理想状况下涡流发生器尾涡特性

采用大涡模拟技术计算了理想工况下54种涡流发生器的水动力特性,以尾涡大小、尾涡间距和尾涡强度作为衡量参数,依次分析了3种流速、3种几何尺寸和6种安装角度时涡流发生器的尾涡特性,并用粒子图像测量方法对计算结果进行了验证.研究结果表明:反向涡与水流方向的夹角远大于同向涡与水流方向的夹角,并且随着涡流发生器与涡旋间距离的增大,各夹角先增大后减小,直至同向涡和逆向涡合并到同一条直线上;随着涡流发生器安装角度绝对值的增大,尾涡大小和强度均线性增大,并且一对涡旋内同向涡和反向涡之间的距离增大,相邻两对涡旋之间的距离逐渐减小;随着流速的增大,尾涡强度显著增大,但各个涡旋之间的距离不变;随着涡流发生器安装边长度的增加,组内同向涡和反向涡之间的距离逐渐增大,但湍动能的分布区域大致相同.

Tail vortex characteristics of vertex generator under ideal condition

The hydrodynamic characteristics of 54 vortex generators under ideal conditions were calcula-ted by using the large eddy simulation(LES)method. The tail vortex size, spacing and strength of vertex generator(VG)under 54 working conditions were analyzed in order of three flow speeds, three geometries and six installing angles. Some of the evaluated hydrodynamics result was validated against the corresponding particle image velocimetry(PIV)experiment. The results show that the con-vortex has a larger angle along the flow-direction than that of the pro-vortex. With the increase of the distance between the vortex generator and vortex, the installing angle firstly increases and then decreases until the con-vortex is consistently coherent with the pro-vortex. It has been also found that as the absolute value of installing angle increases, the size and strength of vortex increases linearly. The distance between con-vortex and pro-vortex in a pair of vortices increases; however, the distance of next two adjacent pairs of vortexes decreases. With the increase of velocity, the vortex strength is enhanced significantly, nevertheless, the distance between successive vortices remains almost constant. The distance between con-vortex and pro-vortex in a pair increases gradually with an increase in the installing length, but the turbulence kinetic energy(TKE)distribution remains almost the same.