Definitions
• Conductivity—W/(m-K) is a thermal transport property of the fluid or solid, relating the heat flux (W/m2) to the temperature gradient according to Fourier's Law
q=– k▽T
• Conjugate Wall—Interface between materials with different thermal properties, such as solid-liquid interfaces and solid-solid interfaces between different solid materials.
• Internal Energy (u)—Thermodynamic specific internal energy (J/kg) of the fluid or solid.
• Enthalpy (h)—Measure of the energy (J/kg) of a thermodynamic system as defined below:
where,
h | enthalpy |
u | internal energy |
P | |
v | specific volume |
• Temperature—Absolute temperature Kelvin (K) in flow analysis or the driving potential for energy transfer as heat in thermodynamic properties.
• Energy Avg T—Average temperature determined by integrating and averaging the energy and then converting to temperature. The energy avg T calculation assumes that the specific heat is constant.
• Flux per Area—Average wattage per area (W/m2) of heat crossing a selected boundary or interface.
• Heat Capacity—(J/(kg-K)) thermal property of the fluid or solid, relating the rate of change of enthalpy with respect to temperature.
• Constant Capacity—Option for computing the relationship between temperature (T) and interfaces (h) based on a constant specific heat.
• Mass Avg. Enthalpy—Average enthalpy in a selected volume based on a mass average, not volume average.
• Total Enthalpy or Stagnation Enthalpy—Related to static enthalpy h as follows:
where,
htotal | total enthalpy (J/kg) |
h | static enthalpy (J/kg) |
V | velocity (m/s) |
• Mass Avg. Tot. Enthalpy—Average total enthalpy in a selected volume based on a mass average, not volume average.
• Mass Avg. Internal Energy—Average internal energy in a selected volume based on a mass average, not volume average.
• Tot. Internal Energy (utotal—Internal energy at stagnation (J/kg) of the fluid or solid.
where,
utotal | total internal energy (J/kg) |
u | internal energy (J/kg) |
V | velocity (m/s) |
• Mass Avg. Tot. Internal Energy—Average total internal energy in a selected volume based on a mass average (as opposed to a volume average).
• Prandtl Number—Ratio of momentum diffusivity (kinematic viscosity) to thermal diffusivity.
• Total Flux—Total wattage (W) of heat crossing a selected boundary or interface.
• Total Temperature or Stagnation Temperature—Related to the static temperature (T) as follows:
Ttotal | total temperature (K) |
T | static temperature (K) |
Cp | specific heat |
V | velocity (m/s) |