转筒黏度计测量液体黏度方法研究

Research on the method for measuring viscosity coefficient by rotating cylinder viscometer

用黏性流体力学理论求得测量装置中旋转液体径向速度梯度的理论公式,进而得到转筒法测量黏度的较精确公式.指出了国内的一些教材和文献在推导中使用近似公式的错误,用参数估计的方法求得测量装置的摩擦阻力力矩,使测量结果得到进一步校正.实验研究表明:按照近似公式与精确公式计算求得的径向速度梯度之差可达到13.1%,求得的液体黏度之差可达到28.6%;在蓖麻油的温度为25.5℃时测得测量装置的摩擦阻力力矩为9.482×10-5 N·m,相当于0.540克重物产生的力矩.

Based on the theory of viscous fluid mechanics, the formula regarding the radial velocity gradient of rotating liquids in the measuring device is obtained, and the more accurately calculation formula of viscosity coeffi- cient for rotating cylinder viseometer is further worked out, the errors of approximate formula used in the derivation in textbooks and documents nationwide are put forward, and the torque of frictional drag in the measuring device is calculated by using the parameter estimation method, which makes the measuring results calibrated be accurately. The experimental results show that the difference of the radial velocity gradient and the liquid viscous coefficient calculated by the approximate and exact formula are 13.1% and 28.6% , respectively; the torque of frictional drag in the measuring device is 9. 482×10-5N · m when temperature of the castor oil is 25.5 ℃ , which is equivalent to the torque caused by 0. 540 grams of weight.