ASTM D2507-93

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Designation: D 2507 – 93
Standard Terminology of
Rheological Properties of Gelled Rocket Propellants
This standard is issued under the fixed designation D 2507; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope Discussion—The ratio decreases asymptotically with dura-
tion of shear.
1.1 These definitions cover the flow properties of gelled
Class III—Non-Newtonian Shear-Thickening Fluid—a
propellants of interest to the aerospace industry.
fluid in which the shear stress is not directly proportional to
2. Terminology the shear rates, and in which the shear stress-shear rate ratio
increases as the shear stress increases.
2.1 Definitions:
(a) Type A—Dilatant Fluid—a Class III fluid that exhibits
apparent viscosity (of a non-Newtonian fluid)——the viscos-
a shear stress-shear rate ratio that is independent of the duration
ity of a Newtonian fluid that produces the same reading in
of application of shear stress.
the same apparatus under identical conditions.
(b) Type B—Rheopectic Fluid—A Class III fluid that
Discussion—Avoidance of this artificial term is recom-
exhibits time-dependent, reversible changes of the shear stress-
mended.
shear rate ratio.
classification of fluids:
Discussion—The ratio increases asymptotically with dura-
Class I—Newtonian Fluid— a fluid that exhibits a direct
tion of shear.
proportionality between shear stress and shear rate in the
emulsion—a two-phase liquid system in which small droplets
region of laminar flow.
of one liquid (the internal phase) are immiscible in, and are
dispersed uniformly throughout, a second, continuous liquid
DISCUSSION—The shear rate is independent of the time of application
phase (the external phase).
of shear stress.
gel—a liquid containing a colloidal structural network that
Class II—Non-Newtonian Shear-Thinning Fluid—a fluid in
forms a continuous matrix and completely pervades the
which the shear stress is not directly proportional to the shear
liquid phase.
rate and in which the shear stress-shear rate ratio decreases
Discussion—A gel deforms elastically upon application of
as the shear stress increases.
shear forces less than the yield stress. At shear forces above the
(a) Type A—Plastic Fluid—a Class II fluid that exhibits a
yield stress, the flow properties are principally determined by
change in shear rate directly proportional to the change in shear
the gel matrix.
stress above the yield stress.
viscosity—the ratio of shear stress to shear rate. For non-
(b) Type B—Pseudoplastic Fluid—a Class II fluid that
Newtonian fluids, it is prefe
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