BROOKFIELD DV-II+ PROGRAMMABLE VISCOMETER Operating ...

The second consideration involves the mechanics of fluid flow. All rheological measurements of fluidflow properties should be made under laminar flow conditions. Laminar flow is flow wherein all particlemovement is in layers directed by the shearing force. For rotational systems, this means all fluidmovement must be circumferential. When the inertial forces on the fluid become too great, the fluid canbreak into turbulent flow wherein the movement of fluid particles becomes random and the flow can notbe analyzed with standard math models. This turbulence creates a falsely high Viscometer reading withthe degree of non-linear increase in reading being directly related to the degree of turbulence in the fluid.For the following geometries, we have found that an approximate transition point to turbulent flowoccurs:1) No. 1 LV Spindle: 15 cP at 60 RPM2) No. 1 RV Spindle: 100 cP at 50 RPM3) UL Adapter: 0.85 cP at 60 RPMTurbulent conditions will exist in these situations whenever the RPM/cP ratio exceeds the values listedabove.Brookfield Engineering Labs., Inc. Page 48 Manual No. M/97-164-F1102