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alec
How does pressure affect density of fluid? View All

10 years ago - 9 months left to answer. - 6 responses - Report Abuse
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hamza
Pressure and density are directly proportional (all other factors constant) for a gas.

10 years ago

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redhandedhaze
Fluid is a constant under any pressure, unlike gas

10 years ago

Source: Basic highschool physics course

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Hendri Ong
if the fluid is saturated steam, the density (kg/m3) is higher by given higher pressure while the specific steam volume (m3/kg) is lower.
if the fluid is cold water, the same temperature, no change in density.
if the fluid is hot water, saturated, the density is higher by given higher pressure.

10 years ago

Source: saturated steam table

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ehyor
fluid can either be gas or liquid. the density of a fluid is inversely proportional to its pressure hence, as pressure is increased, a decrease in density is observed, mass etc. being kept constant.

10 years ago

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swazy
the higher the pressure the less the molecules will be able to move around thus it will be denser the lower the pressure the molecules can move around easier thus it will be less dense until it reaches the vapor point and turns to gas temperature also plays a factor

10 years ago

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David Livingstone
Gases: If the fluid is a gas (and if the temperature remains constant), pressure is inversely proportional to volume for a given mass of gas, ie PV = C where C is a constant.

As volume is the reciprocal of density, P/d = C where d is density.

Liquids: For most purposes liquids are incompressible so density does not change with pressure but at very high pressures density will increase. To calculate this you will need the bulk modulus of the liquid. You can find the bulk modulus of various liquids in Kaye and Laby, Tables of Physical and Chemical Constants [Longmans].

p = -K(dv/v) where K is the bulk modulus.

Example: for water at 15C, K = 2.75/GPa
for a pressure, p = 0.1GPa [ie 1000 atmosphere], dv/v = -0.1 x 2.75
ie dv/v = -0.275 so the original volume, v, is reduced to (1-0.275)v, ie 0.725v.
the density has therefore increased by a factor of 1/.725, ie 1.379

hope this helps.

10 years ago

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