FLUIDFILE™ Glossary

Properties

Specific Heat – Specific heat (also called specific heat capacity) is the amount of heat required to change a unit mass (or unit quantity) of a substance by one degree in temperature. English Units: Btu/(lb · °F), SI Units: kJ/(kg)(K)

Viscosity – Or Absolute Viscosity of a fluid is the internal resistance to flow. English Units: cps, SI Units: mPa(s)

Kinematic Viscosity – is the ratio of absolute or dynamic viscosity to density - a quantity in which no force is involved. Kinematic viscosity at a given temperature can be obtained by dividing the absolute viscosity of a fluid with its mass density at that temperature.

Thermal Conductivity – Thermal conductivity is a measure of the ability of a material to transfer heat. English Units: Btu/(hr · ft2)(°F/ft), SI Units: W/(m)(K)

Density – Density is a material's ratio of mass to volume. English Units: lb/ft3., SI Units: kg/m3

Vapor Pressure – Vapor pressure is the pressure exerted by a vapor in equilibrium with its solid or liquid phase. English Units: psia, SI Units: Bar Abs

Film Coefficient – Film coefficient is the heat transferred by convection per unit area per degree temperature difference between the surface such as a tube wall and the fluid. English Units: Btu/(hr) (ft2)(°F), SI Units: W/(m2)(K)

Pressure Drop – Pressure drop is the calculated decrease in fluid pressure due to friction for a length of pipe or tube. English Units: psi/100 ft of pipe, SI Units: kPa/100 m of pipe

Reynolds Number – A Reynolds number is a dimensionless number that gives a measure of the ratio of inertial forces to viscous forces and quantifies the relative importance of these two types of forces for given flow conditions.

Prandtl Number – A Prandtl number is a dimensionless number used in the study of diffusion in flowing systems, equal to the kinematic viscosity divided by the molecular diffusivity.