Volumetric flow rate


Volumetric flow rate

The volumetric flow rate in fluid dynamics and hydrometry, (also known as volume flow rate or rate of fluid flow) is the volume of fluid which passes through a given surface per unit time (for example cubic meters per second [m3 s-1] in SI units, or cubic feet per second [cu ft/s] ). It is usually represented by the symbol "Q".

Volumetric flow rate should not be confused with volumetric flux, represented by the symbol "q", with units of m3/(m2 s), that is, m s-1. The integration of a flux over an area gives the volumetric flow rate. Volumetric flow rate is also linked to viscosity.

Given an area "A", and a fluid flowing through it with uniform velocity "v" with an angle θ away from the perpendicular to "A", the flow rate is:: Q = A cdot v cdot cos heta.

In the special case where the flow is perpendicular to the area A, that is, θ = 0, the volumetric flow rate is: : Q = A cdot v.

If the velocity of the fluid through the area is non-uniform (or if the area is non-planar) then the rate of fluid flow can be calculated by means of a surface integral:

: Q = iint_{S} mathbf{v} cdot d mathbf{S}

where "d"S is a differential surface described by:: dmathbf{S} = mathbf{n} , dA with n the unit surface normal and "dA" the differential magnitude of the area.

If a surface "S" encloses a volume "V", the divergence theorem states that the rate of fluid flow through the surface is the integral of the divergence of the velocity vector field v on that volume:

:iint_Smathbf{v}cdot dmathbf{S}=iiint_Vleft( ablacdotmathbf{v} ight)dV.

ee also

*Air to cloth ratio
*Darcy's law
*Discharge (hydrology)
*Flowmeter
*Flux (transport definition)
*Mass flow rate
*Orifice plate
*Poiseuille's law
*


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • flow rate —    Volumetric rate of flow [16] …   Lexicon of Cave and Karst Terminology

  • 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… …   Wikipedia

  • Flow measurement — is the quantification of bulk fluid movement. Flow can be measured in a variety of ways. Positive displacement flow meters acumulate a fixed volume of fluid and then count the number of times the volume is filled to measure flow. Other flow… …   Wikipedia

  • Flow — may refer to:In science and technology: *Dataflow, computing term related to the flow of messages between software components *Environmental flow, the amount of water necessary in a watercourse to maintain a healthy ecosystem *Flow (computer… …   Wikipedia

  • Flow chemistry — In flow chemistry, a chemical reaction is run in a continuously flowing stream rather than in batch production. In other words, pumps move fluid into a tube, and where tubes join one another, the fluids contact one another. If these fluids are… …   Wikipedia

  • volumetric flowmeter —    Apparatus designed to measure a volume flow rate [16] …   Lexicon of Cave and Karst Terminology

  • Blood flow — is the continuous running of blood in the cardiovascular system. The human body is made up of several processes all carrying out various functions. We have the gastrointestinal system which aids the digestion and the absorption of food. We also… …   Wikipedia

  • Mass flow meter — A mass flow meter A 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. The… …   Wikipedia

  • Gas flow computer — Originally the gas flow computer was an electronic module that simply provided a dedicated gas flow computer function. Today gas flow computer is a misnomer since the gas flow computer function is a subfunction to an overall data acquisition and… …   Wikipedia

  • Plug flow reactor model — The plug flow reactor (PFR) model is used to describe chemical reactions in continuous, flowing systems. The PFR model is used to predict the behaviour of chemical reactors, so that key reactor variables, such as the dimensions of the reactor,… …   Wikipedia