Turbulent Mixing Losses in the Passages of Centrifugal Impellers

离心叶轮通道中的湍流混合损失

基本信息

批准号：
11650197
负责人：
MIYAMOTO Hiroyuki
金额：
$ 2.18万
依托单位：
Yatsushiro National College of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1999
资助国家：
日本
起止时间：
1999 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11650197/
关键词：
Turbomachinery Blower Internal Flow Centrifugal Impeller Turbulent Flow Secondary Flow Blade Ti Leakage Hot-wire Measurement

项目摘要

Flow measurements were made within the passages of the shrouded and unshrouded centrifugal impellers, by using a hot-wire anemometer rotated with the same speed as that of the impeller. The measurements were made for a flow rate corresponding to nearly zero incidence angle and two other flows with reduced and increased flow rates.In the shrouded impeller, the measurements show that, as the flow rate is reduced, the regions of a low velocity and a dissipation enlarge from the shroud-side to the hub-side near the suction surface and the values of Reynolds normal stresses tend to decrease. The Reynolds shear stresses qualitatively follow the eddy viscosity concept. Near the suction surface, the effects of the flow rate on the shear stresses are remarkable in the cross-component between the passagewise and blade-spanwise directions, but are little in two other cross-components.In the unshrouded impeller, a low relative velocity, a high dissipation and a high Reynolds stress appear around t … More he region of the middle blade-to-blade to the casing side due to both influences of a blade tip leakage and a secondary flow. As the flow rate is reduced, this region enlarges by nearing the hub and also tends to move toward the suction.In the increased flow rate, the Reynolds stress is remarkably high near the casing of the suction side since the tip leakage noticeably influences there. In the reduced flow rate, the stress becomes high also on the suction because of the secondary flow strengthened near the casing. For three flow rates, however, the dissipation is remarkably high near the casing of the suction side ; the influence of the flow rate on the position with the highest dissipation seems to be little.Moreover, the numerical flow analys is made in the passage of the centrifugal impeller using FEM with/without the turbulence model. The turbulence model is low Reynolds k-ε model proposed by Chien. We use the Euler explicit method for the Reynolds averaged Navier-Stokes equations and the transport equations of the turbulent energy and the dissipation rate. All equations are discretized by the Galerkin method. The numerical results qualitatively correspond with those obtained from the experiment. Less

通过使用与叶轮相同的速度旋转的热线风速计旋转的热线风速计，在笼罩和未切开的离心叶轮的通道中进行了流量测量。进行了测量的流速，对应于几乎零入射角，而另外两个流动降低并增加了流速。在浮起的叶轮上，测量值表明，随着流速的降低，速度较低的区域和耗散的区域从shub side shord shord short shol shortion shol shroution表面和值的偏移率变化较大的应力和较高的值。雷诺兹在涡流概念概念上定性地剪切应力。在吸气表面附近，流速对剪切应力的影响在通过方向和叶片方向之间的跨组成部分中很明显和二次流。随着流速的降低，该区域通过接近枢纽而增加，并且倾向于朝任务移动。在增加的流量中，雷诺的压力在任务侧的壳体附近非常高，因为尖端泄漏在那里泄漏明显影响。在降低的流量中，由于壳体附近的二次流动增强，因此在任务上的应力也变得很高。然而，对于三个流速，耗散在吸力侧的壳体附近非常高。流速对最高耗散的位置的影响似乎很小。此外，使用/没有湍流模型的FEM在离心叶轮的通过中进行数值流量分析。湍流模型是Chien提出的低雷诺K-ε模型。我们使用Euler的显式方法，用于雷诺平均的Navier-Stokes方程以及湍流能量的传输方程和耗散速率。所有方程都通过Galerkin方法离散。定性的数值结果与从实验获得的结果相对应。较少的