Efficiency Improvement at Part Load of Multistage Centrifugal Compressor for Turbo Chiller

2011 ◽  
Author(s):  
Daisuke Kawaguchi ◽  
Takeshi Okada ◽  
Yasushi Nakamura ◽  
Masatoshi Terasaki
Keyword(s):  
Centrifugal Compressor ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Efficiency Improvement ◽  
Guide Vanes ◽  
Part Load ◽  
Inlet Guide Vanes ◽  
Opening Ratio ◽  
The One ◽  
Multistage Centrifugal Compressor

The effect of variable inlet guide vanes in the multistage centrifugal compressor for the turbo chiller on the part load efficiency improvement was analyzed by using CFD (computational fluid dynamics). The area we analyzed targeted two stages including the first and second variable inlet guide vanes arranged upstream of each compressor. The numerical simulation involved three-dimensional, steady, and compressible flow analysis with ANSYS-CFX. The flash gas injected from the intermediate inlet of the economizer passage was taken into account. The part-load efficiency was measured while changing the opening ratio for the first and second variable inlet guide vanes. The predicted part-load efficiency corresponded to the one that was measured. The predicted flow pattern indicated that higher efficiency could be obtained by adjusting the opening ratio for the first and second variable inlet guide vanes to suppress excessive prewhirl from the first impeller and stall from the second impeller.

Aerodynamic Analysis of a Multistage Centrifugal Compressor

2003 ◽  
Author(s):  
Duccio Bonaiuti ◽  
Andrea Arnone ◽  
Alberto Milani ◽  
Leonardo Baldassarre
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Three Dimensional ◽  
Operating Range ◽  
Aerodynamic Analysis ◽  
Critical Elements ◽  
Multi Stage ◽  
The One ◽  
Multistage Centrifugal Compressor ◽  
The Impact

The aerodynamic analysis of a four–stage centrifugal compressor was performed by means of a three–dimensional multi stage CFD code. The whole operating range of the compressor was investigated and the critical elements affecting the choke and stall limit were identified. The isolated impellers were also analyzed separately and the flow field was compared to the one coming from the multistage analysis. This allowed us to study the effect of the interactions between components and quantify the impact of the multistage environment on the impellers’ performance.

Effect of Suction Elbow and Inlet Guide Vanes on Flow Field in a Centrifugal Compressor Stage

2002 ◽  
Author(s):  
Michael M. Cui
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Three Dimensional ◽  
Power Laws ◽  
Working Fluid ◽  
Guide Vanes ◽  
Design And Optimization ◽  
Inlet Guide Vanes ◽  
Compressor Design ◽  
Overall Performance

Suction elbows and inlet guide vanes (IGVs) are typical upstream components in front of first-stage impellers in centrifugal compressors. The three-dimensional distortion induced by elbows and IGVs affects the flow field behind the IGV housing. Since the flow field in front of the impeller is subsonic, the flow motion induced by the rotating impeller will interact with the elbow and IGVs as well. The flow field resulting from these interactions is three-dimensional. The nature of this flow field defines design requirements of upstream components and impact overall performance of the compressor. To understand the mechanism controlling the interactions of up-steam components and optimize the compressor design for better efficiency and reliability, a numerical simulation of the flow field inside the entire first stage of the compressor was conducted. The stage studied includes suction elbow, IGV housing with vanes, and first-stage impeller. HFC 134a was used as the working fluid. The thermodynamic and transport properties of the refrigerant gas were modeled by the Martin-Hou equation of state and power laws respectively. The three-dimensional flow field was simulated with a Navier-Stokes solver using the k-ε turbulence model. The overall performance parameters are obtained by integrating the field quantities. The force, torque, and arm of moment acting on the IGVs were then calculated. The results can be used to improve centrifugal compressor design to achieve higher efficiency and improve reliability. The methodology developed in the current study can be applied to centrifugal compressor design and optimization.

scholarly journals Effects of Variable Inlet Guide Vanes on Small Centrifugal Compressor Performance

1999 ◽  
Author(s):  
Minoru Ishino ◽  
Yuji Iwakiri ◽  
Akinobu Bessho ◽  
Hiroshi Uchida
Keyword(s):  
Centrifugal Compressor ◽  
Reverse Flow ◽  
Pressure Ratio ◽  
Flow Analysis ◽  
Flow Distribution ◽  
Suction Side ◽  
High Mass ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
Compressor Performance

Variable inlet guide vanes (VIGVs) have been developed for a small centrifugal compressor of automobile turbocharger. The effects of pre-whirl flow generated by VIGVs on compressor performance have been studied experimentally. Furthermore, the flow condition in impeller passage of the compressor with VIGVs has been compared to that of the compressor without VIGVs by using three-dimensional flow analysis. The results of experimental study have shown that pre-whirl flow is advantageous to the efficiency and surge characteristics of compressor. A weak fluid oscillation, which usually occurs in the region of high pressure-ratio and high mass flow rates, has been controlled by using VIGVs. The results of calculation of the viscous compressible flow have shown that the pre-whirl generated by VIGVs is effective in decreasing the area of the reverse flow which occurs at shroud suction side and smoothing the flow distribution between shroud and hub at the impeller exit.

On the Combined Effect on Operating Range of Adjustable Inlet Guide Vanes and Variable Speed in Process Multistage Centrifugal Compressors

2014 ◽  
Vol 136 (8) ◽  
Author(s):  
Alberto Scotti Del Greco ◽  
Libero Tapinassi
Keyword(s):  
Centrifugal Compressor ◽  
Control Device ◽  
Variable Speed ◽  
Centrifugal Compressors ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
Speed Regulation ◽  
Wide Range ◽  
Mach Numbers ◽  
Multistage Centrifugal Compressor

Adjustable inlet guide vanes (IGVs) and variable speed drivers are known as providing process compressors with an effective regulation all throughout the operating envelope of the machine. A large amount of work exists in literature reporting the successful control of multistage centrifugal compressors by means of IGVs or speed separately, while a few studies document the combined use of both devices and their effect on compressor performance. The present paper details the off-design behavior of a multistage centrifugal compressor equipped with both types of control. It is shown that classical IGVs' advantage in extending the operating envelope of a fixed speed multistage compressor tends to reduce when speed regulation is active too. In this sense, the average level of peripheral Mach numbers inside the compressor may be interpreted as a sort of threshold since it deeply affects the stage mismatching at off-design conditions. This consideration is corroborated by a number of applications in a wide range of design peripheral Mach numbers. Based on those cases, the paper reviews the general effectiveness of the combined regulation, thus outlining some general rules of thumb for the choice of the optimal control device for a multistage centrifugal compressor.

scholarly journals Design and Testing of Swept and Leaned Outlet Guide Vanes to Reduce Stator-Strut-Splitter Aerodynamic Flow Interactions

1998 ◽  
Author(s):  
A. R. Wadia ◽  
P. N. Szucs ◽  
K. L. Gundy-Burlet
Keyword(s):  
Dimensional Analysis ◽  
Test Performance ◽  
Potential Flow ◽  
Flow Analysis ◽  
Three Dimensional ◽  
Angle Distribution ◽  
Two Dimensional ◽  
Guide Vanes ◽  
Flow Interactions ◽  
Design And Testing

Large circumferential varying pressure levels produced by aerodynamic flow interactions between downstream stators and struts present a potential noise and stability margin liability in a compression component. These interactions are presently controlled by tailoring the camber and/or stagger angles of vanes neighboring the fan frame struts. This paper reports on the design and testing of a unique set of swept and leaned fan outlet guide vanes (OGVs) that do not require this local tailoring even though the OGVs are closely coupled with the fan frame struts and splitter to reduce engine length. The swept and leaned OGVs not only reduce core-duct diffusion, but they also reduce the potential flow interaction between the stator and the strut relative to that produced by conventional radial OGVs. First, the design of the outlet guide vanes using a single bladerow three-dimensional viscous flow analysis is outlined. Next, a two-dimensional potential flow analysis was used for the coupled OGV-frame system to obtain a circumferentially non-uniform stator stagger angle distribution to further reduce the upstream static pressure disturbance. Recognizing the limitations of the two-dimensional potential flow analysis for this highly three-dimensional set of leaned OGVs, as a final evaluation of the OGV-strut system design, a full three-dimensional viscous analysis of a periodic circumferential sector of the OGVs, including the fan frame struts and splitter, was performed. The computer model was derived from a NASA-developed code used in simulating the flow field for external aerodynamic applications with complex geometries. The three-dimensional coupled OGV-frame analysis included the uniformly-staggered OGVs configuration and the variably-staggered OGVs configuration determined by the two-dimensional potential flow analysis. Contrary to the two-dimensional calculations, the three-dimensional analysis revealed significant flow problems with the variably-staggered OGVs configuration and showed less upstream flow non-uniformity with the uniformly-staggered OGVs configuration. The flow redistribution in both the radial and tangential directions, captured fully only in the three-dimensional analysis, was identified as the prime contributor to the lower flow non-uniformity with the uniformly-staggered OGVs configuration. The coupled three-dimensional analysis was also used to validate the design at off-design conditions. Engine test performance and stability measurements with both uniformly- and variably-staggered OGVs configurations with and without the presence of inlet distortion confirmed the conclusions from the three-dimensional analysis.

A New Gas Compressor Product Development

1996 ◽  
Author(s):  
Ronald P. Porter
Keyword(s):  
Product Development ◽  
Centrifugal Compressor ◽  
High Efficiency ◽  
Low Cost ◽  
Design Features ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
Compressor Design ◽  
Gas Seals ◽  
Product Definition

A high efficiency, low cost gas compressor is under development. Design has been completed and fabrication is in process. The manufacturer’s background in centrifugal compressor design and current methodology is discussed along with product definition. Assembly and test of the first unit is planned for summer 1996. The design features a single-stage overhung centrifugal compressor, variable inlet guide vanes, and dry gas seals.

scholarly journals Experimental and numerical studies on the influence of inlet guide vanes of centrifugal compressor on the flow field characteristics of inlet chamber

2020 ◽  
Vol 12 (11) ◽  
pp. 168781402097490
Author(s):  
Fenghui Han ◽  
Zhe Wang ◽  
Yijun Mao ◽  
Jiajian Tan ◽  
Wenhua Li
Keyword(s):  
Centrifugal Compressor ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Outlet Section ◽  
Guide Vanes ◽  
Aerodynamic Loss ◽  
Inlet Guide Vanes ◽  
Flow Parameters ◽  
Flow Field Characteristics ◽  
Flow Loss

Inlet chambers (IC) are the typical upstream component of centrifugal compressors, and inlet guide vanes in the IC have a great impact on its internal flow and aerodynamic loss, which will significantly influence the performance of the downstream compressor stages. In this paper, an experimental study was carried out on the flow characteristics inside a radial IC of an industrial centrifugal compressor, including five testing sections and 968 measuring points for two schemes with and without guide vanes. Detailed distributions of flow parameters on each section were obtained as well as the overall performance of the radial IC, and the causes of the flow loss inside the IC and the non-uniformity of flow parameters at the outlet section were investigated. Besides, numerical simulations were performed to further analyze the flow characteristics inside the radial IC. The experimental and numerical results indicate that, in the scheme without guide vanes, sudden expansions in the spiral channel and flow separations in the annular convergence channel are the major sources of flow loss and distortions generated in the radial IC; while in the scheme with guide vanes, the flow impacts, separations and wakes caused by the inappropriate design of guide vanes are the main reasons for the flow loss of the IC itself and the uneven flow distributions at the IC outlet.

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.

Aerodynamic Design of Pivotable Nozzle Vanes for Radial-Inflow Turbines

1992 ◽  
Author(s):  
M. Schölch
Keyword(s):  
Velocity Distribution ◽  
Conformal Transformation ◽  
Flow Analysis ◽  
Aerodynamic Design ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
Static Efficiency ◽  
Radial Plane ◽  
Aerodynamic Investigation

In order to improve the efficiency of a radial inflow turbine new inlet guide vanes were developed. The design was the result of iteratively changing the outline of the blade contour and subsequent aerodynamic investigation of the new cascade generated. The procedure consists of four steps: – Conformal transformation of the radial cascade into a straight cascade – Determination of the incompressible inviscid velocity distribution on the blades of the straight cascade by means of a potential flow analysis – Retransformation of velocity distribution and blade geometry into the radial plane – Application of a boundary layer program to the velocity distribution on the contour of the profile in the radial plane The efficiency of the turbine was measured in operation with the original and the new guide vanes at different pressure ratios and nozzle positions. The total–to–static efficiency of the turbine increased in all measured points, in some points by two percent.

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