scholarly journals An Approximate 3-D Aerodynamic Design Method for Centrifugal Impeller Blades

1989 ◽  
Author(s):  
Zhao Xiaolu ◽  
Qin Lisen

An aerodynamic design method, which based on the Mean Stream Surface Method (MSSM), has been developed in designing the centrifugal compressor impeller blades. As a component of a CAD system for centrifugal compressor, it is convenient to use the presented method for generating impeller blade geometry, taking care of manufacturing as well as aerodynamic aspects. The design procedure starts with an S2m indirect solution. Afterwards from the specified S2m surface, by the use of Taylor series expansion, the blade geometry is generated by straight-line elements to meet the requirement of manufacture. Simultaneously, the fluid dynamic quantities across the blade passage, can be determined directly. In terms of these results, the designer can revise the distribution of angular momentum along the shroud and hub, which are associated with blade loading to get satisfactory velocities along the blade surfaces in order to avoid or delay flow separation.

1990 ◽  
Vol 112 (1) ◽  
pp. 44-49 ◽  
Author(s):  
Zhao Xiaolu ◽  
Qin Lisen

An aerodynamic design method, which is based on the Mean Stream Surface Method (MSSM), has been developed for designing centrifugal compressor impeller blades. As a component of a CAD system for centrifugal compressor, it is convenient to use the presented method for generating impeller blade geometry, taking care of manufacturing as well as aerodynamic aspects. The design procedure starts with an S2m indirect solution. Afterward from the specified S2m surface, by the use of Taylor series expansion, the blade geometry is generated by straight-line elements to meet the manufacturing requirements. Simultaneously, the fluid dynamic quantities across the blade passage can be determined directly. In terms of these results, the designer can revise the distribution of angular momentum along the shroud and hub, which are associated with blade loading, to get satisfactory velocities along the blade surfaces in order to avoid or delay flow separation.


Author(s):  
Kaito Manabe ◽  
Sasuga Ito ◽  
Masato Furukawa ◽  
Kazutoyo Yamada ◽  
Nobuhito Oka ◽  
...  

Abstract The present optimum design method has been advanced for simultaneous optimization of impeller blade loading distribution and meridional geometry. This is based on an aerodynamic design method and a genetic algorithm. The aerodynamic design method consists of two parts: a meridional viscous flow analysis and a two-dimensional inverse blade design procedure. In the meridional viscous flow analysis, an axisymmetric viscous flow is numerically analyzed on a two-dimensional grid to determine the flow distribution around the impeller and diffuser. Effects of blades onto the axisymmetric flow field are considered by a blade force modeling. In the inverse blade design procedure, 3-D impeller geometry can be obtained from the result of meridional viscous flow analysis and the predetermined blade loading distribution. In the optimization procedure, the total pressure ratio and adiabatic efficiency obtained from the meridional viscous flow analysis are employed as objective functions. As a constraint of the optimization, mass flux distribution at the impeller trailing edge is introduced in the evaluation procedure, in order to suppress the boundary layer development near the shroud, especially under low flow rate condition. Total performances and three-dimensional flow fields of centrifugal compressors have been analyzed by 3D-RANS simulations to certify effectiveness of the present design method. The 3D-RANS simulations and the flow visualization have been applied to a conventional centrifugal compressor and optimized design cases. From the analysis results, the performance enhancement of optimized designs is confirmed under low flow rate condition including design point. In addition to that, it is revealed that the constraint works effectively on the performance improvement. As a result, construction of the simultaneous optimization using the aerodynamic design method and the genetic algorithm is successfully achieved.


Author(s):  
Xu Yu-dong ◽  
Li Cong ◽  
Lv Qiong-ying ◽  
Zhang Xin-ming ◽  
Mu Guo-zhen

In order to study the effect of the trailing edge sweep angle of the centrifugal impeller on the aerodynamic performance of the centrifugal compressor, 6 groups of centrifugal impellers with different bending angles and 5 groups of different inclination angles were designed to achieve different impeller blade trailing edge angle. The computational fluid dynamics (CFD) method was used to simulate and analyze the flow field of centrifugal compressors with different blade shapes under design conditions. The research results show that for transonic micro centrifugal compressors, changing the blade trailing edge sweep angle can improve the compressor’s isentropic efficiency and pressure ratio. The pressure ratio of the compressor shows a trend of increasing first and then decreasing with the increase of the blade bending angle. When the blade bending angle is 45°, the pressure ratio of the centrifugal compressor reaches a maximum of 1.69, and the isentropic efficiency is 67.3%. But changing the inclination angle of the blade trailing edge has little effect on the isentropic efficiency and pressure ratio. The sweep angle of blade trailing edge is an effective method to improve its isentropic efficiency and pressure ratio. This analysis method provides a reference for the rational selection of the blade trailing edge angle, and provides a reference for the design of micro centrifugal compressors under high Reynolds numbers.


Author(s):  
M. Zangeneh ◽  
M. Schleer ◽  
F. Plo̸ger ◽  
S. S. Hong ◽  
C. Roduner ◽  
...  

In this paper the 3D inverse design code TURBOdesign-1 is applied to the design of the blade geometry of a centrifugal compressor impeller with splitter blades. In the design of conventional impellers the splitter blades normally have the same geometry as the full blades and are placed at mid-pitch location between the two full blades, which can usually result in a mis-match between the flow angle and blade angles at the splitter leading edge. In the inverse design method the splitter and full blade geometry is computed independently for a specified distribution of blade loading on the splitter and full blades. In this paper the basic design methodology is outlined and then the flow in the conventional and inverse designed impeller is compared in detail by using CFD code TASCflow. The CFD results confirm that the inverse design impeller has a more uniform exit flow, better control of tip leakage flow and higher efficiency than the conventional impeller. The results also show that the shape of the trailing edge geometry has a very appreciable effect on the impeller Euler head and this must be accurately modeled in all CFD computations to ensure closer match between CFD and experimental results. Detailed measurements are presented in part 2 of the paper.


Author(s):  
C. Rodgers

Centrifugal impeller blade trimming has long been used in the turbocharger industry to adapt a single impeller casting to a series of flow capacities, but surprisingly little published literature exists on the effects of trimming to compressor performance. This paper is presented as partial remedy, and describes the performance characteristics of a single stage centrifugal compressor designed and tested to cover a range of flow requirements by impeller blade and diffuser vane trimming. Stage and component test performance characteristics are presented for five trimmed flowpath contours covering a flow capacity range of approximately five to one at a DeLaval number of 0.75. The impeller tip diameter was 356mm, and the highest overall stage efficiency measured was 84.8% at an (air) pressure ratio of 1.5.


2005 ◽  
Vol 127 (1) ◽  
pp. 94-97
Author(s):  
Joseph T. Hamrick

Before and during World War II, the design and development of single stage high pressure ratio centrifugal compressors was essentially a cut-and-try exercise. To reach a high pressure without substantial experimentation required multiple stages of impellers and diffusers with pressure ratios in the 2:1 range. While such arrangements were satisfactory for commercial use where weight was not a major consideration, they were not suitable for jet engines. The centrifugal compressor for the Whittle engine, the first British jet engine, was developed by trial and error with numerous modifications of the hub-shroud profile. The centrifugal compressor section of the National Advisory Committee for Aeronautics (NACA) designed, built, and tested three compressor impellers during and after World War II. They were part of a program designed to evaluate various blade shapes, but encountered such instabilities at the design pressure ratios that the experimental results led to no definitive conclusions. In 1948, the Centrifugal Compressor Section was given the assignment to further investigate the three impellers. The investigation led to the development of a quasi-three-dimensional design procedure that eliminated the guesswork from the basic design of a centrifugal impeller. Since the 1948 to 1955 time period over which the procedure was developed, the advances in computers have allowed refinements in the original computational methods. It is the objective of this presentation to review the history of the NACA centrifugal compressor program and efforts that have led to the latest developments in computational design procedures.


2011 ◽  
Vol 2011 ◽  
pp. 1-11 ◽  
Author(s):  
Matteo Checcucci ◽  
Federica Sazzini ◽  
Michele Marconcini ◽  
Andrea Arnone ◽  
Mario Coneri ◽  
...  

This work provides a detailed description of the fluid dynamic design of a low specific-speed industrial pump centrifugal impeller. The main goal is to guarantee a certain value of the specific-speed number at the design flow rate, while satisfying geometrical constraints and industrial feasibility. The design procedure relies on a modern optimization technique such as an Artificial-Neural-Network-based approach (ANN). The impeller geometry is parameterized in order to allow geometrical variations over a large design space. The computational framework suitable for pump optimization is based on a fully viscous three-dimensional numerical solver, used for the impeller analysis. The performance prediction of the pump has been obtained by coupling the CFD analysis with a 1D correlation tool, which accounts for the losses due to the other components not included in the CFD domain. Due to both manufacturing and geometrical constraints, two different optimized impellers with 3 and 5 blades have been developed, with the performance required in terms of efficiency and suction capability. The predicted performance of both configurations were compared with the measured head and efficiency characteristics.


Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2582
Author(s):  
Cheikh Brahim ABED ◽  
Sofiane KHELLADI ◽  
Michael DELIGANT ◽  
Abdellatif EL EL MARJANI ◽  
Moisés SOLIS ◽  
...  

Turbomachinery with double counter-rotating impellers offers more degrees of freedom in the choice of design and control parameters compared to conventional machines. For these innovative machines, the literature review shows that more publications concerning axial type turbomachines are available than centrifugal ones. This work deals with a design and experimental performance analysis, applied to two counter-rotating impellers of a centrifugal compressor “CRCC”. CRCC was designed with a specifically developed tool based on mean-line approach coupled with optimization algorithms and a stream-curvature through-flow method to satisfy the design criteria. This paper presents an experimental validation of the CRCC design tool and its performances against the baseline “SR”, composed of one centrifugal impeller and a volute for which experimental data are available. CRCC numeric simulations are also validated by experimental data. For a fair comparison between CRCC and SR, the same volute is used for both configurations. The CRCC studied here includes a first conventional impeller with an axial inlet and a radial outlet, while the second impeller is parametrically designed and can be considered a rotating bladed diffuser with a radial inlet and outlet. The obtained results show that CRCC can deliver a pressure rise increase of two compared to SR, along with an increase of isentropic efficiency and also validate the design method of this novel layout. The experimental results also show that the speed ratio of CRCC has a positive effect on the surge and shock margin.


Author(s):  
H Li

The flow driving performance data of a dirty air fan with a semi-open centrifugal impeller and a squirrel volute, designed for household vacuum cleaners, are experimentally obtained with the industry standard tests. The fluid flows in the fan at various conditions are numerically simulated. The agreements between the numerical data and the experimental results are reasonably good. The model-simulated flow structures show that air flow passes over the blade between the impeller blade channels. A high-velocity spot is formed at the top of each blade. The leakage flow, from the fluid-collecting squirrel back to the blade channels, represents a waste of the fluid dynamic energy and the pressure potential energy. However, such leakage flow presses the inlet air to the bottom disc of the impeller and helps in preventing the solid objects from getting to the blade top. Flow energy analysis shows that the main energy loss is in the semi-open impeller. The leakage flow and the disagreements between the flow direction and the blade angles at the leading and the trailing tips are the main causes of the low energy efficiency of the fan.


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