Cascade Blade Loading Analysis With Application to Turbomachinery Design

2007 ◽  
Author(s):  
Ronald C. Pampreen
Keyword(s):  
Blade Loading ◽  
Pressure Surface ◽  
Maximum Loading ◽  
Blade Thickness ◽  
Efficient Performance ◽  
Principal Factors ◽  
Wrap Angle ◽  
Angle Blade ◽  
Turbomachinery Design ◽  
Blade Wrap Angle

The efficient performance of a compressor or pump over a desired stall-free operating range is related to the fluid mechanic loading on the rotating and stationary blades. This loading is a function of the suction and pressure surface velocities and is commonly referred to as aerodynamic (compressors) or hydraulic (pumps) loading. Overall values of maximum limits have been established in design practice as a result of development work. However, the distribution of loading has not been well established. One source of guidance is the database provided by cascade data. Velocity distributions are available, and from this data, blade loading coefficients can be calculated with the intent of applying the results to blade design. In this paper, the blade loading equation is derived to illustrate the principal factors that influence blade loading. These factors include blade number, blade wrap angle, blade length, and the magnitude of the average velocity between blades as determined by flow path contours and blade thickness. The equation gives the designer the ability to make design adjustments to achieve proper loading distribution within recommended values of maximum loading. The review of the cascade data provides the designer with a reference for allowable design distribution and maximum loading limits.

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.

Effect of blade wrap angle in hydraulic turbine with forward-curved blades

2017 ◽  
Vol 42 (29) ◽  
pp. 18709-18717 ◽  
Author(s):  
Yuxing Bai ◽  
Fanyu Kong ◽  
Sunsheng Yang ◽  
Kai Chen ◽  
Tao Dai
Keyword(s):  
Hydraulic Turbine ◽  
Wrap Angle ◽  
Blade Wrap Angle

scholarly journals Control of the Unsteady Flow in a Stator Blade Row Interacting With Upstream Moving Wakes

1993 ◽  
Author(s):  
T. Valkov ◽  
C. S. Tan
Keyword(s):  
Unsteady Flow ◽  
Pressure Fluctuations ◽  
Spectral Element ◽  
Navier Stokes ◽  
Suction Surface ◽  
Model Calculations ◽  
Blade Loading ◽  
Pressure Surface ◽  
Blade Row ◽  
Stator Blade

A computational approach, based on a spectral-element Navier-Stokes solver, has been applied to the study of the unsteady flow arising from wake-stator interaction. Direct, as well as turbulence-model calculations, provide insight into the mechanics of the unsteady flow and demonstrate the potential for controlling its effects. The results show that the interaction between the wakes and the stator blades produces a characteristic pattern of vortical disturbances, which have been correlated to the pressure fluctuations. Within the stator passage, the wakes migrate towards the pressure surface where they evolve into counter-rotating vortices. These vortices are the dominant source of disturbances over the pressure surface of the stator blade. Over the suction surface of the stator blade, the disturbances are due to the distortion and detachment of boundary layer fluid. They can be reduced by tailoring the blade loading or by applying non-uniform suction.

An Integrated Software Procedure to Support Teaching of Radial Inflow Turbine Design

2007 ◽  
Author(s):  
Carlo Cravero ◽  
Martino Marini
Keyword(s):  
Design Analysis ◽  
Design Parameters ◽  
Analysis Tool ◽  
Software Suite ◽  
Computational Tools ◽  
Blade Loading ◽  
Radial Turbine ◽  
Integrated Software ◽  
Turbine Design ◽  
Turbomachinery Design

The authors decided to organize their design/analysis computational tools in an integrated software suite in order to help teaching radial turbine, taking advantage of their research background and a set of codes previously developed. The software is proposed for use during class works and the student can either use a single design/analysis tool or face a complete design loop consisting of iterations between design and analysis tools. The intended users are final year students in mechanical engineering. The codes output are discussed with two practical examples in order to highlight the turbomachinery performance at design and off-design conditions. The above suite gives the student the opportunity of getting used to different concepts (choking, blade loading, performance maps, …) that are encountered in turbomachinery design and of understanding the effects of the main design parameters.

scholarly journals Influence of Blade Wrap Angle on the Hydrodynamic Radial Force of Single Blade Centrifugal Pump

2021 ◽  
Vol 11 (19) ◽  
pp. 9052
Author(s):  
Linwei Tan ◽  
Yongfei Yang ◽  
Weidong Shi ◽  
Cheng Chen ◽  
Zhanshan Xie
Keyword(s):  
Centrifugal Pump ◽  
Flow Rate ◽  
High Efficiency ◽  
Rate Increase ◽  
Radial Force ◽  
Horizontal Component ◽  
Flow Rate Increase ◽  
Wrap Angle ◽  
External Characteristics ◽  
Blade Wrap Angle

To investigate the effect of blade wrap angle on the hydrodynamic radial force of a single blade centrifugal pump, numerical simulation is conducted on the pumps with different blade wrap angles. The effect of the wrap angle on the external characteristics and the radial force of a single blade centrifugal pump was analyzed according to the simulation result. It is found that, with the increase of the blade wrap angle, the head and efficiency of the single blade centrifugal pump are improved, the H-Q curve becomes steeper, and the efficiency also increased gradually, while the high-efficiency area is narrowed. The blade wrap angle has a great effect on the radial force of the single blade centrifugal pump. When the blade wrap angle is less than 360°, the horizontal component of the radial force is negative and the value is reduced with the increase of the wrap angle of the blade. When the wrap angle is larger than 360°, the horizontal component of the radial force is positive and the value increases with the increase of the wrap angle. Under part-loading conditions, the radial force of the single blade pump is significantly reduced with the increase of the blade wrap angle. When the wrap angle is smaller than 360°, the radial force decreases with the flow rate increase. In the condition that the wrap angle is larger than 360°, the radial force increases with the flow rate increase.

scholarly journals Numerical Investigation of an Open-Design Vortex Pump with Different Blade Wrap Angles of Impeller

Processes ◽  
2020 ◽  
Vol 8 (12) ◽  
pp. 1601
Author(s):  
Xiongfa Gao ◽  
Ting Zhao ◽  
Weidong Shi ◽  
Desheng Zhang ◽  
Ya Shi ◽  
...  
Keyword(s):  
Flow Rate ◽  
Front Face ◽  
Structural Parameter ◽  
Pump Efficiency ◽  
Impeller Blade ◽  
Open Design ◽  
Vortex Pump ◽  
Lateral Cavity ◽  
Wrap Angle ◽  
Blade Wrap Angle

The blade wrap angle of impeller is an important structural parameter in the hydraulic design of open-design vortex pump. In this paper, taking a vortex pump with a cylindrical blade structure as the research object, two kinds of different blade wrap angle of vortex pump impellers are designed. The experiment and numerical simulation research is carried out, and the results of external characteristics and internal flow field are obtained under different flow rate. The results show that when ensuring that other main structural parameters remain unchanged, the efficiency and head of open-design vortex pump increase with the blade wrap angle decreases. In the case of blade wrap angle increasing, the length of rotating reflux back from lateral cavity to inlet is longer. For the same type of vortex pump, the length of rotating reflux to inlet decreases with the increase of flow rate. At the inlet area of impeller front face, there is an area where liquid flows back to the lateral cavity. The volute section shows that after passing through the impeller and lateral cavity, the liquid is discharged to the pump outlet with strong spiral strength. It is found that the blade wrap angle decreases and the shaft power increases, while the pump efficiency increases. The impeller blade wrap angle of vortex pump can be considered to select a smaller value.

Aeroelastic Stability Analysis of Supersonic Cascades

1979 ◽  
Vol 101 (4) ◽  
pp. 533-541 ◽  
Author(s):  
J. A. Strada ◽  
W. R. Chadwick ◽  
M. F. Platzer
Keyword(s):  
Flat Plate ◽  
Leading Edge ◽  
Experimental Information ◽  
Nonlinear Method ◽  
Three Solutions ◽  
Blade Loading ◽  
Pressure Distributions ◽  
Blade Thickness ◽  
Analytical Expressions ◽  
Good Agreement

This paper presents three solutions for the analysis of supersonic flow past oscillating cascades with subsonic leading-edge locus. A quite elementary solution is first developed for the case of slowly oscillating finite and infinite flat plate cascades which provides simple analytical expressions for the unsteady pressure distributions. Comparisons with other solutions show generally excellent agreement. Furthermore, a previously developed linearized characteristics solution for finite flat plate cascades is applied to the case of superresonant blade motions. Again, the unsteady blade loading distributions are found to be in good agreement with Verdon’s recent infinite cascade solution for this case. Finally, a nonlinear method of characteristics solution for finite cascades is described which permits the analysis of blade thickness effects on flutter. At this time, only the inlet and passage flow computations have been completed which are compared with the available experimental information.

Effect of Blade Wrap Angle on Performance of a Single-Channel Pump

2018 ◽  
Vol 42 (5) ◽  
pp. 481-490 ◽  
Author(s):  
M. Tan ◽  
Y. Ji ◽  
H. Liu ◽  
X. Wu ◽  
Z. Zhu
Keyword(s):  
Single Channel ◽  
Wrap Angle ◽  
Blade Wrap Angle
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