Centrifugal Compressors

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.

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Experimental investigation of an active control casing treatment of centrifugal compressors

Experimental Thermal and Fluid Science ◽

10.1016/j.expthermflusci.2016.12.013 ◽

2017 ◽

Vol 83 ◽

pp. 107-117 ◽

Cited By ~ 4

Author(s):

Qichao Yang ◽

Liansheng Li ◽

Yuanyang Zhao ◽

Jun Xiao ◽

Yue Shu ◽

...

Keyword(s):

Experimental Investigation ◽

Active Control ◽

Centrifugal Compressors ◽

Casing Treatment

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Backward Traveling Rotating Stall Waves in Centrifugal Compressors

Volume 5: Turbo Expo 2002, Parts A and B ◽

10.1115/gt2002-30379 ◽

2002 ◽

Cited By ~ 10

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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Feedforward compensation control of rotor imbalance for high-speed magnetically suspended centrifugal compressors using a novel adaptive notch filter

Journal of Sound and Vibration ◽

10.1016/j.jsv.2015.12.029 ◽

2016 ◽

Vol 366 ◽

pp. 1-14 ◽

Cited By ~ 19

Author(s):

Shiqiang Zheng ◽

Rui Feng

Keyword(s):

High Speed ◽

Notch Filter ◽

Centrifugal Compressors ◽

Adaptive Notch Filter ◽

Compensation Control ◽

Rotor Imbalance

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Gas Compressor Service With Turbo Compressors

2004 International Pipeline Conference, Volumes 1, 2, and 3 ◽

10.1115/ipc2004-0183 ◽

2004 ◽

Author(s):

Sidney Pereira dos Santos

Keyword(s):

Operating Cost ◽

Gas Pipeline ◽

Feasibility Analysis ◽

Economic Approach ◽

Compressor Station ◽

Centrifugal Compressors ◽

Great Opportunity ◽

Service Contracts ◽

Gas Compression ◽

Capital Intensive

Gas pipeline projects are capital intensive and normally are developed under scenarios of uncertainty. Such uncertainties vary from closing take-or-pay, ship-or-pay or delivery-or-pay agreements to those uncertainties related to the acquisition of equipments, material and construction and assembling contracts. Natural gas compression service contracts with compressor station using gas motors and reciprocating compressors have been widely adopted at PETROBRAS as economically feasible against holding the stations as part of the pipeline asset as well as providing an effective approach to mitigate risks inherent to the gas business and associated to the compressor stations. Although compression service contracts with turbo compressors (gas turbine drivers and centrifugal compressors) have not yet been accomplished at PETROBRAS for gas pipeline projects, studies and preliminaries discussions shows that, taken into consideration certain relevant aspects, they will also present great opportunity to be adopted and will generate the same advantages already perceived for the compression service contracts with stations that uses gas motor drivers and reciprocation compressors. This paper has the objective of presenting an economic approach and a business model addressing the main points that must be considered while doing feasibility analysis between the alternatives of holding property of the compression station asset against the opportunity of having a compression service contract as operating cost for the project. Questions such as how to address depreciation, overhaul costs and tailor made equipment, such as centrifugal compressors, are raised and answered.

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