利用新研制的外筒旋转可调压可视化Couette流变仪,开展了强剪切流的空化试验,发现剪切力矩及瞬态温度对剪切空化的影响非常明显。通过传感器温度阶跃响应试验数据,求得温度传感器在静止液体内受阶跃温度变化时的表面传热系数。采用柱坐标系,基于试验获得的纯剪切力矩和瞬态传热微分方程,由数值计算方法求出不同时刻强剪切Couette流的瞬态温度,理论计算值与试验结果较为吻合,表明新的外筒旋转可调压可视Couette流变仪获得的纯剪切力矩和瞬态温度的准确性,以及间隙的均匀性。利用文献[9]的初步估算方法,也可求出强剪切Couette流的温度变化值。对比分析结果表明,所提方法校核精度高且适用范围广。
By utilizing the newly developed visual Couette rheometer with its outer cylinder rotating and pressure adjustable, cavitation experiments of strong shear flow are carried out. It is found that the influence of transient temperature and shearing torque on shearing cavitation is very obvious. By experimental data of temperature step response of sensor, the convection heat transfer coefficient when the thermocouple is rooted in resting hot liquid and subjected to the step temperature change is obtained. In a cylindrical coordinate system, with the pure shearing torque and transient heat transfer differential equation obtained from the experiment, the transient temperatures of strong shearing Couette flow at different time are calculated by using numerical method. / The theoretical value is consistent with the experimental resuit, thus showing the correctness of pure shearing torque and transient temperature and the uniformity of gap obtained from the said Couette rheometer by using the preliminary estimation method, the temperature change value of strong shearing Couette flow is obtained. The comparison and analysis results show that the proposed method is highly accurate and widely applicable.