scholarly journals Centrifugal Compressor Impeller Aerodynamics: A Numerical Investigation

1990 ◽  
Author(s):  
Daniel J. Dorney ◽  
Roger L. Davis
Keyword(s):  
Centrifugal Compressor ◽  
Equations Of Motion ◽  
Three Dimensional ◽  
Elliptic Partial Differential Equation ◽  
Solution Procedure ◽  
Design Flow ◽  
Navier Stokes ◽  
Impeller Blade ◽  
Compressor Impeller ◽  
Rotor Stator Interaction

A three-dimensional, Navier-Stokes analysis is presented for the prediction of viscous flows through centrifugal impellers. Based on the Navier-Stokes rotor/stator interaction procedure developed by Rai, the present analysis uses a zonal grid methodology to discretize the impeller flow field and to facilitate the relative motion of the impeller. A blade surface oriented O-grid generated from an elliptic partial differential equation solution procedure is patched into an algebraically generated H-grid which is used to discretize the inlet, exit and blade-to-blade regions. The equations of motion are integrated using a spatially third-order accurate, implicit, iterative, upwind, finite difference, time-marching technique. Predicted results are presented for flow through a low speed centrifugal compressor impeller operating at design flow conditions. Comparison of these predicted results with experimental data demonstrates the capability of this procedure to predict impeller blade loading and provide insight into the secondary flow structure within the impeller blade passage.

Centrifugal Compressor Impeller Aerodynamics: An Experimental Investigation

1990 ◽  
Author(s):  
H. David Joslyn ◽  
Joost J. Brasz ◽  
Robert P. Dring
Keyword(s):  
Flow Visualization ◽  
Centrifugal Compressor ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Companion Paper ◽  
Surface Flow ◽  
Navier Stokes ◽  
Pressure Distributions ◽  
Compressor Impeller ◽  
Surface Flow Visualization

The ability to acquire blade loadings (surface pressure distributions) and surface flow visualization on an unshrouded centrifugal compressor impeller is demonstrated. Circumferential and streamwise static pressure distributions acquired on the stationary shroud are also presented. Data was acquired in a new facility designed for centrifugal compressor aerodynamic research. Blade loadings calculated with a blade–to–blade potential flow analysis are compared with the measured results. Surface flow visualization reveals some complex aspects of the flow on the surface of the impeller blading and hub. In a companion paper, Dorney and Davis (1990), a state–of–the–art, three–dimensional, time–accurate, Navier Stokes prediction of the flow through the impeller is presented.

Application of a Three-Dimensional Inverse Method to the Design of a Centrifugal Compressor Impeller

1998 ◽  
Author(s):  
Alain Demeulenaere ◽  
Olivier Léonard ◽  
René Van den Braembussche
Keyword(s):  
Centrifugal Compressor ◽  
Inverse Method ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Centrifugal Impeller ◽  
Mean Velocity ◽  
Blade Shape ◽  
Compressor Impeller ◽  
Real Performance ◽  
The Mean

The use of a three-dimensional Euler inverse method for the design of a centrifugal impeller is demonstrated. Both the blade shape and the endwalls are iteratively designed. The meridional contour is modified in order to control the mean velocity level in the blade channel, while the blade shape is designed to achieve a prescribed loading distribution between the inlet and the outlet. The method salves the time dependent Euler equations in a numerical domain of which some boundaries (the blades or the endwalls) move and change shape during the transient part of the computation, until a prescribed pressure distribution is achieved on the blade surfaces. The method is applied to the design of a centrifugal compressor impeller, whose hub endwall and blade surfaces are modified by the inviscid inverse method. The real performance of both initial and modified geometries are compared through three-dimensional Navier-Stokes computations.

Identification of Acoustic Dipole Sources in a Propylene Centrifugal Compressor Stage

2010 ◽  
Author(s):  
Hongtao Tang ◽  
Datong Qi ◽  
Fuan Lu
Keyword(s):  
Centrifugal Compressor ◽  
Three Dimensional ◽  
Dipole Source ◽  
Compressor Stage ◽  
Impeller Blade ◽  
Centrifugal Compressor Stage ◽  
Rotor Stator Interaction ◽  
Last Stage ◽  
Harmonic Components ◽  
Dipole Sources

Three-dimensional unsteady turbulent flow in a propylene centrifugal compressor stage was numerically studied in order to identify primary acoustic dipole sources. The investigated model is the last stage of a propylene compressor used in the megaton ethylene production. The leakage clearance between the impeller and diffuser was simplified and modeled to capture the rotor-stator interaction accurately. A series of sixth-order polynomials, the use of which significantly sped up the computation compared with directly using Helmholtz real gas equation as the gas model, were fitted with a relative error less than 0.03% based on the thermodynamic data of propylene obtained by the Helmholtz equation. According to Lowson’s equation, the root mean square of the partial derivative of static pressure with respect to time during two revolutions of the impeller was taken as the parameter to measure dipole source intensity. The spatial distribution and frequency characteristics of the dipole sources were also investigated intensively. As a result of the present study, the primary dipole source is located at the junction of the impeller and diffuser, and its intensity is dominated by the components at the impeller blade passing frequency (BPF) and its higher harmonics, which are induced by the strong rotor-stator interaction. The spectrum analysis downstream of the impeller indicates that the higher harmonic components of dipole sources attenuate faster than the BPF component along the streamwise direction, and it is the BPF that dominates the noise characteristic in the volute casing of the studied model.

CFD Analysis of a Centrifugal Compressor Impeller and Volute

1999 ◽  
Author(s):  
Harri Pitkänen ◽  
Hannu Esa ◽  
Petri Sallinen ◽  
Jaakko Larjola
Keyword(s):  
Centrifugal Compressor ◽  
Static Pressure ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Prediction Method ◽  
Navier Stokes ◽  
Recovery Coefficient ◽  
Compressor Impeller ◽  
Compressor Performance ◽  
Pressure Recovery Coefficient

In this study, centrifugal compressor performance was predicted using CFD. Three-dimensional time-averaged impeller and volute simulations were performed using a Navier–Stokes code. The presented performance prediction method has been divided into three phases. Firstly, the impeller was calculated with a vaneless diffuser. That gives inlet boundary conditions for the volute analysis and the pressure ratio at the diffuser exit. Next, the volute analysis was performed and a static pressure recovery coefficient obtained. Finally, that result was combined with the pressure ratio prediction from the impeller analysis, and the overall compressor performance thus obtained.

scholarly journals Numerical Simulation of Internal Flow and Performance Prediction of Tubular Pump with Adjustable Guide Vanes

2014 ◽  
Vol 6 ◽  
pp. 171504 ◽  
Author(s):  
Honggeng Zhu ◽  
Rentian Zhang
Keyword(s):  
Stokes Equations ◽  
Three Dimensional ◽  
Internal Flow ◽  
Design Flow ◽  
Navier Stokes ◽  
Impeller Blade ◽  
Flow Angle ◽  
Guide Vanes ◽  
Operation Conditions ◽  
Setting Angle

Aiming at the performance defect of tubular pump with fixed guide vanes, a design scheme of tubular pump with adjustable guide vanes is proposed, so that the inlet setting angle of guide vanes can be flexibly adjusted to coordinate with the operation conditions of pump, to ensure the inlet setting angle of guide vanes changing with the outlet flow angle of the impeller. The three-dimensional time-averaged incompressible Navier-Stokes equations are adopted to numerically simulate the internal flow field of a tubular pump with fixed and adjustable guide vanes, respectively. Computed results indicate that with the design of adjustable guide vanes and at off-design flow rates the flow conditions inside the diffuser of tubular pump can be improved effectively, and its hydraulic losses can be reduced. When the impeller blade angles are fixed the best efficiency points are within 0.51% while adjusting setting angles of guide vanes within a certain range. Under off-design conditions the hydraulic efficiency of tubular pump with adjustable guide vanes can be obviously improved by 1.70% at 0.75 Q0 and 2.19% at 1.20 Q0, when the blade angle is 0 degrees and the angle of guide vanes is adjusted to be 2 degrees smaller and larger, respectively.

The Aerodynamics of Three-Dimensional Vaned Diffusers in Industrial Centrifugal Compressors

2005 ◽  
Author(s):  
Ahmed Abdelwahab
Keyword(s):  
Centrifugal Compressor ◽  
Dynamic Pressure ◽  
Three Dimensional ◽  
Pressure Recovery ◽  
Navier Stokes ◽  
Spanwise Direction ◽  
Two Dimensional ◽  
Blade Loading ◽  
Recovery Capacity ◽  
Close Proximity

Vaned diffusers have been used successfully as efficient and compact dynamic pressure recovery devices in industrial centrifugal compressor stages. Typically such diffusers consist of a cascade of two-dimensional blades distributed circumferentially at close proximity to the impeller exit. In this paper three low-solidity diffuser blade geometries are numerically investigated. The first geometry employs variable stagger stacking of similar blade sections along the blade span. The second employs linearly inclined stacking to generate blade lean along the diffuser span. The third geometry employs the conventional two-dimensional low-solidity diffuser geometry with no variable stagger or lean. The variable stagger blade arrangement has the potential of better aligning the diffuser leading edges with the highly non-uniform flow leaving the impeller. Both variable stagger and linearly leaned diffuser blade arrangements, however, have the effect of redistributing the blade loading and flow streamlines in the spanwise direction leading to improved efficiency and pressure recovery capacity of the diffuser. In this paper a description of the proposed diffuser geometries is presented. The results of Three-dimensional Navier-Stokes numerical simulations of the three centrifugal compressor arrangements are discussed. Comparisons between the performance of the two and three-dimensional diffuser blade geometries are presented. The comparisons indeed show that the variable stagger and leaned diffusers present an improvement in the diffuser operating range and pressure recovery capacity over the conventional two-dimensional diffuser geometry.

scholarly journals An Experimental and Computational Investigation of Flow in a Radial Inlet of an Industrial Pipeline Centrifugal Compressor

1994 ◽  
Author(s):  
M. B. Flathers ◽  
G. E. Bache ◽  
R. Rainsberger
Keyword(s):  
Centrifugal Compressor ◽  
Numerical Study ◽  
Three Dimensional ◽  
Experimental Results ◽  
Scale Model ◽  
Navier Stokes ◽  
Angle Distribution ◽  
Computational Results ◽  
Industrial Pipeline ◽  
Design Schedule

The flowfield of a complex three dimensional radial inlet for an industrial pipeline centrifugal compressor has been experimentally determined on a half scale model. Based on the experimental results, inlet guide vanes have been designed to correct pressure and swirl angle distribution deficiencies. The unvaned and vaned inlets are analyzed with a commercially available fully 3D viscous Navier-Stokes code. Since experimental results were available prior to the numerical study, the unvaned analysis is considered a postdiction while the vaned analysis is considered a prediction. The computational results of the unvaned inlet have been compared to the previously obtained experimental results. The experimental method utilized for the unvaned inlet is repeated for the vaned inlet and the data has been used to verify the computational results. The paper will discuss experimental, design and computational procedures, grid generation, boundary conditions, and experimental versus computational methods. Agreement between experimental and computational results is very good, both in prediction and postdiction modes. The results of this investigation indicate that CFD offers a measurable advantage in design, schedule and cost and can be applied to complex, three dimensional radial inlets.

scholarly journals Numerical Investigation of Kelvin-Helmholtz Instability in a Centrifugal Compressor Operating Near Stall

2015 ◽  
Author(s):  
Y. Bousquet ◽  
X. Carbonneau ◽  
I. Trebinjac ◽  
N. Binder ◽  
G. Dufour
Keyword(s):  
Centrifugal Compressor ◽  
Vortex Shedding ◽  
Three Dimensional ◽  
Flow Region ◽  
Main Flow ◽  
Helmholtz Instability ◽  
Vaned Diffuser ◽  
Leakage Flows ◽  
Rotor Stator Interaction ◽  
Three Dimensional Simulations

The present works details the occurrence of the Kelvin–Helmholtz instability in a centrifugal compressor operating near stall. The analysis are based on unsteady three dimensional simulations performed on a calculation domain covering the full annulus for the impeller and the vaned diffuser. A detailed investigation of the flow structure is presented, together with its evolution consequent to the mass flow reduction. It is demonstrated that this reduction leads to an enlargement of the low momentum flow region initially induced by the combination of the secondary and leakage flows. When the compressor operates near stall, the shear layer at the interface between the main flow and this low momentum flow becomes unstable and induces a periodic vortex shedding. The frequency of such an unsteady phenomenon is not correlated with the blade passing frequency. Its signature is thus easily isolated from the deterministic rotor/stator interaction. Its detection requires full-annulus simulations with an accurate resolution in time and space, which explains why it has never been previously observed in centrifugal compressors.

An Approximate Three-Dimensional Aerodynamic Design Method for Centrifugal Impeller Blades

1990 ◽  
Vol 112 (1) ◽  
pp. 44-49 ◽  
Author(s):  
Zhao Xiaolu ◽  
Qin Lisen
Keyword(s):  
Centrifugal Compressor ◽  
Design Method ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Design Procedure ◽  
Taylor Series Expansion ◽  
Centrifugal Impeller ◽  
Aerodynamic Design ◽  
Impeller Blade ◽  
Blade Geometry

An aerodynamic design method, which is based on the Mean Stream Surface Method (MSSM), has been developed for designing centrifugal compressor impeller blades. As a component of a CAD system for centrifugal compressor, it is convenient to use the presented method for generating impeller blade geometry, taking care of manufacturing as well as aerodynamic aspects. The design procedure starts with an S2m indirect solution. Afterward from the specified S2m surface, by the use of Taylor series expansion, the blade geometry is generated by straight-line elements to meet the manufacturing requirements. Simultaneously, the fluid dynamic quantities across the blade passage can be determined directly. In terms of these results, the designer can revise the distribution of angular momentum along the shroud and hub, which are associated with blade loading, to get satisfactory velocities along the blade surfaces in order to avoid or delay flow separation.

Unsteady Flow at the Outlet of the High Specific Speed Centrifugal Compressor Impeller

1984 ◽  
Author(s):  
Fumikata Kano ◽  
Takafumi Shirakami
Keyword(s):  
Unsteady Flow ◽  
Centrifugal Compressor ◽  
Coal Gasification ◽  
Three Dimensional ◽  
Axial Direction ◽  
Navier Stokes ◽  
Meridional Plane ◽  
Mixed Flow ◽  
Navier Stokes Equation ◽  
Specific Speed

The unsteady flow at the outlet of the high specific speed mixed flow Impeller was studied. The specific speed is 500 (m3/min)1/2 · rpm · m−3/4. The flow is strongly influenced by the impeller blading. The other hand, the flow influences the performance of the stationary vanes downstream of the impeller. The flow path at the outlet of the mixed flow impeller is inclined to the axial direction and is curved in the meridional plane. The study was carried out to develop the 30 MW centrifugal compressor. This compressor is used in the field of the coal gasification, the geothermal power generation, etc. The distributions of flow velocity, pressure and temperature of three dimensional flow were measured using a high sensitive pressure transducer and a total temperature probe. The flow was surveyed across the entire passage at about ten axial locations including endwall boundary layer. A theoretical analysis was also carried out using the linearized Navier-Stokes equation.

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