Axial flow structure of solids holdup in an 18-m high-density CFB riser based on pressure measurements

Particuology ◽  
2020 ◽  
Author(s):  
Xin Su ◽  
Chengxiu Wang ◽  
Xingying Lan ◽  
Huajian Pei ◽  
Xiaoyang Mao ◽  
...  
Keyword(s):  
Flow Structure ◽  
Axial Flow ◽  
High Density ◽  
Pressure Measurements ◽  
Solids Holdup

Influence of Leading Edge Fillet and Nonaxisymmetric Contoured Endwall on Turbine NGV Exit Flow Structure and Interactions With the Rim Seal Flow

2013 ◽  
Author(s):  
Özhan H. Turgut ◽  
Cengiz Camcı
Keyword(s):  
Flow Structure ◽  
Total Pressure ◽  
Guide Vane ◽  
Axial Flow ◽  
Leading Edge ◽  
Turbine Rotor ◽  
Rotor Blades ◽  
Constant Thickness ◽  
Computational Evaluation ◽  
Nozzle Guide

Three different ways are employed in the present paper to reduce the secondary flow related total pressure loss. These are nonaxisymmetric endwall contouring, leading edge (LE) fillet, and the combination of these two approaches. Experimental investigation and computational simulations are applied for the performance assessments. The experiments are carried out in the Axial Flow Turbine Research Facility (AFTRF) having a diameter of 91.66cm. The NGV exit flow structure was examined under the influence of a 29 bladed high pressure turbine rotor assembly operating at 1300 rpm. For the experimental measurement comparison, a reference Flat Insert endwall is installed in the nozzle guide vane (NGV) passage. It has a constant thickness with a cylindrical surface and is manufactured by a stereolithography (SLA) method. Four different LE fillets are designed, and they are attached to both cylindrical Flat Insert and the contoured endwall. Total pressure measurements are taken at rotor inlet plane with Kiel probe. The probe traversing is completed with one vane pitch and from 8% to 38% span. For one of the designs, area averaged loss is reduced by 15.06%. The simulation estimated this reduction as 7.11%. Computational evaluation is performed with the rotating domain and the rim seal flow between the NGV and the rotor blades. The most effective design reduced the mass averaged loss by 1.28% over the whole passage at the NGV exit.

Analysis of Local Flow Structure and Global Compressor Performance During Rotating Stall

2004 ◽  
Author(s):  
Chiara Palomba
Keyword(s):  
Flow Field ◽  
Flow Structure ◽  
Rotational Speed ◽  
Axial Flow ◽  
Rotating Stall ◽  
Performance Parameters ◽  
Flow Conditions ◽  
Local Flow ◽  
Flow Parameters ◽  
Compressor Performance

Rotating stall is an instability phenomenon that arises in axial flow compressors when the flow is reduced at constant rotational speed. It is characterised by the onset of rotating perturbations in the flow field accompanied by either an abrupt or gradual decrease of performances. Although the flow field is unsteady and non axisymmetric, the global operating point is stable and a stalled branch of performance curve may be experimentally determined. The number, rotational speed, circumferential extension of the rotating perturbed flow regions named rotating cells may vary from one compressor to another and may depend on the throttle position. The present work focuses on the interaction between local flow parameters and global compressor performance parameters with the aim of reaching a better understanding of the phenomenon. Starting from the Day, Greitzer and Cumpsty [1] model the detailed flow conditions during rotating stall are studied and related to the global performance parameters. This is done both to verify if the compressor under examination fits to the model and if the detailed flow structure may highlight the physics that in the simple model may hide behind the correlation’s used.

scholarly journals Study of the internal flow structure of an ultra-small axial flow hydraulic turbine

2019 ◽  
Vol 139 ◽  
pp. 1000-1011 ◽  
Author(s):  
Yasuyuki Nishi ◽  
Tomoyuki Kobori ◽  
Nozomi Mori ◽  
Terumi Inagaki ◽  
Norio Kikuchi
Keyword(s):  
Flow Structure ◽  
Axial Flow ◽  
Internal Flow ◽  
Hydraulic Turbine

Comparison Between NACA 65 Profile and Circular Arc Blade Based on Numerical Investigation

2017 ◽  
Author(s):  
Tao Bian ◽  
Qianpeng Han ◽  
Martin Böhle
Keyword(s):  
Flow Structure ◽  
Lower Cost ◽  
Flow Behavior ◽  
Axial Flow ◽  
Leading Edge ◽  
Circular Arc ◽  
Spacing Ratio ◽  
Flow Loss ◽  
The Difference ◽  
And Behavior

For the axial flow fans NACA profiles have been well explored. However, the development and production of NACA profiles are also very expensive. Due to their lower cost of production circular arc blades are also applied to axial flow fans. But there is few information in the open literature focusing on flow loss and behavior of circular arc blades. Therefore, one question remains: how much is the difference of flow loss and behavior between NACA profiles and circular arc blades. In this paper NACA 65 profile and circular arc blade are examined by numerical method. The paper shows the flow loss of both blades in dependence of incidence, Reynolds number and spacing ratio. The occurrence of flow behavior, such as separation bubbles on the leading edge and flow structure on the sidewall is examined and discussed. The flow structure is given on basis of numerical flow picture. Additionally, the flow loss in the sidewall region of both investigated blades are worked out and compared.

scholarly journals The energetics of flow through a rapidly oscillating tube with slowly varying amplitude

2011 ◽  
Vol 369 (1947) ◽  
pp. 2989-3006 ◽  
Author(s):  
Robert J. Whittaker ◽  
Matthias Heil ◽  
Sarah L. Waters
Keyword(s):  
Flow Structure ◽  
Energy Budget ◽  
High Frequency ◽  
Axial Flow ◽  
Multiple Scale ◽  
Amplitude Equations ◽  
Long Wavelength ◽  
First Order ◽  
Collapsible Tubes ◽  
Flow Through

Motivated by the problem of self-excited oscillations in fluid-filled collapsible tubes, we examine the flow structure and energy budget of flow through an elastic-walled tube. Specifically, we consider the case in which a background axial flow is perturbed by prescribed small-amplitude high-frequency long-wavelength oscillations of the tube wall, with a slowly growing or decaying amplitude. We use a multiple-scale analysis to show that, at leading order, we recover the constant-amplitude equations derived by Whittaker et al . (Whittaker et al. 2010 J. Fluid Mech. 648 , 83–121. ( doi:10.1017/S0022112009992904 )) with the effects of growth or decay entering only at first order. We also quantify the effects on the flow structure and energy budget. Finally, we discuss how our results are needed to understand and predict an instability that can lead to self-excited oscillations in collapsible-tube systems.

Sign in / Sign up

Export Citation Format

Share Document