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preface to fifteenth edition

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5.138 SECTION 5<br />

TABLE 5.21<br />

Aqueous Glycerol Solutions<br />

% Weight<br />

glycerol<br />

Grams<br />

per liter<br />

Relative<br />

density<br />

25/25C<br />

Viscosity, mN · s · m 2<br />

20C 25C 30C<br />

100 1261 1.262 01 1 495 942 622<br />

99 1246 1.259 45 1 194 772 509<br />

98 1231 1.256 85 971 627 423<br />

97 1216 1.254 25 802 521 353<br />

96 1201 1.251 65 659 434 296<br />

95 1186 1.249 10 543.5 365 248<br />

80 966.8 1.209 25 61.8 45.72 34.81<br />

50 563.2 1.127 20 6.032 5.024 4.233<br />

25 265.0 1.061 15 2.089 1.805 1.586<br />

10 102.2 1.023 70 1.307 1.149 1.021<br />

Kinematic viscosity v is the ratio ofthe dynamic viscosity <strong>to</strong> the density ofa fluid. The SI unit<br />

is meter squared per second<br />

2 1<br />

The c.g.s. units are called s<strong>to</strong>kes<br />

2 <br />

[m · s ]. [cm · s 1]; poises <br />

s<strong>to</strong>kes density.<br />

Fluidity is the reciprocal ofthe dynamic viscosity.<br />

The primary reference liquid for viscosity measurements is water. The absolute viscosity of water<br />

at 20C is 1.0019 (0.0003) mN · s · m 2 (or centipoise), as determined by Swindells, Coe, and<br />

Godfrey, J. Research Natl. Bur. Standards 48:1 (1952). The relative viscosity ofwater, / 20,<br />

is<br />

0.8885 at 25C, 0.7960 at 30C, and 0.6518 at 40C. Values at temperatures between 15 and 60C<br />

are best represented by Cragoe’s equation:<br />

1.2348(20 t) 0.001 467(t 20)<br />

log <br />

2<br />

20<br />

t 96<br />

The Reynolds number for flow in a tube is defined by dv/, where d is the diameter ofthe tube,<br />

v is the average velocity ofthe fluid along the tube, is the density ofthe fluid, and is its dynamic<br />

viscosity. At flow velocities corresponding with values ofthe Reynolds number ofgreater than 2000,<br />

turbulence is encountered.<br />

TABLE 5.22<br />

Aqueous Sucrose Solutions<br />

% Weight<br />

sucrose<br />

Grams<br />

per liter<br />

Relative<br />

density<br />

20/4C<br />

Viscosity, mN · s · m 2<br />

15C 20C 25C<br />

75 1034 1.379 0 4 039 2 328 1 405<br />

70 943.0 1.347 2 746.9 481.6 321.6<br />

65 855.6 1.316 3 211.3 147.2 105.4<br />

60 771.9 1.286 5 79.49 58.49 40.03<br />

50 614.8 1.299 6 19.53 15.43 12.40<br />

40 470.6 1.176 4 7.463 6.167 5.164<br />

30 338.1 1.127 0 3.757 3.187 2.735

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