Parametric Study and Meanline Design of Multistage Axial Flow Compressor for Process Application

2015 ◽  
Author(s):  
Ambrish Singh ◽  
Nand Kumar Singh
Keyword(s):  
Axial Compressor ◽  
Axial Flow ◽  
Flow Coefficient ◽  
Detailed Design ◽  
Axial Flow Compressor ◽  
Wide Range ◽  
Last Stage ◽  
Flow Compressor ◽  
High Level ◽  
Selection Of

An industrial axial compressor has to meet a wide range of operation requirements. These machines have to run continuously for four to five years before going for overhaul. Hence, overall high level of efficiency may be slightly relaxed to meet this requirement. This requires axial flow compressor design to be more conservative and flexible to accommodate changes required for process industry through modern design & development approaches. This paper deals with finding of optimum flow path configuration that will allow a successful detailed design to follow. The effect of various parameters such as hub to tip ratio, proper selection of design rpm, reactions, work coefficient & flow coefficient has been investigated and selected for optimal performance of the machine. Last stage of the compressor is selected as radial stage with the advantage of reduction in axial length and to provide radial outlet, which is more suitable outlet configuration. Meanline design and streamline analysis for each configuration is determined to find out good operating range (stall-free operation) before starting the detailed design.

Stalling Pressure Rise Capability of Axial Flow Compressor Stages

1981 ◽  
Vol 103 (4) ◽  
pp. 645-656 ◽  
Author(s):  
C. C. Koch
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Axial Flow ◽  
Pressure Rise ◽  
Tip Clearance ◽  
Flow Coefficient ◽  
Low Speed ◽  
Axial Flow Compressor ◽  
Wide Range ◽  
Flow Compressor

A procedure for estimating the maximum pressure rise potential of axial flow compressor stages is presented. A simplified stage average pitchline approach is employed so that the procedure can be used during a preliminary design effort before detailed radial distributions of blading geometry and fluid parameters are established. Semi-empirical correlations of low speed experimental data are presented that relate the stalling static-pressure-rise coefficient of a compressor stage to cascade passage geometry, tip clearance, bladerow axial spacing and Reynolds number. Blading aspect ratio is accounted for through its effect on normalized clearances, Reynolds number and wall boundary layer blockage. An unexpectedly strong effect of airfoil stagger and of the resulting flow coefficient of the stage’s vector triangle is observed in the experimental data. This is shown to be caused by the differing ability of different types of stage vector triangles to re-energize incoming low-momentum fluid. Use of a suitable “effective” dynamic head in the pressure rise coefficient gives a good correlation of this effect. Stalling pressure rise data from a wide range of both low speed and high speed compressor stages are shown to be in good agreement with these correlations.

Stability of Multi-Stage Axial Flow Compressors

1964 ◽  
Vol 15 (4) ◽  
pp. 328-356 ◽  
Author(s):  
W. T. Howell
Keyword(s):  
Axial Flow ◽  
Rotational Frequency ◽  
Oscillatory Instability ◽  
Operating Point ◽  
Axial Flow Compressor ◽  
Multi Stage ◽  
Wide Range ◽  
Surge Line ◽  
Flow Compressor ◽  
The Stability

SummaryThe following theoretical investigation is concerned with the stability of the flow through a system composed of a multi-stage axial flow compressor followed by a throttle.Such an investigation was carried out by Pearson and Bowmer in 1949. In 1962 Pearson’s work on the analysis of axial flow compressor characteristics, and the accumulation of empirical data regarding factors affecting the surge line, re-awakened interest in the possibility of predicting the surge line of a multi-stage axial flow compressor-throttle system.In this paper the equations governing the stability of flow at any operating point in such a system are obtained by applying Kirchhoff’s laws to the associated electric circuit at that operating point, and the analysis is applied to a wide range of flows of the calculated characteristics of a seven-stage axial flow compressor.A study of the simplest compressor-throttle system is given, in which the equations of motion of the system are derived mechanically and electrically, and the range of validity of the equations and their stability are discussed in order to bring out the relation between the mathematics and physics of the simple system before applying these methods to multi-stage axial flow compressors.For the relatively simple electrical representation used in this paper for an axial compressor of n stages, there are shown to be 2n possible values of p, the transient rotational frequency, and these are determined over a sufficiently wide range of flows on the seven-stage compressor studied.As a result, a region of the compressor characteristic map can be marked out in which all the values of the transient rotational frequency have their real parts less than zero, corresponding to stability of operation, a region where at least one of the values of p is real and positive corresponding to non-oscillatory instability of operation, and an intermediate region where some of the values of the rotational frequency p are complex with positive real part, corresponding to oscillatory instability of operation.It is suggested that the non-oscillatory instability found here is associated with the surge and the line of inception of non-oscillatory instability with the surge line.

scholarly journals A Wide-Range Axial-Flow Compressor Stage Performance Model

1992 ◽  
Author(s):  
Gregory S. Bloch ◽  
Walter F. O’Brien
Keyword(s):  
Axial Flow ◽  
Operating Conditions ◽  
System Response ◽  
Compressor Stage ◽  
Operating Characteristics ◽  
Compression System ◽  
Axial Flow Compressor ◽  
Multi Stage ◽  
Wide Range ◽  
Flow Compressor

Dynamic compression system response is a major concern in the operability of aircraft gas turbine engines. Multi-stage compression system computer models have been developed to predict compressor response to changing operating conditions. These models require a knowledge of the wide-range, steady-state operating characteristics as inputs, which has limited their use as predicting tools. The full range of dynamic axial-flow compressor operation spans forward and reversed flow conditions. A model for predicting the wide flow range characteristics of axial-flow compressor stages was developed and applied to a 3-stage, low-speed compressor with very favorable results and to a 10-stage, high-speed compressor with mixed results. Conclusions were made regarding the inception of stall and the effects associated with operating a stage in a multistage environment. It was also concluded that there are operating points of an isolated compressor stage that are not attainable when that stage is operated in a multi-stage environment.

Turbomachinery Committee Best 1994 Paper Award: Dynamic Control of Rotating Stall in Axial Flow Compressors Using Aeromechanical Feedback

1995 ◽  
Vol 117 (3) ◽  
pp. 307-319 ◽  
Author(s):  
D. L. Gysling ◽  
E. M. Greitzer
Keyword(s):  
Control Strategy ◽  
Dynamic Control ◽  
Axial Flow ◽  
Rotating Stall ◽  
Operating Conditions ◽  
Flow Coefficient ◽  
Compression System ◽  
Axial Flow Compressor ◽  
Flow Compressor ◽  
Axial Flow Compressors

Dynamic control of rotating stall in an axial flow compressor has been implemented using aeromechanical feedback. The control strategy developed used an array of wall jets, upstream of a single-stage compressor, which were regulated by locally reacting reed valves. These reed valves responded to the small-amplitude flow-field pressure perturbations that precede rotating stall. The valve design was such that the combined system, compressor plus reed valve controller, was stable under operating conditions that had been unstable without feedback. A 10 percent decrease in the stalling flow coefficient was obtained using the control strategy, and the extension of stable flow range was achieved with no measurable change in the steady-state performance of the compression system. The experiments demonstrate the first use of aeromechanical feedback to extend the stable operating range of an axial flow compressor, and the first use of local feedback and dynamic compensation techniques to suppress rotating stall. The design of the experiment was based on a two-dimensional stall inception model, which incorporated the effect of the aeromechanical feedback. The physical mechanism for rotating stall in axial flow compressors was examined with focus on the role of dynamic feedback in stabilizing compression system instability. As predicted and experimentally demonstrated, the effectiveness of the aeromechanical control strategy depends on a set of nondimensional control parameters that determine the interaction of the control strategy and the rotating stall dynamics.

Flow Fields in an Axial Flow Compressor During Four-Quadrant Operation

2013 ◽  
Author(s):  
Andrew Gill ◽  
Theodor W. von Backström ◽  
Thomas M. Harms ◽  
Dwain Dunn
Keyword(s):  
Flow Direction ◽  
Tangential Velocity ◽  
Axial Compressor ◽  
Axial Flow ◽  
Pressure Rise ◽  
Flow Fields ◽  
Time Dependent ◽  
Axial Flow Compressor ◽  
Compressor Rotor ◽  
Flow Compressor

It has been shown in previous investigations that when all combinations of both positive and negative direction of rotation and flow direction are allowed in operating a multistage axial flow compressor, the operating point may be in any of the four quadrants of the pressure rise versus flow characteristic. The present paper is the first discussion of the flow field of all possible modes of operation of an axial flow compressor. During the present study interstage time dependent hot film velocity measurements and five hole pneumatic probe measurements were combined with steady and time dependent CFD solutions to investigate the flow fields in the three-stage axial compressor. Results are presented in terms of mean-line velocity triangles, mean stream surface plots, mid-span radial velocity contours right through the compressor, rotor-downstream radial distributions of axial and tangential velocity, stator-downstream axial velocity contours and mid-span entropy contours through the compressor. Main flow features are pointed out and discussed. The study was instigated in an effort to understand possible accident scenarios in a three-shaft closed cycle nuclear powered helium gas turbine.

A Numerical Investigation of Loss Coefficient Variation in Various Incidence Angles in Tandem Blades Cascade

2014 ◽  
Author(s):  
Arash Soltani Dehkharqani ◽  
Masoud Boroomand ◽  
Hamzeh Eshraghi
Keyword(s):  
Pressure Ratio ◽  
Axial Flow ◽  
Suction Side ◽  
Loss Coefficient ◽  
Flow Coefficient ◽  
Flow Angle ◽  
Multi Stage ◽  
Wide Range ◽  
And Performance ◽  
Flow Compressor

There is a severe tendency to reduce weight and increase power of gas turbine. Such a requirement is fulfilled by higher pressure ratio of compressor stages. Employing tandem blades in multi-stage axial flow compressors is a promising methodology to control separation on suction sides of blades and simultaneously implement higher turning angle to achieve higher pressure ratio. The present study takes into account the high flow deflection capabilities of the tandem blades consisting of NACA-65 airfoil with fixed percent pitch and axial overlap at various flow incidence angles. In this regard, a two-dimensional cascade model of tandem blades is constructed in a numerical environment. The inlet flow angle is varied in a wide range and overall loss coefficient and deviation angles are computed. Moreover, the flow phenomena between the blades and performance of both forward and afterward blades are investigated. At the end, the aerodynamic flow coefficient of tandem blades are also computed with equivalent single blades to evaluate the performance of such blades in both design and off-design domain of operations. The results show that tandem blades are quite capable of providing higher deflection with lower loss in a wide range of operation and the base profile can be successfully used in design of axial flow compressor. In comparison to equivalent single blades, tandem blades have less dissipation because the momentum exerted on suction side of tandem blades confines the size of separation zone near trailing edges of blades.

scholarly journals The Use of Experimental Interstate Data for Matching the Performance of Axial Compressor Stages Having Variable-Setting-Angle Blade Rows

1976 ◽  
Author(s):  
L. E. Brown
Keyword(s):  
Rotor Blade ◽  
Axial Compressor ◽  
Axial Flow ◽  
Performance Characteristics ◽  
Test Rig ◽  
Axial Flow Compressor ◽  
Component Test ◽  
Experimental Tool ◽  
Angle Blade ◽  
Flow Compressor

Stage performance characteristics provide a powerful analytic tool for experimentally matching the stages and blade rows of an axial-flow compressor, while the variable stage compressor component test rig provides a most powerful experimental tool for developing compressors. This paper describes: Why and how the stage characteristics “normalized” to correct them for changes of stator setting angles, how these normalized characteristics can be fully defined for every stage; and how these characteristic can point the way to a well-matched configuration of setting angles. In addition, it proposes methods for distinguishing between the stall of rotors and stators and for normalizing the characteristics of stages with variable-setting rotor blade rows.

Flow Analysis of Axial Compressor AV63-15 Variable Stator Simulation

2012 ◽  
Vol 532-533 ◽  
pp. 474-478
Author(s):  
Wei Hua Cheng ◽  
Mian Chang Li ◽  
Chuan Peng Li
Keyword(s):  
Flow Analysis ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Axial Flow ◽  
Operating Conditions ◽  
Axial Flow Compressor ◽  
Air Supply ◽  
The Difference ◽  
And Performance ◽  
Flow Compressor

This paper conducts numerical simulation to a 15-stage civil axial flow compressor and obtains its main parameters distribution and performance curve by a full three-dimensional viscid flow computation software. The computation result indicates that, the developed axial flow compressor meets the anticipated design requirements, and satisfies the customers’ indicators. Under the designed compression ratio, the difference between the maximum air supply quantity in summer and the minimum air supply quantity in winter is 22%. By comparing the operating conditions and data analysis, obtained the change trend of axial velocity, static pressure and temperature, and Ma, and discovered that, under opening of 48° and outlet back pressure of 550KPa, flow separation occurred on the section of machine set close to hud, which indicated that operating condition was close to surging condition.

Modified Surge in an Axial Flow Compressor

1992 ◽  
Author(s):  
Libor Půst
Keyword(s):  
Experimental Study ◽  
Unsteady Flow ◽  
Axial Flow ◽  
Rotating Stall ◽  
Design Flow ◽  
Flow Coefficient ◽  
Axial Flow Compressor ◽  
Flow Compressor

This paper deals with an experimental study of the unsteady flow in a multistage axial-flow compressor with a high design flow coefficient (p = 1.2) at rpm lower than the design ones. A detailed description of the rotating stall during the so-called “modified surge” is given. In this surge type the rotating stall exists during all the surge cycle, in contradistinction of classic surge, when the rotating stall exists only in a part of the surge cycle.

Three-Dimensional Blade Shape Optimization for a Transonic Axial Flow Compressor Through Incorporating Surrogate Model and Sequential Sampling

2018 ◽  
Author(s):  
Xuesong Wang ◽  
Jinju Sun ◽  
Peng Song ◽  
Youwei He ◽  
Da Xu
Keyword(s):  
Surrogate Model ◽  
Pareto Front ◽  
Sequential Sampling ◽  
Axial Flow ◽  
Aerodynamic Performance ◽  
Axial Flow Compressor ◽  
Overall Performance ◽  
Flow Compressor ◽  
High Level ◽  
Performance Gains

High level aerodynamic performance has been always expected for the axial flow compressors, and it is the consistent goal for axial flow compressor research. To achieve such a goal, the incorporation of CFD with optimization algorithm and surrogate model in blade geometry optimization has become a common practice and been used extensively. But the conventional surrogate model based on merely initial sampling often deviates from the real optimization problem during optimization process and then brings the optimizer to search locally, leading to the compromised optimal results. There are yet much to do to improve such optimization design method. An optimization method of surrogate model being updated by sequential sampling strategy is developed to achieve global optimal design geometry and permit high-level of aerodynamic performance for axial flow compressor. Preliminary Kriging surrogate model is constructed with a small number of selected DOE samplings, where the multiple optimization objective functions are obtained based on CFD simulations. The optimization is performed on the surrogate model with NSGA-II optimization algorithm and Pareto fronts successively obtained. To improve the surrogate model, the MSE (Mean Squared Error) criteria is used to select the refinement point from the newest Pareto front, and it is used to update and improve the surrogate model gradually during the optimization. Such adaptive feature of the surrogate model has enabled the optimizer to search globally. The method is used to optimize transonic Rotor 37 at design flow rate, where the blade shape is varied simultaneously in terms of sweep and lean, and the geometry is optimized. In the converged Pareto front, abundant candidate designs with significant performance gains are produced. Three points over the Pareto front are selected and analyzed to take an insight into the optimization effectiveness. Overall performance curves of optimized geometries are predicted over the entire flow range and they are significantly improved compared with the original ones. Significant overall performance gains arising from the blade optimization are supported by the improved flow behavior. The overall pressure ratio or efficiency gains of the optimized blades are attributed to the significant improvement in the radial distribution of aerodynamic parameters. Further research shows that the shock structure is changed and separation zone is reduced with the optimized blades, which are the major reasons for the improvement of the aerodynamic performance of optimized blades.

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