The Impact of Reciprocating Compressor Pulsations on the Surge Margin of Centrifugal Compressors

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Klaus Brun ◽  
Sarah Simons ◽  
Rainer Kurz
Keyword(s):  
Centrifugal Compressor ◽  
Pressure Pulsation ◽  
Piping System ◽  
Reciprocating Compressor ◽  
Centrifugal Compressors ◽  
Surge Margin ◽  
Periodic Pressure ◽  
Compressor Surge ◽  
The Impact ◽  
Asme Paper

Pressure pulsations into a centrifugal compressor can move its operating point into surge. This is concerning in pipeline stations where centrifugal compressors operate in series/parallel with reciprocating compressors. Sparks (1983, “On the Transient Interaction of Centrifugal Compressors and Their Piping Systems,” ASME Paper No. 83-GT-236); Kurz et al. (2006, “Pulsations in Centrifugal Compressor Installations,” ASME Paper No. GT2006-90700); and Brun et al. (2014, “Impact of the Piping Impedance and Acoustic Characteristics on Centrifugal Compressor Surge and Operating Range,” ASME J. Eng. Turbines Power, 137(3), p. 032603) provided predictions on the impact of periodic pressure pulsation on the behavior of a centrifugal compressor. This interaction is known as the “compressor dynamic response” (CDR) theory. Although the CDR describes the impact of the nearby piping system on the compressor surge and pulsation amplification, it has limited usefulness as a quantitative analysis tool, due to the lack of prediction tools and test data for comparison. Testing of compressor mixed operation was performed in an air loop to quantify the impact of periodic pressure pulsation from a reciprocating compressor on the surge margin (SM) of a centrifugal compressor. This data was utilized to validate predictions from Sparks’ CDR theory and Brun’s numerical approach. A 50 hp single-stage, double-acting reciprocating compressor provided inlet pulsations into a two-stage 700 hp centrifugal compressor. Tests were performed over a range of pulsation excitation amplitudes, frequencies, and pipe geometry variations to determine the impact of piping impedance and resonance responses. Results provided clear evidence that pulsations can reduce the surge margin of centrifugal compressors and that geometry of the piping system immediately upstream and downstream of a centrifugal compressor will have an impact on the surge margin reduction. Surge margin reductions of over 30% were observed for high centrifugal compressor inlet suction pulsation.

The Impact of Reciprocating Compressor Pulsations on the Surge Margin of Centrifugal Compressors

2016 ◽  
Author(s):  
Klaus Brun ◽  
Rainer Kurz ◽  
Sarah Simons
Keyword(s):  
Centrifugal Compressor ◽  
Pressure Pulsation ◽  
Numerical Approach ◽  
Piping System ◽  
Analysis Tool ◽  
Reciprocating Compressor ◽  
Centrifugal Compressors ◽  
Surge Margin ◽  
Periodic Pressure ◽  
The Impact

Pressure pulsations into a centrifugal compressor can move its operating point into surge. This is concerning in pipeline stations where centrifugal compressors operate in series/parallel with reciprocating compressors. Sparks (1983), Kurz et al., (2006), and Brun et al., (2014) provided predictions on the impact of periodic pressure pulsation on the behavior of a centrifugal compressor. This interaction is known as the “Compressor Dynamic Response” (CDR) theory. Although the CDR describes the impact of the nearby piping system on the compressor surge and pulsation amplification, it has limited usefulness as a quantitative analysis tool, due to the lack of prediction tools and test data for comparison. Testing of compressor mixed operation was performed in an air loop to quantify the impact of periodic pressure pulsation from a reciprocating compressor on the surge margin of a centrifugal compressor. This data was utilized to validate predictions from Sparks' CDR theory and Brun's numerical approach. A 50 hp single-stage, double-acting reciprocating compressor provided inlet pulsations into a two-stage 700 hp centrifugal compressor. Tests were performed over a range of pulsation excitation amplitudes, frequencies, and pipe geometry variations to determine the impact of piping impedance and resonance responses. Results provided clear evidence that pulsations can reduce the surge margin of centrifugal compressors and that geometry of the piping system immediately upstream and downstream of a centrifugal compressor will have an impact on the surge margin reduction. Surge margin reductions of <30% were observed for high centrifugal compressor inlet suction pulsation.

The Impact of Reciprocating Compressor Pulsations on the Surge Margin of Centrifugal Compressors

2016 ◽  
Author(s):  
Klaus Brun ◽  
Sarah Simons ◽  
Rainer Kurz
Keyword(s):  
Centrifugal Compressor ◽  
Piping System ◽  
Reciprocating Compressor ◽  
Test Results ◽  
Centrifugal Compressors ◽  
Numerical Predictions ◽  
Surge Margin ◽  
Periodic Pressure ◽  
And Performance ◽  
The Impact

Strong pressure pulsations into the suction or discharge of a centrifugal compressor can move its operating point into operational instability regions such as surge, rotating stall, or choke. This is of special operational and safety concern in mixed pipeline compressor stations where many centrifugal compressors operate in series or parallel with reciprocating compressors. Over the last 30 years, several authors have discussed the impact of piping flow pulsations on centrifugal compressor stability and specifically, on the impact on surge margin and performance. For example, Sparks (1983), Kurz et al., (2006), and Brun et al. (2014) provided analysis and numerical predictions on the impact of discrete and periodic pressure pulsation on the behavior of a centrifugal compressor. This interaction came to be known as the “Compressor Dynamic Response (CDR) theory.” CDR theory explains how pulsations are amplified or attenuated by a compression system’s acoustic response characteristic superimposed on the compressor head-flow map. Although the CDR Theory describes the impact of the nearby piping system on the compressor surge and pulsation amplification, it provides only limited usefulness as a quantitative analysis tool, primarily due to the lack of numerical prediction tools and test data for comparison. Recently, Brun et al. (2014) utilized an efficient 1-D transient Navier-Stokes flow solver to predict CDR in real life compression systems. Numerical results showed that acoustic resonances in the piping system can have a profound impact on a centrifugal compressor’s surge margin. However, although interesting, the fundamental problem with both Spark’s and Brun’s approach was that no experimental data was available to validate the analytical and numerical predictions. In 2014, laboratory testing of reciprocating and centrifugal compressor mixed operation was performed in an air loop at Southwest Research Institute’s (SwRI®) compressor laboratory. The specific goal was to quantify the impact of periodic pressure and flow pulsation originating from a reciprocating compressor on the surge margin and performance of a centrifugal compressor in a series arrangement. This data was to be utilized to validate predictions from Sparks’ CDR theory and Brun’s numerical approach. For this testing, a 50 hp single-stage, double-acting reciprocating compressor provided inlet pulsations into a two-stage 700 hp centrifugal compressor operating inside a semi-open recycle loop which uses near atmospheric air as the process gas. Tests were performed over a range of pulsation excitation amplitudes, frequencies, and pipe geometry variations to determine the impact of piping impedance and resonance response. Detailed transient velocity and pressure measurements were taken by a hot wire anemometer and dynamic pressure transducers installed near the compressor’s suction and discharge flanges. Steady-state flow, pressure, and temperature data were also recorded with ASME PTC-10 compliant instrumentation. This paper describes the test facility and procedure, reports the reduced test results, and discusses comparisons to predictions. Results provided clear evidence that suction pulsations can significantly reduce the surge margin of a centrifugal compressors and that the geometry of the piping system immediately upstream and downstream of a centrifugal compressor will have an impact on the surge margin reduction. In severe cases, surge margin reductions of over 30% were observed for high centrifugal compressor inlet suction pulsation. Pulsation impact results are presented as both flow versus surge margin and operating map ellipses. Some basic design rules were developed from the test results to relate predicted flow pulsation amplitudes to corresponding reductions in surge margin.

scholarly journals Impact of Piping Impedance and Acoustic Characteristics on Centrifugal Compressor Surge and Operating Range

2014 ◽  
Vol 137 (3) ◽  
Author(s):  
Klaus Brun ◽  
Marybeth G. Nored ◽  
Rainer Kurz
Keyword(s):  
Centrifugal Compressor ◽  
Piping System ◽  
Compressor Station ◽  
Acoustic Response ◽  
Design Review ◽  
Operating Range ◽  
Periodic Pressure ◽  
Compressor Surge ◽  
Flow Map ◽  
The Impact

The performance of a centrifugal compressor is usually defined by its head versus flow map, limited by the surge and stall regions. This map is critical to assess the operating range of a compressor for both steady state and transient system scenarios. However, the compressor map does not provide a complete picture on how the compressor will respond to rapid transient inputs and how its surge behavior is affected by these events. Specifically, the response of the compressor to rapid transient events such as single or multiple (periodic) pressure pulses, is also a function of the compressor's upstream and downstream piping system's acoustic response and impedance characteristics. This unique response phenomenon was first described in the 1970 s and came to be known as the “compressor dynamic response (CDR) theory.” CDR theory explains how pulsations are amplified or reduced by a compression system's acoustic response characteristic superimposed on the compressor head-flow map. Although the CDR theory explained the impact of the nearby piping system on the compressor surge and pulsation amplification, it provided only limited usefulness as a quantitative analysis tool, mainly due to the lack of computational numerical tools available at the time. To fully analyze pulsating flows in complex centrifugal compressor suction and discharge header piping systems, the principles of the CDR theory should be implemented in a dynamic flow model to quantify the magnitude of the amplifications of pressure pulses near the surge region. When designing centrifugal compressor stations within a transmission piping system, it is critically important to have a full understanding of the impact of the station's piping system on compressor dynamic behavior. For example, if a compressor system's piping impedance amplifies the suction side pulsations, the compressor's operating range will be severely limited and will produce unacceptable discharge piping vibrations. Whereas it is usually desirable to limit the downstream volume between the compressor discharge and the check valve to reduce the potential for transient surge events, a small discharge volume results in high piping impedance. This will amplify pressure pulsations passing through the compressor. The small downstream volume provides limited ability for any transient peak (such as a pressure pulse) passing through the compressor to be absorbed quickly, and an amplified discharge pressure spike will be the result. Also, if any periodic pressure excitation from upstream vortex shedding or any other continuously varying flow disturbance couples with a pipe resonance length, the result can be high fluctuations of the compressor operating point on its speed line, effectively resulting in a reduced operating range and higher than expected surge margin (surge line moves to the right). Both acoustic resonance and system impedance are functions of pipe friction, pipe and header interface connections, valve/elbow locations, pipe diameter, and valve coefficients, i.e., the entire piping system connected to the compressor. Thus, a careful acoustic and impedance design review of a compressor station design should be performed to avoid impacting the operating range of the machine. This paper describes the methodology of such a design review using modern pulsation analysis software. Examples and parametric studies are presented that demonstrate the impact of system impedance and piping acoustics on the dynamic operating response of the compressor in a typical compressor station. Some recommendations to reduce the risk of pulsation amplification and unsteady operation are also provided.

scholarly journals Impact of Piping Impedance and Acoustic Characteristics on Centrifugal Compressor Surge and Operating Range

2014 ◽  
Author(s):  
Klaus Brun ◽  
Rainer Kurz ◽  
Marybeth G. Nored
Keyword(s):  
Centrifugal Compressor ◽  
Piping System ◽  
Compressor Station ◽  
Acoustic Response ◽  
Design Review ◽  
Operating Range ◽  
Periodic Pressure ◽  
Compressor Surge ◽  
Flow Map ◽  
The Impact

The performance of a centrifugal compressor is usually defined by its head versus flow map, limited by the surge and stall regions. This map is critical to assess the operating range of a compressor for both steady state and transient system scenarios. However, the compressor map does not provide a complete picture on how the compressor will respond to rapid transient inputs and how its surge behavior is affected by these events. Specifically, the response of the compressor to rapid transient events, such as single or multiple (periodic) pressure pulses, is also a function of the compressor’s upstream and downstream piping system’s acoustic response and impedance characteristics. This unique response phenomenon was first described in the 1970s and came to be known as the “Compressor Dynamic Response (CDR) Theory”. CDR Theory explains how pulsations are amplified or reduced by a compression system’s acoustic response characteristic superimposed on the compressor head-flow map. Although the CDR Theory explained the impact of the nearby piping system on the compressor surge and pulsation amplification, it provided only limited usefulness as a quantitative analysis tool, mainly due to the lack of computational numerical tools available at the time. To fully analyze pulsating flows in complex centrifugal compressor suction and discharge header piping systems, the principles of the CDR Theory should be implemented in a dynamic flow model to quantify the magnitude of the amplifications of pressure pulses near the surge region. When designing centrifugal compressor stations within a transmission piping system, it is critically important to have a full understanding of the impact of the station’s piping system on compressor dynamic behavior. For example, if a compressor system’s piping impedance amplifies the suction side pulsations, the compressor’s operating range will be severely limited and will produce unacceptable discharge piping vibrations. Whereas it is usually desirable to limit the downstream volume between the compressor discharge and the check valve to reduce the potential for transient surge events, a small discharge volume results in high piping impedance. This will amplify pressure pulsations passing through the compressor. The small downstream volume provides limited ability for any transient peak (such as a pressure pulse) passing through the compressor to be absorbed quickly, and an amplified discharge pressure spike will be the result. Also, if any periodic pressure excitation from upstream vortex shedding or any other continuously varying flow disturbance couples with a pipe resonance length, the result can be high fluctuations of the compressor operating point on its speed line, effectively resulting in a reduced operating range and higher than expected surge margin (surge line moves to the right). Both acoustic resonance and system impedance are functions of pipe friction, pipe and header interface connections, valve/elbow locations, pipe diameter, and valve coefficients, i.e., the entire piping system connected to the compressor. Thus, a careful acoustic and impedance design review of a compressor station design should be performed to avoid impacting the operating range of the machine. This paper describes the methodology of such a design review using modern pulsation analysis software. Examples and parametric studies are presented that demonstrate the impact of system impedance and piping acoustics on the dynamic operating response of the compressor in a typical compressor station. Some recommendations to reduce the risk of pulsation amplification and unsteady operation are also provided.

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.

scholarly journals Surge Margin Optimization of Centrifugal Compressors Using a New Objective Function Based on Local Flow Parameters

2019 ◽  
Vol 4 (4) ◽  
pp. 42
Author(s):  
Johannes Ratz ◽  
Sebastian Leichtfuß ◽  
Maximilian Beck ◽  
Heinz-Peter Schiffer ◽  
Friedrich Fröhlig
Keyword(s):  
Objective Function ◽  
Centrifugal Compressor ◽  
Computational Effort ◽  
Angle Distribution ◽  
Centrifugal Compressors ◽  
Local Flow ◽  
Vaned Diffuser ◽  
Flow Parameters ◽  
Surge Margin ◽  
Beta Angle

Currently, 3D-CFD design optimization of centrifugal compressors in terms of the surge margin is one major unresolved issue. On that account, this paper introduces a new kind of objective function. The objective function is based on local flow parameters present at the design point of the centrifugal compressor. A centrifugal compressor with a vaned diffuser is considered to demonstrate the performance of this approach. By means of a variation of the beta angle distribution of the impeller and diffuser blade, 73 design variations are generated, and several local flow parameters are evaluated. Finally, the most promising flow parameter is transferred into an objective function, and an optimization is carried out. It is shown that the new approach delivers similar results as a comparable optimization with a classic objective function using two operating points for surge margin estimation, but with less computational effort since no second operating point near the surge needs to be considered.

Excitation of Blade Vibration due to Surge of Centrifugal Compressors

1992 ◽  
Author(s):  
D. Jin ◽  
U. Haupt ◽  
H. Hasemann ◽  
M. Rautenberg
Keyword(s):  
Centrifugal Compressor ◽  
Rotational Speed ◽  
High Performance ◽  
Dynamic Pressure ◽  
Rotating Stall ◽  
Blade Vibration ◽  
High Rotational Speed ◽  
Blade Thickness ◽  
Periodic Pressure ◽  
Compressor Surge

Centrifugal compressor surge at high rotational speed and reduced blade thickness can produce dangerous excitation effects which have numerous resulted in problems in the past. This paper presents an investigation of blade excitation during surge in a high performance single stage centrifugal compressor with various impeller and diffuser geometry. The blade vibration was measured using blade mounted strain gages. The flow characteristics during surge as the cause of blade excitation were simultaneously determined by fast response dynamic pressure transducers. The experiments have been performed using a radial and a backswept impeller, as well as a vanless and vaned diffusers. The rotational speed of the compressor was varied from 5,000 to 14,500 rpm. The characteristics of unsteady flow during surge, such as, the flow pattern of rotating stall and the non-periodic pressure fluctuation during surge were studied in detail. The experimental results demonstrated that, in addition to the excitation of rotating stall during surge, strong non-periodic pressure fluctuations at the beginning and the end of the surge induced dangerous blade excitations in all compressor configurations. The maximum strain values of blade vibration for all compressor versions at different rotational speeds of the compressor were measured to estimate the danger of blade excitation during surge. The results showed that the blade excitation during compressor surge with vaned diffusers is stronger than the excitation with a vanless diffuser and that the blade excitation with a radial impeller is stronger than the excitation with a backswept impeller.

Attenuation of Gas Pulsation in a Reciprocating Compressor Piping System by Using a Volume-Choke-Volume Filter

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Boxiang Liu ◽  
Jianmei Feng ◽  
Zhongzhen Wang ◽  
Xueyuan Peng
Keyword(s):  
Characteristic Frequency ◽  
Pressure Pulsation ◽  
Natural Frequencies ◽  
Three Dimensional ◽  
Piping System ◽  
Reciprocating Compressor ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Response Characteristics ◽  
Low Pass

This paper presents an investigation of the use of a volume-choke-volume low-pass filter to achieve gas pulsation attenuation in a reciprocating compressor piping system, with a focus on its frequency response characteristics and influence on the actual attenuation effects. A three-dimensional acoustic model of the gas pulsation was established for a compressor discharge piping system with and without the volume-choke-volume filter, based on which the gas column natural frequencies of the piping system and the pressure wave profiles were predicted by means of the finite element method. The model was validated by comparing the predicted results with the experimental data. The results showed that the characteristic frequency of the filter was sensitive to both diameter and length of the choke but independent of the parameters of the piping beyond the filter. It is worth noting that the characteristic frequency of the filter constituted one order of the gas column natural frequencies of the piping system with the filter. The pressure pulsation levels in the piping system downstream of the filter could be significantly attenuated especially for the pulsation components at frequencies above the filter’s characteristic frequency. The measured peak-to-peak pressure pulsation at the outlet of the filter was approximately 61.7% lower than that of the surge bottle with the same volume.

scholarly journals A Comprehensive Modeling of Centrifugal Compressor Vibrations for Early Fault Detection

2020 ◽  
Author(s):  
François Libeyre ◽  
Francis Bainier ◽  
Pascal Alas
Keyword(s):  
Fault Detection ◽  
Centrifugal Compressor ◽  
Historical Data ◽  
Flow Coefficient ◽  
Clear Correlation ◽  
Physical Parameters ◽  
Centrifugal Compressors ◽  
Usual Condition ◽  
Early Fault Detection ◽  
The Impact

Abstract In the last decade, the development of machine connectivity has made possible early fault detection with remote analysis of operating data. Solutions aiming to reduce maintenance costs and production losses due to unplanned downtimes were brought to market. These solutions provide with a model of the equipment in healthy conditions using machine learning techniques applied on historical data. During operation a warning is issued when expected and actual measurements do not match. Although these solutions have proven their value to detect abnormal behaviors, they generate a large number of alarms that require resource to be analyzed. Moreover, these solutions rely on a large number of sensors that need to work correctly both for the learning and the monitoring phase. This generates additional maintenance even though these sensors are often not essential to operate the machine. Lastly the solutions are expensive: their application is usually limited to critical machines with risks of production loss. Indeed, they are not economic for a Transmission System Operator that has ensured the availability of its network with redundancy. The objective of the authors was to focus on the monitoring of radial vibrations of centrifugal compressors. Experience proves this is one of the most critical data for early fault detection. The goal was to develop a smart modelling based on historical data using essential parameters influencing rotor-dynamics. As a result, a clear correlation was found between the operating point and the vibration level. That can be easily shown on a centrifugal compressor map. A second-degree polynomial equation was successfully tested. The model equation relies only on two compressor physics parameters: flow coefficient and speed. We discuss in the paper the impact of other essential parameters. The method has been applied on different type of centrifugal compressors, with different bearing technology (magnetic...) or shaft driving equipment (gas turbine, electric motor drive). A fault detection case study using this method is described, eg: vibration variation due to abnormal opening of an anti-surge control valve. In conclusion this method is a simple alternative to usual condition monitoring solutions. Similarly to what was described in the GT2014-25242 for a Predictive Emission Monitoring System [1], equations based on physical parameters prove to be an efficient modelling technique. Moreover, it helps monitoring teams to better understand the underlying relation between parameters. Indeed, to achieve a complete monitoring of a centrifugal compressor health, this method can be combined with first-principle performance models that use the same physical parameters.

scholarly journals Design and Development of an Advanced Two-Stage Centrifugal Compressor

1994 ◽  
Author(s):  
D. L. Palmer ◽  
W. F. Waterman
Keyword(s):  
Centrifugal Compressor ◽  
High Performance ◽  
Low Cost ◽  
Pressure Ratio ◽  
Tip Clearance ◽  
Development Effort ◽  
Design And Development ◽  
Two Stage ◽  
Surge Margin ◽  
The Impact

This paper describes the aero-mechanical design and development of a 3.3 kg/sec (7.3 lb/sec), 14:1 pressure ratio two-stage centrifugal compressor which is used in the T800-LHT-800 helicopter engine. The design employs highly nonradial, splitter bladed impellers with swept leading edges and compact vaned diffusers to achieve high performance in a small and robust configuration. The development effort quantified the effects of impeller diffusion and passive inducer shroud bleed on surge margin as well as the effects of impeller loading on tip clearance sensitivity and the impact of sand erosion and shroud roughness on performance. The developed compressor exceeded its performance objectives with a minimum of 23-percent surge margin without variable geometry. The compressor provides a high performance, rugged, low-cost configuration ideally suited for helicopter applications.

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