Experimental and Theoretical Analysis of the Flow in a Centrifugal Compressor Volute

1993 ◽  
Vol 115 (3) ◽  
pp. 582-589 ◽  
Author(s):  
E. Ayder ◽  
R. Van den Braembussche ◽  
J. J. Brasz
Keyword(s):  
Centrifugal Compressor ◽  
Cross Sections ◽  
Swirling Flow ◽  
Three Dimensional ◽  
Elliptical Cross ◽  
Loss Model ◽  
Tangential Flow ◽  
Static Pressure Distribution ◽  
Flow Loss ◽  
Mean Streamline Analysis

Detailed measurements of the swirling flow in a centrifugal compressor volute with elliptical cross section are presented. They show important variations of the swirl and throughflow velocity, total and static pressure distribution at the different volute cross sections and at the diffuser exit. The basic mechanisms defining the complex three dimensional flow structure are clarified. The different sources of pressure loss have been investigated and used to improve the prediction capability of one-dimensional mean streamline analysis correlations. The tangential flow loss model under decelerating flow conditions and the friction loss model are confirmed. New empirical loss coefficients are proposed for the exit cone loss model and the tangential flow loss model for the case of accelerating flow in the volute.

Experimental and Theoretical Analysis of the Flow in a Centrifugal Compressor Volute

1992 ◽  
Author(s):  
E. Ayder ◽  
R. Van den Braembussche ◽  
J. J. Brasz
Keyword(s):  
Centrifugal Compressor ◽  
Cross Sections ◽  
Swirling Flow ◽  
Elliptical Cross ◽  
Loss Model ◽  
Pressure Losses ◽  
Tangential Flow ◽  
Static Pressure Distribution ◽  
Flow Loss ◽  
Mean Streamline Analysis

Detailed measurements of the swirling flow in a centrifugal compressor volute with elliptical cross section are presented. They show important variations of the swirl- and throughflow velocity, total and static pressure distribution at the different volute cross sections and at the diffuser exit. The basic mechanisms defining the complex 3D flow structure are clarified. The different sources of pressure losses have been investigated and used to improve the prediction capability of one dimensional mean streamline analysis correlations. The tangential flow loss model, under decelerating flow conditions, and friction loss model are confirmed. New emprical loss coefficients are proposed for the exit cone loss model and the tangential flow loss model for the case of accelerating flow in the volute.

Experimental and Theoretical Study of the Swirling Flow in Centrifugal Compressor Volutes

1990 ◽  
Vol 112 (1) ◽  
pp. 38-43 ◽  
Author(s):  
R. A. Van den Braembussche ◽  
B. M. Ha¨nde
Keyword(s):  
Centrifugal Compressor ◽  
Cross Sections ◽  
Swirling Flow ◽  
Three Dimensional ◽  
Maximum Velocity ◽  
Three Dimensional Flow ◽  
Static Pressure Distribution ◽  
Swirl Velocity ◽  
Isentropic Flows ◽  
Operating Points

Measurements of the three-dimensional flow in a simplified model of a centrifugal compressor volute at design and off-design operation are presented. A nearly constant swirl velocity is observed near the walls and a forced vortex type of flow is observed in the center. This velocity distribution is almost identical at all cross sections and all operating points. An explanation is given on how this swirl distribution results from the specific way a volute is filled with fluid. The throughflow velocity component shows a large crosswise variation. A minimum or maximum velocity is observed at the volute center depending on the operating point. A simple analytic model, based on the radial equilibrium of forces, is described. Calculations for isentropic flows reveal the relation between the swirl distribution and the large increase of throughflow velocity toward the center. This explains why volutes should be designed with negative blockage. Nonisentropic calculations, using the experimental loss distribution, correctly reproduce the measured throughflow velocity and static pressure distribution.

Numerical Analysis of the Three-Dimensional Swirling Flow in Centrifugal Compressor Volutes

1994 ◽  
Vol 116 (3) ◽  
pp. 462-468 ◽  
Author(s):  
E. Ayder ◽  
R. Van den Braembussche
Keyword(s):  
Centrifugal Compressor ◽  
Swirling Flow ◽  
Three Dimensional ◽  
Numerical Procedure ◽  
Elliptical Cross ◽  
Hexahedral Elements ◽  
Flow Mechanisms ◽  
Radial Forces ◽  
Finite Volume Approach ◽  
Euler Solver

The improvement of centrifugal compressor performance and the control of the radial forces acting on the impeller due to the circumferential variation of the static pressure caused by the volute require a good understanding of the flow mechanisms and an accurate prediction of the flow pattern inside the volute. A three-dimensional volute calculation method has been developed for this purpose. The volute is discretized by means of hexahedral elements. A cell vertex finite volume approach is used in combination with a time-marching procedure. The numerical procedure makes use of a central space discretization and a four-step Runge–Kutta time-stepping scheme. The artificial dissipation used in the solver is based on the fourth-order differences of the conservative variables. Implicit residual smoothing improves the convergence rate. The loss model implemented in the code accounts for the losses due to internal shear and friction losses on the walls. A comparison of the calculated and measured results inside a volute with elliptical cross section reveals that the modified Euler solver accurately predicts the velocity and pressure distribution inside and upstream of the volute.

scholarly journals Experimental and Theoretical Study of the Swirling Flow in Centrifugal Compressor Volutes

1989 ◽  
Author(s):  
R. A. Van Den Braembussche ◽  
B. M. Hände
Keyword(s):  
Centrifugal Compressor ◽  
Theoretical Study ◽  
Swirling Flow ◽  
Three Dimensional ◽  
Simplified Model ◽  
Three Dimensional Flow ◽  
Dimensional Flow

Measurements of the three-dimensional flow in a simplified model of a centrifugal compressor volute at design and off-design operation are presented.

scholarly journals Computational Study of Zigzag Spacer Design with Elliptical Cross-Section Filaments

2020 ◽  
Vol 307 ◽  
pp. 01047
Author(s):  
Gohar Shoukat ◽  
Farhan Ellahi ◽  
Muhammad Sajid ◽  
Emad Uddin
Keyword(s):  
Mass Transfer ◽  
Cross Section ◽  
Cross Sections ◽  
Computational Study ◽  
Flow Direction ◽  
Three Dimensional ◽  
Circular Cross Section ◽  
Two Dimensional ◽  
Permeate Flux ◽  
Elliptical Cross

The large energy consumption of membrane desalination process has encouraged researchers to explore different spacer designs using Computational Fluid Dynamics (CFD) for maximizing permeate per unit of energy consumed. In previous studies of zigzag spacer designs, the filaments are modeled as circular cross sections in a two-dimensional geometry under the assumption that the flow is oriented normal to the filaments. In this work, we consider the 45° orientation of the flow towards the three-dimensional zigzag spacer unit, which projects the circular cross section of the filament as elliptical in a simplified two-dimensional domain. OpenFOAM was used to simulate the mass transfer enhancement in a reverse-osmosis desalination unit employing spiral wound membranes lined with zigzag spacer filaments. Properties that impact the concentration polarization and hence permeate flux were analyzed in the domain with elliptical filaments as well as a domain with circular filaments to draw suitable comparisons. The range of variation in characteristic parameters across the domain between the two different configurations is determined. It was concluded that ignoring the elliptical projection of circular filaments to the flow direction, can introduce significant margin of error in the estimation of mass transfer coefficient.

scholarly journals Three-dimensional reconstruction of the fast-start swimming kinematics of densely schooling fish

2011 ◽  
Vol 9 (66) ◽  
pp. 77-88 ◽  
Author(s):  
Sachit Butail ◽  
Derek A. Paley
Keyword(s):  
Cross Sections ◽  
Tracking System ◽  
Three Dimensional ◽  
Three Dimensions ◽  
Verbal Cues ◽  
Elliptical Cross ◽  
Fish School ◽  
Schooling Fish ◽  
Dimensional Reconstruction ◽  
Fast Start

Information transmission via non-verbal cues such as a fright response can be quantified in a fish school by reconstructing individual fish motion in three dimensions. In this paper, we describe an automated tracking framework to reconstruct the full-body trajectories of densely schooling fish using two-dimensional silhouettes in multiple cameras. We model the shape of each fish as a series of elliptical cross sections along a flexible midline. We estimate the size of each ellipse using an iterated extended Kalman filter. The shape model is used in a model-based tracking framework in which simulated annealing is applied at each step to estimate the midline. Results are presented for eight fish with occlusions. The tracking system is currently being used to investigate fast-start behaviour of schooling fish in response to looming stimuli.

Experimental Study of the Swirling Flow in the Volute of a Centrifugal Pump

1990 ◽  
Author(s):  
T. Elholm ◽  
E. Ayder ◽  
R. Van Den Braembussche
Keyword(s):  
Velocity Distribution ◽  
Mass Flow ◽  
Cross Sections ◽  
Swirling Flow ◽  
Three Dimensional ◽  
Pressure Rise ◽  
High Mass ◽  
Return Flow ◽  
Flow Visualisation ◽  
Through Flow

The detailed three-dimensional velocity distributions, corresponding to design and off-design operation, were measured in two different circumferential cross sections of a volute by means of LDV. It is shown that the swirl has a forced vortex type velocity distribution and that the location of the swirl center is changing with mass flow. The through flow velocity distribution is primarily defined by the conservation of angular momentum. A strong interaction between the through flow and swirl velocity is observed. Flow visualisation in the tongue region reveals a reversal of the velocity at the volute inlet with increasing mass flow. The pressure drop between volute outlet and inlet at low mass flow pushes extra fluid through the tongue gap and increases the mass flow in the volute. The abrupt pressure rise at high mass flow results in local return flow perturbing the flow in the outlet pipe.

Design and Off-Design Numerical Investigation of a Transonic Double-Splitter Centrifugal Compressor

2008 ◽  
Author(s):  
Michele Marconcini ◽  
Filippo Rubechini ◽  
Andrea Arnone ◽  
Seiichi Ibaraki
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Cross Sections ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Secondary Flows ◽  
Operating Conditions ◽  
Complex Flow ◽  
Flow Measurements ◽  
Vaned Diffuser

The flow field of a high pressure ratio centrifugal compressor for turbocharger applications is investigated using a three-dimensional Navier-Stokes solver. The compressor is composed of a double-splitter impeller followed by a vaned diffuser. The flow field of the transonic open-shrouded impeller is highly three-dimensional, and it is influenced by shock waves, tip leakage vortices and secondary flows. Their interactions generate complex flow structures which are convected and distorted through the impeller blades. Both steady and unsteady computations are performed in order to understand the physical mechanisms which govern the impeller flow field while the operation ranges from choke to surge. Detailed Laser Doppler Velocimetry (LDV) flow measurements are available at various cross-sections inside the impeller blades at both design and off-design operating conditions.

scholarly journals Numerical Analysis of the 3D Swirling Flow in Centrifugal Compressor Volutes

1993 ◽  
Author(s):  
E. Ayder ◽  
R. Van den Braembussche
Keyword(s):  
Centrifugal Compressor ◽  
Swirling Flow ◽  
Numerical Procedure ◽  
Cross Sectional ◽  
Elliptical Cross ◽  
Hexahedral Elements ◽  
Flow Mechanisms ◽  
Radial Forces ◽  
Finite Volume Approach ◽  
Euler Solver

The improvement of centrifugal compressor performance and the control of the radial forces acting on the impeller due to the circumferential variation of the static pressure caused by the volute require a good understanding of the flow mechanisms and an accurate prediction of the flow pattern inside the volute. A 3D volute calculation method has been developed for this purpose. The volute is discretized by means of hexahedral elements. A cell vertex finite volume approach is used in combination with a time marching procedure. The numerical procedure makes use of a central space discretization and a four step Runge-Kutta time stepping scheme. The artificial dissipation used in the solver is based on the fourth order differences of the conservative variables. Implicit residual smoothing improves the convergence rate. The loss model implemented in the code accounts for the losses due to internal shear and friction losses on the walls. A comparison of the calculated and measured results inside a volute with elliptical cross sectional shape reveals that the modified Euler solver accurately predicts the velocity and pressure distribution inside and upstream of the volute.

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