The Influence of Inlet Flow Distortion on the Performance of a Centrifugal Compressor and the Development of Improved Inlet Using Numerical Simulations—Part II: Development of Improved Inlet for a Centrifugal Compressor Using Numerical Simulations

2000 ◽  
Author(s):  
Yunbae Kim ◽  
Abraham Engeda ◽  
Ron Aungier ◽  
Greg Direnzi
Keyword(s):  
Numerical Simulations ◽  
Centrifugal Compressor ◽  
Curvature Radius ◽  
Flow Properties ◽  
Inlet Pipe ◽  
Flow Distortion ◽  
Cross Sectional ◽  
Inlet System ◽  
Compressor Inlet ◽  
Compressor Performance

Abstract Part I of this paper reported the experimental investigation on the effect of the curved inlet pipe flow distortion on a centrifugal compressor performance, which motivated the need of a new inlet design as well as a clear picture of the detailed flow field in the existing inlet design using numerical simulations. In Part II, new designs of different inlet systems as well as the design methods are discussed based on the comparison of flow properties at pipe exit of each design. The goal of the compressor inlet system design is to reduce the secondary flow and provide uniform flow for a compressor. Two design approaches are reported in this paper, one of which is the location of vanes and the other is the length of curvature radius, resulting in four new designs. The vanes are spaced in such a way that each passage shares the same pressure difference in radial direction. Numerical simulation results are presented in terms of mass averaged parameters and flow structures on the exit cross-sectional area. The design of original bend pipe with two vanes inside shows advantages over others.

Investigation of Inlet Bent-Pipe’s Effect on a Turbocharger Compressor: Unsteadiness of Mass Glow and Location of Main Flow Loss

2014 ◽  
Author(s):  
Ben Zhao ◽  
Dazhong Lao ◽  
Liangjun Hu ◽  
Ce Yang
Keyword(s):  
Centrifugal Compressor ◽  
High Load ◽  
Bench Test ◽  
Inlet Pipe ◽  
Straight Pipe ◽  
Flow Distortion ◽  
Design Point ◽  
Bent Pipe ◽  
Flow Loss ◽  
Compressor Performance

As inlet bent-pipes are often used in vehicle turbocharger compressors, understanding of the inlet bent-pipe’s effect on centrifugal compressor and the mechanism of flow loss is important to improve the turbocharger compressor performance. Experiment and numerical simulation were carried out on a centrifugal compressor with straight pipe and bent-pipe. Numerical simulated compressor performance was compared with test data obtained from compressor flow bench test and to validate the numerical method. The analysis is mainly based on numerical results and it indicated that the inlet bent pipe induces a serious distortion at impeller inlet and increases the risk of blade high-cycle fatigue. The level of distortion changes to be more serious as the operation point of compressor varies from design point to high load. When an impeller channel enters distortion, the larger pressure difference between inlet and outlet makes this channel get clogged and the flow rate through this channel is reduced. At design point the bent pipe mainly influences the flow loss in the inlet pipe and impeller while at high load more serious flow distortion induced by bent-pipe is able to extend its stronger effect to the downstream diffuser and volute.

The Investigation of Distorted and Enhanced Inlet Flow Influence on the Performance of a Centrifugal Compressor Stage

2001 ◽  
Author(s):  
Yunbae Kim ◽  
Abraham Engeda ◽  
Ron Aungier ◽  
Greg Direnzi
Keyword(s):  
Centrifugal Compressor ◽  
Design Method ◽  
Compressor Stage ◽  
Flow Properties ◽  
Flow Distortion ◽  
Inlet System ◽  
Inlet Flow ◽  
Centrifugal Compressor Stage ◽  
Stage Performance ◽  
Inlet Flow Distortion

Abstract The performance of a centrifugal compressor can be seriously affected by inlet flow distortions due to the unsatisfactory nature of the inlet configuration and the resulting inlet flow structure. In the previous work, experimental tests were carried out for the comparison of a centrifugal compressor stage performance with two different inlet configurations: one of which was a straight pipe with constant cross-sectional area as an ideal model and the other is a 90-degree curved pipe with nozzle shape as an actual model. The comparative test results indicated significant compressor stage performance difference between the two different inlet configurations. In addition, the numerical simulation part of the previous work clearly showed that the inlet flow distortion is caused by the pressure driven secondary flow developed in the curved section in the case of the bend inlet, resulting in locally concentrated incidence at the impeller inlet and thus the compressor stage performance degradation. An improved inlet model with the design method has been proposed based on the comparisons of the designated flow properties. In the present work, further numerical simulations on the compressor stage including the impeller and the diffuser with three different inlets are carried out to investigate the performance behavior of the compressor exposed to different inlet configurations. The three different inlet systems include the original bend inlet as well as the proposed inlet model based on the developed design method. Since the flow from the bend inlet is not axisymmetric due to the circumferential and radial distortion on the cross-section, the impeller and the diffuser are modeled with fully 360-degree passages, which accommodates the inlet flow distortion and the impeller-diffuser interaction influence on the entire flow passage of the compressor. The stage performance with the different inlet systems are evaluated and compared with the previous experimental result. The diffuser performance and the flow properties in the vaneless region are compared among those inlet models. The proposed inlet system indicated the benefit of performance improvement over the original inlet system.

Parametric Studies of Pipe Diffuser on Performance of a Highly Loaded Centrifugal Compressor

2014 ◽  
Vol 136 (12) ◽  
Author(s):  
Ge Han ◽  
Xingen Lu ◽  
Shengfeng Zhao ◽  
Chengwu Yang ◽  
Junqiang Zhu
Keyword(s):  
Centrifugal Compressor ◽  
Performance Enhancement ◽  
Detailed Comparison ◽  
Flow Distortion ◽  
Flow Solver ◽  
Beneficial Effects ◽  
Physical Mechanisms ◽  
Parametric Studies ◽  
Compressor Performance ◽  
Highly Loaded

Pipe diffusers with several different geometries were designed for a highly loaded centrifugal compressor originally using a wedge diffuser. Parametric studies on the effect of pipe diffuser performance of a highly loaded centrifugal compressor by varying pipe diffuser inlet-to-impeller exit radius ratio, throat length, divergence angle, and throat area on centrifugal compressor performance were performed using a state-of-the-art multiblock flow solver. An optimum design of pipe diffuser was obtained from the parametric study, and the numerical results indicate that this pipe diffuser has remarkable advantageous effects on the compressor performance. Furthermore, a detailed comparison of flow visualization between the pipe diffuser and the wedge diffuser was conducted to identify the physical mechanism that account for the beneficial effects of the pipe diffuser on the performance and stability of the compressor. It was found that the performance enhancement afforded by the pipe diffuser is a result of the unique diffuse inlet flow pattern. Alleviating flow distortion in the diffuser inlet and reducing the possibility of a flow separation in discrete passages are the physical mechanisms responsible for improving the highly loaded centrifugal compressor performance.

Effect of Different Geometrical Inlet Pipes on a High Speed Centrifugal Compressor

2013 ◽  
Author(s):  
Ce Yang ◽  
Ben Zhao ◽  
C. C. Ma ◽  
Dazhong Lao ◽  
Mi Zhou
Keyword(s):  
Centrifugal Compressor ◽  
High Speed ◽  
Pressure Ratio ◽  
Inlet Pipe ◽  
Unsteady Pressure ◽  
Bent Pipe ◽  
Low Mass ◽  
Compressor Performance ◽  
Spectral Frequency ◽  
The One

Two different inlet configurations, including a straight pipe and a bent pipe, were experimentally tested and numerically simulated using a high-speed, low-mass flow centrifugal compressor. The pressure ratios of the compressor with the two inlet configurations were tested and then compared to illustrate the effect of the bent inlet pipe on the compressor. Furthermore, different circumferential positions of the bent inlet pipe relative to the volute are discussed for two purposes. One purpose is to describe the changes in the compressor performance that result from altering the circumferential position of the bent inlet pipe relative to the volute. This change in performance may be the so-called clocking effect, and its mechanism is different from the one in multistage turbomachinery. The other purpose is to investigate the unsteady flow for different matching states of the bent inlet pipe and volute. Thus, the frequency spectrum of unsteady pressure fluctuation was applied to analyze the aerodynamic response. Compared with the straight inlet pipe, the experimental results show that the pressure ratio is modulated and that the choke point is shifted in the bent inlet pipe. Similarly, the pressure ratio can be influenced by altering the circumferential position of the bent inlet pipe relative to the volute, which may have an effect on the unsteady pressure in the rotor section. Therefore, the magnitude of interest spectral frequency is significantly changed by clocking the bent inlet pipe.

Numerical Investigation of the Effect of Diffuser and Volute Design Parameters on the Performance of a Centrifugal Compressor Stage

2016 ◽  
Author(s):  
Lei Yu ◽  
William T. Cousins ◽  
Feng Shen ◽  
Georgi Kalitzin ◽  
Vishnu Sishtla ◽  
...  
Keyword(s):  
Centrifugal Compressor ◽  
Gas Flow ◽  
Pressure Rise ◽  
Design Parameters ◽  
Compressor Stage ◽  
Flow Distortion ◽  
Cross Sectional ◽  
Centrifugal Stage ◽  
And Performance ◽  
The Impact

In this effort, 3D CFD simulations are carried out for real gas flow in a refrigeration centrifugal compressor. Both commercial and the in-house CFD codes are used for steady and unsteady simulations, respectively. The impact on the compressor performance with various volute designs and diffuser modifications are investigated with steady simulations and the analysis is focused on both the diffuser and the volute loss, in addition to the flow distortion at impeller exit. The influence of the tongue, scroll diffusion ratio, diffuser length, and cross sectional area distribution is examined to determine the impact on size and performance. The comparisons of total pressure loss, static pressure recovery, through flow velocity, and the secondary flow patterns for different volute designs show that the performance of the centrifugal compressor depends upon how well the scroll portion of the volute collects the flow from the impeller and achieves the required pressure rise with minimum flow losses in the overall diffusion process. Finally, the best design is selected based on compressor stage pressure rise and peak efficiency improvement. An unsteady simulation of the full wheel compressor stage was carried out to further examine the interaction of impeller, diffuser and the volute. The unsteady flow interactions are shown to have a major impact on the performance of the centrifugal stage.

Investigation of variable geometry orifice design for improving centrifugal compressor low-end performance and stable operating range

2021 ◽  
pp. 095441002110476
Author(s):  
Ben Zhao ◽  
Qingjun Zhao ◽  
Xiaorong Xiang ◽  
Wei Zhao ◽  
Jianzhong Xu
Keyword(s):  
Numerical Simulations ◽  
Centrifugal Compressor ◽  
Control Device ◽  
Design Parameters ◽  
Variable Geometry ◽  
Flow Area ◽  
Stall Margin ◽  
Setting Angle ◽  
Compressor Inlet ◽  
Two Parameters

Active control of the inlet flow area in a centrifugal compressor is a method to improve compressor aerodynamic performance and stall margin. As a core part of the area control device, the variable geometry orifice is investigated and its two key design parameters are analyzed in detail, the setting angle of the orifice with respect to the shroud casing and the radial height of the orifice to the shroud casing from the orifice inner rim. This paper proposes a physics-based equation that describes the relationship of the two parameters with compressor mass flow rate and then validates the equation using numerical simulations. As far as the setting angle, the physics-based equation suggests not to be larger than 90°. The numerical results not only validate the physics-based equation but also show the most optimal angle of 78°. In terms of the orifice height, both the physics-based equation and the numerical simulations suggest an active height control of orifice in the compressor inlet duct.

Study on the Influence of Meridional Channel to Centrifugal Compressor Performance

2012 ◽  
Vol 220-223 ◽  
pp. 592-596
Author(s):  
Jie Wang ◽  
Dong Wang ◽  
Wen Xiang Cai ◽  
Ke Gong
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Compressor ◽  
High Performance ◽  
Channel Model ◽  
Flow Properties ◽  
Distribution Law ◽  
Stream Surface ◽  
Flow Capacity ◽  
Stable Operating ◽  
Compressor Performance

The meridional channel has an important effect on the flow properties of centrifugal compressor. High performance meridional channel can be obtained by determining Bezier curves, which can realize local optimization to the airfoil expediently. Three kinds of meridional channel model are established basing on Bezier theory. A method to calculate the meridional channel width is proposed using the expression of UG and the distribution law of inscribed circle and stream surface is given as well. By means of numerical simulation, the effects on the flow capacity of different variation of inscribed circle and stream surface are compared in the same inlet and outlet geometric parameters. The result indicates that reasonable design of meridional channel increases the efficiency, improves the blockage point flow significantly, and provides with a broader and stable operating range to compressor.

Analysis and Design Outlines of Centrifugal Compressor Inlet Volutes

2000 ◽  
Author(s):  
Simone Pazzi ◽  
Vittorio Michelassi
Keyword(s):  
Flow Field ◽  
Centrifugal Compressor ◽  
Tangential Direction ◽  
Flow Distortion ◽  
Analysis And Design ◽  
Test Geometry ◽  
Compressor Inlet ◽  
Symmetric Geometry ◽  
Experimental Approaches ◽  
Typical Test

The flow inside centrifugal compressor inlet volutes is studied by means of numerical and experimental approaches. The performance of a typical test geometry is briefly compared with experiments and the relative performance of the various proposed modifications is discussed in terms of flow distortion and loss coefficient. The flow is analyzed at the exit of the volute. The effects of modifications to the standard axi-symmetric geometry are evaluated. The study includes the effect of flow splitters, the number of which is found to considerably alter the flow field. The analysis also includes changes in the geometry aimed at a better redistribution of the mass in the tangential direction.

Vortices and Performance of Internal and External Volutes

2015 ◽  
Author(s):  
Hua Chen ◽  
Ding Tong ◽  
Xiaochun Wang
Keyword(s):  
Numerical Simulation ◽  
Shear Stress ◽  
Cross Section ◽  
Centrifugal Compressor ◽  
Cross Flow ◽  
Cross Sectional ◽  
Compressor Performance ◽  
And Performance ◽  
Sectional Shape ◽  
Different Levels

In this paper, the cross flow in several internal and external volutes of a small centrifugal compressor is examined to highlight its effects on compressor performance. Different levels of the loss associated with shear stress related to the vortices in the volute cross section are shown to be the reason behind the diverse performance of internal volutes and external volutes. A numerical simulation is carried out to substantiate this and to further study this effect of cross sectional shape of volutes.

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