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When positive pressure is applied to a standard cubic foot of gas, it is compressed. When a vacuum is applied to a standard cubic foot of gas, it expands. The volume of gas after it is pressurized or rarefied is referred to as its "actual" volume. SCF and ACF for an ideal gas are related in accordance with the combined gas law: [2] [3]
Actual cubic feet per minute (ACFM) is a unit of volumetric flow. It is commonly used by manufacturers of blowers and compressors. [1] This is the actual gas delivery with reference to inlet conditions, whereas cubic foot per minute (CFM) is an unqualified term and should only be used in general and never accepted as a specific definition without explanation.
An actual volume can be converted to a standard volume using the following equation: [6] [7] V s = V a × F p × F t × (F pv) 2. Where, V s: standard volume V a: actual volume (sometimes shown as V r for registered volume) F p: pressure factor (sometimes shown as P m for pressure multiplier)
Flux F through a surface, dS is the differential vector area element, n is the unit normal to the surface. Left: No flux passes in the surface, the maximum amount flows normal to the surface.
Having the same units on both sides of an equation does not ensure that the equation is correct, but having different units on the two sides (when expressed in terms of base units) of an equation implies that the equation is wrong. For example, check the universal gas law equation of PV = nRT, when: the pressure P is in pascals (Pa)
Volumetric flow rate is defined by the limit [3] = ˙ = =, that is, the flow of volume of fluid V through a surface per unit time t.. Since this is only the time derivative of volume, a scalar quantity, the volumetric flow rate is also a scalar quantity.
The definition of Standard Temperature in Europe is most often 0°C (32°F). However, in the United States numerous basis are used. Common Standard Temperetures include: 32°F, 60°F (15.5°C), 68°F (20°C), 70°F (21.1°C), 77°F (25°C) and 95°F (25°C). The definition of Standard Relative Humidity is often 0% or dry for non-air applications.
For example, such a regulation might limit the concentration of NOx to 55 ppmv in a dry combustion exhaust gas corrected to 3 volume percent O 2. As another example, a regulation might limit the concentration of particulate matter to 0.1 grain per standard cubic foot (i.e., scf) of dry exhaust gas corrected to 12 volume percent CO 2.