可调压可视化微间隙Couette流变仪的研究及应用

采用精密的机械加工和独特的气动旋转密封技术，研制出可调压可视化微间隙Couette流变仪。外圆筒旋转内圆筒静止的特点，使该流变仪能产生剪切速率高达105/s数量级稳定的纯剪切流。利用商业旋转流变仪，测量试验用中、低粘度硅油在低剪切速率和不同温度下的粘度，应用粘温关系，推算出高剪切速率下粘性热使粘度下降的量，其值与微间隙Couette流变仪的测量结果较为吻合。在一定的切应力下，观察到淡水和中低粘度硅油在微间隙中发生剪切空化的现象，发现剪切空化的发生还强烈依赖于流体中气体的相对溶解量。

RESEARCH AND APPLICATION OF FILM GAP COUETTE RHEOMETER WITH FLOW VISUALIZATION AND PRESSURE CONTROL

A Couette rheometer with flow visualization and pressure control is made boy using the techniques of high-precision machining and dynamic sealing.With the rotat-ing outer cylinder and static inner cylinder,the rheometer can realize stable and uniform simple shear flow of the shear rate up to 105/s.Utilizing the well-known viscosity-temperature formula,the viscosities of water and silicone oils at high shear rates measured by this rheometer agree well with that obtained by the commercial rotational rheometer at low shear rates and various temperatures.At a certain shear stress,cavitation oc-curred for fresh water and two silicone oils with low and me-dium viscosities.Strong dependence of the onset of shear cavi-tation on the amount of dissolved gas is observed.