scholarly journals Numerical and Experimental Aerodynamic Investigation of an S-Shaped Intermediate Compressor Duct With Bleed

2021 ◽  
pp. 1-16
Author(s):  
Elias Siggeirsson ◽  
Niklas Andersson ◽  
Markus Olander Burak

Abstract A series of CFD simulations are performed to analyse the effects a rotor off-take bleed has on the performance of an Intermediate Compressor Duct (ICD). To validate the CFD results, a comparison is made to measurements obtained from an experimental facility located at GKN Aerospace Engine Systems in Sweden. To achieve a deeper understanding of the flow physics, hybrid RANS/LES simulations are performed for a single operating condition. The CFD simulations are capable of predicting the behavior when extracting large amount of air through the bleed pipe, where an improved prediction is obtained with the hybrid simulation. The performance of the ICD is severely compromised with increased amount of bleed as the flow delivered to the downstream component is highly disturbed. The disturbed flow is caused by the extraction of axial flow through the bleed pipe, increasing the incidence into the low-pressure compressor's outlet guide vanes resulting in unfavorable velocity profiles into the ICD. This behavior causes the flow to separate at the OGV blades, where the separation increases with increase bleed. Furthermore, when including the full bleed system, significant circumferential distortions are observed, showing the necessity of the integrated design.

Author(s):  
Elias M. V. Siggeirsson ◽  
Niklas Andersson ◽  
Markus Burak Olander

Abstract A series of CFD simulations are performed to analyse the effects a rotor off-take bleed has on the performance of an Intermediate Compressor Duct (ICD). To validate the CFD results, a comparison is made to measurements obtained from an experimental facility located at GKN Aerospace Engine Systems in Sweden. To achieve a deeper understanding of the flow physics, hybrid RANS/LES simulations are performed for a single operating condition. The CFD simulations are capable of predicting the behavior when extracting large amount of air through the bleed pipe, where an improved prediction is obtained with the hybrid simulation. The performance of the ICD is severely compromised with increased amount of bleed as the flow delivered to the downstream component is highly disturbed. The disturbed flow is caused by the extraction of axial flow through the bleed pipe, increasing the incidence into the low-pressure compressor’s outlet guide vanes resulting in unfavorable velocity profiles into the ICD. This behavior causes the flow to separate at the OGV blades, where the separation increases with increase bleed. Furthermore, when including the full bleed system, significant circumferential distortions are observed, showing the necessity of the integrated design.


1990 ◽  
Vol 112 (2) ◽  
pp. 294-297 ◽  
Author(s):  
J. H. Horlock

An actuator disk analysis is given of the flow through a guide vane and rotor combination. It is shown that changes in total pressure across the rotor are in general related to circumferential variations in guide vane outlet angle. In particular known variations in inlet total pressure may be eliminated by suitable circumferential changes in guide vane stagger.


Author(s):  
Alexander Wright ◽  
Ali Mahallati ◽  
Martin J. Conlon ◽  
Julio Militzer

The efficacy of integrating the lobed mixer with the core flow deswirling struts to create a single component for reducing the exhaust system length, beyond that attainable through mixer optimization alone, has been investigated. This investigation has been conducted via CFD simulations of a medium-bypass turbofan exhaust system at engine cruise representative conditions. Comparative analysis shows that integration augmented thrust output by about 0.02% while total pressure loss was increased by 3.6%. The aim of the study, to show that this new integrated design would have either minimal impact on or improve exhaust system performance, was confirmed. Comparisons of the flow fields and characteristic quantities downstream of the mixer also showed minimal impact on flow through the nozzle. The deswirling strut was offset by 0.65 Dh axially when integrated with the mixer, therefore it can be concluded that the exhaust system ducting could be reduced in length by this same measure — saving engine weight in the process.


Author(s):  
Alexey N. Kochevsky ◽  
Stanislav N. Kozlov ◽  
Khin Maung Aye ◽  
Alexander Y. Schelyaev ◽  
Vladimir N. Konshin

The article describes numerical research of fluid flow inside an axial-flow pump that includes adjustable guide vanes, impeller and discharge channel. The guide vanes in the extreme position cut off the flow through the pump. The article presents the performance curves of the pump at different pitch angle of those guide vanes, as well as some corresponding flow patterns. Cavitation characteristics are also presented. The results were obtained using the CFD software tools CFX-BladeGenPlus, CFX-TASCflow and CFX-5. In the previous article, the authors have presented a comprehensive comparison of numerical results with available experimental results for a similar pump. As it was demonstrated, the performance curves of the pump depend strongly on the guide vanes pitch angle. Conclusions concerning these dependencies are drawn. A particular attention is paid for evaluation of performance of the pump with swirl flow downstream of it.


Author(s):  
Marcel Escudier

This chapter is concerned primarily with the flow of a compressible fluid through stationary and moving blading, for the most part using the analysis introduced in Chapter 11. The principles of dimensional analysis are applied to determine the appropriate non-dimensional parameters to characterise the performance of a turbomachine. The analysis of incompressible flow through a linear cascade of aerofoil-like blades is followed by the analysis of compressible flow. Velocity triangles for flow relative to blades, and Euler’s turbomachinery equation, are introduced to analyse flow through a rotor. The concepts introduced are applied to the analysis of an axial-turbomachine stage comprising a stator and a rotor, which applies to either a compressor or a turbine.


Author(s):  
John J. Adamczyk

This paper summarizes the state of 3D CFD based models of the time average flow field within axial flow multistage turbomachines. Emphasis is placed on models which are compatible with the industrial design environment and those models which offer the potential of providing credible results at both design and off-design operating conditions. The need to develop models which are free of aerodynamic input from semi-empirical design systems is stressed. The accuracy of such models is shown to be dependent upon their ability to account for the unsteady flow environment in multistage turbomachinery. The relevant flow physics associated with some of the unsteady flow processes present in axial flow multistage machinery are presented along with procedures which can be used to account for them in 3D CFD simulations. Sample results are presented for both axial flow compressors and axial flow turbines which help to illustrate the enhanced predictive capabilities afforded by including these procedures in 3D CFD simulations. Finally, suggestions are given for future work on the development of time average flow models.


2016 ◽  
Vol 99 ◽  
pp. 1146-1152 ◽  
Author(s):  
Zhongdong Qian ◽  
Fan Wang ◽  
Zhiwei Guo ◽  
Jie Lu

Author(s):  
Sang-Won Kim ◽  
Youn-Jea Kim

An axial-flow pump has a relatively high discharge flow rate and specific speed at a relatively low head and it consists of an inlet guide vane, impeller, and outlet guide vane. The interaction of the flow through the inlet guide vane, impeller, and outlet guide vane of the axial-flow pump has a significant effect on its performance. Of those components, the guide vanes especially can improve the head and efficiency of the pump by transforming the kinetic energy of the rotating flow, which has a tangential velocity component, into pressure energy. Accordingly, the geometric configurations of the guide vanes such as blade thickness and angle are crucial design factors for determining the performance of the axial-flow pump. As the reliability of Computational Fluid Dynamics (CFD) has been elevated together with the advance in computer technology, numerical analysis using CFD has recently become an alternative to empirical experiment due to its high reliability to measure the flow field. Thus, in this study, 1,200mm axial-flow pump having an inlet guide vane and impeller with 4 blades and an outlet guide vane with 6 blades was numerically investigated. Numerical study was conducted using the commercial CFD code, ANSYS CFX ver. 16.1, in order to elucidate the effect of the thickness and angle of the guide vanes on the performance of 1,200mm axial-flow pump. The stage condition, which averages the fluxes between interfaces and is accordingly appropriate for the evaluation of pump performance, was adopted as the interface condition between the guide vanes and the impeller. The rotational periodicity condition was used in order to enable a simplified geometry to be used since the guide vanes feature multiple identical regions. The shear stress transport (SST) k-ω model, predicting the turbulence within the flow in good agreement, was also employed in the CFD calculation. With regard to the numerical simulation results, the characteristics of the pressure distribution were discussed in detail. The pump performance, which will determine how well an axial-flow pump will work in terms of its efficiency and head, was also discussed in detail, leading to the conclusion on the optimal blade thickness and angle for the improvement of the performance. In addition, the total pressure loss coefficient was considered in order to investigate the loss within the flow paths depending on the thickness and angle variations. The results presented in this study may give guidelines to the numerical analysis of the axial-flow pump and the investigation of the performance for further optimal design of the axial-flow pump.


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