Study on Mechanism of Unstable Flow Inception at Small Flow Rates in a Centrifugal Blower

离心鼓风机小流量不稳定流动萌生机理研究

• 批准号: 14550154
• 负责人: ISHIDA Masahiro
• 金额: $ 2.3万
• 依托单位: Nagasaki University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 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-14550154/
• 关键词: Centrifugal Blower; Unstable Flow at Small Flow Rate; CFD Analysis; Inducer Stall; Diffuser Stall; Improvement in Stall Margin; Formation of Inlet Recirculation; Reduction of Diffuser Width; ディフューザ失速; 低流領域不安定流動

In order to clarify the mechanism of the unstable flow inception in a high specific speed type open shrouded centrifugal impeller, and to analyze the effect of the ring groove arrangement on inducer stall and/or that of the diffuser width on diffuser stall, the 3-D turbulent flow simulation and the experimental work were performed. It was found that the steady flow simulation was very helpful for understanding unsteady stall phenomena, and the following concluding remarks were obtained.(1)The incipient unstable flow is caused by the rolling-up vortex flow near the pressure side of the adjacent blade, resulting from the interaction between the tip leakage flow and the accumulated reverse flow zone, in which the strong streamwise vorticity component seems to be included due to the tip leakage vortex.(2)The formation of inlet recirculation is very effective for suppression of the unstable flow due to inducer stall, one factor is the suction of the tip leakage vortex together with the reve … More rse flow, and another one is a decrease in the flow incidence due to an increase in the inlet recirculation flow rate, which increases with a decrease in the through-flow rate.(3)The optimum location of the suction ring groove is in the region near the inducer tip throat, resulting i n suppression of inducer stall (without deterioration of the impeller characteristics even at the design flow rate.(4)The unstable flow due to diffuser stall occurs when the reverse flow zone extends to the diffuser exit.(5)The unstable flow occurring between φ=0.278 and 0.213 was suppressed by reducing the diffuser width from the impeller exit height to two-thirds between the diffuser inlet and R=1.2, by which the pressure recovery in the diffuser is not deteriorated.(6)The unstable flow range of the test blower was reduced significantly by about 45% in total from φ=0.316 to 0.174 by implementing the ring groove arrangement for the inducer inlet as well as the narrowed diffuser width for the diffuser exit. Less

为了阐明高比转速型开式带冠离心叶轮的不稳定流动机理，并分析环槽布置对导流轮失速和/或扩压器宽度对导流器失速的影响，将3-进行了湍流模拟和实验工作，发现稳定流模拟对于理解非稳定失速现象非常有帮助，并得到以下结论：(1)初期不稳定流动是由不稳定流动引起的。相邻叶片压力侧附近的卷起涡流，是由叶尖泄漏流与累积逆流区相互作用产生的，其中由于叶尖泄漏涡，似乎包含了强流向涡量分量。(2 ）入口再循环的形成对于抑制因诱导轮失速引起的不稳定流量非常有效，一个因素是叶尖泄漏涡流连同反向流量的吸力，另一个因素是流量的减少(3)吸环槽的最佳位置在靠近诱导轮尖端喉部的区域，从而抑制诱导轮失速（即使在设计流量下，叶轮特性也不会恶化。（4）当逆流区延伸至扩压器出口时，会出现由于扩压器失速而导致的不稳定流动。（5）在 φ=0.278 和通过将扩压器宽度从叶轮出口高度减小到扩压器入口之间的三分之二且R=1.2，可以抑制0.213，这样扩压器中的压力恢复不会恶化。（6）试验鼓风机的不稳定流量范围为通过在导流入口处采用环形槽布置以及扩压器的扩压器宽度变窄，总共显着减少约 45%，从 φ=0.316 降至 0.174退出。少

项目成果

石田正弘: "遠心送風機の低流量域不安定流動の抑制;ディフューザ失速の抑制"日本機械学会2003年次大会講演会講演論文集. No. 03-1. 29-30 (2003)

Masahiro Ishida：“离心式鼓风机低流量区域的不稳定流动的抑制；扩散器失速的抑制”日本机械工程学会2003年年会论文集第03-1号（2003年）。

石田正弘: "遠心送風機のインデューサ失速に及ぼす入口循環流の影響"日本機械学会九州支部第56期総会講演会講演論文集. No.038-1. 127-128 (2003)

石田正宏：《入口循环流对离心式鼓风机诱导轮失速的影响》日本机械工程学会九州分会第56次大会论文集第038-128号（2003年）。

Ishida, Masahiro: "Numerical Investigation of Inducer Stall at Small Flow Rates in a Centrifugal Blower (Effect of Blade Leading Shape on Flow Separation)"Proc.of the 4th International Conference on Pumps and Fans. 206-212 (2002)

Ishida, Masahiro：“离心鼓风机中小流量导流失速的数值研究（叶片引导形状对流动分离的影响）”第四届国际泵和风机会议论文集。

石田正弘: "遠心送風機の低流量域不安定流動の抑制;インデューサ・ディフューザ失速の同時抑制"日本機械学会2003年次大会講演会講演論文集. No. 03-1. 31-32 (2003)

石田正宏：“离心式鼓风机低流量区域不稳定流动的抑制；诱导轮和扩压器失速的同时抑制”日本机械工程师学会2003年年会论文集第03-1号。 ）

Masahiro Ishida, Zixiang Sun, Taufan Surana, Daisaku Sakaguchi: "Numerical Investigation of Inducer Stall at Small Flow ate in a Centrifugal Blower (Effect of Blade Leading Shape on Flow Separation)"Proc. of 4^ International Conference on Pumps and Fu

Masahiro Ishida，Zixiang Sun，Taufan Surana，Daisaku Sakaguchi：“离心鼓风机小流量诱导器失速的数值研究（叶片引导形状对流动分离的影响）”Proc。