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Unsteady Behaviors and Bifurcation Phenomena observed in an Impeller-Rotating Shaft System of a Centrifugal Fluid Machinery

离心流体机械叶轮转轴系统的不稳定行为和分叉现象

基本信息

批准号：
14550162
负责人：
OHTA Yutaka
金额：
$ 2.11万
依托单位：
Waseda 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 2004
项目状态：
已结题

项目摘要

Concerning about centrifugal as well as axial-flow type fluid machinery, the following unsteady phenomena appearing in an impeller-rotating shaft system are investigated by experiments and also by the CFD analyses : (1)The unsteady behavior and bifurcation of the Taylor vortex flow generated in a mechanical bearing. (2)The aerodynamic noise generated in a centrifugal type of fluid machinery system and its noise source bifurcation. (3)The rotating stall pattern of the axial-flow compressor and bifurcation of stall cells. The detailed contents are as follows.(1)In order to understand the unsteady behavior of the Taylor vortex flow generated between two rotating cylinders with large eccentricity, a 3-D N-S simulation was carried out. As a result, while clarifying unsteady bifurcation of the cell, the first attempt which controls a cell using a jet from an outer cylinder was also performed. Furthermore, an unsteady temperature field and cooling technology were also examined by applying energy equation. The experimental apparatus for verifying numerical results was manufactured, and the preliminary experiment was conducted. (2)With respect to the noise generated from centrifugal fluid machines, the sound source characteristics and their bifurcation at the time of changing various operating conditions were experimentally investigated. Particularly, the noise source extent of the high-order BPF components shows irregular movement and bifurcation against the change of the operating conditions. Moreover, the numerical analysis aiming at understanding this phenomenon in detail was started. (3)Also about the rotating stall of a three-stage axial flow compressor and the bifurcation of a stall cell, by changing various stagger angles of rotor and stator, all kinds of stall inception patterns and the bifurcation of the stall cell were able to be confirmed. The active control technology of the compressor rotating stall by sensing the stall inception sign was also examined.

针对离心和轴流型流体机械，通过实验和CFD分析，研究了叶轮-转轴系统中出现的以下非定常现象：(1)机械轴承内产生的泰勒涡的非定常行为和分岔。(2)离心式流体机械系统产生的气动噪声及其噪声源分岔。(3)轴流压气机旋转失速模式及失速单元分岔。具体内容如下：(1)为了解大偏心旋转圆柱间Taylor涡的非定常特性，进行了三维N-S模拟。结果表明，在澄清胞体非定常分岔的同时，还进行了利用外柱射流控制胞体的首次尝试。应用能量方程对非定常温度场和冷却技术进行了研究。制作了验证数值结果的实验装置，并进行了初步实验。(2)针对离心流体机械产生的噪声，实验研究了不同工况变化时的声源特性及其分岔。特别是高阶BPF分量的噪声源范围随着工况的变化呈现出不规则的运动和分岔。并对这一现象进行了数值分析。(3)对于三级轴流压气机的旋转失速和失速单元的分岔，通过改变转子和定子的不同错开角，可以确定各种失速发生模式和失速单元的分岔。研究了基于失速信号感知的压缩机旋转失速主动控制技术。