旋转对缩扩蜿蜒通道流动及换热特性影响

Influence of rotation on flow and heat transfer characteristics of con⁃stricted and expanded serpentine channels

为了探究旋转状态下涡轮叶片内冷通道的流动换热特性变化,研究了入口雷诺数为3×10^(4),旋转数分别为0、0.03、0.06、0.09和0.3时缩扩蜿蜒通道流阻及换热性能。结果表明:哥氏力与离心力共同将通道中心流体推向压力面,再由流程上壁面回流与中心流体形成涡旋,进而改变通道内流场结构。随着旋转数增加,通道阻力系数表现出先增大后减小的趋势。当旋转数从0上升至0.3时,通道阻力系数下降了53.79%。旋转通过强化流体扰动来破坏吸力面与压力面的边界层,增强通道整体换热能力,当旋转数从0上升至0.3时,第一、二流程局部换热能力增长速率明显高于其他流程,相较静止通道提升了68.49%,缩扩蜿蜒通道整体换热能力较静止状态提升了21.18%。

In order to explore the changes in the flow and heat transfer characteristics of the internal cold channel in turbine blades,the effects of rotation numbers 0,0.03,0.06,0.09 and 0.3 on the flow re-sistance and heat transfer capacity of constricted and expanded serpentine channels with inlet Reynolds number Re=3×10^(4) were investigated.The results show that the Coriolis force and centrifugal force to‐gether push the fluid in the center of the channel to the pressure surface,and then the upper wall of the channel is returned to form a vortex with the central fluid,thereby changing the flow structure in the channel.With the increase of the rotation number,the channel resistance coefficient shows a trend of first increasing and then decreasing.When the rotation number rises from 0 to 0.3,the channel resis‐tance coefficient decreases by 53.79%.Rotation destroys the boundary layers of the suction surface and the pressure surface by strengthening the fluid disturbance to enhance the overall heat transfer capacity of the channel.When the rotation number increases from 0 to 0.3,the local heat transfer capacity of the first and second processes increases significantly higher than that of other processes,and increases by 68.49%compared with the relative stationary channel.The overall heat transfer capacity of the constrict‐ed and expanded serpentine channel is increased by 21.18%compared with the stationary state.