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

基于对级联反应的空化流量的稳定性分析，为抑制空化不稳定性的级联设计指南提供了指南。提出了几种新的抑制方法，并通过实验显示了它们的有效性。通过数值模拟阐明了抑制的机制。通过对通过圆形电弧和钢琴 - 串联液压级联反应的稳定性分析来显示，可以通过减小从无需减震角度通过摩擦式凸轮和厚度分布的无冲击流量来延迟各种空化不稳定性的发生。详细研究了壳体几何形状对不稳定性的影响。发现通过增加诱导的入口处的尖端间隙或外壳直径来抑制空化不稳定性。发现进口回流增加了，并且通过CASI的修改降低了入口的入口角度……更多NG.NEXT，检查了以下三种抑制方法：（1）刀片尖端的圆形，（2）（2）通过使用Inlet，（3）注射Angient Endent Extriential Jetlectiential jets inslet inslet neslet inslet inslet inslet inslet inslet neslet inslet inslet inslet inslet inslet inslet inslet inslet inslet inslet inslet inslet inslet inslet inslet inslet inslet inslet inslet inslet inslet inslet inselet shelet。通过实验表明，所有三种方法都可以改善带旋转空化的空化数范围。该方法（2）的有效性也通过稳定性分析显示。在方法（1）和（3）中，抑制与增强入口回流密切相关。通过使用数值模拟研究了入口回流的稳定和不稳定的特征。首先，通过使用K-E湍流模型进行计算来阐明回流的角动量是由叶片的压力表面的流动提供的。通过LES计算成功模拟了围绕回流区域的回流涡流系统。发现回流涡流响应流速波动作为一阶延迟元件。这表明回流涡流空化对低频分布具有不稳定作用，但对频率高于旋转频率的10％的灾害具有稳定作用。这表明回流的不稳定响应比抑制空化不稳定性更重要。这表明，通过圆周喷射对回流的主动控制将是抑制空化不稳定性的强大工具。较少的

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）。