ضرایب تبدیل( CONVERSION FACTORS)

CONVERSION FACTORS FOR   

SOME COMMON UNITS

 ضرایب تبدیل 


 

Length

1 in                  =          25.4 mm                     

1 ft                   =          0.304 8 m

1 yd                 =          0.914 4 m                   

1 mile               =          1.609 3 km

1 Å (angstrom)=          10-10m                         

 

Time

1 min               =          60 s                             

1 h                   =          3.6 ks

1 day                =          86.4 ks                        

1 year               =          31.5 Ms

 

Area

1 in2                 =          645.16 mm2                

1 ft2                  =          0.092 903 m2

1 yd2                =          0.836 13 m2                

1 acre               =          4046.9 m2

1 mile2              =          2.590 km2                   

 

Volume

1 in3                 =          16.387 cm3                       

1 ft3                  =          0.028 32 m3

1 yd3                =          0.764 53 m3                

1 UK gal           =          4546.1 cm3

1 US gal           =          3785.4 cm3

 

Mass

1 oz                  =          28.352 g                     

1 lb                  =          0.453 592 37 kg

1 cwt                =          50.802 3 kg                

1 ton                =          1016.06 kg

1 metric ton     =          1000 kg

 

Force

1 pdl                =          0.138 26 N                  

1 lbf                 =          4.448 2 N

1 kgf                =          9.806 7 N                    

1 tonf               =          9.964 0 kN

1 dyn               =          10-5N

 

Temperature difference

1 deg F (degR) 5/9 deg C (deg K)

 

Power (heat flow)

1 hp (British)    =          745.70 W                    

1 hp (metric)    =          735.50 W

1 erg/s             =          10-7 W                         

1 ft lbf/s           =          1.355 8 W

1 Btu/h             =          0.293 07 W                 

1 ton of refrigeration    3516.9 W

 

Energy (work, heat)

1 ft lbf              =          1.355 8 J                     

1 ft pdl             =          0.042 14 J

1 cal

(int table)         =          4.186 8 J                     

1 erg                =          10-7 J

1 Btu                =          1.055 06 kJ                 

1 hp h              =          2.684 5 MJ

1 kWh              =          3.6 MJ                         

1 therm            =          105.51 MJ

1 thermie         =          4.185 5 MJ

 

Calorific value (volumetric)

1 Btu/ft3           =          37.259 kJ/m3

 

Velocity

1 ft/s                =          0.304 8 m/s                

1 mile/h            =          0.447 04 m/s

 

Volumetric Flow

1 ft3/s               =          0.028 316 m3/s           

1 ft3/h              =          7.865 8 cm3/s

1 UK gal/h        =          1.262 8 cm3/s              

1 US gal/h        =          1.051 5 cm3/s

 

Mass Flow

1 lb/h               =          0.126 00 g/s               

1 ton/h             =          0.282 24 kg/s

 

Mass per unit area

1 lb/in2             =          703.07 kg/m2              

1 lb/ft2              =          4.882 4 kg/m2

1 ton/sq mile    =          392.30 kg/km2

 

Density

1 lb/in3             =          27.680 g/cm3              

1 lb/ft3              =          16.019 kg/m3

1 lb/UK gal       =          99.776 kg/m3              

1 lb/US gal       =          119.83 kg/m3

 

Pressure

1 lbf/in2 (psi)    =          6.894 8 kN/m2             

1 tonf/in2          =          15.444 MN/m2

1 lbf/ft2             =          47.880 N/m2                     

1 standard atm 101.325 kN/m2 (kPa)

1 bar                =          105 N/m2

1 ft water         =          2.989 1 kN/m2             

1 in water         =          249.09 N/m2

1 in Hg             =          3.386 4 kN/m2             

1 mm Hg (1 torr)          133.32 N/m2

 

Moment of inertia

1 lb ft2              =          0.042 140 kg m2

 

Momentum

1 lb ft/s            =          0.138 26 kg m/s

 

Angular momentum

1 lb ft2/s           =          0.042 140 kg m2/s

 

Viscosity, dynamic

1 P (poise)        =          0.1 N s/m2                   

1 lb/ft h            =          0.413 38 mN s/m2

1 lb/ft s            =          1.488 2 N s/m2            

 

Viscosity, kinematic

1 S (stokes)      =          10-4 m2/s                     

1 ft2/h              =          0.258 06 cm2/s

 

Surface energy (surface tension)

1 dyn/cm2 (1 erg/cm)   =   10-3 J/m2

 

Mass flux density

1 lb/h ft2           =          1.356 2 g/s m2

 

Heat flux density

1 Btu/h ft3        =          3.154 6 W/m2             

1 kcal/h m2       =          1.163 W/m2

 

Heat transfer coefficient

1 Btu/h ft2 °F    =          5.678 3 W/m2 K

 

Specific enthalpy (latent heat, etc)

1 Btu/lb            =          2.326 kJ/kg

 

Heat capacity (specific heat)

1 Btu/lb °F       =          4.186 8 kJ/kg K

 

Thermal conductivity

1 Btu/h ft °F     =          1.730 7 W/m K            

1 kcal/h m °C   =          1.163 W/m°K

 

 


 

SOME COMMON PHYSICAL CONSTANTS

 

Avogadro’s number                                          N = 6.023 x 1026 kmol-1

Boltzmann’s constant                                       k = 1.3805 x 10-23 J/K

Planck’s constant                                              h = 6.626 x 10-34 J s

Gravitational acceleration                                  g = 9.807 m/s2

Universal gas constant  R = 8.314 kJ/kmol K = 0.082 l atm/mol K

Stefan-Boltzmann constant                               [ = 5.6697 x 10-8 W/m2 K4

Universal constant of gravitation                       G = 6.67 x 10-11 N m2/kg2

Electronic charge                                              e = 1.602 x 10-19C

Electron volt                                                     eV = 1.602 x 10-19 J

Velocity of light in vacuum                                c = 2.99795 x 108 m/s

Volume of 1 kmol of ideal gas at stp                 = 22.41 m3

S.t.p.                                                                = 1.013 x 105 N/m2 and 273.15 K

 

APPROXIMATE VALUES OF SOME COMMON PROPERTIES

 

Density of water                                               ~ 103 kg/m3

Viscosity of water (18°C)                                  ~ 10-3 N s/m2

Heat capacity of water  ~ 4 kJ/kg K

Thermal conductivity of water                           ~ 0.6 W/m K

Latent heat of boiling water                              ~ 2 MJ/kg

Density of air at s.t.p.                                       ~ 1 kg/m3

Viscosity of air at s.t.p.  ~ 1.7 x 10-5 N s/m2

Heat capacity of air at s.t.p.                              ~ 1 kJ/kg K

Thermal conductivity of air at s.t.p.                   ~ 0.024 W/m K

 

FORMULAE FOR CONVERTING ABSOLUTE TEMPERATURE:

0 ºC = 273 K

0 ºF = 460 ºR

0 ºC = 273 K

0 ºF = 460 ºR

 

 

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