scholarly journals Empirical Design Considerations for Industrial Centrifugal Compressors

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Cheng Xu ◽  
Ryoichi S. Amano
Keyword(s):  
Centrifugal Compressor ◽  
Centrifugal Compressors ◽  
Design Guideline ◽  
Stage Design ◽  
Centrifugal Stage ◽  
Complex Design ◽  
Compressor Design ◽  
Computational Fluid Dynamics Cfd ◽  
Ported Shroud ◽  
Empirical Design

Computational Fluid Dynamics (CFD) has been extensively used in centrifugal compressor design. CFD provides further optimisation opportunities for the compressor design rather than designing the centrifugal compressor. The experience-based design process still plays an important role for new compressor developments. The wide variety of design subjects represents a very complex design world for centrifugal compressor designers. Therefore, some basic information for centrifugal design is still very important. The impeller is the key part of the centrifugal stage. Designing a highly efficiency impeller with a wide operation range can ensure overall stage design success. This paper provides some empirical information for designing industrial centrifugal compressors with a focus on the impeller. A ported shroud compressor basic design guideline is also discussed for improving the compressor range.

Centrifugal Compressor Design Considerations

2006 ◽  
Author(s):  
C. Xu
Keyword(s):  
Centrifugal Compressor ◽  
Three Dimensional ◽  
Compressor Stage ◽  
Centrifugal Compressors ◽  
Stage Design ◽  
Training Time ◽  
Operating Range ◽  
Design Considerations ◽  
Compressor Design ◽  
Design Experience

Initial design considerations of centrifugal compressor are commonly performed with experience base, although computer technology and numerical methods had made significantly progress. Three-dimensional Computational Fluid Dynamics (CFD) codes are still not major design tools for centrifugal compressors. Major design systems for industrial centrifugal compressor design are largely based on one-dimensional meanline and two-dimensional through flow tools. The experience of designers is one of the key factors to drive design success. The impeller is one of the key components of a centrifugal compressor stage. Design of the impeller is critical to the success of compressor stage design. Basic sizing information to establish the initial parameters can save development time for industrial centrifugal compressor development. The diffuser plays an important role in the compressor operating range. A poorly designed diffuser reduces compressor operating range and stage efficiency. The volute design impacts the compressor performance and bearing life. For successful design all compressor components, the design experience is one of a key factor to make design success. This paper presents author’s design experience for centrifugal compressors. The discussions and information on compressor design considerations in open literature are also reviewed. The purpose of the paper is to serve as a part of compressor design experience database for young engineers and college students in order to reduce their training time to become compressor designers.

The Development of a Low Specific Speed Centrifugal Compressor Research Facility

2016 ◽  
Author(s):  
Jeanne Methel ◽  
William J. Gooding ◽  
John C. Fabian ◽  
Nicole L. Key ◽  
Mark Whitlock
Keyword(s):  
High Pressure ◽  
Centrifugal Compressor ◽  
Axial Compressor ◽  
Centrifugal Compressors ◽  
Centrifugal Stage ◽  
High Pressure Compressor ◽  
Low Specific Speed ◽  
Last Stage ◽  
Specific Speed ◽  
Consumption Goals

To achieve aggressive specific fuel consumption goals, aircraft engines are tending toward higher overall pressure ratios and higher bypass ratios for turbofans. As sizes decrease to meet these requirements, centrifugal compressors become a viable option as the last stage of the high pressure compressor. The last stages of an axial compressor in a small core engine face reduced efficiency due to the relatively large tip clearances with respect to blade height, and therefore, it may be more appropriate to finish the final compression stage with a low specific speed centrifugal compressor. A new facility, the Centrifugal STage for Aerodynamics Research (CSTAR) Facility, has been developed at Purdue University in cooperation with Rolls-Royce to gain further understanding of the complex aerodynamics found in such centrifugal compressors. The experimental data acquired in this facility will be utilized to develop and validate design tools for centrifugal compressors used in axial-centrifugal high-pressure compressors. The facility models the last (centrifugal) stage of an axial-centrifugal compressor and operates at engine-representative Mach numbers. In this paper, the facility is described in detail, and the baseline steady-state performance of the compressor is presented.

Matching of Gas Turbines and Centrifugal Compressors: Oil and Gas Industry Practice

2012 ◽  
Author(s):  
Matt Taher ◽  
Cyrus Meher-Homji
Keyword(s):  
Gas Turbine ◽  
Centrifugal Compressor ◽  
Gas Turbines ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Site Conditions ◽  
Centrifugal Compressors ◽  
Gas Industry ◽  
Compressor Design ◽  
Selection Of

Gas turbine driven centrifugal compressors are widely used in the oil and gas industry. In evaluating the optimum selection of gas turbine drivers for centrifugal compressors, one of the main objectives should be to verify proper integration and matching of the centrifugal compressor to its gas turbine driver. Gas turbines are of standard designs, while centrifugal compressors are specifically designed to meet customer requirements. The purchaser should clearly specify process requirements and define possible operating scenarios for the entire life of the gas turbine driven centrifugal compressor train. Process requirements defined by the purchaser, will be used by the compressor designer to shape the aero-thermodynamic behavior of the compressor and characterize compressor performance. When designing a centrifugal compressor to be driven by a specific gas turbine, other design requirements are automatically introduced to centrifugal compressor design. Off-design performance, optimum power turbine speeds at site conditions as well as optimum power margin required for a future-oriented design must all be considered. Design and off-design performance of the selected gas turbine at site conditions influences the final selection of a properly matched centrifugal compressor design. In order to evaluate different designs and select the most technically viable solution, the purchaser should have a clear understanding of the factors influencing a proper match for a centrifugal compressor and its gas turbine driver. This paper discusses criteria for evaluating the most efficient combination of a centrifugal compressor and its gas turbine driver as an integral package from a purchaser’s viewpoint. It also addresses API standard requirements on gas turbine driven centrifugal compressors.

Casing Treatment of Centrifugal Compressors

2015 ◽  
Author(s):  
Jisha Noushad ◽  
Anand Babu Dhamarla ◽  
Pavan Kumar
Keyword(s):  
Mass Flow ◽  
Centrifugal Compressor ◽  
Reverse Flow ◽  
Pressure Fluctuations ◽  
Centrifugal Compressors ◽  
Flow Rates ◽  
Casing Treatment ◽  
Operating Range ◽  
Mass Flow Rates ◽  
Ported Shroud

The operating range of any compressor is controlled by Surge and Choke. Surge occurs at lower mass flow rates with large pressure fluctuations and flow reversals, while choke occurs at higher mass flow rates when the flow rate reaches the limit which compressor can discharge. Ported shroud is a cost effective casing treatment that can greatly improve operating range of centrifugal compressors. By removing the stagnant and reverse flow from shroud wall boundary-layer region and recirculating it to impeller inlet, it has been demonstrated that larger range of operability can be achieved without much loss on compressor efficiency. This paper demonstrates the improvement of a centrifugal compressor operational range with ported shroud configuration. A series of CFD simulations were carried out with open source centrifugal compressor geometry (NASA HPCC 4:1) to create performance characteristics/speed-lines. The CFD methodology and practices were validated by comparing the results with the experimental data. Performance evaluation of ported shroud configuration is done with respect to solid shroud. Ported shroud compressor is proven to give higher choke mass flow and also a better surge margin compared to the Solid shroud model. The phenomena of in-flowing and out-flowing port have also been demonstrated. Emphasis was given to understand how ported shroud helps to achieve a better performance. A design optimization study has also been carried out in order to establish the optimum ported shroud configuration. Design parameter such as port location has been selected and the effect of this parameter on the performance of the compressor is studied using CFD. Optimum port geometry was proposed.

Centrifugal compressor design

1998 ◽  
Vol 213 (2) ◽  
pp. 139-155 ◽  
Author(s):  
P. M. Came ◽  
C. J. Robinson
Keyword(s):  
Centrifugal Compressor ◽  
State Of The Art ◽  
Mechanical Design ◽  
Preliminary Design ◽  
Aerodynamic Design ◽  
Design Procedures ◽  
Wide Range ◽  
Compressor Design ◽  
Computational Fluid Dynamics Cfd ◽  
Physical Phenomena

Centrifugal compressors are used in a wide range of applications in which performance and mechanical integrity are invariably among the paramount design objectives. There is therefore continuing interest in the development of a sound understanding of the relevant physical phenomena and in the systematic application of the knowledge base that is the forerunner of the established design procedures. The paper reviews centrifugal compressor design methods that are commonly used in industry and reviews the underlying engineering science supporting the design practices. The design process, starting with the preliminary design and its reliance on empirical rules through to state-of-the-art aerodynamic design using computational fluid dynamics (CFD), is presented. The essentials of impeller mechanical design are also included in the paper.

Axial groove casing treatment in an automotive turbocharger centrifugal compressor

2017 ◽  
Vol 232 (24) ◽  
pp. 4472-4484 ◽  
Author(s):  
PXL Harley ◽  
A Starke ◽  
T Bamba ◽  
D Filsinger
Keyword(s):  
Centrifugal Compressor ◽  
Limited Effect ◽  
Gasoline Engines ◽  
Casing Treatment ◽  
Automotive Market ◽  
Surge Margin ◽  
Baseline Case ◽  
Computational Fluid Dynamics Cfd ◽  
Ported Shroud ◽  
Casing Treatments

The automotive market is continually driving the suppliers of turbochargers to push their designs into new unexplored realms. The most recent request is to have improvements to the surge margin at higher pressure ratios due to the demands of modern Diesel and gasoline engines. This study looked back at historic casing treatments and investigated the concept of axial grooves being applied to the shroud of a centrifugal compressor. This paper presents a literature review of previous centrifugal compressor casing treatments and explores in detail the axial groove type casing treatment. The study is comprised of two main sections, a test campaign and a numerical investigation. The test campaign compares the axial groove casing treatment against a baseline case without a casing treatment and a typical ported shroud casing treatment. Results are presented along with an explanation of the changes to the performance over the baseline case. The axial groove casing treatment is shown to be able to improve the surge margin as desired in a very package orientated manner. The second part of this paper looks at a similar axial groove casing treatment but for a different centrifugal compressor stage. A computational fluid dynamics (CFD) study was carried out to investigate and provide understanding to the fluid mechanics surrounding the axial groove casing treatment. The CFD and test data are not compared; rather an independent CFD study explains the basic mechanics of how the axial grooves interact with the impeller in order to explain the performance changes seen between a baseline case, and a case including the axial groove casing treatment. Axial grooves at the impeller inlet are shown to be an effective method of improving the surge margin with a limited effect on efficiency, whilst working within a package restricted design space.

Rotordynamic Force Prediction of Centrifugal Compressor Impellers Using Computational Fluid Dynamics

2007 ◽  
Author(s):  
J. Jeffrey Moore ◽  
David L. Ransom ◽  
Flavia Viana
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Centrifugal Compressor ◽  
Cross Coupling ◽  
Operating Pressure ◽  
Centrifugal Compressors ◽  
Computational Fluid Dynamics Cfd ◽  
New Generation ◽  
Semi Empirical ◽  
Fluid Interaction

The energy industry depends on centrifugal compressors to produce, process, re-inject and transport many different gases. Centrifugal compressors use one or more impellers to impart momentum to the flowing gas and, thereby, produce an increase in pressure through diffusion. As the operating pressure in a compressor increases, the fluid-rotor interaction at the seals and impellers become more important. Also, the new generation of mega-scale Liquefied Natural Gas (LNG) compressors is dependent on accurate assessment of these forces. The aerodynamic forces and cross-coupled stiffness from the impellers cannot be accurately predicted with traditional methods and must be estimated with semi-empirical formulations. The result of these inaccuracies is a potential for compressor designs that can experience unexpected, dangerous, and damaging instabilities and subsynchronous vibrations. The current investigation is intended to advance the state-of-the-art to achieve an improved, physics-based method of predicted aerodynamic destabilizing cross-coupling forces on centrifugal compressor impellers using Computational Fluid Dynamics (CFD). CFD was employed in this study to predict the impeller-fluid interaction forces, which gives rise to the aerodynamic cross-coupling. The procedure utilized in this study was developed by Moore and Palazzolo [10], which applied the method to liquid pump impellers. Their results showed good correlation to test data. Unfortunately, no such data exists for centrifugal compressors. Therefore, in order to validate the present model, comparisons will be made to predict the instability of an industrial centrifugal compressor. A parametric CFD study is then presented leading to a new analytical expression for predicting the cross-coupled stiffness for centrifugal impellers.

scholarly journals The Problem of Accounting for Heat Exchange between the Flow and the Flow Part Surfaces When Modeling a Viscous Flow in Low-Flow Stages of a Centrifugal Compressor

2020 ◽  
Vol 10 (24) ◽  
pp. 9138
Author(s):  
Sergey Kartashov ◽  
Yuri Kozhukhov ◽  
Vycheslav Ivanov ◽  
Aleksei Danilishin ◽  
Aleksey Yablokov ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchange ◽  
Centrifugal Compressor ◽  
Calculation Model ◽  
Flow Coefficient ◽  
Low Flow ◽  
Relative Width ◽  
Adiabatic Wall ◽  
Flow Part ◽  
Computational Fluid Dynamics Cfd

In this paper, we review the problem of accounting for heat exchange between the flow and the flow part surfaces when creating a calculation model for modeling the workflow process of low-flow stages of a centrifugal compressor using computational fluid dynamics (CFD). The objective selected for this study was a low-flow intermediate type stage with the conditional flow coefficient Փ = 0.008 and the relative width at the impeller exit b2/D2 = 0.0133. We show that, in the case of modeling with widespread adiabatic wall simplification, the calculated temperature in the gaps between the impeller and the stator elements is significantly overestimated. Modeling of the working process in the flow part was carried out with a coupled heat exchanger, as well as with simplified accounting for heat transfer by setting the temperatures of the walls. The gas-dynamic characteristics of the stage were compared with the experimental data, the heat transfer influence on the disks friction coefficient was estimated, and the temperature distributions in the gaps between disks and in the flow part of the stage were analyzed. It is shown that the main principle when modeling the flow in low-flow stage is to ensure correct temperature distribution in the gaps.

Roles of vanes in diffuser on stability of centrifugal compressor

2019 ◽  
Vol 233 (14) ◽  
pp. 5380-5392
Author(s):  
Wangzhi Zou ◽  
Xiao He ◽  
Wenchao Zhang ◽  
Zitian Niu ◽  
Xinqian Zheng
Keyword(s):  
High Pressure ◽  
Centrifugal Compressor ◽  
Dynamic Pressure ◽  
Pressure Ratio ◽  
Pressure Rise ◽  
Rotating Stall ◽  
Centrifugal Compressors ◽  
Compression System ◽  
The Stability ◽  
Rotating Instability

The stability considerations of centrifugal compressors become increasingly severe with the high pressure ratios, especially in aero-engines. Diffuser is the major subcomponent of centrifugal compressor, and its performance greatly influences the stability of compressor. This paper experimentally investigates the roles of vanes in diffuser on component instability and compression system instability. High pressure ratio centrifugal compressors with and without vanes in diffuser are tested and analyzed. Rig tests are carried out to obtain the compressor performance map. Dynamic pressure measurements and relevant Fourier analysis are performed to identify complex instability phenomena in the time domain and frequency domain, including rotating instability, stall, and surge. For component instability, vanes in diffuser are capable of suppressing the emergence of rotating stall in the diffuser at full speeds, but barely affect the characteristics of rotating instability in the impeller at low and middle speeds. For compression system instability, it is shown that the use of vanes in diffuser can effectively postpone the occurrence of compression system surge at full speeds. According to the experimental results and the one-dimensional flow theory, vanes in diffuser turn the diffuser pressure rise slope more negative and thus improve the stability of compressor stage, which means lower surge mass flow rate.

Backward Traveling Rotating Stall Waves in Centrifugal Compressors

2002 ◽  
Author(s):  
Z. S. Spakovsky
Keyword(s):  
Mass Flow ◽  
Centrifugal Compressor ◽  
First Principles ◽  
Rotating Stall ◽  
Air Injection ◽  
System Stability ◽  
Centrifugal Compressors ◽  
Injection Scheme ◽  
Surge Margin ◽  
Low Order

Rotating stall waves that travel against the direction of rotor rotation are reported for the first time and a new, low-order analytical approach to model centrifugal compressor stability is introduced. The model is capable of dealing with unsteady radially swirling flows and the dynamic effects of impeller-diffuser component interaction as it occurs in centrifugal compression systems. A simple coupling criterion is developed from first principles to explain the interaction mechanism important for system stability. The model findings together with experimental data explain the mechanism for first-ever observed backward traveling rotating stall in centrifugal compressors with vaned diffusers. Based on the low-order model predictions, an air injection scheme between the impeller and the vaned diffuser is designed for the NASA Glenn CC3 high-speed centrifugal compressor. The steady air injection experiments show an increase of 25% in surge-margin with an injection mass flow of 0.5% of the compressor mass flow. In addition, it is experimentally demonstrated that this injection scheme is robust to impeller tip-clearance effects and that a reduced number of injectors can be applied for similar gains in surge-margin. The results presented in this paper firmly establish the connection between the experimentally observed dynamic phenomena in the NASA CC3 centrifugal compressor and a first principles based coupling criterion. In addition, guidelines are given for the design of centrifugal compressors with enhanced stability.

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