细小直角弯管流道的压力损失及迪恩涡特性

摘要

利用RNG k-ε模型对旋流雾化喷嘴中的直径为2 mm的细小直角弯管流道的流场进行了三维数值模拟,获得了流道内的压力分布和不同截面的迪恩涡结构.结果表明:沿着流动方向,弯曲段流道中内外壁面的压差先增大后减小,内壁面45°截面附近,压力下降到最低,最大下降幅度为74.1%.弯管流道中迪恩涡形成于弯曲段10°截面附近,迪恩涡的旋转中心,从两侧中心位置附近向两侧上端偏移,在65°截面偏移方向发生转折,最后又回到两侧中心位置.迪恩涡的边界和强度先增大后减小,在下游直管段中消失.%The 3D numerical simulation was carried out on the field in a small right-angle bend flow channel of 2 mm diameter in the swirl atomizing nozzle using RNG k-ε model,so as to obtian the pressure distribution and dean vortices structure in different cross sections in the flow channel.The results show that along the flow direction,the pressure difference between the inside and the outside increases first and then decreases in bending section.The pressure drops to the lowest near the 45 ° section of the inside internal wall where the biggest drop is 74.1%.Dean vortices form near 10 ° section of the bending section.And the rotational centers of the dean vortices move from the centers of both side to the above,the migration directions turn at 65 ° section,finally return to the side near the center positions.At the same time the boundary and intensity of the dean vortices first increase then decrease,until disappear in the downstream straight pipe.