[关键词]
[摘要]
为了探究主流旋流和湍流对转静盘腔燃气入侵规律及机理的影响,在封严冷气量固定的条件下,针对主流旋流角、湍流强度以及二者共同作用对燃气入侵规律的影响开展数值模拟研究。研究结果揭示:当仅存在旋流时,腔内Batchelor流动核心的分布位置和规模直接受主流旋流角的影响,同时,该核心的流动特性引起了封严效率的显著变化;此外,旋流角通过影响封严出口上游的压力分布,进一步影响了下游的燃气入侵程度。当无旋流角、改变主流湍流强度时,在极端湍流强度I=20%的工况下,静盘侧Batchelor核心几乎完全消失,盘腔受到严重燃气入侵。当主流湍流强度I固定为20%,旋流角与其共同作用时,入侵状况相较于无旋流角时有所改善,但旋流角SA=15°的工况封严效率反而略低于SA=30°的工况,这主要是因为封严出口上游压力分布在湍流和旋流耦合作用下呈现出不同的波动特征。
[Key word]
[Abstract]
In order to investigate the influence of mainstream swirl and turbulence on the gas ingestion rules and mechanisms in the rotorstator cavity, this study conducted numerical simulations of the influence of three different operating conditions including mainstream swirl angle (SA), turbulence intensity and the combined effect of swirl and turbulence on the gas ingestion rules under a fixed sealing cold air mass flow. The results reveales that when only swirl exists, the distribution position and scale of the Batchelor flow core within the cavity are directly affected by the mainstream swirl angle, meanwhile, the flow characteristics of the core also cause significant changes in the sealing efficiency; additionally, the swirl angle affects the gas ingestion downstream by influencing the pressure distribution upstream of the sealing outlet. When there is no swirl angle and the mainstream turbulence intensity changes, under the condition of extreme turbulence intensity I=20%, the Batchelor core on the stator side almost disappears, and the disc cavity suffers severe gas ingestion. When the mainstream turbulence intensity I is fixed at 20%, and the swirl angle acts together with it, the ingestion is alleviated compared to SA=0°, but the sealing efficiency under the condition of SA=15° is slightly lower than that under SA=30°. This is mainly because the pressure distribution upstream of the sealing outlet exhibits different fluctuation characteristics under the coupled action of turbulence and swirl.
[中图分类号]
V231.1
[基金项目]
国家自然科学基金(52006178,U2241268);国家科技重大专项(2022DCI002001)