A numerical study of the effects of blade angle distribution on the performance and loss generation of centrifugal compressor impellers

Author(s):  
S Kim ◽  
J Park ◽  
J Baek
Author(s):  
M. B. Flathers ◽  
G. E. Bache ◽  
R. Rainsberger

The flowfield of a complex three dimensional radial inlet for an industrial pipeline centrifugal compressor has been experimentally determined on a half scale model. Based on the experimental results, inlet guide vanes have been designed to correct pressure and swirl angle distribution deficiencies. The unvaned and vaned inlets are analyzed with a commercially available fully 3D viscous Navier-Stokes code. Since experimental results were available prior to the numerical study, the unvaned analysis is considered a postdiction while the vaned analysis is considered a prediction. The computational results of the unvaned inlet have been compared to the previously obtained experimental results. The experimental method utilized for the unvaned inlet is repeated for the vaned inlet and the data has been used to verify the computational results. The paper will discuss experimental, design and computational procedures, grid generation, boundary conditions, and experimental versus computational methods. Agreement between experimental and computational results is very good, both in prediction and postdiction modes. The results of this investigation indicate that CFD offers a measurable advantage in design, schedule and cost and can be applied to complex, three dimensional radial inlets.


1988 ◽  
Vol 110 (1) ◽  
pp. 110-114 ◽  
Author(s):  
H. Harada

The overall performance of two- and three-dimensional impellers of a centrifugal compressor were tested and compared. A closed-loop test stand with Freon gas as the working fluid was employed for the experiments. The inlet and outlet velocity distributions of all impellers were measured using three-hole cobra probes. As a result, it has been revealed that three-dimensional impeller in terms of efficiency, head coefficient, and operating range. Further, it has also been clarified that the impeller slip factor is affected by blade angle distribution.


1996 ◽  
Vol 118 (2) ◽  
pp. 371-384 ◽  
Author(s):  
M. B. Flathers ◽  
G. E. Bache ◽  
R. Rainsberger

The flow field of a complex three-dimensional radial inlet for an industrial pipeline centrifugal compressor has been experimentally determined on a half-scale model. Based on the experimental results, inlet guide vanes have been designed to correct pressure and swirl angle distribution deficiencies. The unvaned and vaned inlets are analyzed with a commercially available fully three-dimensional viscous Navier–Stokes code. Since experimental results were available prior to the numerical study, the unvaned analysis is considered a postdiction while the vaned analysis is considered a prediction. The computational results of the unvaned inlet have been compared to the previously obtained experimental results. The experimental method utilized for the unvaned inlet is repeated for the vaned inlet and the data have been used to verify the computational results. The paper will discuss experimental, design, and computational procedures, grid generation, boundary conditions, and experimental versus computational methods. Agreement between experimental and computational results is very good, both in prediction and postdiction modes. The results of this investigation indicate that CFD offers a measurable advantage in design, schedule, and cost and can be applied to complex, three-dimensional radial inlets.


1986 ◽  
Author(s):  
H. Harada

The overall performance of two- and three-dimensional impellers of a centrifugal compressor were tested and compared. A closed loop test stand with Freon gas as working fluid was employed for the experiments. The inlet and outlet velocity distribtions of all impellers were measured using three hole cobra probes. As a result, it has been revealed that three-dimensional impellers are superior to two-dimensional one in terms of efficiency, head coefficient and operating range. Further, it has also been clarified that the impeller slip factor is affected by blade angle distribution.


Author(s):  
Arindam Bera ◽  
N. K. Singh

Return channel de-swirl vanes form an integral part of a centrifugal compressor stage for multi-stage configuration. In this paper, a few configurations of return channel vanes (RCV) are arrived at by modifying the blade angle and thickness distribution from leading edge to the trailing edge. Influence of these two parameters on the overall performance of return channel in terms of total pressure loss co-efficient and static pressure recovery co-efficient along with stage exit flow angle are evaluated through CFD analysis. CFD results show that, proper thickness distribution after maximum thickness point to the trailing edge improves the stage exit flow angle but not the total pressure loss co-efficient and static pressure recovery co-efficient. Whereas, by suitably modifying the blade angle distribution, all the three performance parameters can be improved considerably.


Author(s):  
Justin (Jongsik) Oh

Growing demands for higher specific output power in turbomachinery applications have drawn attention to aerodynamic design philosophy for a single-stage transonic centrifugal compressor with higher pressure ratios. As Part 1 of numerical efforts, some fundamental approaches in aerodynamic design were carried out in a classical 6:1 pressure-ratio compressor design of 1970’s which was selected as a baseline. The effects of the impeller blade angle distribution, the addition of the splitter blade, the changes of the tangential divergence angle of the channel-wedge diffuser and some tweaks in diffuser vane shapes near the trailing-edge were investigated in steady-state RANS CFD solutions with the conventional mixing plane interface. New blade angle distributions together with the introduction of splitter blades in the impeller brought significant improvements in the compressor pressure ratio, efficiency and operability, thanks to reduced shock strengths and enhanced blade loadings in the spanwise direction. Helicity contours on the cross sectional planes in the impeller support the benefits observing a power balance among the shroud passage vortex, the blade vortices and the tip leakage vortex. With a reduced tangential divergence in the channel-wedge diffuser passage from the original design, an impressively extended surge margin was obtained. It was confirmed from the helicity contours that a streamwise vortex structure at the entrance region of the diffuser vane plays a key role in the range of operation. A diffuser vane shape with the curved pressure surface near the trailing-edge provided a slightly higher pressure ratio and efficiency around design flow than that with the original cut-off trailing-edge. An elliptical trailing-edge diffuser vane showed rather performance drops because of the counter-clockwise hub vortex breakdown near the suction surface, resulting in less flow diffusion. Through investigations of a set of design cases, two final compressor designs, differing in the diffuser vane shape near the trailing-edge, were obtained within the work scope of the present study. However, selecting one of the two will depend on design duties for the following component because of the level of exit swirls and their rate of changes over the flow rates.


Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4292
Author(s):  
Kirill Kabalyk ◽  
Andrzej Jaeschke ◽  
Grzegorz Liśkiewicz ◽  
Michał Kulak ◽  
Tomasz Szydłowski ◽  
...  

The article describes an assessment of possible changes in constant fatigue life of a medium flow-coefficient centrifugal compressor impeller subject to operation at close-to-surge point. Some aspects of duct acoustics are additionally analyzed. The experimental measurements at partial load are presented and are primarily used for validation of unidirectionally coupled fluid-structural numerical model. The model is based on unsteady finite-volume fluid-flow simulations and on finite-element transient structural analysis. The validation is followed by the model implementation to replicate the industry-scale loads with reasonably higher rotational speed and suction pressure. The approach demonstrates satisfactory accuracy in prediction of stage performance and unsteady flow field in vaneless diffuser. The latter is deduced from signal analysis relying on continuous wavelet transformations. On the other hand, it is found that the aerodynamic incidence losses at close-to-surge point are underpredicted. The structural simulation generates considerable amounts of numerical noise, which has to be separated prior to evaluation of fluid-induced dynamic strain. The main source of disturbance is defined as a stationary region of static pressure drop caused by flow contraction at volute tongue and leading to first engine-order excitation in rotating frame of reference. Eventually, it is concluded that the amplitude of excitation is too low to lead to any additional fatigue.


2014 ◽  
Vol 663 ◽  
pp. 347-353
Author(s):  
Layth H. Jawad ◽  
Shahrir Abdullah ◽  
Zulkifli R. ◽  
Wan Mohd Faizal Wan Mahmood

A numerical study that was made in a three-dimensional flow, carried out in a modified centrifugal compressor, having vaned diffuser stage, used as an automotive turbo charger. In order to study the influence of vaned diffuser meridional outlet section with a different width ratio of the modified centrifugal compressor. Moreover, the performance of the centrifugal compressor was dependent on the proper matching between the compressor impeller along the vaned diffuser. The aerodynamic characteristics were compared under different meridional width ratio. In addition, the velocity vectors in diffuser flow passages, and the secondary flow in cross-section near the outlet of diffuser were analysed in detail under different meridional width ratio. Another aim of this research was to study and simulate the effect of vaned diffuser on the performance of a centrifugal compressor. The simulation was undertaken using commercial software so-called ANSYS CFX, to predict numerically the performance charachteristics. The results were generated from CFD and were analysed for better understanding of the fluid flow through centrifugal compressor stage and as a result of the minimum width ratio the flow in diffuser passage tends to be uniformity. Moreover, the backflow and vortex near the pressure surface disappear, and the vortex and detachment near the suction surface decrease. Conclusively, it was observed that the efficiency was increased and both the total pressure ratio and static pressure for minimum width ratio are increased.


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