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采用粒子图像测速技术测试多孔介质与流体复合腔体内的二维自然对流流场,用水平错列的细玻璃圆柱表示多孔介质,着重分析了多孔介质与流体空间交界面处的速度及剪切应力变化,并通过实验确定了特定跳跃边界条件下的应力跳跃系数。实验测试结果表明,应力跳跃系数随对流强度的增加而产生非线性变化,不同高度处的跳跃系数值在0.1~0.3范围内变化。通过回归分析得到了测试范围内应力跳跃系数与瑞利数的表达式,为数学建模和分析提供了计算依据。
Particle image velocimetry was used to test the two-dimensional natural convection flow in porous media and fluid composite cavity. Porous media was represented by horizontally misaligned thin glass cylinder, and the velocity and shear stress at the interface between porous media and fluid space were emphatically analyzed Changes, and through experiments to determine the specific jump boundary conditions of stress jump coefficient. The experimental results show that the coefficient of jump in stress produces a nonlinear change with the increase of convection intensity, and the jumping coefficient at different heights changes in the range of 0.1-0.3. The expressions of stress jump coefficient and Rayleigh number in the test range are obtained by regression analysis, which provides the basis for mathematical modeling and analysis.