Performance improvement of a transonic centrifugal compressor impeller with splitter blade by three-dimensional optimization

Energy ◽  
2020 ◽  
Vol 201 ◽  
pp. 117582
Author(s):  
Khalil Ekradi ◽  
Ali Madadi
Keyword(s):  
Performance Improvement ◽  
Centrifugal Compressor ◽  
Three Dimensional ◽  
Transonic Centrifugal Compressor ◽  
Compressor Impeller ◽  
Dimensional Optimization

Unsteady and Three-Dimensional Flow Phenomena in a Transonic Centrifugal Compressor Impeller at Rotating Stall

2009 ◽  
Author(s):  
Kenichiro Iwakiri ◽  
Masato Furukawa ◽  
Seiichi Ibaraki ◽  
Isao Tomita
Keyword(s):  
Centrifugal Compressor ◽  
Wavelet Transforms ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Internal Flow ◽  
Leading Edge ◽  
Rotating Stall ◽  
Detached Eddy Simulation ◽  
Transonic Centrifugal Compressor ◽  
Compressor Impeller

This paper presents a combined experimental and numerical analysis of rotating stall in a transonic centrifugal compressor impeller for automotive turbochargers. Stall characteristics of the compressor were examined by two high-response pressure transducers mounted on the casing wall near the impeller inlet. The pressure traces were analyzed by wavelet transforms to estimate the disturbance waves quantitatively. Three-dimensional unsteady internal flow fields were simulated numerically by Detached Eddy Simulation (DES) coupled LES-RANS approach. The analysis results show good agreements on both compressor performance characteristics and the unsteady flow features at the rotating stall. At stall inception, spiral-type breakdown of the full-blade tip leakage vortex was found out at some passages and the brokendown regions propagated against the impeller rotation. This phenomenon changed with throttling, and tornado-type separation vortex caused by the full-blade leading edge separation dominated the flow field at developed stall condition. It is similar to the flow model of short-length scale rotating stall established in an axial compressor rotor.

Suppression of Secondary Flows in a Transonic Centrifugal Compressor Impeller Using an Inverse Design Method Based on Meridional Viscous Flow Analysis

2019 ◽  
Author(s):  
Sasuga Ito ◽  
Shin Okada ◽  
Yuki Kawakami ◽  
Kaito Manabe ◽  
Masato Furukawa ◽  
...  
Keyword(s):  
Viscous Flow ◽  
Secondary Flow ◽  
Centrifugal Compressor ◽  
Pressure Ratio ◽  
Aerodynamic Performance ◽  
Secondary Flows ◽  
Low Energy ◽  
Design Concept ◽  
Transonic Centrifugal Compressor ◽  
Compressor Impeller

Abstract Secondary flows in transonic centrifugal compressor impellers affect their aerodynamic performance. In open-type impellers, low energy fluids can accumulate on the suction surfaces near the trailing edge tip side since the secondary flows and tip leakage flows interfere each other and complex flow phenomena can be generated around the impellers. Therefore, designers must consider the effect of secondary flows to avoid the aerodynamic performance degradation while designing compressor impellers. In this paper, a novel design concept about suppression of secondary flows in centrifugal compressor impellers to improve their aerodynamic performance. A transonic centrifugal compressor impeller was redesigned with the present design concept by a two-dimensional inverse method based on a meridional viscous flow calculation in this study. A design concept was introduced in above calculation process. As the design concept, by bending vortex filaments with controlling peak positions of the blade loading distributions, induced velocity due to bound vortices at the blades was generated in radial opposite direction of the secondary flows on the suction surface. Due to investigate the effect of the design concept in this paper, three-dimensional Reynolds Averaged Navier-Stokes simulations were carried out, and the vortex cores were visualized by a critical point theory and colored by non-dimensional helicity. In the conventional transonic centrifugal compressor impeller, the secondary flow vortices were confirmed and one of the vortices was broken down. In the redesigned impeller, the breakdown of the secondary flow vortices was not observed and the accumulation of the low energy fluids was suppressed compared with the conventional impeller. The total pressure ratio and adiabatic efficiency of the redesign impeller were higher than that of the conventional impeller, and the secondary flows were successfully suppressed in this research.

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.

scholarly journals Comparative Study of Unsteady Flows in a Transonic Centrifugal Compressor With Vaneless and Vaned Diffusers

2001 ◽  
Author(s):  
Michael M. Cui
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Centrifugal Compressor ◽  
Three Dimensional ◽  
Power Laws ◽  
Working Fluid ◽  
Local Flow ◽  
Transonic Centrifugal Compressor ◽  
Compressor Performance ◽  
Overall Performance

To reduce vibration and noise level, the impeller and diffuser blade numbers inside an industrial compressor are typically chosen without common divisors. The shapes of volutes or collectors in these compressors are also not axis-symmetric. When impeller blades pass these asymmetric structures, the flow field in the compressor is time-dependent and three-dimensional. To obtain a fundamental physical understanding of these three-dimensional unsteady flow fields and assess their impact on the compressor performance, the flow field inside the compressors needs to be studied as a whole to include asymmetric and unsteady interaction between the compressor components. In current study, a unified three-dimensional numerical model was built for a transonic centrifugal compressor including impeller, diffusers, and volute. 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 unsteady flow field was simulated with a Navier-Stokes solver using the k-ε turbulent model. The overall performance parameters are obtained by integrating the field quantities. Both unsteady flow field and overall performance are analyzed comparatively for each component. The compressor was tested in a water chiller system instrumented to obtain both overall performance data and local flow field quantities. The experimental and numerical results agree well. The correlation between the overall compressor performance and local flow field quantities is defined. The methodology developed and data obtained in these studies can be applied to centrifugal compressor design and optimization.

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.

Vortical Flow Structure and Loss Generation Process in a Transonic Centrifugal Compressor Impeller

2007 ◽  
Author(s):  
Seiichi Ibaraki ◽  
Masato Furukawa ◽  
Kenichiro Iwakiri ◽  
Kazuya Takahashi
Keyword(s):  
Flow Field ◽  
Flow Structure ◽  
Centrifugal Compressor ◽  
Secondary Flows ◽  
Vortical Flow ◽  
Generation Process ◽  
Tip Leakage ◽  
Transonic Centrifugal Compressor ◽  
Compressor Impeller ◽  
Flow Phenomena

Transonic centrifugal compressors are used in turbochargers and turboshaft engines because of their small dimensions, relatively high efficiency and wide operating range. The flow field of the transonic centrifugal compressor impeller is highly three dimensional, and is complicated by shock waves, tip leakage vortices, secondary flows and the interactions among them. In order to improve the performance, it is indispensable to understand these complicated flow phenomena in the impeller. Although experimental and numerical research on transonic impeller flow has been reported, thus providing important flow physics, some undetected flow phenomena remain. The authors of the present report carried out detailed Navier-Stokes computations of a transonic impeller flow measured by Laser Doppler Velocimetry (LDV) in previous work. The highly complicated vortical flow structure and the mechanism of loss generation were revealed by a visual data mining technique, namely vortex identification based on the critical point theory and limiting streamline mapping by means of line integral convolution. As a result, it was found that the tip leakage vortices have a significant impact on the flow field and vortex breakdowns that increase the blockage of the flow passage, and that these were caused by shock wave interaction.

Aerodynamic Optimization of a Transonic Centrifugal Compressor by Using Arbitrary Blade Surfaces

2018 ◽  
Vol 140 (5) ◽  
Author(s):  
Alexander Hehn ◽  
Moritz Mosdzien ◽  
Daniel Grates ◽  
Peter Jeschke
Keyword(s):  
Centrifugal Compressor ◽  
Three Dimensional ◽  
Leading Edge ◽  
Suction Side ◽  
Ruled Surfaces ◽  
Flank Milling ◽  
Specific Work ◽  
Vaneless Diffuser ◽  
Aerodynamic Optimization ◽  
Transonic Centrifugal Compressor

A transonic centrifugal compressor was aerodynamically optimized by means of a numerical optimization process. The objectives were to increase the isentropic efficiency and to reduce the acoustic signature by decreasing the amplitude of pre-shock pressure waves at the inlet of the compressor. The optimization was performed at three operating points on the 100% speed line in order to maintain choke mass flow and surge margin. At the design point, the specific work input was kept equal. The baseline impeller was designed by using ruled surfaces due to requirements for flank milling. To investigate the benefits of arbitrary blade surfaces, the restrictions of ruled surfaces were abolished and fully three-dimensional (3D) blade profiles allowed. In total, therefore, 45 parameters were varied during the optimization. The combined geometric and aerodynamic analysis reveals that a forward swept leading edge (LE) and a concave suction side at the tip of the LE are effective design features for reducing the shock strength. Beyond that, the blade shape of the optimized compressor creates a favorable impeller outlet flow, which is the main reason why the performance of the vaneless diffuser improves. In total, a gain of 1.4% points in isentropic total-to-static efficiency, evaluated by computational fluid dynamics (CFD) at the exit plane of the vaneless diffuser, is achieved.

PIV Investigation of a High Speed Centrifugal Compressor Diffuser: Spanwise and Loading Variations

2008 ◽  
Author(s):  
Beni Cukurel ◽  
Patrick B. Lawless ◽  
Sanford Fleeter
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
High Speed ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Vaned Diffuser ◽  
Operation Conditions ◽  
Diffuser Flow ◽  
Transonic Centrifugal Compressor ◽  
Flow Features

An efficient diffuser is essential to a modern compressor stage, due to its significance in stage performance, durability and operability. To address the need for data that describe the complex, unsteady flow field in a vaned diffuser, Particle Image Velocity is utilized to characterize the spanwise and circumferential variations of the flow features in the vaned diffuser passage of a transonic centrifugal compressor. The spanwise variation in the diffuser flow field is further investigated by comparison of 3 different operating conditions representative of low, nominal and high loading. These data demonstrate that not only the diffuser flow field is highly dependent on the operation conditions, e.g. hub-to-shroud variation increases with loading, but also the circumferential periodicity, created by the highly three dimensional impeller discharge flow, generates a larger unsteadiness towards the hub region of the vaned diffuser.

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