流体在内外管同时旋转的偏心环空中螺旋流的稳定性参数

Stability parameter of Newton helical flow in eccentric annuli with the inner and outer cylinders rotating simultaneously

利用Newton流体在内外管同时旋转的偏心环空中螺旋流的流函数和轴向速度函数,推导出该流动条件下的稳定性参数H的解析表达式;并以水为例,绘制了稳定性参数H的分布曲线,分析了环空偏心距、环空内外管转速对稳定性参数H分布的影响.结果表明:稳定性参数H的峰值随偏心距增大而增大,同时峰值出现的区域由内管附近流动区逐渐向外管附近流动区移动;随外管正向转速的增大,峰值由外管附近流动区移向内管附近流动区;在外管正向转速较小时,内管的转速对稳定性参数H的分布影响较大,稳定性参数H的峰值随着内管转速的增大而增大,并由外管附近流动区移向内管附近流动区;内管转速较小的情况下,外管的旋转方向对稳定性参数H的分布影响不大,对峰值的影响也很小.

The expression of stability parameter H is developed based on the stream function and axial velocity function of Newton helical flow in eccentric annuli with the inner and outer cylinders rotating simultaneously in this paper. The value of H is calculated and its distribution curves are plotted taking water for example, and the effects of eccentric distance, the rotational velocities of the inner and outer cylinders are analyzed. The results indicate that the greater the eccentric distance is, the bigger the maximum value of H will be; and the maximum point of H moves from the neighborhood of the inner cylinder to the outer one with the increasing of eccentric distance, and moves from the neighborhood of the outer cylinder to the inner one with the increasing of the positive rotational velocity of the outer cylinder; the rotational velocity of the inner cylinder affects the distribution of H greatly when the rotational velocity of outer one is in a positive and small condition, and the maximum point of H moves from the neighborhood of the outer cylinder to the inner one; while the direction of the outer cylinder affects the distribution and the maximum of H inconspicuously when the rotational velocity of the inner one is in a small condition.