scholarly journals Investigations Concerning the Optimum Blade Loading of Centrifugal Impeller : 2nd Report, In the Case of Flow Patterns within Impeller Channels at the Design-Point

1975 ◽  
Vol 41 (342) ◽  
pp. 515-525 ◽  
Author(s):  
Shinpei MIZUKl ◽  
Ichiro ARIGA ◽  
Ichiro WATANABE
Keyword(s):  
Flow Patterns ◽  
Centrifugal Impeller ◽  
Blade Loading ◽  
Design Point

scholarly journals A Study on the Flow Mechanism Within Centrifugal Impeller Channels

1975 ◽  
Author(s):  
Shimpei Mizuki ◽  
Ichiro Ariga ◽  
Ichiro Watanabe
Keyword(s):  
Secondary Flow ◽  
Flow Patterns ◽  
Centrifugal Impeller ◽  
Production Mechanism ◽  
Flow Mechanism ◽  
Design Point ◽  
Production Mechanisms

Investigations concerning the flow patterns within centrifugal impeller channels have been made for many years. However, many of the problems remain unresolved about the secondary flow and the loss production mechanism within impeller channels. In the present study, measurements of the flow mechanism within impeller channels under the off-design conditions were performed by employing yaw probes to compare the results with those at the design point. The impellers with straight radial blades employed in the present study were of the same configuration except the shroud profiles which made diffusion ratios different from each other. From the present results, it became clear that the loss production mechanisms and the flow patterns within impeller channels were essentially unvaried both under design and off-design operations. The results thus obtained by the present study were furthermore compared with the others to examine the reliability of these results.

Improving a Vaned Diffuser for a Given Centrifugal Impeller by 3D Inverse Design

2002 ◽  
Author(s):  
Mehrdad Zangeneh ◽  
Damian Vogt ◽  
Christian Roduner
Keyword(s):  
Flow Field ◽  
Viscous Flow ◽  
Centrifugal Compressor ◽  
Inverse Method ◽  
Flow Distribution ◽  
Inverse Design ◽  
Centrifugal Impeller ◽  
Design Code ◽  
Vaned Diffuser ◽  
Blade Loading

In this paper the application of 3D inverse design code TURBOdesign−1 to the design of the vane geometry of a centrifugal compressor vaned diffuser is presented. For this study the new diffuser is designed to match the flow leaving the conventional impeller, which is highly non-uniform. The inverse method designs the blade geometry for a given specification of thickness and blade loading distribution. The paper describes the choice of loading distribution used in the design as well as the influence of the diffuser inlet flow distribution on the vane geometry and flow field. The flow field in the new diffuser is analysed by a 3D viscous flow code and the result is compared to that of the conventional diffuser. Finally the results of testing the stage performance of the new diffuser is compared with that of the conventional stage.

Investigations of the Flow Through a High Pressure Ratio Centrifugal Impeller

2002 ◽  
Author(s):  
Gernot Eisenlohr ◽  
Hartmut Krain ◽  
Franz-Arno Richter ◽  
Valentin Tiede
Keyword(s):  
High Pressure ◽  
Flow Separation ◽  
Pressure Ratio ◽  
Leading Edge ◽  
Centrifugal Impeller ◽  
Angle Distribution ◽  
Blade Angle ◽  
Minor Variation ◽  
Design Point ◽  
High Pressure Ratio

In an industrial research project of German and Swiss Turbo Compressor manufacturers a high pressure ratio centrifugal impeller was designed and investigated. Performance measurements and extensive laser measurements (L2F) of the flow field upstream, along the blade passage and downstream of the impeller have been carried out. In addition to that, 3D calculations have been performed, mainly for the design point. Results have been presented by Krain et al., 1995 and 1998, Eisenlohr et al., 1998 and Hah et al.,1999. During the design period of this impeller a radial blade at the inlet region was mandatory to avoid a rub at the shroud due to stress reasons. The measurements and the 3D calculations performed later, however, showed a flow separation at the hub near the leading edge due to too high incidence. Additionally a rather large exit width and a high shroud curvature near the exit caused a flow separation near the exit, which is enlarged by the radially transported wake of the already addressed hub separation. Changes to the hub blade angle distribution to reduce the hub incidence and an adaptation of the shroud blade angle distribution for the same impeller mass-flow at the design point were investigated by means of 3D calculations first with the same contours at hub and shroud; this was followed by calculations with a major change of the shroud contour including an exit width change with a minor variation of the hub contour. These calculations showed encouraging results; some of them will be presented in conjunction with the geometry data of the original impeller design.

Multi-objective optimization design of a centrifugal impeller considering both aerodynamic efficiency and structural machinability

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xing Xie ◽  
Zhenlin Li ◽  
Baoshan Zhu ◽  
Hong Wang
Keyword(s):  
Optimization Design ◽  
Inverse Design ◽  
Centrifugal Impeller ◽  
Multi Objective Optimization ◽  
Blade Angle ◽  
Aerodynamic Efficiency ◽  
Blade Loading ◽  
Content Type ◽  
Wrap Angle ◽  
Blade Wrap Angle

Purpose This study aims to complete the optimization design of a centrifugal impeller with both high aerodynamic efficiency and good structural machinability. Design/methodology/approach First, the design parameters were derived from the blade loading distribution and the meridional geometry in the impeller three-dimensional (3D) inverse design. The blade wrap angle at the middle span surface and the spanwise averaged blade angle at the blade leading edge obtained from inverse design were chosen as the machinability objectives. The aerodynamic efficiency obtained by computational fluid dynamics was selected as the aerodynamic performance objective. Then, using multi-objective optimization with the optimal Latin hypercube method, quadratic response surface methodology and the non-dominated sorting genetic algorithm, the trade-off optimum impellers with small blade wrap angles, large blade angles and high aerodynamic efficiency were obtained. Finally, computational fluid dynamics and computer-aided manufacturing were performed to verify the aerodynamic performance and structural machinability of the optimum impellers. Findings Providing the fore maximum blade loading distribution at both the hub and shroud for the 3D inverse design helped to promote the structural machinability of the designed impeller. A straighter hub coupled with a more curved shroud also facilitated improvement of the impeller’s structural machinability. The preferred impeller was designed by providing both the fore maximum blade loading distribution at a relatively straight hub and a curved shroud for 3D inverse design. Originality/value The machining difficulties of the designed high-efficiency impeller can be reduced by reducing blade wrap angle and enlarging blade angle at the beginning of impeller design. It is of practical value in engineering by avoiding the follow-up failure for the machining of the designed impeller.

A Flow Information Based Prediction Model Applied to the Non-axisymmetric Hub Optimization of a Centrifugal Impeller

2021 ◽  
pp. 1-17
Author(s):  
Cheng Ji ◽  
Zhiheng Wang ◽  
Yonghong Tang ◽  
Guang Xi
Keyword(s):  
Flow Field ◽  
Prediction Model ◽  
Pressure Ratio ◽  
Full Range ◽  
Centrifugal Impeller ◽  
Layer By Layer ◽  
Design Point ◽  
Field Information ◽  
Artificial Neural Network Ann ◽  
Hidden Layer

Abstract A full range prediction model for turbomachinery based on the flow field information code is established in this paper, to solve the problems that traditional models do not have enough prediction accuracy and cannot reflect the complete performance characteristics of the impeller. The model, which can predict the complete performance curve of the impeller with higher accuracy, consists of two multilayer Artificial Neural Network (ANN) submodels. Different from the traditional model, the ANN submodel uses the flow field information code for pre-training layer-by-layer. The flow field information code is the characteristic information extracted from the impeller flow field through the Proper Orthogonal Decomposition (POD) method. By implicitly learning the flow field information, the prediction error of the model is reduced by 29.7% compared with the single hidden layer ANN. Based on this model, the non-axisymmetric hub optimization of a centrifugal impeller with 30 variables is carried out, with the goals of the higher efficiency and the wider flow range at the specified pressure ratio and the massflow rate at the design point. The result shows that, after the optimization, the isentropic efficiency at the design point increases by 1% and the flow range increases by 2% compared to the baseline.

Comparison of Three Slip Velocity Models for a Centrifugal Impeller

2015 ◽  
Author(s):  
Yu-Tai Lee
Keyword(s):  
Slip Velocity ◽  
Tangential Velocity ◽  
Suction Side ◽  
Velocity Model ◽  
Centrifugal Impeller ◽  
Centrifugal Fan ◽  
Vaned Diffuser ◽  
Blade Loading ◽  
Velocity Models ◽  
The Difference

The slip velocity model has been created to account for the effects produced by the difference in velocities between the suction side and the pressure side of the blade at the centrifugal impeller exit. The model is applied to reduce the ideal tangential velocity and provides an estimation of the impeller exit velocity and blade loading for use in turbomachinery meanline modeling. Wiesner reviewed all the proposed models in 1967 and came up with a set of formulations which are only dependent on the impeller geometry, such as number of blades, exit blade angle and blade inlet-to-exit radius ratio. In order to cover flow induced effects and off-design conditions, Qiu recently proposed a formula which contains the effects from the radial rotation, blade turning and passage width variation. For a centrifugal impeller, often the impeller exit condition is affected by downstream components. Pfleiderer’s model of 1961 includes effects of downstream vaned diffuser, vaneless diffuser, or a volute. This paper focuses on the comparisons of the three models in predicting blade loading for a centrifugal-fan impeller with a double-discharge volute at both design and off-design conditions. The comparisons reveal not only each model’s prediction accuracy, but also the flexibility of each model.

scholarly journals Investigation Concerning the Blade Loading of Centrifugal Impellers

1974 ◽  
Author(s):  
Shinpei Mizuki ◽  
Ichiro Ariga ◽  
Ichiro Watanabe
Keyword(s):  
Experimental Data ◽  
Secondary Flow ◽  
Theoretical Investigation ◽  
Static Pressure ◽  
Flow Patterns ◽  
Blade Loading ◽  
Pressure Distributions

An investigation concerning the optimum blade loading of centrifugal impellers was performed. The three impellers with straight radial blades employed in the present study were of the same configurations except the shroud profiles which rendered to bring different diffusion ratios from each other. The static pressure distributions on blade surfaces, flow patterns within the impeller channel as well as at impeller inlet and at outlet were measured for these impellers. The effect of a secondary flow within impeller channel was clarified to some extent from the measurements. Theoretical investigation was also performed in order to compare with the experimental data.

Influence of Blade Loading Criteria and Design Limits on the Cordier-Line for Axial Flow Fans

2014 ◽  
Author(s):  
Reinhard Willinger ◽  
Michael Köhler
Keyword(s):  
High Efficiency ◽  
Velocity Ratio ◽  
Empirical Relationship ◽  
Axial Flow ◽  
Theoretical Interpretation ◽  
Outer Diameter ◽  
Performance Curve ◽  
Compressor Cascade ◽  
Blade Loading ◽  
Design Point

Volume flow rate, specific isentropic enthalpy difference, rotor outer diameter and rotational speed of a fan can be transformed to speed number and diameter number. These two non-dimensional numbers are related together in the so-called Cordier-diagram. For axial, radial and mixed flow fans, there is a single empirical relationship between both quantities and it is well accepted that this line represents “optimum” fan designs with high efficiency. Based on velocity triangles, a relationship between flow coefficient and pressure coefficient exists. This so-called performance curve captures off-design operating points as well as the design point of a fan. Therefore, the performance curve can be transformed to the Cordier-diagram to predict the relationship between speed number and diameter number. It is shown that the Cordier-line depends mainly on velocity triangles and the common argument of high efficiency, claimed in the majority of the literature, plays only a secondary role. Nevertheless, the requirement of high efficiency influences the fan design for a certain design point. This paper focuses mainly on axial flow fans. It gives a theoretical interpretation of the influence of blade loading criteria and design limits on the Cordier-line: (1) De Haller number, (2) cascade loading parameter, (3) Lieblein diffusion factor, (4) Strscheletzky swirl number. Criterion (1) reflects the minimum velocity ratio to avoid endwall separation in a linear compressor cascade. Criterion (2) is a combination of lift coefficient and cascade solidity. It reflects the aerodynamic loading of the suction side blade boundary layer. Criteria (1) and (2) are included in criterion (3). Finally, criterion (4) indicates the risk of hub separation due to strong swirl flow. The investigation shows that the transformation of these criteria to the Cordier-diagram gives very similar results. Furthermore, it is shown that the axial fan design limits in the Cordier-diagram are represented by certain hub-to-tip radius ratios.

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