Page 73 - 48Fundamentals of Compressible Fluid Mechanics

3.7. SOUND SPEED IN TWO PHASE MEDIUM 35
material reference Value [m/sec]
Diamond 12000
Pyrex glass 5640
Steel longitudinal wave 5790
Steel transverse shear 3100
Steel longitudinal wave (extensional 5000
wave)
Iron 5130
Aluminum 5100
Brass 4700
Copper 3560
Gold 3240
Lucite 2680
Lead 1322
Rubber 1600

Table 3.3: Solids speed of sound, after Aldred, John, Manual of Sound Recording, Lon-
don:Fountain Press, 1972

(3.38)

3

(/%'3
Compared to one tabulated value the example values for stainless steel
#
lays between the speed for longitudinal and transverse waves.

3.7 Sound Speed in Two Phase Medium
The gas flow in many industrial situations contains other particles. In actuality,
there could be more than one speed of sound for two phase flow. Indeed there is
double chocking phenomenon in two phase flow. However, for homogeneous and
under certain condition a single velocity can be considered. There can be several
models that approached this problem. For simplicity, it assumed that two materials
are homogeneously mixed. Topic for none homogeneous mixing are beyond the
scope of this book. It further assumed that no heat and mass transfer occurs
between the particles. In that case, three extreme cases suggest themselves:
the flow is mostly gas with drops of the other phase (liquid or solid), about equal
parts of gas and the liquid phase, and liquid with some bubbles. The first case is
analyzed.
The equation of state for the gas can be written as

(3.39)