润滑脂壁滑移管流测试系统的设计

由于壁滑移的影响,在不同管径中测得的流变模型不重合,若求任一管径的流变模型就必须进行对应的实验,不方便工程应用,实质上不论用何种流变装置测得同一润滑脂试样的真实流变模型都应相同,润滑脂为高粘度半固态的非牛顿流体,第一法向应力差、触变性等因素也使得流变模型不相同.设计研制无孔穴误差的低压力波动润滑脂泵、精确测压接头、测试数据自动采集装置等,组成高精度壁滑移管流测试系统,并制定了合理的测试步骤和方法,达到尽量消除壁滑移以外因素的影响,分离壁滑移流动.测试润滑脂在不同管径中的流动,得出壁滑移速度,验证扣除壁滑移后的真实流变模型不随管径变化和壁滑移减阻效果.

The Wall-Slip Testing System of Lubricating Grease in Flowing Pipe

Due to the existence of wall-slip,rheologic models can be inconsistent with each other.So the corresponding experiments should be caried out for the rheologic model of certain tube-diameter,which is discommodious for engineering application.But in fact,by use of any rheologic instrument,the real rheologic models should be the same for one lubricating grease sample.Because of the primary normal stress difference,thixotropy and other factors,the rheologic models are be different.In order to eliminate all the influence factor except wall-slip,a precise testing system of wall-slip and a rational testing method were developed.The system was composed of the low pressure fluctuation pump,the precise pressure testing tie-in,the auto-collection instrument of testing data and so on.The lubricating grease flow in different-diameter pipes was tested,and the wall-slip was educed.The drag reduction function of wall-slip was validated and the real rheologic model without wall-slip don't change with the various tube diameters.