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Next: Isentropic Flow Up: Speed of Sound Previous: Speed of Sound in Index
The equation of state for the gas can be written as
The average density can be expressed as
where is the mass ratio of the materials.
For small value of equation (3.40) can be approximated as
where is mass flow rate per gas flow rate.
A approximation of addition droplets of liquid or dust (solid) results in reduction of and yet approximate equation similar to ideal gas was obtained. It must noticed that . If the droplets (or the solid particles) can be assumed to have the same velocity as the gas with no heat transfer or fiction between the particles isentropic relation can be assumed as
Assuming that partial pressure of the particles is constant and applying the second law for the mixture yields
Therefore, the mixture isentropic relationship can be expressed as
Recalling that reduces equation (3.46) into
In a way the definition of was so chosen that effective specific pressure heat and effective specific volumetric heat are and respectively. The correction factors for the specific heat is not linear.
Since the equations are the same as before hence the familiar equation for speed of sound can be applied as
It can be noticed that and are smaller than similar variables in a pure gas. Hence, this analysis results in lower speed of sound compared to pure gas. Generally, the velocity of mixtures with large gas component is smaller of the pure gas. For example, the velocity of sound in slightly wed steam can be about one third of the pure steam speed of sound.
For a mixture of two phases, speed of sound can be expressed as
where is defined as
Next: Isentropic Flow Up: Speed of Sound Previous: Speed of Sound in Index Created by:Genick Bar-Meir, Ph.D.
On: 2007-11-21 include("aboutPottoProject.php"); ?>