论文部分内容阅读
早在六十年代初期，Ｓｍｉｔｈ提出了弦向倾斜叶片￣［１］。叶片的这种倾斜集叶片的后掠（叶片展向与气流不垂直）和上反（叶片表面与端壁斜交）于一身。根据理论分析可知，弦向倾斜叶片与周向倾斜叶片比较，在相同倾斜角下，它更能有效地抑制通道涡的形成和发展￣［２］。但是，到现在为止还没有实验数据证实这一计算结果。本文继文献￣［３］详细测量了弦向倾斜叶片叶栅由栅前至栅后诸截面上的气动参数。实验结果表明，弦向倾斜对损失的发展起到了与周向倾斜相类似的作用，但是前者比后者减小了叶栅进口段的流向逆压梯度，从而降低了二次旋涡损失。本文还测量了大转角常规直叶栅与反弯叶片叶栅端壁与叶片表面上的静压分布，探讨了反弯叶片降低损失的原因，认为：减小叶栅进口段流向逆压梯度，在叶片吸力面前部形成垂直于端壁的平行静压等值线、在中部形成反“Ｃ”型静压等值线，以及在流道内建立沿叶高的反“Ｃ”型静压分布，是反弯叶片降低损失的三要素。
As early as the early 1960s, Smith proposed a chordwise tilting blade [1]. This tilting of the blade sets the swept back of the blade (the blade is not oriented perpendicular to the airflow) and is upturned (the blade surface is oblique to the end wall). According to the theoretical analysis, it is found that the chordwise inclined blade is more effective in suppressing the formation and development of the channel vortex at the same inclination angle compared with the circumferential inclined blade [2]. However, up to now, no experimental data confirm the result of this calculation. In this paper, the aerodynamic parameters of the chordwise inclined blade cascade from the front of the gate to the back of the gate are measured in detail [3]. The experimental results show that the chordwise tilt plays a similar role as the circumferential tilt in loss development, but the former reduces the reverse pressure gradient of the cascade at the inlet of the cascade and reduces the secondary vortex loss. The paper also measured the distribution of static pressure on the end wall and blade surface of conventional straight blade cascades with large turning angles and inverse curved blade cascades, and discussed the reasons for the loss reduction of the inverted curved blades. It is concluded that: A parallel hydrostatic contour perpendicular to the end wall is formed in the front of the suction side of the blade, an anti-C-shaped hydrostatic contour is formed in the middle, and an anti-C-shaped static pressure distribution is established in the flow channel along the height of the vane. Is reverse bending blade to reduce the loss of the three elements.