Meridional shape design and the internal flow investigation of centrifugal impeller

Author(s):  
Yan Wang ◽  
Quanlin Dong ◽  
Yulian Zhang

This paper describes an inverse design method for calculating the shape of meridional plane of centrifugal impeller. This design method permits the shroud and hub contours to be indirectly calculated by medial axis contour and constraint equations. The design process is computationally inexpensive and can conveniently modify the shroud and hub shapes as the design’s demand. Based on this design method, new constraint equations are used for a new shape design of meridional plane that lead to a uniform velocity distribution in the inlet of impeller. Numerical simulations are employed to investigate the fluid flows of centrifugal fan. After validation of the numerical strategy, the pressure and velocity distributions in centrifugal fan are illustrated. The numerical results show that the inlet performance is improved and the velocity distribution is more uniform. Furthermore, in order to understand the flow mechanism inside the centrifugal fan, the secondary flow in the blade passage and velocity distribution at the shroud and hub have been carried out a detailed investigation and study.

2012 ◽  
Vol 233 ◽  
pp. 96-99
Author(s):  
Ya Jun Fan ◽  
Zhang Xu ◽  
Ding Wensi

Centrifugal fan in series with high wind pressure is the key facility of pneumatic transport equipment. To consider the impact of changed conditions on performance of centrifugal fan, internal flow of three-stage centrifugal fan at rated speed in different total pressure conditions is analyzed by CFD software FLUENT6.3 in this paper. Flow characteristics are obtained and the differences of total pressure and velocity distribution in each impeller are analyzed under different conditions, velocity distribution on the meridian plane and section of wind guide plates are compared. Finally, curves of P-Q and P-η at 4600 r/min are forecasted through the analysis of the data, which provide references for reducing impact that condition alteration on fan performance and improving the efficiency of the fan.


1990 ◽  
Vol 112 (1) ◽  
pp. 19-24 ◽  
Author(s):  
M. Ishida ◽  
Y. Senoo ◽  
H. Ueki

The velocity distribution was measured at the exit of two different types of un-shrouded centrifugal impeller under four different tip clearance conditions each; one with 20 radial blades and inducers and the other with 16 backward-leaning blades. The effect of tip clearance on input power was also measured. By increasing the tip clearance, the input power was hardly changed in the radial blade impeller and was reduced in the backward-leaning blade impeller. The velocity distribution normalized by the passage width between hub and shroud wall was hardly changed at the exit of the radial blade impeller by varying the tip clearance. On the other hand, the relative flow angle was reduced significantly and monotonously by an increase of tip clearance in the backward-leaning blade impeller. The change in input power due to the tip clearance was clearly related to the change of flow pattern at the exit of impeller due to the secondary flow. This is most likely caused by the component, normal to the blade, of the shear force to support the fluid in the clearance space against the pressure gradient in the meridional plane without blades.


2014 ◽  
Vol 525 ◽  
pp. 251-255 ◽  
Author(s):  
Sheng Li Zhang ◽  
Hua Xing Li

This paper points out that the traditional design method of multi blade centrifugal fan are great uncertainty in selecting the structure parameters: lead to many design results, do many tests. Internal flow field of multi blade centrifugal fan was simulated with the computational fluid dynamics software Fluent, and the numerical results are analyzed. Comparison of the numerical results with the test results shows that numerical simulation has good accuracy and reliability. The design program and a design example is gived according to the design theory of multi blade centrifugal fan. Method is verified by numerical simulation for the example. Test results show that the design program is reliable.


Author(s):  
Yu-Tai Lee ◽  
Vineet Ahuja ◽  
Ashvin Hosangadi ◽  
Michael E. Slipper ◽  
Lawrence P. Mulvihill ◽  
...  

A design method is presented for re-designing the double-discharge, double-width, double-inlet (DWDI) centrifugal impeller for the lift fans of a hovercraft. Given the current high performance of impellers, the design strategy uses a computational method, which is capable of predicting flow separation and vortex-dominated flow fields, enabling a detailed comparison of all aerodynamic losses. The design method, assuming a weak interaction between the impeller and the volute, employs a blade optimization procedure and several effective flow path modifications. Simplified CFD calculations were performed on fans with two existing impellers and the newly designed impeller to evaluate the impeller design criterion. The calculation was made with the impeller/volute coupling calculation and a frozen impeller assumption. Further refined CFD calculations, including the gap between the stationary bellmouth and the rotating shroud, revealed a reduction in the new impeller’s gain in efficiency due to the gap. The calculations also further supported the necessity of matching the volute and the impeller to improve the fan’s overall efficiency. Measured data of three fans validated CFD predictions in pressure rise at design and off-design conditions. CFD calculations also demonstrated the Reynolds number effect between the model- and full-scale fans. Power reduction data were compared between the measurements and the predictions along with the original design requirements.


1969 ◽  
Vol 11 (5) ◽  
pp. 454-467 ◽  
Author(s):  
K. Murugesan ◽  
J. W. Railly

An extension of Martensen's method is described which permits an exact solution of the inverse or blade design problem. An equation is derived for the normal velocity distributed about a given contour when a given tangential velocity is imposed about the contour and from this normal velocity an initial arbitrarily chosen blade shape may be successively modified until a blade is found having a desired surface velocity distribution. Five examples of the method are given.


Author(s):  
Kisun Song ◽  
Kyung Hak Choo ◽  
Jung-Hyun Kim ◽  
Dimitri N. Mavris

In modern automotive industry market, there have been a lot of state-of-art methodologies to perform a conceptual design of a car; functional methods and 3D scanning technology are widely used. Naturally, the issues frequently boiled down to a trade-off decision making problem between quality and cost. Besides, to incorporate the design method with advanced optimization methodologies such as design-of-experiments (DOE), surrogate modeling, how efficiently a method can morph or recreate a vehicle’s shape is crucial. This paper accomplishes an aerodynamic design optimization of rear shape of a sedan by incorporating a reverse shape design method (RSDM) with the aforementioned methodologies based on CFD analysis for aerodynamic drag reduction. RSDM reversely recovers a 3D geometry of a car from several 2D schematics. The backbone boundary lines of 2D schematic are identified and regressed by appropriate interpolation function and a 3D shape is yielded by a series of simple arithmetic calculations without losing the detail geometric features. Besides, RSDM can parametrize every geometric entity to efficiently manipulate the shape for application to design optimization studies. As the baseline, an Audi A6 is modeled by RSDM and explored through CFD analysis for model validation. Choosing six design variables around the rear shape, 77 design points are created to build neural networks. Finally, a significant amount of CD reduction is obtained and corresponding configuration is validated via CFD.


1990 ◽  
Author(s):  
A. Kirschner ◽  
H. Stoff

A cascade design-method is presented which complements the meridional through-flow design procedure of turbomachines. Starting from an axisymmetric flow field and the streamline geometry in the meridional plane this simple method produces a solution for the quasi three-dimensional flow field and the blade-element geometry on corresponding stream surfaces. In addition, it provides intra-blade data on loss and turning required for a consistent design and a convenient means of optimizing blade loading. The purpose of this paper is to describe the theoretical basis of the method and to illustrate its application in the design of transonic compressors.


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