Gas Dynamic Designs of Centrifugal Compressors for Gas Industry

2015 ◽  
Author(s):  
Y. Galerkin ◽  
A. Rekstin ◽  
K. Soldatova ◽  
A. Drozdov
Keyword(s):  
High Efficiency ◽  
Pressure Ratio ◽  
Design Procedure ◽  
Flow Coefficient ◽  
Design Parameters ◽  
Centrifugal Compressors ◽  
Gas Industry ◽  
Design Point ◽  
Optimal Values ◽  
And Performance

Centrifugal compressors for gas industry consume huge amount of energy. As a rule, they are single-shaft, with two or more stages and with comparatively low pressure ratio. Compressors operate at low Mach numbers and high Reynolds numbers. Two design parameters influence mostly stage performances. Stage flow coefficient optimal values lie in range 0.060–0.11. Chosen number of stages establishes value of this coefficient if speed of a rotor rotation is fixed. Design loading factor optimal values are 0.42–0.52. It corresponds to high efficiency, shifts a surge limit far from a design point and makes power maximal in a design point. Some considerations about impeller and diffuser types are presented. Design procedure consists on application of the Universal modeling programs for main dimensions optimization and performance calculations. Q3D non-viscid velocity diagrams are analyzed for optimization of blade configuration. Samples of design are presented, 32 MW single-stage pipeline compressor stage with record efficiency included.

An Optimization Method for Centrifugal Compressor Design Using the Surrogate Management Framework

2011 ◽  
Author(s):  
Kyoung Ku Ha ◽  
Shin Hyoung Kang
Keyword(s):  
Optimal Design ◽  
Centrifugal Compressor ◽  
Design Space ◽  
Optimization Method ◽  
Pattern Search ◽  
Flow Coefficient ◽  
Design Parameters ◽  
Centrifugal Compressors ◽  
Management Framework ◽  
Design Point

A variety of centrifugal compressors are used in various fields of industry these days. The design requirements are more complicated, and it is difficult to determine the optimal design point of a centrifugal compressor. The aim of this study was to propose an efficient optimization method for centrifugal compressors considering the impeller, the vaneless diffuser, and the overhung type volute. The optimization was performed using the surrogate management framework (SMF). The design parameters were the impeller exit radius, the exit blade angle, and the flow coefficient. Sample points in the design space were selected according to the Design of Experiments (DoE) theory. The CFD simulations were executed on the impeller and the diffuser at every sampled point. The volutes were described using a one-dimensional but reliable theory to reduce the simulation time. An approximation model based on the Kriging method was constructed using this dataset. Then, an optimal design point that minimized the objective function was determined in a substitute design space using the pattern search method because of its efficiency and rigorous convergence. The optimization process, underlying methods, and results are described in this paper.

Influence of Reynolds Number on the Performance of Process Centrifugal Compressors

2016 ◽  
Author(s):  
Yan Liu ◽  
Li-hua Tao ◽  
Jian Wang ◽  
Yang Wang ◽  
Xue-jun Wang ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Mach Number ◽  
Flow Coefficient ◽  
Design Parameters ◽  
Centrifugal Compressors ◽  
Empirical Formulas ◽  
Design Point ◽  
Reliable Performance ◽  
High Reynolds ◽  
Large Flow

Over the past 60 years, effects of changes in Reynolds number on performance of centrifugal compressors have been widely investigated. However most of cases deal with those compressors with small or medium flow coefficients. Studies on the influence of Reynolds number on centrifugal compressors with large flow coefficients and high machine Mach number are rarely seen in the literature. This paper deals with two types of centrifugal compressors. One type of compressor (Model 1) has a relatively large capacity with high machine Mach number. The flow coefficient and machine Mach number are 0.16 and 1.05 respectively at the design condition. Those design parameters for the other type of compressor (Model 2) are 0.11 and 0.7 respectively. Both experimental and numerical results show that with increase in Re, aerodynamic performance of centrifugal compressors is improved. However, to what extent that improvement is gained depends on properties of the baseline compressor. When Reynolds number of Model 1 becomes about 5 times large due to increase in the inlet pressure, its polytropic efficiency is only improved 0.7% at the design point in experiment. Flow field inside the impeller is similar to its prototype. For Model 2, when Reynolds number becomes 1.78 times large due to scaling up, the polytropic efficiency of the enlarged one is improved about 2% at the design point. These results demonstrate that for a compressor with large flow coefficient and high machine Mach number, i.e. originally high Reynolds number, the influence of Reynolds number on its performance is limited. In addition to experiment and CFD, two empirical formulas are applied to work out performance correction due to a change in Reynolds number for Model 1 and Model 2. Although CFD results are more accurate than the empirical results, empirical formula is still useful to get relatively reliable performance correction.

Design and Performance Evaluation of a 10:1 Pressure Ratio Centrifugal Compressor Impeller

2010 ◽  
Author(s):  
Marco Vagani ◽  
Christopher D. Bolin
Keyword(s):  
Pressure Ratio ◽  
Design Procedure ◽  
Flow Simulation ◽  
Single Stage ◽  
Centrifugal Impeller ◽  
Centrifugal Compressors ◽  
Slip Factor ◽  
Auxiliary Power ◽  
Compressor Impeller ◽  
And Performance

Small gas turbine engines for advanced helicopter application and for auxiliary power have strong interest in centrifugal compressors, where high pressure ratios are required in a single stage. But there are few single stage centrifugal compressors capable of pressure-ratios around 10:1, due to stress considerations which severely limit the compressor’s safety, durability and life expectancy. In this work, design considerations are carried out for single stage centrifugal impeller with a pressure ratio of 10:1 and mass flow of 3 kg/s. One-D design procedure is used to compute the skeletal geometry of the impeller and to set a rough description of the flow at inlet and outlet. The theoretical head will be evaluated from Euler’s equation using slip factor. Determining the pressure ratio and efficiency of the impeller are achieved through evaluation of the slip factor and the internal and external losses. The losses evaluated in the impeller are those due to incidence, transonic inlet, skin friction, blade loading, shroud clearance, and recirculation. The design procedure adopted will be verified and compared with the well-documented Eckardt impellers and data. After one-D design, three-D geometry of the impeller is developed, and CFD flow simulation of the impeller flow is carried out to determine the performance of the impeller.

Design and Analysis of a High Pressure Turbine Using Computational Methods for Small Gas Turbine Application

2013 ◽  
Author(s):  
Kishor Kumar ◽  
R. Prathapanayaka ◽  
S. V. Ramana Murthy ◽  
S. Kishore Kumar ◽  
T. M. Ajay Krishna
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Computational Methods ◽  
Gas Turbine Engine ◽  
Flow Coefficient ◽  
Design Parameters ◽  
Convergence Criterion ◽  
Turbine Engine ◽  
Design Point ◽  
Ansys Cfx

This paper describes the aerodynamic design and analysis of a high-pressure, single-stage axial flow turbine suitable for small gas turbine engine application using computational methods. The specifications of turbine were based on the need of a typical high-pressure compressor and geometric restrictions of small gas turbine engine. Baseline design parameters such as flow coefficient, stage loading coefficient are close to 0.23 and 1.22 respectively with maximum flow expansion in the NGV rows. In the preliminary design mode, the meanline approach is used to generate the turbine flow path and the design point performance is achieved by considering three blade sections at hub, mean and tip using the AMDC+KO+MK+BSM loss models to meet the design constraints. An average exit swirl angle of less than 5 degrees is achieved leading to minimum losses in the stage. Also, NGV and rotor blade numbers were chosen based on the optimum blade solidity. Blade profile is redesigned using the results from blade-to-blade analysis and through-flow analysis based on an enhanced Dawes BTOB3D flow solver. Using PbCFD (Pushbutton CFD) and commercially available CFD software ANSYS-CFX, aero-thermodynamic parameters like pressure ratios, aerodynamic power, and efficiencies are computed and these results are compared with one another. The boundary conditions, convergence criterion, and turbulence model used in CFD computations are set uniform for comparison with 8 per cent turbulence intensity. Grid independence study is performed at design point to optimize the grid density for off-design performance predictions. ANSYS-CFX and PbCFD have predicted higher efficiency of 3.4% and 1.2% respectively with respect to targeted efficiency of 89 per cent.

scholarly journals Pipeline Compressor Redesign With the Consideration of Both Noise and Performance

2000 ◽  
Author(s):  
Yuri I. Biba ◽  
Zheji Liu ◽  
D. Lee Hill
Keyword(s):  
High Efficiency ◽  
Aerodynamic Characteristics ◽  
The Body ◽  
Design Parameters ◽  
Original Design ◽  
Tonal Noise ◽  
Experimental Performance ◽  
Expected Performance ◽  
Computational Fluid Dynamics Cfd ◽  
And Performance

A complete effort to redesign the aerodynamic characteristics of a single-stage pipeline compressor is presented. The components addressed are the impeller, diffuser region, and the volute. The innovation of this effort stems from the simultaneous inclusion of both the noise and aerodynamic performance as primary design parameters. The final detailed flange-to-flange analysis of the new components clearly shows that the operating range is extended and the tonal noise driven by the impeller is reduced. This is accomplished without sacrificing the existing high efficiency of the baseline machine. The body of the design effort uses both Computational Fluid Dynamics (CFD) and vibro-acoustics technology. The predictions are anchored by using the flange-to-flange analysis of the original design and its experimental performance data. By calculating delta corrections and assuming that these deltas are approximately the same for the new design, the expected performance is extrapolated.

1D and 3D-Design Strategies for Pressure Slope Optimization of High-Flow Transonic Centrifugal Compressor Impellers

2018 ◽  
Author(s):  
A. Hildebrandt ◽  
T. Ceyrowsky
Keyword(s):  
Centrifugal Compressor ◽  
High Flow ◽  
Flow Coefficient ◽  
Design Parameters ◽  
Angle Distribution ◽  
Compressor Stage ◽  
Impeller Blade ◽  
Design Point ◽  
Centrifugal Compressor Stage ◽  
Transonic Centrifugal Compressor

The present paper deals with the numerical and theoretical investigations of the effect of geometrical dimensions and 1D-design parameters on the impeller pressure slope of a transonic centrifugal compressor stage for industrial process application. A database being generated during the multi-objective and multi-point design process of a high flow coefficient impeller, comprising 545 CFD (Computational Fluid Dynamics) designs is investigated in off-design and design conditions by means of RANS (Reynolds Averaged Navier Stokes) simulation of an impeller with vaneless diffuser. For high flow coefficients of 0.16 < phi < 0.18, the CFD-setup has been validated against measurement data regarding stage and impeller performance taken from MAN test rig experimental data for a centrifugal compressor stage of similar flow coefficient. The paper aims at answering the question how classical design parameter, such as the impeller blade angle distribution, impeller suction diameter and camber line length affect the local and total relative diffusion and pressure slope towards impeller stall operation. A second order analysis of the CFD database is performed by cross-correlating the CFD data with results from impeller two-zone 1D modelling and a rapid loading calculation process by Stanitz and Prian. The statistical covariance of first order 1D-analysis parameters such as the mixing loss of the impeller secondary flow, the slip factor, impeller flow incidence is analyzed, thereby showing strong correlation with the design and off-design point efficiency and pressure slope. Finally, guide lines are derived in order to achieve either optimized design point efficiency or maximum negative pressure slope characteristics towards impeller stall operation.

scholarly journals Numerical verification of variable friction cladding connection for multihazard mitigation

2020 ◽  
pp. 107754632092393
Author(s):  
Yongqiang Gong ◽  
Liang Cao ◽  
Simon Laflamme ◽  
James Ricles ◽  
Spencer Quiel ◽  
...  
Keyword(s):  
Sliding Friction ◽  
Design Procedure ◽  
Design Parameters ◽  
Numerical Verification ◽  
Structural System ◽  
Passive Energy Dissipation ◽  
Variable Friction ◽  
Friction Cladding ◽  
And Performance ◽  
Selection Of

The motion of cladding systems can be leveraged to mitigate natural and man-made hazards. The literature counts various examples of connections enhanced with passive energy dissipation capabilities at connections. However, because such devices are passive, their mitigation performance is typically limited to specific excitations. The authors have recently proposed a novel variable friction cladding connection capable of mitigating hazards semi-actively. The variable friction cladding connection is engineered to transfer lateral forces from the cladding element to the structural system. Its variation in friction force is generated by a toggle-actuated variable normal force applied onto sliding friction plates. In this study, a multiobjective motion-based design methodology integrating results from the previous work is proposed to leverage the variable friction cladding connection for nonsimultaneous wind, seismic, and blast hazard mitigation. The procedure starts with the quantification of each hazard and performance objectives. It is followed by the selection of dynamic parameters enabling prescribed performance under wind and seismic loads, after which an impact rubber bumper is designed to satisfy motion requirements under blast. Last, the peak building responses are computed and iterations conducted on the design parameters on the satisfaction of the motion objectives. The motion-based design procedure is verified through numerical simulations on two example buildings subjected to the three nonsimultaneous hazards. The performance of the variable friction cladding connection is also assessed and compared against different control cases. Results show that the motion-based design procedure yields a conservative design approach in meeting all of the motion requirements and that the variable friction cladding connection performs significantly well at mitigating vibrations.

Affinity Law Modified to Predict the Pump Head Performance for Different Viscosities Using the Morrison Number

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Abhay Patil ◽  
Gerald Morrison
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Flow Coefficient ◽  
Design Parameters ◽  
Sharp Change ◽  
Fluid Viscosity ◽  
Pump Head ◽  
Laminar And Turbulent Flow ◽  
Computational Fluid Dynamics Cfd ◽  
And Performance

The goal of this study is to provide pump users a simple means to predict a pump's performance change due to changing fluid viscosity. During the initial investigation, it has been demonstrated that pump performance can be represented in terms of the head coefficient, flow coefficient, and rotational Reynolds number with the head coefficient data for all viscosities falling on the same curve when presented as a function of ф*Rew−a. Further evaluation of the pump using computational fluid dynamics (CFD) simulations for wider range of viscosities demonstrated that the value of a (Morrison number) changes as the rotational Reynolds number increases. There is a sharp change in Morrison number in the range of 104<Rew<3*104 indicating a possible flow regime change between laminar and turbulent flow. The experimental data from previously published literature were utilized to determine the variation in the Morrison number as the function of rotational Reynolds number and specific speed. The Morrison number obtained from the CFD study was utilized to predict the head performance for the pump with known design parameters and performance from published literature. The results agree well with experimental data. The method presented in this paper can be used to establish a procedure to predict any pump's performance for different viscosities; however, more data are required to completely build the Morrison number plot.

scholarly journals Design Specifications and Performance analysis of Single and Two Stage HB LLC Converters

2019 ◽  
Vol 9 (1S) ◽  
pp. 192-196
Keyword(s):  
Performance Analysis ◽  
Software Package ◽  
Design Procedure ◽  
Input Voltage ◽  
Design Parameters ◽  
Basic Operation ◽  
Two Stage ◽  
Design Specifications ◽  
Converter Topologies ◽  
And Performance

In this paper a Single stage and Two stage Half Bridge LLC (HB LLC) converter topologies for DC/DC applications with low input voltage. The basic operation and design procedure for LLC converter is illustrated. Simulation of the proposed converter is done using the design parameters and the results are discussed and then analysis is done to know its performance. The efficiency of the converters is analyzed by MATLAB Software Package.

scholarly journals Design Options to Improve the Dynamic Behavior and the Control of Small H-Darrieus VAWTs

2021 ◽  
Vol 11 (19) ◽  
pp. 9222
Author(s):  
Lorenzo Battisti
Keyword(s):  
Built Environment ◽  
Urban Environment ◽  
Wind Turbines ◽  
Rational Design ◽  
Design Procedure ◽  
Design Parameters ◽  
Site Characteristics ◽  
Acceleration And Deceleration ◽  
And Performance ◽  
Wind Resource

H-VAWTs or straight blades VAWTs are the most common turbine architecture employed for small VAWTs. The manufacture of straight, constant chord blades, coupled with the transport advantages, make this choice technologically simpler, compared to curved (eggbeater) type or curved-bent (Gorlov) type, allowing a large selection of materials, and design solutions. Recently, the strategies to accomplish the task of zero-emission buildings identified wind energy exploitation in the urban environment as one of the most promising. Micro and mini wind turbines installed on buildings (BAWT—building-augmented wind turbines) are considered the candidate technology after that of photovoltaic panels; under certain conditions, these technologies can be combined to obtain the maximum natural resources exploitation in the urban environment. VAWT, compared to HAWT, would ideally perform better in the fast-changing, turbulent winds, typical of the built environment. Additionally, its 3D shape favors a better architectonic integration with the volumes of the building. Nevertheless, despite these claimed advantages, this architecture did still not come to the expected fruition and experience, which revealed that the stochastic nature of the wind resource in the built environment determines a quite challenging context, reflecting not only the structural endurance, but also the operations and the annual energy production. These site characteristics stress the detrimental effect of the high polar inertia of this architecture hampering, be it a reduction in the acceleration and deceleration capability of the rotor, the required adaptation of the rotational speed to the varying wind conditions, or compromising any form of robust control. This leads to poor aerodynamic performance and potential structural damages. This paper contributes to mitigating the issue of the high rotor polar inertia of the H-VAWT without affecting other essential design requirements (strength, performances, needs of smooth control). The work identifies the design parameters governing the rotor acceleration and deceleration and develops a rational design procedure aimed at improving the H-VAWT control and performance.

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