scholarly journals Unsteady numerical analysis of waver of secondary flow on channel flows with triangular roughness on side walls

2011 ◽  
Vol 67 (2) ◽  
pp. I_721-I_730
Author(s):  
Yuichi Kouchi ◽  
Takasi Hosoda ◽  
Ichiro Kimura ◽  
Toshiaki Kimura
Keyword(s):  
Numerical Analysis ◽  
Secondary Flow ◽  
Channel Flows ◽  
Side Walls

Reduction of Secondary Flow Losses in Turbine Cascades by Leading Edge Modifications at the Endwall

2000 ◽  
Vol 123 (2) ◽  
pp. 207-213 ◽  
Author(s):  
H. Sauer ◽  
R. Mu¨ller ◽  
K. Vogeler
Keyword(s):  
Numerical Analysis ◽  
Secondary Flow ◽  
Leading Edge ◽  
Suction Side ◽  
Side Branch ◽  
Profile Modification ◽  
Flow Losses ◽  
Passage Vortex ◽  
Theoretical Investigations ◽  
Experimental Findings

Experimental results are presented which show the influence on the secondary flow and its losses by a profile modification of the leading edge very close to the endwall. The investigation was carried out with a well-known turbine profile that originally was developed for highly loaded low pressure turbines. The tests were done in a low speed cascade wind tunnel. The geometrical modification was achieved by a local thickness increase; a leading edge endwall bulb. It was expected that this would intensify the suction side branch of the horse-shoe (hs-) vortex with a desirable weakening effect on the passage vortex. The investigated configuration shows a reduction of secondary losses by 2.1 percent points that represents approximately 50 percent of these losses compared to the reference profile. Detailed measurements of the total pressure field behind the cascade are presented for both the reference and the modified profile. The influence of the modified hs-vortex on the overall passage vortex can be clearly seen. The results of a numerical analysis are compared with the experimental findings. A numerical analysis shows that the important details of the experimental findings can be reproduced. Quantitative values are locally different. The theoretical approach taken cannot yet be used for an exact prediction of the loss reduction. However, the analysis of the interaction and the resulting tendencies are considered to be valid. Hence, theoretical investigations as a guideline for the design of a leading edge bulb at the endwall are a valuable tool.

The Analysis of Multistage Deep Drawing of AA5754 Aluminum Alloy

2010 ◽  
Vol 55 (4) ◽  
pp. 1173-1184 ◽  
Author(s):  
M. Paćko ◽  
M. Dukat ◽  
T. Śleboda ◽  
M. Hojny
Keyword(s):  
Aluminum Alloy ◽  
Numerical Analysis ◽  
Numerical Simulations ◽  
Contact Surface ◽  
Deep Drawing ◽  
Material Flow ◽  
Drawing Process ◽  
Deep Drawing Process ◽  
Side Walls ◽  
Good Agreement

The Analysis of Multistage Deep Drawing of AA5754 Aluminum AlloyThis work is focused on the multistage deep drawing of AA5754 aluminum alloy box-type part with flange. Both experimental and numerical analysis were performed in this study to predict causes of contraction and cracking occurring in deformed product in respect to the changes of friction conditions on tool-drawn part contact surface. The numerical simulations were performed using eta/DYNAFORM software and LS-DYNA® solver. The research showed, that the results of the simulation are in very good agreement with the results of the real multistage deep drawing processes. Moreover, this study showed, that proper conditions of friction on the tool-drawpiece contact surface is crucial for the correctness of the analyzed deep drawing process. Too large friction can restrict the material flow, particularly along the edge connecting the bottom and side-walls of the drawpiece, causing wrinkling and cracking.

Numerical Analysis of Effects of Centrifugal Compressor Impeller Design on Overall- and Flow Field Performance

2011 ◽  
Author(s):  
A. Hildebrandt ◽  
H. Franz ◽  
C. Jakiel
Keyword(s):  
Numerical Analysis ◽  
Secondary Flow ◽  
Centrifugal Compressor ◽  
Pressure Coefficient ◽  
Field Performance ◽  
Computational Fluid Dynamics Analysis ◽  
Compressor Impeller ◽  
Fluid Properties ◽  
Secondary Zone ◽  
The One

The present paper deals with two different subjects in the field of centrifugal compressors, namely impeller design and its aerodynamic analysis. The paper provides results of aerodynamic design of low specific speed centrifugal compressor impellers. The design objective is the improvement of the efficiency of a 2D-impeller by means of a 3D-impeller design. The design volume flow and isentropic pressure coefficient of the 3D-impeller should be similar to the one of the 2D-impeller. The numerical CFD (Computational Fluid Dynamics) analysis comprises non-dimensional results of overall impeller and stage performance as well as flow details (circumferentially averaged fluid properties in the impeller exit plane). Furthermore, the paper presents the analysis of secondary flow development of different impellers in comparison with a 2D-impeller of prismatic blade profile. The numerical analysis focuses on understanding of different development of the impeller secondary zone. Results show a direct correlation between the overall performance and secondary flow of the different impellers providing more insight into the aerodynamic philosophy of design of centrifugal compressor impellers.

Numerical Analysis of the Flow in a Curved Duct

2013 ◽  
Vol 706-708 ◽  
pp. 1450-1453 ◽  
Author(s):  
Xiao Yun Wu ◽  
Shang Ding Lai ◽  
Kyoji Yamamoto ◽  
Shinichiro Yanase
Keyword(s):  
Stability Analysis ◽  
Numerical Analysis ◽  
Secondary Flow ◽  
Cross Section ◽  
Linear Stability Analysis ◽  
Multiple Solutions ◽  
Outer Wall ◽  
Multiple Solution ◽  
Curved Duct ◽  
Actual Flow

The Secondary flow in a curved duct of square cross-section, is investigated numerically using the spectral method. The walls of the duct except the outer wall rotate around the centre of curvature and an azimuthal pressure gradient is imposed. Multiple solutions are obtained at the same flow condition. It is also found that the secondary flow in a cross-section consists of two-vortex, four-vortex, eight-vortex or even non-symmetric vortex with respect to the centre line of the cross-section. The linear stability analysis for the multiple solution is also carried out to investigate the actual flow patterns.

Sign in / Sign up

Export Citation Format

Share Document