计入剪切速率与含气率的润滑油黏温特性研究

Study on Viscosity-Temperature Characteristics of Lubricating Oil Considering Shear Rate and Void Fraction

为探究剪切速率对油液黏温特性的影响,利用TADHR-2旋转式流变仪测试含气与不含气2种状态下润滑油的黏度;采用动态测量法利用倒置荧光显微镜连续拍摄含气油液,运用视觉方法对原始图片进行二值化并计算了油气两相油的含气率。通过Levenberg-Marquardt优化算法对试验数据进行拟合并建立计入剪切速率与含气率的黏温模型。研究表明:润滑油的黏度变化与温度、剪切速率和含气率有关,润滑油黏度的剪切变稀现象随温度的升高而逐渐减弱;低温时,含气油的黏度高于纯油且随含气率的增加而增加;中高温时,含气油的黏度在低剪切速率下高于纯油且随着含气率的增加而增加,而在高剪切速率下低于纯油且随含气率的增加而减小。

To investigate the effect of shear rate on the viscosity temperature characteristics of oil,the viscosity of lubricating oil with and without gas was tested by TADHR-2 rotary rheometer.The gas-containing oil was continuously captured with the inverted fluorescence microscope by using the dynamic measurement method,and the original images were binarized using visual method,and the gas content of oil-gas two-phase oil was calculated.A viscosity-temperature model including shear rate and void fraction was established by fitting the experimental data with Levenberg-Marquardt optimization algorithm.The results show that the viscosity change of lubricating oil is related to temperature,shear rate and void fraction.The shear thinning phenomenon of lubricating oil viscosity gradually weakens with the increase of temperature.At low temperature,the viscosity of gas-containing oil is higher than that of pure oil,and it increases with the increase of gas content.At medium and high temperature,the viscosity of gas-bearing oil is higher than that of pure oil at low shear rate and it increases with the increase of gas content,while it is lower than that of pure oil at high shear rate and it decreases with the increase of gas content.