A rheometer shear stress feedback control system and method in the unsteady state test stage

Abstract

The invention discloses a rheometer shear stress feedback control system and method in the non-steady state test stage. The invention is based on the premise that the rheological curve of the test sample is smooth and continuous, and the discretization is carried out in the initial torque loading time domain of the rheometer. Determine the mathematical relationship between the measured angular velocity of the rotor and the torque to be applied at the next moment, obtain approximately the angular acceleration of the rotor at the next moment based on the measured rotor speed, and obtain the angular acceleration of the rotor according to the preset shear stress, angular acceleration of the rotor and the rotation of the rheometer The moment of inertia of the component is calculated to obtain the torque value that should be applied at the next moment and used for regulation. The invention ensures that the real shear stress on the surface of the rotor conforms to the preset value, is suitable for the rheological test under the loading of the rheology and time-related fluid control shear stress, and has certain versatility and applicability.

Description

technical field [0001] The invention relates to a rheometer shear stress feedback control system and method in an unsteady test stage. Background technique [0002] Various fluids are involved in various fields such as industry, medical treatment, food, and life. Researching the rheological properties of different materials is an inevitable requirement for in-depth understanding of their fluid properties and their application. Therefore, the accuracy of material rheological measurement will be the key to accurately understanding its rheological properties. With the rapid development of intelligent rheometers, advanced rotational rheometers such as Anton Paar in Austria and HAAKE in Germany are playing an important role in the field of rheological measurement. [0003] For time-independent fluids such as Newtonian fluids and power-law fluids, the rheological data is usually tested after the rheometer rotates stably. For viscoelastic and thixotropic materials such as polymer...

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Problems solved by technology

However, for the test process under the mode of "controlled shear stress", such as "constant shear stress", the rheological test system applies "constant torque" according to formula (1), but due to the unsteady rotation of the rotor, the formula (4 )middle is not 0, which causes the real shear stress on the rotor surface to deviate from the preset value

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