Matrix viscosity model

The matrix viscosity model is used to determine the viscosity from measured data supplied at specific temperatures, shear rates, and pressures.

To be able to use the matrix viscosity model, the raw data that you enter must comply with the following rules:

• The data must be entered in the following columns:

  • Temperature (deg C)
  • Shear rate (1/s)
  • Pressure (MPa)
  • Viscosity (Pa.s)
• The data points should be listed in order of increasing temperature.
• Group the data points into "blocks" of the same temperature.
• Each temperature should have the same number of data points associated with it; the "blocks" should be of equal size.
• Within each temperature "block", the data points must be arranged in order of increasing shear rate.
• The same set of shear rates should be used in each "block".
• If the data is pressure dependent, all of the temperature "blocks" should repeat for each pressure.
• If the data is independent of pressure, the pressure column should contain zeroes.
• There should be no redundant entries (two data points with the same temperature and shear rate).

Important: If the raw viscosity data does not comply with all the above requirements for matrix viscosity data, then the matrix model cannot be used for analysis. Instead, you should select another viscosity model based on this data and then use that viscosity model for analysis.

Viscosity interpolation (between data points) and extrapolation (outside the data point range) is done on log(viscosity) versus pressure, temperature, and log(shear rate).

Note: An example is given in the table below:

Table 1. Example of matrix viscosity data

Temperature	Shear Rate	Pressure	Viscosity
200	10	0	1588.14976
200	100	0	499.72072
200	1000	0	104.84577
200	10000	0	19.62513
250	10	0	893.17063
250	100	0	354.65616
250	1000	0	82.22354
250	10000	0	15.74756
300	10	0	561.25237
300	100	0	265.61970
300	1000	0	68.20139
300	10000	0	13.41388
200	10	100	2133.99428
200	100	100	596.17034
200	1000	100	120.19162
200	10000	100	22.30935
250	10	100	1198.26646
250	100	100	422.93819
250	1000	100	92.83596
250	10000	100	17.55214
300	10	100	741.10595
300	100	100	316.38216
300	1000	100	76.24789
300	10000	100	14.74524