Bulk modulus of compressibility
Bulk modulus of compressibility
(OP)
Well that should be a basic question but for me it needs some clarification .
for the bulk modulus of compressibility : K = - dP / (dV/V)
why does K = 0 for compressible fluids ?? ,,,, I think of it like if we compress gas ie:decrease a certain masses volume (compressible fluid) its pressure will increase . So K would have a value greater than zero .
Can anyone help me figure out why it should be = 0 ??
for the bulk modulus of compressibility : K = - dP / (dV/V)
why does K = 0 for compressible fluids ?? ,,,, I think of it like if we compress gas ie:decrease a certain masses volume (compressible fluid) its pressure will increase . So K would have a value greater than zero .
Can anyone help me figure out why it should be = 0 ??
RE: Bulk modulus of compressibility
RE: Bulk modulus of compressibility
You are right, non-zero but low values as may be seen for air in:
http://en.wikipedia.org/wiki/Bulk_modulus
Another site:
http://www-mdp.eng.cam.ac.uk/web/library/enginfo/a...
RE: Bulk modulus of compressibility
isothermal compressibility coefficient = -(1/V)*dV/dP
or the derivative of volume vs. pressure,
bulk modulus is not 0 for real gases, see below,
for the derivative of volume vs. temperature
volumetric expansivity coefficient = (1/V) dV/dT
for mixture you can calculate these properties for both vapors and liquids
with a EOS or equivalent procedures,
see for example the Excel macros StrGIC, StrLIC, StrGVE, StrLVE in
"http://www.prode.com/en/properties.htm"
another possibility is
"http://www.nist.gov/srd/nist23.cfm"
RE: Bulk modulus of compressibility
you must get smarter than the software you're using.