一个基于恢复时间的新剪稀模型及其对聚合油PAO 650流变特性的模拟

用球-杆比拟流体层上的分子,通过分析两流体层上球-杆的接触、通过和恢复的过程,基于球-杆恢复到原状态的时间,建立了一个新剪稀模型.该模型虽然在形式上与Carreau模型有相似之处,但其公式仅含有两个流变参数,且是经由严格的理论推导得到的.通过与Carreau模型得到的广义黏度曲线的比较,确定了新流变公式的待定参数.在点接触流变热弹流润滑的数学模型中使用新流变公式,数值模拟了大黏度聚合油PAO 650的流变特性,并与该油在文献中的试验曲线进行了比对.结果表明新流变模型能够较好地模拟大黏度聚合油的流变特性,从而证实了其正确性.进一步,使用新公式计算得到了更多工况下的流变特性曲线,光滑的、合理的曲线分布说明新流变模型具有广泛的适用性.

A New Rheology Model Based on the Time of Recovery and a Simulation of the Rheological Behavior of PAO 650

A new rheology model was established by simulating the liquid molecules with a rod-ball configuration. This model was derived by analyzing the process of the contact, passing and recovery of the rod-balls between two adjacent liquid layers. The new model is somehow similar to the Carreau model, however, it was strictly derived theoretically, and possesses only two rheological parameters, which can be determined by fitting the generalized viscosity curves given by the Carreau model. Moreover, using the new formula to the point contact thermal elastohydrodynamic lubrication problem, the rheological property of the high viscosity polymer PAO 650 was simulated, and a comparison was made with the experimental results published in the literature. Good agreement shows clearly the correctness of the new model, indicating that the new model is able to predict the rheological features of the high viscosity lubricant accurately. Its extensive applicability is further confirmed from the rheology curves under a variety of operating conditions.