Page 54 - Fluid Power Engineering
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Hydraulic Oils and Theor etical Backgr ound 31
FIGURE 2.15 Effect of the pressure on the bulk modulus of a typical
mineral-based hydraulic oil at constant temperature.
FIGURE 2.16 Effect of the temperature on the bulk modulus of a typical
mineral-based hydraulic oil at constant pressure.
pressure and temperature on the bulk modulus of typical mineral-
based industrial hydraulic oil. The bulk modulus increases with the
pressure increase and decreases with the temperature increase. The
increase of oil pressure from zero to 300 bar increases the bulk modu-
lus by about 21%, while the temperature increase by 40°C decreases
the bulk modulus by 25%. However, the bulk modulus is usually
assumed constant when working at the ordinary range of pressures
and temperatures.
