Factores de conversión - Facultad de Ingeniería Mecánica

Factores de conversión
Dr. Carlos Rubio Maya
Facultad de Ingeniería Mecánica, U.M.S.N.H.
Septiembre 2011
DIMENSION
Aceleración
METRICO
METRICO/INGLES
1 m/s2 = 100 cm/s2
Area
1 m2 = 104 cm2 = 106 mm2 = 10−6 km2
Densidad
1 g/cm3 = 1 kg/L = 1000 kg/m3
Energía
1 kJ = 1000 J = 1000 N · m = 1 kP a · m3
1 kJ/kg = 1000 m2 /s2
1 kW h = 3600 kJ
1 cal = 4.184 J
1 IT cal = 4.1868 J
1 Cal = 4.1868 kJ
Fuerza
1 N = 1 kg · m/s2 = 105 dina
1 kgf = 9.80665 N
1 W/cm2 = 104 W/m2
1 m/s2 = 3.2808 f t/s2
1 f t/s2 = 0.3048 m/s2
1 m2 = 1550 in2 = 10.764 f t2
1 f t2 = 144 in2 = 0.09290304 m2
1 g/cm3 = 62.428 lbm/f t3 = 0.036127 lbm/in3
1 lbm/in3 = 1728 lbm/f t3
1 kg/m3 = 0.062428 lbm/f t3
1 kJ = 0.94782 Btu
1 Btu = 1.055056 kJ
= 5.40395 psia · f t3 = 778.169 lbf · f t
1 Btu/lbm = 25, 037 f t2 /s2 = 2.326 kJ/kg
1 kJ/kg = 0.430 Btu/lbm
1 kW h = 3412.14 Btu
1 termia = 105 Btu = 1.055x105 kJ (G.N.)
1 N = 0.22481 lbf
1 lbf = 32.174 lbm · f t/s2 = 4.44822 N
1 W/m2 = 0.3171 Btu/h · f t2
Flujo de calor
Coeciente de
transferencia
de calor
Longitud
1 W/m2 ·◦ C = 1 W/m2 · K
1 m = 100 cm = 1000 mm = 106 µm
1 km = 1000 m
Masa
1 kg = 1000 g
1 ton metrica = 1000 kg
Potencia
1 W = 1 J/s
1 kW = 1000 W = 1.341 hp
1 hp = 745.7 kW
Presión
1 P a = 1 N/m2
1 kP a = 103 P a = 10−3 M P a
1 atm = 101.325 kP a = 1.01325 bars
= 760 mm Hg (0◦ C) = 760 torr
= 1.03323 kgf /cm2 = 10.3323 m c.a.
1 mm Hg = 0.1333 kP a
1 W/m2 ·◦ C = 0.17612 Btu/h · f t2 ·◦ F
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 lbm
1 lbm = 0.45359237 kg
1 onza = 28.3495 g
1 slug = 32.174 lbm = 14.5939 kg
1 ton corta = 2000 lbm = 907.1847 kg
1 kW = 3412.14 Btu/h
= 737.56 lbf · f t/s
1 hp = 550 lbf · f t/s = 0.7068 Btu/s
= 42.41 Btu/min = 2544.5 Btu/h
= 0.74570 kW
1 hp caldera = 33, 475 Btu/h
1 Btu/h = 1.055056 kJ/h
1 ton de ref rigeracion = 200 Btu/min
1 P a = 1.4504x10−4 psia
= 0.020886 lbf /f t2
1 psi = 144 lbf /f t2 = 6.894757 kP a
1 atm = 14.696 psia = 29.92 in Hg (30◦ F )
1 in Hg = 3.387 kP a
DIMENSION
Calor especíco
METRICO
Volumen especíco
1 m3 /kg = 1000 L/kg = 1000 cm3 /g
Temperatura
T (K) = T (◦ C) + 273.15
∆T (K) = ∆T (◦ C)
1 kJ/kg ·◦ C = 1 kJ/kg · K
Conductividad
térmica
Velocidad
1 W/m ·◦ C = 1 W/m · K
1 m/s = 3.60 km/h
Volumen
1 m3 = 1000 L = 106 cm3
Flujo
volumétrico
1 m3 /s = 60, 000 L/min = 106 cm3 /s
Viscosidad
1 P oise(P ) = 1 g/cm · s = 0.1 kg/m · s
1 P a · s = 1 kg/m · s
METRICO/INGLES
1 Btu/lbm ·◦ F = 4.168 kJ/kg ·◦ C
1 Btu/lbmol · R = 4.1868 kJ/kmol · K
1 kJ/kg ·◦ C = 0.23885 Btu/lbm · F
= 0.23885 Btu/lbm · R
1 m3 /kg = 16.02 f t3 /lbm
1 f t3 /lbm = 0.062428 m3 /kg
T (R) = T (◦ F ) + 459.67 = 1.8T (K)
T (◦ F ) = 1.8 T (◦ C) + 32
∆T (◦ F ) = ∆T (R) = 1.8 ∆T (K)
1 W/m ·◦ C = 0.57782 Btu/h · f t ·◦ F
1 m/s = 3.2808 f t/s = 2.237 mi/h
1 mi/h = 1.46667 f t/s
1 mi/h = 1.6093 km/h
1 m3 = 6.1024x104 in3 = 35.315 f t3
= 264.17 gal(U S)
1 U S galon = 231 in3 = 3.7854 L
1 f l onza = 29.5735 cm3 = 0.0295735 L
1 U S galon = 120 f l onzas
1 m3 /s = 15, 850 gal/min (gpm) = 35.315 f t3 /s
= 2118.9 f t3 /min (cf m)
1 slug/f t · s = 47.88 kg/m · s
1 lbm/f t · s = 0.031081 lbf · s/f t2
Constantes físicas
Constante universal de los gases
Aceleración de la gravedad estándar
Presión atmosférica estándar
Constante de Stefan-Boltzmann
Constante de Boltzmann
Velocidad de la luz en el vacío
Velocidad del sonido en aire seco (0o C y 1 atm)
Calor de fusión del agua (1 atm)
Entalpía de vaporización del agua (1 atm)
Ru = 8.31447 kJ/kmol · K
= 8.31447 kP a · m3 /kmol · K
= 0.0831447 bar · m3 /kmol · K
= 82.05 L · atm/kmol · K
= 1.9858 Btu/lbmol · R
= 1545.37 f t · lbf /lbmol · R
= 10.73 psia · f t3 /lbmol · R
g = 9.80665 m/s2
= 32.174 f t/s2
1 atm = 101.325 kP a
= 1.01325 bar
= 14.696 psia
= 760 mm Hg (0◦ C)
= 29.9213 in Hg (32◦ F )
= 10.3323 m H2 O (4◦ C)
σ = 5.6704x10−8 W/m2 · K 4
= 0.1714x10−8 Btu/h · f t2 · R4
k = 1.380650x10−23 J/K
co = 2.9979x108 m/s
= 9.836x108 f t/s
c = 331.6 m/s
= 1089 f t/s
hif = 333.7 kJ/kg
= 143.5 Btu/lbm
hf g = 2256.5 kJ/kg
= 970.12 Btu/lbm