573 Appendix C Units Conversions © 2006 by Taylor & Francis Group, LLC 574 Modeling of Combustion Systems: A Practical Approach TABLE C.1 Common Conversions TEMPERATURE CONVERSIONS °C = 5/9 (°F – 32) °F = 9/5°C + 32 K = °C + 273.15 °R = °F + 459.67 From: Baukal, C.E., Heat Transfer in Industrial Combustion, CRC Press, Boca Raton, FL, 2000. 1 Btu = 252.0 cal 1 in. = 2.540 cm 1055 J 25.40 mm 1 Btu/ft 3 = 0.00890 cal/cm 3 1 J = 0.000948 Btu 0.0373 MJ/m 3 0.239 cal 1 Btu/hr = 0.0003931 hp 1 W/sec 0.2520 kcal/hr 1 kcal = 3.968 Btu 0.2931 W 1000 cal 1,000,000 Btu/hr = 0.293 MW 4187 J 1 Btu/hr-ft 2 = 0.003153 kW/m 2 1 kcal/hr = 3.968 Btu/hr 1 Btu/hr-ft-°F = 1.730 W/m-K 1.162 J/sec 1 Btu/hr-ft 2 -°F = 5.67 W/m 2 -K 1 kcal/m 3 = 0.1124 Btu/ft 3 1 Btu/lb = 0.5556 cal/g 4187 J/m 3 2326 J/kg 1 kg = 2.205 lb 1 Btu/lb-°F = 1 cal/g-°C 1 kg/hr-m = 0.00278 g/sec-cm 4187 J/kg-K 0.672 lb/hr-ft 1 cal = 0.003968 Btu 1 kg/m 3 = 0.06243 lb/ft 3 4.187 J 1 kW = 3413 Btu/hr 1 cal/cm 2 -sec = 3.687 Btu/ft 2 -sec 1.341 hp 41.87 kW/m 2 660.6 kcal/hr 1 cal/cm-sec-°C = 241.9 Btu/ft-hr-°F 1 kW/m 2 = 317.2 Btu/hr-ft 2 418.7 W/m-K 1 kW/m 2 -°C = 176.2 Btu/hr-ft 2 -°F 1 cal/g = 1.80 Btu/lb 1 lb = 0.4536 kg 4187 J/kg 1 lb/ft 3 = 0.0160 g/cm 3 1 cal/g-°C = 1 Btu/lb-°F 16.02 kg/m 3 4187 J/kg-K 1 lbm/hr-ft = 0.413 centipoise 1 centipoise = 2.421 lbm/hr-ft 1 m = 3.281 ft 1 cm 2 /sec = 100 centistokes 1 mm = 0.03937 in. 3.874 ft 2 /hr 1 m 2 /sec = 10.76 ft 2 /sec 1 ft = 0.3048 m 1 mton = 1000 kg 1 ft 2 /sec = 0.0929 m 2 /sec 2205 lb 1 g/cm 3 = 1000 kg/m 3 1 MW = 3,413,000 Btu/hr 62.43 lb/ft 3 1000 kW 0.03613 lb/in. 3 1 therm = 100,000 Btu 1 hp = 33,000 ft-lb/min 1 W = 1 J/sec 550 ft-lb/sec 1 W/m-K = 0.5778 Btu/ft-hr-°F 641.4 kcal/hr 745.7 W © 2006 by Taylor & Francis Group, LLC Units Conversions 575 TABLE C.2 Unit Dimensions for Some Combustion-Related Quantities Generic Name Examples Exponents Moles Mass Length Time Temperature [N] [M] [L] [θθ θθ ] [T] Acceleration ft/sec 2 m/sec 2 1–2 Area ft 2 m 2 2 Concentration, mass lbm/ft 3 kg/m 3 1–3 Concentration, molar lbmol/ft 3 kgmol/m 3 1–3 Density lbm/ft 3 kg/m 3 1–3 Diameter ft m 1 Energy Btu kJ 1 2 –2 Energy, kinetic lbm ft 2 /sec 2 kg m 2 /sec 2 1 2 –2 Energy, potential lbm ft 2 /sec 2 kg m 2 /sec 2 1 2 –2 Enthalpy, molar Btu/lbmol W/kgmol –1 1 2 –2 Enthalpy, specific Btu/lbm W/kg 2 –2 Enthalpy, volumetric Btu/ft 3 kJ/m 3 1–1–2 Entropy, molar Btu/lbmol °R J/mol K –1 1 2 –2 –1 Flow rate, molar lbmol/h kgmol/h 1 –1 Flow rate, specific lbm/h kg/h 1 –1 Flow rate, volumetric ft 3 /h m 3 /sec 3 –1 Force lbf N 1 1 –2 Free energy, molar Btu/lbmol W/kgmol –1 1 2 –2 Gas constant, universal psia ft 3 /lbmol °R m 3 kPa/kgmol K –1 1 2 –2 –1 Heat Btu/h W 1 2 –3 Heat capacity, molar Btu/lbmol °F J/mol K –1 1 2 –2 –1 Heat capacity, specific Btu/lbm °F kJ/kg K 2 –2 –1 Heat flux Btu/ft 2 W/m 2 1–2 Heat transfer coefficient Btu/h ft 2 °F W/m 2 K 1 –3 –1 Heating value, molar Btu/lbmol J/mol 1 2 –2 Heating value, specific Btu/lbm kJ/kg 2 –2 © 2006 by Taylor & Francis Group, LLC 576 Modeling of Combustion Systems: A Practical Approach TABLE C.2 (continued) Unit Dimensions for Some Combustion-Related Quantities Generic Name Examples Exponents Moles Mass Length Time Temperature [N] [M] [L] [θθ θθ ] [T] Heating value, volumetric Btu/ft 3 kJ/m 3 1–1–2 Kinematic viscosity ft 2 /h m 2 /sec 2 –1 Mass diffusivity ft 2 /h m 2 /sec 2 –1 Mass flux lbm ft 2 kg m 2 1–2 Mass velocity lbm/ft 2 sec kg/m 2 sec 1 –2 –1 Molar density lbmol/ft 3 kgmol/m 3 1–3 Molar velocity lbmol/ft 2 sec kgmol/m 2 sec 1 –2 –1 Molar volume ft 3 /lbmol m 3 /kgmol –1 3 Molecular weight lbm/lbmol kg/kgmol –1 1 Momentum lbm ft/sec kg m/sec 1 1 –1 Momentum, rate of lbm ft/sec 2 kg m/sec 2 1 1 –2 Power Btu/h W 1 2 –3 Pressure lbf/in 2 kPa 1 –1 –2 PV work lbf ft 3 /in 2 kPa m 3 1 2 –2 Rate of reaction per volume lbm/ft 3 h kg/m 3 h 1 –3 –1 Specific volume ft 3 /lbm m 3 /kg –1 3 Stefan–Boltzman constant Btu/h ft 2 °R 4 W/m 2 K 4 1–3–4 Thermal conductivity Btu/h ft °F W/m K 1 1 –3 –1 Thermal diffusivity ft 2 /h m 2 /sec 2 –1 Torque ft lbf N m 1 2 –2 Velocity ft/sec m/sec 1 –1 Viscosity lbm/ft sec kg/m sec 1 –1 –1 Work Btu/h W 1 2 –3 © 2006 by Taylor & Francis Group, LLC . 3 –1 Heating value, molar Btu/lbmol J/mol 1 2 –2 Heating value, specific Btu/lbm kJ/kg 2 –2 © 2006 by Taylor & Francis Group, LLC 576 Modeling of Combustion Systems: A Practical Approach TABLE. 5 73 Appendix C Units Conversions © 2006 by Taylor & Francis Group, LLC 574 Modeling of Combustion Systems: A Practical Approach TABLE C.1 Common Conversions TEMPERATURE CONVERSIONS °C. Temperature [N] [M] [L] [θθ θθ ] [T] Acceleration ft/sec 2 m/sec 2 1–2 Area ft 2 m 2 2 Concentration, mass lbm/ft 3 kg/m 3 1 3 Concentration, molar lbmol/ft 3 kgmol/m 3 1 3 Density lbm/ft 3 kg/m 3 1–3