RESEARCH ON SUPPRESSION OF CAVITATION INSTABILITIES IN INDUCERS

诱导轮空化不稳定性的抑制研究

• 批准号: 14205030
• 负责人: TSUJIMOTO Yoshinobu
• 金额: $ 29.62万
• 依托单位: OSAKA UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (A)
• 财政年份: 2002
• 资助国家: 日本
• 起止时间: 2002 至 2003
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-14205030/
• 关键词: cavitation; instability; rotating cavitation; control; backflow; inducer; 翼端漏れ渦; LES; キャビテーションサージ; 逆流渦

A guideline for cascade design for the suppression of cavitation instabilities was provided based on a stability analysis of cavitating flow through cascades. Several new methods for the suppression are proposed and their validity was shown by experiments. The mechanism of the suppression was clarified through numerical simulations.It was shown by a stability analysis of the flow through circular arc and piano-convex hydrofoil cascades that the occurrence of various cavitation instabilities can be delayed by decreasing the flow angle measured from the shockless flow angle through the adjustments of blade camber and thickness distribution. The effects of casing geometry on the instabilities were examined in detail. It was found that the cavitation instabilities are suppressed by enlarging the tip clearance or the casing diameter at the inlet of an inducer. It was found that the inlet backflow is increased and the incidence angle at the inlet is decreased by the modifications of the casi … More ng.Next, the following three methods for the suppression were examined: (1) rounding of blade tip, (2) equalizing the circumferential pressure distribution by using an accumulator at the inlet, (3) injecting circumferential jets at the inlet. It was shown by experiments that the range of the cavitation number with rotating cavitation can be decreased by all of the three methods. The effectiveness of the method (2) was also shown by a stability analysis. In the methods (1) and (3), the suppression was closely related with the enhancement of the inlet backflow.The steady and unsteady characteristics of the inlet backflow were investigated by using numerical simulations. It was first clarified by calculations using the k-E turbulence model that the angular momentum of the backflow is supplied by a flow from the pressure surface of the blades turning around the swept leading edge. The backflow vortex system surrounding the backflow region was successfully simulated by a LES calculation. It was found that the backflow vortex responds to the flow rate fluctuation as a first order delay element. This shows that the backflow vortex cavitation have a destabilizing effects on low frequency disturbances but have a stabilizing effects for disturbances with the frequency higher than about 10% of the rotational frequency. This shows that the unsteady response of the backflow is more important than the existence of the backflow, for the suppression of the cavitation instabilities. This suggests that an active control of backflow by circumferential jet would be a powerful tool for the suppression of cavitation instabilities. Less

基于SCADE提供了用于tavitaties的指南。可以详细检查角度的角度。刀片的调整和分布详细检查了壳体几何学对不稳定性的影响。 CASI…更多的ng.ng，抑制的前前方法是：（1）刀片尖端的圆形，（2）通过在入口处使用累加器来均衡圆周的压力分布，（3）在INT上注入圆周的喷气机通过使用数值模拟研究了所有三种方法（2）的效力（2）。模型是由土耳其人的压力表面的流动提供的，将回流涡流的surtex surtem围绕着，回流涡流响应波动作为第一阶延迟元素的波动。随着频率高于旋转频率的旋转的10％，这表明背流的不稳定响应比背流的存在更重要通过圆周喷射对回流的控制将是抑制空化不稳定性的强大工具

项目成果

Fujii, A., Mizuno, S., Horiguchi, H., Tsujimoto,Y.: "Suppression of the Cavitation Instabilities by Circumferential Jet at the Inlet of Inducer"Transactions of the JSME, Series B (in Japanese). (to be presented).

Fujii, A.、Mizuno, S.、Horiguchi, H.、Tsujimoto,Y.：“诱导器入口处的圆周射流抑制空化不稳定性”JSME 交易，B 系列（日语）。

Fukao, S., Yamanishi, N., Qiao, X., Kato, C., Tsujimoto,Y.: "Computational Fluid Dynamics for Backflow Vortex Structure at the Inlet of Inducer"Transactions of the JSME, Series B (in Japanese). (to be presented).

Fukao, S.、Yanishi, N.、Qiao, X.、Kato, C.、Tsujimoto,Y.：“诱导器入口处回流涡结构的计算流体动力学”JSME B 系列交易（日语）

川村有輔, 日高達哉, 藤井明, 内海政春, 吉田義樹, 辻本良信: "インデューサの揚程低下時に発生する高次の旋回キャビテーション"日本機械学会論文集(B編). 69巻678号. 120-128 (2002)

Yusuke Kawamura、Tatsuya Hidaka、Akira Fujii、Masaharu Utsumi、Yoshiki Yoshida、Yoshinobu Tsujimoto：“诱导轮头下降时发生的高阶旋转空化”日本机械工程师学会汇刊（编辑 B），第 69 卷。 678. 120-128 (2002)

Qiao X., Fukao, S., Horiguchi, H., Tsujimoto, Y., Kato,C.: "A Numerical Study of the Mechanism of Backflow at the Inlet of 3-bladed Inducers"Turbomachinery. (to be presented).

Qiao X.、Fukao, S.、Horiguchi, H.、Tsujimoto, Y.、Kato,C.：“三叶导流器入口回流机理的数值研究”涡轮机械。

藤井明, 水野伸一, 堀口祐憲, 辻本良信: "インデューサ上流の条件が旋回キャビテーションに及ぼす影響"日本機械学会論文集B編. (発表予定).

Akira Fujii、Shinichi Mizuno、Yukenori Horiguchi、Yoshinobu Tsujimoto：“诱导轮上游条件对旋转空化的影响”，日本机械工程师学会会议录，B 版（即将发表）。