# Nomenclature

Nomenclature used in mathematical formula in this help file. A Area (m2) Ap Pipe cross sectional area (m2) β Orifice hole/Pipe diameter ratio (-) C1 Orifice plate discharge coefficient (-) Cp Heat capacity at constant pressure (J/kg °C) Cd Drag coefficient on a particle at the terminal settling velocity (-) Cs Coefficient of friction between the bed flow and the pipe wall. Cv Volume fraction concentration of a slurry. This is the concentration that is discharged from the pipe and may be different to the concentration in individual pipe segments (-). Also this term is used to express valve flow coefficient (see Kv) D Diameter or Hydraulic diameter (m) Dh Hydraulic diameter (m) D1/ D2 Pump Impeller diameter ratio. (-) Dc Cyclone body inner diameter (m) Dis Inside shell diameter of a shell and tube exchanger (m) DR Displacement volume per revolution (m3) Dp Packed bed equivalent spherical diameter defined as 6 x Volume of the particle/surface area of the particle (m) d50 For settling slurries, the mass mean particle diameter. (m) d85 For settling slurries, the particle diameter for which 85% of the particles are finer. Percentage is mass percent. (m) ε Void fraction of a packed bed, which is the ratio of the void volume to the total volume (-) fD Darcy friction factor. FluidFlow uses the Darcy friction factor in all calculations and results (-) fF Fanning friction factor used by some formula. Note fD = 4fF (-) fp Friction factor used in a packed bed, defined by the Ergun Equation (-) fTP Two phase friction factor (-) Fr Froude number (-) G Mass Flux. Mass flow per unit area (kg/m2 s) g Acceleration due to gravity (m/s2) Hb Height of a packed bed (m) Hv Heat of Vaporization (J/kg) H1/H2 Pump head ratio (-) η Pump Efficiency (-) K Pressure loss coefficient (-) Kf Pressure loss coefficient expressed in terms of equivalent length in pipe diameters (-) Kv Valve flow coefficient expressed in terms of volumetric flow per unit of pressure loss (e.g. m3h/kPa or usgpm/psi) Ks Nominal K for a sprinkler (m3/s Pa0.5) L Pipe length (m) m Mass flow (kg/s) M Mass fraction of a phase (-) or the exponent to the stratification ratio which accounts for the distribution of particle sizes. N Coriolis Coefficient (-) N1/N2 Pump speed ratio (-) m Dynamic viscosity (Pa/s) Φ Frictional increase in pressure drop due to the presence of solid particles (-) or Friedel correction factor po Stagnation pressure (Pa) p Static pressure (Pa) ΔP Total pressure loss (or gain) (Pa) ΔPs Pressure drop due to friction for the slurry mixture (Pa) ΔPf Pressure drop due to friction of the carrier fluid (Pa) Ph Pump, Fan or Compressor Power (W). ρ Static density (kg/m3) Q Volumetric flowrate (m3/s) Q1/Q2 Pump volumetric flow ratio (-) Rep Packed bed Reynolds Number, Dp Vs ρ / ((1-ε) μ) (-) S Speed (Revolutions per second) Ss Relative density of the solids (-) Sf Relative density of the carrier fluid (-) T0 Stagnation Temperature (°C) T Static Temperature (°C) Tb Boiling point temperature at any given pressure (°C) Tk Thermal conductivity (W/m °C) U Internal specific heat energy (J/kg) v Velocity (m/s) V50 Value of Vm at which 50% of the solids are in suspension (m/s) Vf The actual velocity of the carrier fluid in the vertical section Vm Velocity of a two phase mixture (m/s) Vs Superficial fluid velocity in a packed bed (m/s) VsG Superficial gas velocity (m/s) VsL Superficial liquid velocity (m/s) w Mass flow (kg/s) X Vapor quality (-) z Elevation at any point (m) Subscripts: 1 Refers to properties at the inlet to an element 2 Refers to properties at the outlet to an element L Refers to the liquid phase G Refers to the vapor phase