Centrifugal Compressor Surge Behaviour

1984 ◽  
Author(s):  
J. Wachter ◽  
K.-H. Rohne
Keyword(s):  
Centrifugal Compressor ◽  
Industrial Design ◽  
Theoretical Models ◽  
Transient Characteristic ◽  
Sufficient Data ◽  
System Behaviour ◽  
Different Types ◽  
Piping Systems ◽  
Compressor Surge ◽  
Surge Line

The unsteady behaviour of compressor systems near the surge line and during surge was investigated. Experimental examinations were carried out using a three stage centrifugal compressor of industrial design in different types of piping systems. The results obtained were compared with different theoretical models. It is demonstrated that the compressor system behaviour can be calculated adequately, if sufficient data concerning the transient characteristic of the compressor are available.

Dynamic Model of Multistage Centrifugal Compressor With a Stage-by-Stage Anti-Surge Recirculating System

2021 ◽  
Author(s):  
Nicola Casari ◽  
Michele Pinelli ◽  
Alessio Suman ◽  
Matteo Manganelli ◽  
Mirko Morini ◽  
...  
Keyword(s):  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Suction Side ◽  
System Level ◽  
Low Flow ◽  
Return Flow ◽  
Control Line ◽  
Compressor Surge ◽  
Surge Control ◽  
Surge Line

Abstract The operability region of a centrifugal compressor is bounded by the low-flow (or high-pressure ratio) limit, commonly referred to as surge. The exact location of the surge line on the map can vary depending on the operating condition and, as a result, a typical Surge Avoidance Line is established at 10% to 15% above the stated flow for the theoretical surge line. The current state of the art of centrifugal compressor surge control is to utilize a global recycle valve to return flow from the discharge side of a centrifugal compressor to the suction side to increase the flow through the compressor and, thus, avoid entering the surge region. This is conventionally handled by defining a compressor surge control line that conservatively assumes that all stages must be kept out of surge at all the time. In compressors with multiple stages, the amount of energy loss is disproportion-ally large since the energy that was added in each stage is lost during system level (or global) recycling. This work proposes an internal stage-wise recycling that provides a much more controlled flow recycling to affect only those stages that may be on the verge of surge. The amount of flow needed for such a scheme will be much smaller than highly conservative global recycling approach. Also, the flow does not leave the compressor casing and therefore does not cross the pressure boundary. Compared to global recycling this inherently has less loss depending upon application and specific of control design.

scholarly journals Active Stabilization of Centrifugal Compressor Surge

1990 ◽  
Author(s):  
J. E. Pinsley ◽  
G. R. Guenette ◽  
A. H. Epstein ◽  
E. M. Greitzer
Keyword(s):  
Centrifugal Compressor ◽  
Control Strategies ◽  
Pressure Rise ◽  
Control Valve ◽  
Lumped Parameter Model ◽  
Stable Operation ◽  
Time Resolved ◽  
Compression System ◽  
Compressor Surge ◽  
Surge Line

Active suppression of centrifugal compressor surge has been demonstrated on a centrifugal compressor equipped with a servo-actuated plenum exit throttle controller. The control scheme is fundamentally different from conventional surge control techniques in that it addresses directly the dynamic behavior of the compression system to displace the surge line to lower mass flows. The method used is to feed back perturbations in plenum pressure rise, in real time, to a fast acting control valve. The increased aerodynamic damping of incipient oscillations due to the resulting valve motion allows stable operation past the normal surge line. For the compressor used, a 25% reduction in the surge point mass flow was achieved, over a range of speeds and pressure ratios. Time-resolved measurements during controlled operation revealed that the throttle required relatively little power to suppress the surge oscillations, because the disturbances are attacked in their initial stages. Although designed for operation with small disturbances, the controller was also able to eliminate existing, large amplitude, surge oscillations. Comparison of experimental results with theoretical predictions showed that a lumped parameter model appeared adequate to represent the behavior of the compression system with the throttle controller and, perhaps more importantly, to be used in the design of more sophisticated control strategies.

Active Stabilization of Centrifugal Compressor Surge

1991 ◽  
Vol 113 (4) ◽  
pp. 723-732 ◽  
Author(s):  
J. E. Pinsley ◽  
G. R. Guenette ◽  
A. H. Epstein ◽  
E. M. Greitzer
Keyword(s):  
Centrifugal Compressor ◽  
Control Strategies ◽  
Pressure Rise ◽  
Control Valve ◽  
Lumped Parameter Model ◽  
Stable Operation ◽  
Time Resolved ◽  
Compression System ◽  
Compressor Surge ◽  
Surge Line

Active suppression of centrifugal compressor surge has been demonstrated on a centrifugal compressor equipped with a servo-actuated plenum exit throttle controller. The control scheme is fundamentally different from conventional surge control techniques in that it addresses directly the dynamic behavior of the compression system to displace the surge line to lower mass flows. The method used is to feed back perturbations in plenum pressure rise, in real time, to a fast-acting control valve. The increased aerodynamic damping of incipient oscillations due to the resulting valve motion allows stable operation past the normal surge line. For the compressor used, a 25 percent reduction in the surge point mass flow was achieved over a range of speeds and pressure ratios. Time-resolved measurements during controlled operation revealed that the throttle required relatively little power to suppress the surge oscillations, because the disturbances are attacked in their initial stages. Although designed for operation with small disturbances, the controller was also able to eliminate existing, large-amplitude, surge oscillations. Comparison of experimental results with theoretical predictions showed that a lumped parameter model appeared adequate to represent the behavior of the compression system with the throttle controller and, perhaps more importantly, to be used in the design of more sophisticated control strategies.

High speed centrifugal compressor surge initiation characterization

1996 ◽  
Author(s):  
William Oakes ◽  
Patrick Lawless ◽  
John Fagan ◽  
Sanford Fleeter
Keyword(s):  
Centrifugal Compressor ◽  
High Speed ◽  
Compressor Surge

Evaluation of Representative Piping Systems Designed by Implicit Fatigue Concept

2008 ◽  
Author(s):  
Shin-Beom Choi ◽  
Sun-Hye Kim ◽  
Yoon-Suk Chang ◽  
Jae-Boong Choi ◽  
Young-Jin Kim ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Nuclear Power ◽  
Heat Removal ◽  
Environmental Water ◽  
Lessons Learned ◽  
Metal Fatigue ◽  
Aging Effects ◽  
Age Related ◽  
Piping Systems ◽  
Surge Line

NUREG-1801 provides generic aging lessons learned to manage aging effects that may occur during continued operation beyond the design life of nuclear power plant. According to this report, the metal fatigue, among several age-related degradation mechanisms, is identified as one of time-limited aging analysis item. The objective of this paper is to introduce fatigue life evaluation of representative surge line and residual heat removal system piping which was designed by implicit fatigue concept. For the back-fitting evaluation employing explicit fatigue concept, detailed parametric CFD as well as FE analyses results are used. The well-known ASME Section III NB-3600 procedure is adopted for the metal fatigue and NUREG/CR-5704 procedure is further investigated to deal with additional environmental water effects. With regard to the environmental effect evaluation, two types of fatigue life correction factors are considered, such as maximum Fen and individual Fen. As a result, it was proven that a thermal stratification phenomenon is the governing factor in metal fatigue life of the surge line and strain rate is the most important parameter affecting the environmental fatigue life of both piping. The evaluation results will be used as technical bases for continued operation of OPR 1000 plant.

scholarly journals Surge and Stall Detection Using Acoustic Analysis for Gas Turbine Hybrid Cycles

2019 ◽  
Author(s):  
Keishaly Cabrera Cruz ◽  
Paolo Pezzini ◽  
Lawrence Shadle ◽  
Kenneth M. Bryden
Keyword(s):  
Gas Turbine ◽  
Natural Frequencies ◽  
Acoustic Analysis ◽  
General Nature ◽  
Acoustic Sensors ◽  
Frequency Range ◽  
Surge Margin ◽  
Compressor Surge ◽  
Surge Line ◽  
Transient Operations

Abstract Compressor dynamics were studied in a gas turbine – fuel cell hybrid power system having a larger compressor volume than traditionally found in gas turbine systems. This larger compressor volume adversely affects the surge margin of the gas turbine. Industrial acoustic sensors were placed near the compressor to identify when the equipment was getting close to the surge line. Fast Fourier transform (FFT) mathematical analysis was used to obtain spectra representing the probability density across the frequency range (0–5000 Hz). Comparison between FFT spectra for nominal and transient operations revealed that higher amplitude spikes were observed during incipient stall at three different frequencies, 900, 1020, and 1800 Hz. These frequencies were compared to the natural frequencies of the equipment and the frequency for the rotating turbomachinery to identify more general nature of the acoustic signal typical of the onset of compressor surge. The primary goal of this acoustic analysis was to establish an online methodology to monitor compressor stability that can be anticipated and avoided.

Multistage Centrifugal Compressor Surge Analysis: Part II—Numerical Simulation and Dynamic Control Parameters Evaluation

1999 ◽  
Vol 121 (2) ◽  
pp. 312-320 ◽  
Author(s):  
G. L. Arnulfi ◽  
P. Giannattasio ◽  
C. Giusto ◽  
A. F. Massardo ◽  
D. Micheli ◽  
...  
Keyword(s):  
Active Control ◽  
Centrifugal Compressor ◽  
Dynamic Control ◽  
Point Of View ◽  
Lumped Parameter Model ◽  
Theoretical Point ◽  
Control Parameters ◽  
Compression System ◽  
Compressor Surge ◽  
Multistage Centrifugal Compressor

This paper describes, from a theoretical point of view, the behavior of compression systems during surge and the effect of passive and active control devices on the instability limit of the system. A lumped parameter model is used to simulate the compression system described in Part I of this work (Arnulfi et al., 1999), based on an industrial multistage centrifugal compressor. A comparison with experimental results shows that the model is accurate enough to describe quantitatively all the features of the phenomenon. A movable wall control system is studied in order to suppress surge in the compressor. Passive and active control schemes are analyzed; they both address directly the dynamic behavior of the compression system to displace the surge line to lower flow rates. The influence of system, geometry and compressor speed is investigated: the optimum values of the control parameters and the corresponding increase in the extent of the stable operating range are presented in the paper.

Where is morphological complexity?

2020 ◽  
pp. 306-328
Author(s):  
Marianne Mithun
Keyword(s):  
First Language ◽  
Theoretical Models ◽  
Formal Description ◽  
Morphological Complexity ◽  
Different Types

A number of approaches have been taken to defining complexity in language. The issue is important, since underlying some theoretical models has been an assumption, sometimes explicit, sometimes unconscious, that the simplest formal description of a language naturally matches speaker knowledge. But it is not clear that complexity is the same for the analyst, the speaker, and the learner. Here the issue is explored in two languages with relative morphological complexity, but of different types, Central Pomo and Mohawk. First the speech of bilinguals with varying degrees of English dominance is compared. Next, the development of morphological complexity is traced in children learning Mohawk as a first language. The results indicate that complexity is indeed not the same for analysts, speakers, and learners, findings more in tune with abstractive models of morphology than constructive ones.

Assessment of the Fatigue Life of a PWR Surge Line Including the Effect of Coolant Environment

2009 ◽  
Author(s):  
Gu¨nter Ko¨nig ◽  
Jaroslav Bartonicek ◽  
Horst Rothenho¨fer
Keyword(s):  
Boundary Conditions ◽  
Power Plants ◽  
Measurement Data ◽  
Real Life ◽  
Actual State ◽  
Optimized Design ◽  
Design Phase ◽  
Damage Mechanisms ◽  
Piping Systems ◽  
Surge Line

In Germany, the integrity concept is applied to important piping systems in most of the nuclear power plants. Regarding the framework of this concept, those damage mechanisms that cannot be controlled by analysis have to be excluded using appropriate measures. In most of the cases, these damage mechanisms are a result of local effects (like loads, medium, material characteristics) that cannot be determined exactly in advance and thus cannot be controlled by analysis, reliably. Examples are strain induced corrosion (LCF area) and corrosion fatigue (HCF area). For cases like these and given medium, suitable materials have to be chosen in combination with optimized design, appropriate manufacturing procedures (incl. welding), construction and operation. The loads and the water chemistry in operation have to be monitored and the effectiveness of the measures has to be verified, regularly, taking into account the actual state of knowledge. Regarding these boundary conditions the fatigue evaluations that have been performed until today seem to be sufficient, as experience shows with piping systems where this procedure has been applied. There are usually no significant failures (indication of failures); failures detected have been attributed to violation of the boundary conditions. With this background, there seems to be no need to change this procedure to safeguard the effect of environment. In this paper, the measures to guarantee integrity in design and operation state are discussed, first. Using the example of a surge line and the comprehensive monitoring results of this system the evaluation of fatigue usage and the assessment of the effect of coolant environment is discussed with reference to the ANL approach. Where the ANL approach is meant to be applied only in the design phase of a new reactor its relevance for the operation phase is cross-checked with real life measurement data. The conclusion summarizes where the effect of coolant environment has to be taken into account and gives advice how to find realistic transients for the design phase of new reactors.

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