Brookfield DV-III Rheometer - Manual (Page 65)

Brookfield Engineering Laboratories, Inc. Page 65 Manual No. M/98-211-A0701
The Shear Rate calculation is:
Shear Rate (1/sec)
=
SRC * RPM
where:
SRC = Shear Rate Constant from Table D1
Using Non-standard spindles with DV-III+ and RHEOCALC Software
Spindle Entry 99 allows entry of spindle constants which the DV-III+ will use to calculate Viscosity,
Shear Rate and Shear Stress for spindles in boundary conditions other than the 600ml beaker or
specified chamber.
The spindles must conform to geometries that allow for mathematical calculations of Shear Rate and
Shear Stress i.e. coaxial cylinder.
Two constants are required:
a) SMC (Spindle Multiplier Constant) which is used to calculate cP value.
b) SRC (Shear Rate Constant) which is used to calculate Shear Rate and Shear Stress.
If SRC=0 (Example, LV #1-4, RV,HA,HB #1-7 spindles), Shear Rate and Shear Stress values are
not calculated and can not be displayed.
The SMC value for a spindle may be calculated as follows:
a) For new spindle conditions you calculate the SMC using a Newtonian fluid of known
viscosity (Brookfield Viscosity Standard). This is done in the container with the new
dimensions at the controlled temperature specified for the viscosity standard fluid.
b) The new full scale viscosity range is calculated for a selected RPM:
R1
=
100 n
Y
where:
R1 = The new full scale viscosity range
n = The viscosity (in cP) of the Newtonian fluid
Y = The Torque % reading at the selected RPM
c) The SMC Value is then calculated:
SMC
= [Full Scale Viscosity Range (cP)] * [Selected RPM]
TK * 10,000
where:
TK = DV-III+ Torque Constant from Table D2
The SRC value may be calculated for cylindrical spindle geometry using the following equation:
2
ω
R
c2
R
b2
χ 2 [Rc2 – Rb2]
Shear Rate (1/sec) =