The Research For The System Of Viscosity Measurement Based On The Rotation Method

Viscosity is one of the important parameters which is used to characterize the fluid properties,the measurement of fluid viscosity plays a major role in identifying fluid quality and determining its use direction.Rotary viscometer is a type of viscosity measurement device which can not only measure dynamic viscosity of Newtonian fluid but also measure the same fluid under different shear rate,so it is also widely used in measuring the apparent viscosity and rheological properties of Non-newtonian fluid,but the torque measuring element of traditional viscometer is difficult to guarantee the accuracy and stability of viscosity measurement results,the separate temperature control heating device increased the complexity of the device and the automation degree is low because of the traditional way of measurement,so based on the rotation method,a new kind of liquid viscosity measurement system is studied in this paper.This system has three improvements in comparison with the traditional rotary viscometer:Firstly,the dynamic torque sensor is adopted as torque measuring element and improved the accuracy and reliability of the device;Secondly,the temperature measurement and control system which is an integration with the outer cylinder is added to this system and satisfied the requirements that measure viscosity at any temperature vary from room temperature to 200? by means of PID adjustment;In addition,the measurement and control program,operation and display interface of torque measurement part,rotary speed measurement part and temperature measurement and control part are designed in this paper,develop a measuring system with greater controllable degree of automation.After the design and construction of the viscosity measurement system,the possible error sources in the process of viscosity measurement are analyzed and the laws of influence on the result of the viscosity detection by the error sources are revealed.Finally,the corresponding error control methodsare proposed,on that basis the calibration of resistance moment and instrument constants is finished,confirmed that system additional torque of 3.01 mN·m and instrument constant of 0.70×103.After the calibration the viscosity of four samples of viscous fluid are measured with the viscosity measurement system which is designed in this paper,the measurement result is compared with that made by traditional capillary viscometer,for four viscous fluid samples,tests show that the measurement error between two measurement methods are relatively small and keep within 10%,prove that the viscosity measurement system studied in this paper has certain feasibility and reliablity.