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Bulk Modulus for Materials Metals and Liquids

Engineering Materials

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