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### Bulk Modulus for Materials Metals and Liquids

Bulk Modulus for Materials Metals and Liquids

A liquid‘s compressibility is measured in terms of its bulk modulus of elasticity. Compressibility is the percentage change in unit volume per unit change in pressure:

The mass flow rate can be determined, since it is related to the differential pressure within the uncertainty limits stated in ISO 5167, using Equation (1):

Eq. 1
C = δv / v / δp

The bulk modulus of elasticity K is its reciprocal:

Eq. 2
K = 1/C

or

K = v · δp / δv

Where:

K = pressure
C
= Coefficient of discharge
v = original volume
δv = change in volume
δp = change in pressure

Bulk Modulus for Selected Solid (Metals)

 Material Bulk Modulus Units (106 psi) Units (1010 Pa) Aluminum, var. alloys 9.9 - 10.2 6.8258 - 7.033 Boron Carbide (B4) 29.0 20 - 24 Brass, 70–30 15.7 1.0825 Brass, cast 16.8 11.583 Carbon (Diamond) 79.77 55 - 64 Cast steel 20.2 13.927 Concrete 0.8702 - 4.06 0.6 - 2.8 Copper 17.9 12.342 Elektron (magnesium alloy) 4.8 3.3095 Iron, cast 8.4 -15.5 5.7916 - Iron, malleable 17.2 10.687 Magnesium alloy 4.8 3.3095 Monel metal 22.5 15.513 Phosphor bronze 16.3 11.238 Silver 13.924 - 15.374 9.6 - 10.6 Solder (Tin-Lead) 4.786 - 8.4122 3.3 - 5.8 Stainless steel 18–8 23.6 16.272 Steel, cast 20.2 13.927 Steel, cold-rolled 23.1 15.927 Steel, all others 22.6 - 24.0 15.582 - 16.547 Tin 6.09 - 8.4 4.2 - 6.0 Tobin bronze 16.3 11.238 Tungsten 44.53 - 15.542 30.7 - 31.4

Data represent typical values, but material properties may vary widely, depending on exact composition, material condition, and processing.

Bulk Modulus for Liquids

English Units
( 10 5 PSI) SI Units
( 10 9 Pa)
Bulk Modulus for Liquids
Units

(105 psi)

Units

(109 Pa)

Acetone 1.34 0.92
Benzene 1.5 1.05
Carbon Tetrachloride 1.91 1.32
Ethyl Alcohol 1.54 1.06
Gasoline 1.9 1.3
Glycerin 6.31 4.35
ISO 32 Mineral Oil 2.6 1.8
Kerosene 1.9 1.3
Mercury 41.4 28.5
Paraffin Oil 2.41 1.66
Petrol 1.55 - 2.16 1.07 - 1.49
Phosphate Ester 4.4 3
SAE 30 Oil 2.2 1.5
Seawater 3.39 2.34
Sulfuric Acid 4.3 3.0
Water 3.12 2.15
Water - Glycol 5 3.4
Water - Oil Emulsion 3.3

2.3

Bulk modulus elasticity may also be expressed in terms of pressure and density:

K = (p1 - p0 ) / [(ρ1 - ρ0 ) / ρ0 ]

Here, ρ0 and (ρ1 are the initial and final density values.

Related:

Reference:

Rules of Thumb for Mechanical Engineers