Equal to the sound power level/heat release. A value used to characterize the amount of combustion noise emitted from a flame. Defined as the ratio of the acoustical power emitted from the flame to the total heat release of the flame. Approximately equal to 1 X 106 for premixed and turbulent flames and equal to 1 X 109 for diffusion and laminar flames.
Related Terms 
FILTRATION (BETA) RATIO
The ratio of the number of particles greater than a given size in the influent fluid to the number of particles greater than the same size in the effluent fluid.

ADIABATIC EFFICIENCY
The ratio of actual work output of a heat engine to the ideal output.

BETARATIO (ßRATIO)
The ratio of the number of particles greater than a given size in the influent fluid to the number of particles greater than the same size in the effluent fluid, under specified test conditions (see 'MultiPass Test').

BULK MODULUS (OF ELASTICITY)
A ratio of normal stress to a change in volume. A term used in determining the compressibility of a fluid. Data for petroleum products can be found in the International Critical Tables.

AIRFUEL RATIO
The ratio weight, or volume, of air to fuel.

SENSIBLE HEAT FACTOR
The ratio of sensible heat to total heat.

POISE
A measure of viscosity (absolute viscosity) numerically equal to the force required to move a plane surface of one square centimeter per second when the surfaces are separated by a layer of fluid one centimeter in thickness. It is the ratio of the shearing stress to the shear rate of a fluid and is expressed in dyne seconds per square centimeter (DYNE SEC/CM2); 1 centipoise equals .01 poise.

POROSITY
The ratio of pore volume to total volume of a filter medium expressed as a percent.

SLIP RATIO
The ratio between two phase velocities.

THERMAL EFFICIENCY
Ratio of shaft work out of a system to the heat energy into the system.
