412.14 Btu/h = 1.341 hp = 737.56 Ibf . ft/s 1 hp = 550 Ibf . ft/s = 0.7068 Btuls = 42.41 Btulmin = 2544.5 Btulh = 0.74570 kW 1 Btulh = 1.055056 kJ/h 1 Pa = 1.4504 x psi = 0.020886 Ibf/ft2 1 psi = 144 Ibf/ft2 = 6.894757 kPa 1 atm = 14.696 psi = 29.92 pulgadas Hg a 30°F 1 pulgada Hg = 13.60 pulgadas H20 = 3.387 kPa 1 Btullbm . "F = 4.1868 kJ/kg . "C 1 Btu/lbmol . R = 4.1868 kJ/kmol . K 1 kJ/kg. "C = 0.23885 Btullbm . "F = 0.23885 Btullbm . R 1 m3/kg = 16.02 ft3/lbm 1 ft3/lbm = 0.062428 m3/kg T(R) = T("F) + 459.67 = 1.8T(K) R°F) = 1.8 T("C) + 32 AT("F) = AT(R) = 1.8* ARK) 1 mls = 3.2808 ft/s = 2.237 mi/h 1 milh = 1.46667 ft/s 1 milh = 1.6093 kmlh Viscosidad, dinamica 1 1 kglm . s = 1 N . s/m2 = 1 Pa . s = 10 poise] 1 kg/m . s = 2419.1 Ibm/ft - h I i I = 0.020886 Ibf . s/ft2 = 0.67197 Ibmlft . s .~. . ~ - - ~ .- ::>-Z?r..: :<:"iiii*.liiH n':::""-." .~~ - . - - .... .. . ,. ..... ,...,,~,~ ~~jm~i;i~fl$~~f~~~~jf~$#~~~a#~~j~~i~jii~P . - -----. -" . , ---.- -, cc- .zrs 31 exacio entre unidades metricas e inglesas. . - - - - - . . -- - - - - - - - - - - - - - -- . .. - . - - -- . -- -- -- , -.= - 5 .- &trica se toma exactamente cotno 746 W
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Transcript of Factores de Conversion y Constantes
Factores de conversion
MAGNITUD SISTEMA METRICO SISTEMA METRICO INGLES
Aceleracion
Area
Densidad
Energia, calor, trabajo y energia especifica
Fuerza
Longitud
Masa
Potencia
Presion o esfuerzo, y presion expresada como carga hidrostatica
Calor especifico
Volumen especifico
Temperatura
Velocidad
, 1 N = 1 kg.m/s2 = 105dlnas 1 kgf = 9.80665 N
I 1 k g = 1OOOg 1 tonelada = 1000 kg
1 Pa = 1 N/m2 1 kPa = lo3 Pa = MPa 1 atm = 101.325 kPa = 1.01325 bar
= 760 mm Hg a 0°C = 1.03323 kgf/cm2
1 mm Hg = 0.1333 kPa
1 kJ/kg . "C = 1 kJ/kg . K = 1 Jlg . "C
1 m/s2 = 3.2808 ft/s2 1 ft/s2 = 0.3048* m/s2
1 m2 = 1550 in2 = 10.764 ft2 1 f t2 = 144 in2 = 0.09290304* m2
1 g/cm3 = 62.428 Ibm/ft3 = 0.036127 Ibm/in3 1 Ibm/in3 - 1728 Ibm/ft3 1 kg/m3 = 0.062428 Ibm/ft3
1 kJ = 0.94782 Btu 1 Btu = 1.055056 kJ
= 5.40395 psia . ft3 = 778.169 Ibf . f t 1 Btullbm = 25,037 ft2/s2 = 2.326* kJ/kg 1 kwh = 3412.14 Btu
1 N = 0.22481 Ibf 1 Ibf = 32.174 Ibrn . ft/s2 - 4.44822 N 1 Ibf - 1 slug.f t /s2
1 m = 39.370 in = 3.2808 f t - 1.0926 yd 1 f t = 12 in = 0.3048* m 1 milla = 5280 f t = 1.6093 km 1 in = 2.54" cm
1 kg = 2.2046226 Ibrn 1 Ibm = 0.45359237* kg 1 onza = 28.3495 g 1 slug = 32.174 Ibrn = 14.5939 kg 1 tonelada corta = 2000 Ibrn = 907.1847 kg
1 kW = 3412.14 Btu/h = 1.341 hp = 737.56 Ibf . ft/s
1 hp = 550 Ibf . ft/s = 0.7068 Btuls = 42.41 Btulmin = 2544.5 Btulh = 0.74570 kW
1 Btulh = 1.055056 kJ/h
1 Pa = 1.4504 x psi = 0.020886 Ibf/ft2
1 psi = 144 Ibf/ft2 = 6.894757 kPa 1 atm = 14.696 psi
= 29.92 pulgadas Hg a 30°F 1 pulgada Hg = 13.60 pulgadas H20 = 3.387 kPa
1 Btullbm . "F = 4.1868 kJ/kg . "C 1 Btu/lbmol . R = 4.1868 kJ/kmol . K 1 kJ/kg. "C = 0.23885 Btullbm . "F
= 0.23885 Btullbm . R
1 m3/kg = 16.02 ft3/lbm 1 ft3/lbm = 0.062428 m3/kg
T(R) = T("F) + 459.67 = 1.8T(K) R°F) = 1.8 T("C) + 32 AT("F) = AT(R) = 1.8* ARK)
1 mls = 3.2808 ft/s = 2.237 mi/h 1 milh = 1.46667 ft/s 1 milh = 1.6093 kmlh
Viscosidad, dinamica 1 1 kglm . s = 1 N . s/m2 = 1 Pa . s = 10 poise] 1 kg/m . s = 2419.1 Ibm/ft - h I i
I = 0.020886 Ibf . s/ft2 = 0.67197 Ibmlft . s
. ~ . . ~ - - ~ .- ::>-Z?r..: :<:"iiii*.liiH n':::""-." .~~ - . - - ~ .... .. . ,. .....,...,,~,~ ~ ~ j m ~ i ; i ~ f l $ ~ ~ f ~ ~ ~ ~ j f ~ $ # ~ ~ ~ a # ~ ~ j ~ ~ i ~ j i i ~ P
. - -----. -" . , ---.- -, c c - .zrs 31 exacio entre unidades metricas e inglesas.
. - - - - - . . -- - - - - - - - - - - - - - -- . .. - . - - - - . - - - - -- , -.= - 5 .- &trica se toma exactamente cotno 746 W
MAGNITUD SISTEMA METRICO SISTEMA INGLES
V~scos~dad, c~nernat~ca 1 1 rn2/s - l o 4 crn2/s 1 stoke = 1 crn2/s = rn2/s
Volurnen / 1 rn3 = 1000 L = l o 6 crn3 (cc) 1 rn3 = 6.1024 x l o 4 in3 = 35.315 ft3 = 264.17 gal (U.S.)
1 galon de EUA = 2 3 1 in3 - 3.7854 L
i 1 onza liquida = 29.5735 crn3 = 0.0295735 L 1 galon de EUA = 128 f l onzas liquidas
Flujo volurnetrico I 1 rn3/s = 6 0 000 Urnin = l o 6 crn3/s !
*Factor de conversion exacto entre unidades rnetricas e inglesas.
Algunas constantes fisicas
CONSTANTE F ~ S I C A SISTEMA METRICO SISTEMA IIVGLES
Aceleracion gravitational estandar g = 9.80665 rn/s2 g = 32.174 ft/s2 Presi6n atrnosferica estandar Pat, = 1 atrn - 101.325 kPa Pat, = 1 atrn = 14 .696 psia
= 1.01325 bar = 2116 .2 1bf/ft2 = 7 6 0 rnrn Hg (0°C) - 29.9213 pulg H g (32°F) = 10 .3323 rn H20 (4°C) = 4 0 6 . 7 8 pulg H20 (39.2"F)
Constante universal de 10s gases R, = 8.31447 kJ/krnol . K R, = 1.9859 Btu/lbrnol . R = 8 .31447 kN . rn/krnol K = 1 545.37 f t . lbf/lbrnol . R
Prooiedades de uso cornljn
PROPI EDAD SISTEMA METRICO SISTEMA INGLES
Aire a 20°C (68°F) y 1 atm
Constante especifica del gas* R,,,, = 0.2870 kJ/kg . K R,,,, = 0.06855 Btullbrn . R = 287.0 rn2/s2 - K = 5 3 . 3 4 f t . Ibfl lbm . R
= 1 7 1 6 ft2/s2 . R
Razon de calores especif~cos k = c,/c, = 1 .40 k = c,/c, = 1.40
Calores especif icos
Velocidad del sonido
Densidad p = 1 .204 kg/rn3 p - 0 . 0 7 5 1 8 Ibrn/ft3
Viscosidad p = 1.825 x kg/rn . s p = 1.227 x lbrnlft . s
Viscosidad cinernatica v = 1.516 x rn2/s v = 1 . 6 3 2 X ft2/s
Agua liquida a 20°C (68°F) y I atm
Calor especifrco (c = c, = c,) c = 4.182 kJ/kg . K c = 0 . 9 9 8 9 Btullbrn . R = 4 1 8 2 rn2/s2 K = 777.3 f t . Ibfllbrn . R
= 2 5 0 0 9 ft2/s2 . R
Densidad p = 9 9 8 . 0 kg/rn3 p = 62 .30 Ibrn/ft3
Viscosidad dinarnica = 1.002 x 10-~.kg/rn . s p = 6.733 x Ibrnlft . s
Viscosidad cinernitica v = 1.004 x rn2/s u = 1 . 0 8 1 X ft2/s -
* lndependiente de la ternperatura o la presi6n
Temperatura ( O F )
20 60 100 140 180 220
0 20 40 60 80 100 120
Ternperatura ("C)
Figura B.l Viscosidad en funci6n de la ternperatura. (De R. W. Fox y T. A. McDonald, Ii~trodztctior~ to Fllrid Mechmlics, 2a. ed., John Wiley & Sons, Inc.. Nueva York. 1978.)
Temperatura ( O F )
20 60 100 140 180 220
0 20 40 60 80 100 120
Ternperatura ("C)
Figura B.l Viscosidad en funci6n de la ternperatura. (De R. W. Fox y T. A. McDonald, Ii~trodztctior~ to Fllrid Mechmlics, 2a. ed., John Wiley & Sons, Inc.. Nueva York. 1978.)
