Understanding the Interaction Between an Impeller and Its Inlet Guide Vanes

2002 ◽  
Author(s):  
D. Lee Hill ◽  
Zheji Liu
Keyword(s):  
Dynamic Interaction ◽  
Centrifugal Impeller ◽  
Impeller Blade ◽  
Primary Parameter ◽  
Guide Vanes ◽  
Sliding Mesh ◽  
Inlet Guide Vanes ◽  
Wide Range ◽  
Guide Blade ◽  
And Performance

Industrial turbocompressors often experience a wide range of operation. The dynamic interaction between stage components has long been recognized as an important effect that impacts both range and performance of the machine. The non-integral blade count between stationary and rotating blades has forced researchers to develop alternative numerical techniques to avoid full 360-degree sliding-mesh calculations. The relative low number of impeller blade used on a compressor, however, makes the full 360-degree simulation just as practical. This study focuses on the dynamic interaction between the inlet guide vanes and a shrouded centrifugal impeller. The primary parameter varied is the inlet guide blade count. The results between the different configurations are used to study performance implications as well as dynamic loading on the impeller itself.

Redesign of a Compressor Stage for a High-Performance Electric Supercharger in a Heavily Downsized Engine

2017 ◽  
Vol 140 (4) ◽  
Author(s):  
Peng Wang ◽  
Mehrdad Zangeneh ◽  
Bryn Richards ◽  
Kevin Gray ◽  
James Tran ◽  
...  
Keyword(s):  
Design Method ◽  
Pressure Ratio ◽  
Compressor Stage ◽  
Impeller Blade ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
Surge Margin ◽  
Stable Operating ◽  
Inverse Design Method ◽  
Ported Shroud

Engine downsizing is a modern solution for the reduction of CO2 emissions from internal combustion engines. This technology has been gaining increasing attention from industry. In order to enable a downsized engine to operate properly at low speed conditions, it is essential to have a compressor stage with very good surge margin. The ported shroud, also known as the casing treatment, is a conventional way used in turbochargers to widen the working range. However, the ported shroud works effectively only at pressure ratios higher than 3:1. At lower pressure ratio, its advantages for surge margin enhancements are very limited. The variable inlet guide vanes are also a solution to this problem. By adjusting the setting angles of variable inlet guide vanes, it is possible to shift the compressor map toward the smaller flow rates. However, this would also undermine the stage efficiency, require extra space for installing the inlet guide vanes, and add costs. The best solution is therefore to improve the design of impeller blade itself to attain high aerodynamic performances and wide operating ranges. This paper reports a recent study of using inverse design method for the redesign of a centrifugal compressor stage used in an electric supercharger, including the impeller blade and volute. The main requirements were to substantially increase the stable operating range of the compressor in order to meet the demands of the downsized engine. The three-dimensional (3D) inverse design method was used to optimize the impeller geometry and achieve higher efficiency and stable operating range. The predicted performance map shows great advantages when compared with the existing design. To validate the computational fluid dynamics (CFD) results, this new compressor stage has also been prototyped and tested. It will be shown that the CFD predictions have very good agreement with experiments and the redesigned compressor stage has improved the pressure ratio, aerodynamic efficiency, choke, and surge margins considerably.

scholarly journals Development of a Centrifugal Compressor With a Variable Geometry Split-Ring Pipe Diffuser

1998 ◽  
Author(s):  
J. W. Salvage
Keyword(s):  
Leading Edge ◽  
Lessons Learned ◽  
Operating Point ◽  
Maximum Efficiency ◽  
Variable Geometry ◽  
Impeller Blade ◽  
Guide Vanes ◽  
Part Load ◽  
Inlet Guide Vanes ◽  
Surge Line

Higher noise levels resulted when a compressor was scaled to larger capacity. The machine’s sound pressure level was relieved by increasing the distance between the impeller blade tip and diffuser leading edge. However, the part-load surge line deteriorated severely as a consequence. A variable geometry pipe diffuser solved this problem, permitting operation at stringent off-design conditions. The addition of a variable diffuser permits compressor selection very near its most efficient full-load operating point, without regard for limitations normally imposed by part-load requirements. The principal lessons learned during aerodynamic design refinement include (a) how performance and surge depend upon positioning the variable inlet guide vanes and variable diffuser, and (b) how to define simultaneous variation of inlet guide vanes and diffuser for specific operational objectives. Generally, each operating point requires a unique setting of the variable components to achieve maximum efficiency. However, linked movement is shown to yield both a satisfactory surge line and improved performance for most applications when compared to a compressor without the variable geometry pipe diffuser.

Development of a Centrifugal Compressor With a Variable Geometry Split-Ring Pipe Diffuser

1999 ◽  
Vol 121 (2) ◽  
pp. 295-304 ◽  
Author(s):  
J. W. Salvage
Keyword(s):  
Leading Edge ◽  
Lessons Learned ◽  
Operating Point ◽  
Maximum Efficiency ◽  
Variable Geometry ◽  
Impeller Blade ◽  
Guide Vanes ◽  
Part Load ◽  
Inlet Guide Vanes ◽  
Surge Line

Higher noise levels resulted when a compressor was scaled to larger capacity. The machine’s sound pressure level was relieved by increasing the distance between the impeller blade tip and diffuser leading edge. However, the part-load surge line deteriorated severely as a consequence. A variable geometry pipe diffuser solved this problem, permitting operation at stringent off-design conditions. The addition of a variable diffuser permits compressor selection very near its most efficient full-load operating point, without regard for limitations normally imposed by part-load requirements. The principal lessons learned during aerodynamic design refinement include (a) how performance and surge depend upon positioning the variable inlet guide vanes and variable diffuser, and (b) how to define simultaneous variation of inlet guide vanes and diffuser for specific operational objectives. Generally, each operating point requires a unique setting of the variable components to achieve maximum efficiency. However, linked movement is shown to yield both a satisfactory surge line and improved performance for most applications when compared to a compressor without the variable geometry pipe diffuser.

Non-Periodic 3D Diffusers for Mitigating Aerodynamic Exciters

2014 ◽  
Author(s):  
Mikhail Grigoriev ◽  
James Hitt
Keyword(s):  
Energy Distribution ◽  
Three Dimensional ◽  
Leading Edge ◽  
Great Majority ◽  
Temporal Variations ◽  
Centrifugal Impeller ◽  
Pressure Waves ◽  
Impeller Blade ◽  
Wide Range ◽  
Leading Edges

The great majority of the modern centrifugal stages utilize periodic stationary structures such as inlet guide vanes and/or diffuser vanes. To maximize the aerodynamic performance of the centrifugal stage, these vanes must be positioned at a close proximity of the centrifugal impeller. This arrangement results in a dramatic interaction between rotating impeller and stationary vanes due to reflection of the pressure waves from the periodic vanes back onto the impeller blades. The periodic nature of the reflected pressure waves may lead to an excitation of the impeller blade eigenmodes if the fundamental frequency (or, its multiple) of the external force matches with the natural frequency of the subject impeller. As the impeller blades provide very little to no damping, there is a strong possibility of the high cycle fatigue resonance failure of the impeller blades if the impeller design does not provide with a sufficient separation from the resonance modes. We should note that ensuring such a separation is not straightforward task for many stages with periodic exciters, and may not be even feasible for some practical design cases. This presentation focuses on a novel way to mitigate possible resonance issues for centrifugal impellers due to pressure reflection waves emanating from the diffuser blades. We propose to utilize non-periodic centrifugal diffuser together with the sculpting leading edges for the three-dimensional diffuser vanes. In order to demonstrate the attractiveness and feasibility of this approach, we have utilized Computational Fluid Dynamics (CFD) tools to perform time-accurate unsteady turbulent flow analyses in centrifugal stages and capture cyclic pressure waves acting on the impeller blades. The present work considers a regular periodic low-solidity diffuser with two-dimensional vanes, a three-dimensional periodic diffuser with a sculpted leading edge, and, finally, a non-periodic three-dimensional diffuser with an unequal, non-repeating stagger. We have utilized eighteen CFD pressure probes located on the impeller blade pressure and suction sides to monitor temporal variations of the static pressure that capture the pressure reflection waves from the diffuser vanes. The Fourier series decomposition facilitates detailed analyses of the pressure energy distribution over a wide range of frequencies. The results of the numerical studies demonstrate that even the use of the periodic diffuser with 3D sculpted leading edges help reduce the magnitude of the pressure oscillations at the dominant frequency and its integer multiples. However, the pressure energy distribution changes dramatically when using the non-periodic diffuser arrangement together with the sculpted leading edge vanes. The strength of the pressure waves associated with the dominant harmonics and its integer multiples are reduced about 30% to 85% and spread over the frequencies that constitute integer multiples of the fundamental impeller frequency. This pressure energy redistribution of the 3D non-periodic diffuser is a significant aid to the aerodynamicist. By significantly reducing the mechanical constraint compromises, the designer is allowed to focus more on aerodynamic component efficiency.

An Experimental Investigation on the Clocking Effect Between Inlet Guide Vanes and Vaned Diffuser in a Centrifugal Compressor Stage

2008 ◽  
Author(s):  
Jiang Hua ◽  
Xi Guang ◽  
Zhang Wei ◽  
WuQi Gong ◽  
ZhiHeng Wang
Keyword(s):  
Experimental Investigation ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Axial Compressor ◽  
Centrifugal Impeller ◽  
Vaned Diffuser ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
Stage Efficiency ◽  
Peak Value

Different circumferential angle positions between stator or rotor vane rows in turbomachinery can lead to different flow structures or stage performances. The clocking effect phenomenon has been detected in axial compressor and turbine by investigators, but rarely reported on centrifugal compressor. The present work is an experimental investigation on the stator clocking effect between inlet guide vanes (IGV) and vaned diffuser in a low-speed centrifugal compressor. The experimental rig consists of a circumferentially rotatable IGV, an unshrouded centrifugal impeller, a vaned diffuser, a volute and etc. The impeller diameter is 796mm, and the rotate speed is about 3100 rpm. At each inlet prewhirl angle of −20°, 0° and +20°, the stage performance curves are measured at three clocking angle positions of 0°, 8° and 16°. The result shows that at the circumferential angles of 0° and 8°, the efficiency curve has a double peak value feature, but at the angle of 16° being the conventional single peak value curve. Further, at the circumferential angles of 0° and 8°, the stage efficiency is bigger 3.6% than that case of the angle being 16°, where the IGV prewhirl angles are 0° and 20°. When the IGV prewhirl angle is changed into −20°, the stage efficiency increases about 2.0% near the first peak value position at the circumferential angles of 0°and 8° than at 16°, however, at the second peak value position, the stage efficiency at the circumferential angle of 0° is bigger about 1.4% than at 8° and 16°. Moreover, the circumferential angle positions between IGV and vaned diffuser have corresponding influence on the pressure ratio.

Numerical Study of the Flow in the Flow Path of a Centrifugal Natural Gas Compressor at Different Positions of the Inlet Guide Vane

2021 ◽  
pp. 94-108
Author(s):  
M.V. Krutikov ◽  
V.L. Blinov
Keyword(s):  
Natural Gas ◽  
Gas Flow ◽  
Numerical Study ◽  
Guide Vane ◽  
Flow Path ◽  
Inlet Guide Vane ◽  
Guide Vanes ◽  
Operating Modes ◽  
Inlet Guide Vanes ◽  
Wide Range

The paper focuses on the problem of a possible expansion of the range of operating modes of a centrifugal natural gas compressor due to the rotation of the inlet guide vanes at different rotor speeds. The geometry of the flow path of the investigated object, obtained by three-dimensional scanning, is presented. On its basis, a numerical model is built and the influence of various factors of the formulation of the computational problem on the results of modeling the gas flow in the flow path of the compressor is analyzed. The calculations were performed using the k--ε and SST turbulence models for various parameters of the computational grid and conditions for averaging the flow parameters between the computational domains. The results obtained were compared with the nameplate and operational data. Recommendations on the formulation of the modeling problem are proposed, the results of the calculations are described, and the characteristics of the centrifugal compressor are plotted at different angles of the inlet guide vanes in a wide range of rotor speeds. The possible range of expansion of the operating modes of the investigated compressor is described, which can be provided by varying the position of the inlet guide vane

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.

Investigation of Electrohydraulic Control of A Gas Turbine Engine’s Inlet Guide Vanes

2017 ◽  
Vol 17 (17) ◽  
pp. 1-10
Author(s):  
Mostafa Samy ◽  
Mohamed Metwally ◽  
Wael Elmayyah ◽  
Ibrahem Elsherif
Keyword(s):  
Gas Turbine ◽  
Guide Vanes ◽  
Inlet Guide Vanes

Analysis of organic removal rates in the aerated submerged fixed film process

1998 ◽  
Vol 38 (8-9) ◽  
pp. 213-221 ◽  
Author(s):  
Mohamed F. Hamoda ◽  
Ibrahim A. Al-Ghusain
Keyword(s):  
Pilot Plant ◽  
Removal Rate ◽  
Domestic Wastewater ◽  
Removal Rates ◽  
Hydraulic Loading ◽  
Organic Removal ◽  
Wide Range ◽  
Fixed Film ◽  
Cod Removal Rate ◽  
And Performance

Performance data from a pilot-plant employing the four-stage aerated submerged fixed film (ASFF) process treating domestic wastewater were analyzed to examine the organic removal rates. The process has shown high BOD removal efficiencies (> 90%) over a wide range of hydraulic loading rates (0.04 to 0.68 m3/m2·d). It could also cope with high hydraulic and organic loadings with minimal loss in efficiency due to the large amount of immobilized biomass attained. The organic (BOD and COD) removal rate was influenced by the hydraulic loadings applied, but organic removal rates of up to 104 kg BOD/ m2·d were obtained at a hydraulic loading rate of 0.68 m3/m2·d. A Semi-empirical model for the bio-oxidation of organics in the ASFF process has been formulated and rate constants were calculated based on statistical analysis of pilot-plant data. The relationships obtained are very useful for analyzing the design and performance of the ASFF process and a variety of attached growth processes.

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