Mass flow rate
Encyclopedia
Mass flow rate is the mass
of substance which passes through a given surface per unit time
. Its unit is mass divided by time
, so kilogram
per second
in SI
units, and slug per second or pound
per second in US customary units. It is usually represented by the symbol
.
Mass flow rate can be calculated from the density
of the substance, the cross sectional area through which the substance is flowing, and its velocity
relative to the area of interest.
where:
is the mass flow rate
This is equivalent to multiplying the volumetric flow rate
by the density.
where:
The symbol for mass flow rate in Newton's notation for a derivative
is as follows:
Mass
Mass can be defined as a quantitive measure of the resistance an object has to change in its velocity.In physics, mass commonly refers to any of the following three properties of matter, which have been shown experimentally to be equivalent:...
of substance which passes through a given surface per unit time
Time
Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....
. Its unit is mass divided by time
Time
Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects....
, so kilogram
Kilogram
The kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...
per second
Second
The second is a unit of measurement of time, and is the International System of Units base unit of time. It may be measured using a clock....
in SI
Si
Si, si, or SI may refer to :- Measurement, mathematics and science :* International System of Units , the modern international standard version of the metric system...
units, and slug per second or pound
Pound (mass)
The pound or pound-mass is a unit of mass used in the Imperial, United States customary and other systems of measurement...
per second in US customary units. It is usually represented by the symbol
.Mass flow rate can be calculated from the density
Density
The mass density or density of a material is defined as its mass per unit volume. The symbol most often used for density is ρ . In some cases , density is also defined as its weight per unit volume; although, this quantity is more properly called specific weight...
of the substance, the cross sectional area through which the substance is flowing, and its velocity
Velocity
In physics, velocity is speed in a given direction. Speed describes only how fast an object is moving, whereas velocity gives both the speed and direction of the object's motion. To have a constant velocity, an object must have a constant speed and motion in a constant direction. Constant ...
relative to the area of interest.
where:
is the mass flow rate
- ρ is the density
- v is the velocity
- A is the flow area
This is equivalent to multiplying the volumetric flow rate
Volumetric flow rate
The volumetric flow rate in fluid dynamics and hydrometry, is the volume of fluid which passes through a given surface per unit time...
by the density.
where:
- ρ is the density
- Q is the volumetric flow rate
The symbol for mass flow rate in Newton's notation for a derivative
Derivative
In calculus, a branch of mathematics, the derivative is a measure of how a function changes as its input changes. Loosely speaking, a derivative can be thought of as how much one quantity is changing in response to changes in some other quantity; for example, the derivative of the position of a...
is as follows:
See also
- Continuity equationContinuity equationA continuity equation in physics is a differential equation that describes the transport of a conserved quantity. Since mass, energy, momentum, electric charge and other natural quantities are conserved under their respective appropriate conditions, a variety of physical phenomena may be described...
- Fluid dynamicsFluid dynamicsIn physics, fluid dynamics is a sub-discipline of fluid mechanics that deals with fluid flow—the natural science of fluids in motion. It has several subdisciplines itself, including aerodynamics and hydrodynamics...
- Mass flow controllerMass Flow ControllerA mass flow controller is a device used to measure and control the flow of fluids and gases. A mass flow controller is designed and calibrated to control a specific type of fluid or gas at a particular range of flow rates...
- Mass flow meterMass flow meterA mass flow meter, also known as an inertial flow meter is a device that measures mass flow rate of a fluid traveling through a tube. The mass flow rate is the mass of the fluid traveling past a fixed point per unit time....
- Mass fluxMass fluxMass flux is the rate of mass flow across a unit area .-See also:*Flux*Fick's law*Darcy's law...
- Orifice plateOrifice plateAn orifice plate is a device used for measuring the volumetric flow rate. It uses the same principle as a Venturi nozzle, namely Bernoulli's principle which states that there is a relationship between the pressure of the fluid and the velocity of the fluid...
- Thermal mass flow meterThermal mass flow meter-Introduction:There are two types of thermal flow meters in industry. Industrial thermal mass flow meters, also known as thermal dispersion or immersible mass flow meters comprise a family of instruments for the measurement of the total mass flow rate of a fluid, primarily gases, flowing through...
- Volumetric flow rateVolumetric flow rateThe volumetric flow rate in fluid dynamics and hydrometry, is the volume of fluid which passes through a given surface per unit time...