Stall and surge phenomena in compressors hvac machinery. We had huge axial air compressors whose acceleration upon. A noticeable feature of any compressor performance map, such as figure 5. Axial compressor performance during surge aiaa arc. Surge detection in an industrial axial flow compressor by david h. This paper reports an experimental study of axial compressor surge and rotating stall. Axialflow compressors an overview sciencedirect topics. The flatness of the large b characteristic contrasts with the characteristic of an axial. Surging happens when the forward flow stops and tries to move back. A stall that results in the complete disruption of the airflow through the compressor is referred to as a compressor surge. Due to this the components of the compressor such as thrust bearings, bearing. Antisurge systems for axial compressors turbomachinery.
Global stability and control analysis of axial compressor. Axialflow compressors are used in the majority of large gas turbines, both in powerplants and aircraft jet engines. During the surge, a significant mass gas will flow in the reverse direction. The phenomena of stall and surge in axialcentrifugal compressors is investigated through highresponse measurements of both the pressure field and the flowfield throughout the surge cycle. A dynamic model has been developed which includes effects of speed variations, compressibility, and time lags. Surging and choking in centrifugal compressor in fluid. Active controllers that allow the compressor to operate safely at its. Some stall and surge phenomena in axialflow compressors. There is limited information available in the literature about flow conditions in axial compressors during surge. This research investigated unsteady events such as stall inception, stallcell development, and surge.
Over the last 75 years these compressors have been improved continuously, today achieving component efficiencies of more than 90%. The antisurge controller is one of the most critical turbomachinery control applications that protect a compressor from surge by. Compressor stall can lead to surge which is characterized by quasiaxisymmetric fluctuations in mass flow and pressure. The experiments were carried out using a three stage axial flow compressor. Pdf a model for rotating stall and surge in axial flow. I learned early in my career that compressor surge is the fastest phenomenon that occurs in process industries around turbomachinery, and with the most disastrous consequences. If turbine engines are designed to run with maximum efficiency at their design point 100%, then the. The term describes violent air flow oscillating in the axial direction of a compressor, which indicates the axial component of fluid velocity varies periodically. The dynamic model of an axial compressor should be accurately validated considering the criticality of the surge and disastrous consequences of a surge event in an axial compressor.
The instability is characterized by large limit cycle oscillations in compressor. The surge line could change with a slightly different gas condition or composition. Centrifugal compressor surge, modeling and identification. Axial compressor middle stage secondary flow study joel h. Surge and rotating stall in axial flow compressorspart ii. The main difference is in how they operate, vs how they are maintained. A nonlinear model is developed to predict the transient response of a compression system subsequent to a perturbation from steady operating conditions. This line is formed by joining surge points at different rpms. This paper reports a theoretical study of axial compressor surge. He is responsible for overall engineering and specifically the hot.
The problem is that their delicate blades are susceptible to surge induced damage or separation. Surge control a surge event can damage or even separate the fragile blades of an axial compressor. Surge, rotating stall, compressor map, surge line, surge avoidance line, jet engine. Further increase in pressure till point p surge point, compressor pressure will increase. The phenomena of stall and surge in axialcentrifugal compressors is in. Bhge axial compressors are based on decades of experience from nuovo pignone, allis chalmers, conmec, and ge.
There is an unstable limit of operation known as surging, and it is shown on the performance map as the surge line. Avoidance of severe axial compressor rotating stall prevention of blade rubbing in the compressor or turbine due to an increased rate of thermal expansion and vibration although these are all important issues, this paper focuses only on the issue of axial compressor rotating stall during startup as shown highlighted in red in figure 1. Unstable flow in axial compressors due to complete breakdown of the steady through flow is termed as surging. Extensive discussion is presented on the differences. Stall is characterized by a decrease in overall pressure rise and nonaxisymmetric throughflow. These data are critical and play important roles in axial compressor system dynamic simulation results, an antisurge system design, reliability and overall safety. It is found that for the system investigated there is an important nondimensional parameter on which this response depends. As a result of a large dynamic force act on the impeller or blading within the compressor. Axial and centrifugal compressor mean line flow analysis. Linden is an executive vice president and one of the founders of conmec, inc. Surge in centrifugal and axial compressors often manifests itself as oscillations of flow and pressure, as well as related compressor parameters, such as rotating speed. The paper presents an investigation into the onset and transient behavior of rotating stall and surge in an eightstage high speed axial compressor at offdesign conditions, based on 3d reynolds. Compressor surge is a form of aerodynamic instability in axial compressors or centrifugal compressors. Centrifugal and axial compressor control kindle edition by mcmillan, gregory k.
Sometimes an anti surge valve is installed in the discharge to lower pressure drop and thus increase flow which moves the compressor away trom the surg. The model is based on quasi 3d euler equations with source. Compressor performance has a large influence on total engine performance. Section 3 description of surge 31 surge versus stall surge is a dynamic instability that occurs in dynamic compressors. Several axialcentrifugal compressors are examined, both in compressor rigs and engines. As a result, surge that is not aborted, becomes a cyclical event, with frequency dependent on the design of the compressor and, on piping and volumes of the process system typically observed, surge cycle times are 15 sec. Antisurge control ccc compressor controls corporation. An axialflow compressor is one in which the flow enters the compressor in an axial direction parallel. The original ms3002 compressor did not require bleed valves, variableinlet guide vanes, or variableangle stator vanes for the turbine to accelerate and operate over a wide speed range without compressor surge.
Deep surge 22 july 2014 journal of turbomachinery, vol. An axial compressor is a gas compressor that can continuously pressurize gases. Axial and centrifugal compressor mean line flow analysis method joseph p. Flow through a centrifugal compressor is turned perpendicular to the axis of rotation, while air in an axial compressor flows parallel to the axis of rotation. Axial compressor performance during surge journal of.
Protecting a centrifugal compressor from surge pipeline. Construction and working of axial flow compressor in fluid power engineering duration. There are two main types of compressors used in modern jet engines. Robust control of surge and rotating stall in an axial.
The steep pressurevolume curve allows the axial compressor to operate well in parallel with other axial compressors. Axial compressors are often employed as air compressors when large capacities are required, as well as in smaller highcapacity process gas applications such as the first stage of a mixed refrigerant mr lng plant. Axial compressors an overview sciencedirect topics. Surge and rotating stall in axial flow compressorspart i. Due to this the components of the compressor such as thrust bearings, bearing, casing exposed to large changes in axial force on the rotor. Observations of the growth and decay of stall cells during. A description of antistall technology applied to axial compressors in gas turbine engines. This compressor is best suited to applications with very high flow rates with typical polytropic efficiency exceeding 90%. Pdf the dynamics of stall and surge behavior in axialcentrifugal. Veres national aeronautics and space administration glenn research center cleveland, ohio 445 abstract this paper describes a method to estimate key aerodynamic parameters of single and multistage axial and centrifugal compressors.
What is the difference between axial compressor blades and. Surge dynamics and unsteady flow phenomena in centrifugal. Robust control of surge and rotating stall in an axial compressor by shengfang liao submitted to the department of aeronautics and astronautics on august 11, 2000, in partial fulfillment of the requirements for the degree of doctor of philosophy abstract this thesis presents an investigation of the stability of axial compression systems. Boyce, in gas turbine engineering handbook fourth edition, 2012. The dynamics of stall and surge behavior in axial centrifugal compressors by william t. An overview of rotating stall and surge control for axial. Methodologies for controlling compressor trains in these arrangements piping layout considerations to be observed is discussed. Unsteady measurements of the flow field around the compressor rotor are examined. Axial and centrifugal compressors application guide.
What is the difference between axial flow compressor and. Global stability and control analysis of axial compressor stall and surge phenomena using bifurcation methods n ananthkrishnan1,ugvaidya2andvwwalimbe3 1indian institute of technology bombay, powai, mumbai, india 2university of california, santa barbara, ca, usa 3georgia institute of technology, atlanta, ga, usa abstract. Numerical simulation of aerodynamic instabilities in a multistage highspeed highpressure compressor on its test rigpart ii. Centrifugal compressor surge is seen as a very dangerous and detrimental phenomenon in compressed air systems, dangerous because it causes the compressor to vibrate and detrimental because it causes damage to the compressor parts. Index terms bifurcation, compressor, jet engine, rotating stall, surge. The dynamics of stall and surge behavior in axialcentrifugal compressors by william t.
Centrifugal and axial compressors are susceptible to surge which can cause catastrophic damage to your turbomachinery train. Obrien department of mechanical engineering abstract the phenomena of stall and surge in axial centrifugal compressors is investigated through highresponse measurements of both the pressure field and. Actually, the working principle of a centrifugal compressor is increasing the kinetic energy of the fluid with a rotating. It is a rotating, airfoilbased compressor in which the gas or working fluid principally flows parallel to the axis of rotation, or axially. Additionally, axial compressors can be challenging due to complex surge line mapping. Axial compressors are rotating, aerofoil based compressors in which the working fluid principally flows parallel to the axis of rotation. Get up to speed on axial compressors chemical processing. Axialflow compressors national energy technology laboratory. Surge is defined as the operating point at which centrifugal compressor peak head capability and minimum flow limits are reached. Axial flow compressors are used in the majority of large gas turbines, both in powerplants and aircraft jet engines. This line denotes the limit to stable operation, and it is traditionally referred to as a surge line, even though the instability that occurs may be surge or stall. Prediction of rotating stall during start up for axial. Compressor loadsharing control and surge detection.
The stall or surge limit of the highpressureratio axialflow compressor, however. Axial compressor considerations flow control network. Bladetoblade view of threestage, axialflow compressor blade rows 41 figure 3. Pdf design and cfd analysis of a multi stage axial flow. This is in contrast with centrifugal, axicentrifugal and mixedflow compressors where the air may enter axi. Obrien department of mechanical engineering abstract the phenomena of stall and surge in axialcentrifugal compressors is investigated through highresponse measurements of both the pressure field and. Modification of axialflow compressor stall margin by. Pressures do not have to match exactly to allow load sharing, as the steepness of the curve allows for adjustment without the possibility of going into surge or experiencing extreme load swings as normally happens when attempts are made to operate centrifugal compressors in. The paper presents a cfd based model for prediction of aerodynamic instabilities like rotating stall and surge in axial flow compressors. A unique highresponse forwardfacing and aftfacing probe provides flow information. Download it once and read it on your kindle device, pc, phones or.
With the experimental facility the physical parameters of the compression system could be independently varied so that their influence on the transient system behavior can be clearly. As a result, thrust reversal causing high axial vibration, temperature increase because of recompression of the same portion of gas are. Axial flow compressors are usually less forgiving than centrifugal compressors, thus more precision and accurate matching of rotor and stator flows are needed. Coordinate system for axialflow compressor figure 5 shows the pressure, velocity, and total temperature variation for.
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