The Effect of Wet Compression on a Multistage Subsonic Compressor

2013 ◽  
Vol 136 (3) ◽  
Author(s):  
Mingcong Luo ◽  
Qun Zheng ◽  
Lanxin Sun ◽  
Qingfeng Deng ◽  
Junjie Yang
Keyword(s):  
Working Condition ◽  
Pressure Ratio ◽  
Rotating Stall ◽  
Compression Effect ◽  
Flow Capacity ◽  
Compressor Design ◽  
Flow Field Characteristics ◽  
Compressor Performance ◽  
Dry And Wet Conditions ◽  
Wet Compression

In this paper, wet compression effect on an eight-stage axial subsonic compressor is simulated by steady numerical methods. Special attention is paid to the compressor design operating condition and rotating stall boundary to contrast and analyze the changes, such as the compressor performance and the flow-field characteristics under dry and wet conditions. The motions of water droplets are also simulated and analyzed. The results indicate that wet compression could weaken or eliminate the flow separation; improve the flow capacity, efficiency, and pressure ratio of this compressor; and make the compressor operating near the rotating stall boundary enter into the normal working condition.

Numerical Simulation of an Eight-Stage Axial Subsonic Compressor With Wet Compression

2013 ◽  
Author(s):  
Mingcong Luo ◽  
Qun Zheng ◽  
Lanxin Sun ◽  
Qingfeng Deng ◽  
Junjie Yang
Keyword(s):  
Working Condition ◽  
Pressure Ratio ◽  
Rotating Stall ◽  
Flow Capacity ◽  
Compressor Design ◽  
Flow Field Characteristics ◽  
Compressor Performance ◽  
Dry And Wet Conditions ◽  
Wet Compression ◽  
Compression Effects

In this paper, wet compression effects on an eight-stage axial subsonic compressor is simulated by steady numerical methods. Special attention is paid to the compressor design operating condition and rotating stall boundary to contrast and analyze the changes such as the compressor performance and the flow field characteristics under dry and wet conditions. The motions of water droplets are also simulated and analyzed. The results indicate that wet compression could weaken or eliminate the flow separation, improve the flow capacity, efficiency and pressure ratio of this compressor and make the compressor operating near the rotating stall boundary enter into the normal working condition.

Centrifugal Compressor Blade Trimming for a Range of Flows

2001 ◽  
Author(s):  
C. Rodgers
Keyword(s):  
Centrifugal Compressor ◽  
Test Performance ◽  
Pressure Ratio ◽  
Performance Characteristics ◽  
Centrifugal Impeller ◽  
Impeller Blade ◽  
Flow Capacity ◽  
Component Test ◽  
Compressor Performance ◽  
Stage Efficiency

Centrifugal impeller blade trimming has long been used in the turbocharger industry to adapt a single impeller casting to a series of flow capacities, but surprisingly little published literature exists on the effects of trimming to compressor performance. This paper is presented as partial remedy, and describes the performance characteristics of a single stage centrifugal compressor designed and tested to cover a range of flow requirements by impeller blade and diffuser vane trimming. Stage and component test performance characteristics are presented for five trimmed flowpath contours covering a flow capacity range of approximately five to one at a DeLaval number of 0.75. The impeller tip diameter was 356mm, and the highest overall stage efficiency measured was 84.8% at an (air) pressure ratio of 1.5.

Prediction of Compressor Performance in Rotating Stall

1978 ◽  
Vol 100 (1) ◽  
pp. 1-12 ◽  
Author(s):  
I. J. Day ◽  
E. M. Greitzer ◽  
N. A. Cumpsty
Keyword(s):  
Axial Velocity ◽  
Hysteresis Loops ◽  
Rotating Stall ◽  
Design Parameters ◽  
Heuristic Model ◽  
Axial Compressors ◽  
Large Hysteresis ◽  
Compressor Design ◽  
Compressor Performance ◽  
Design Value

A correlation is presented for predicting the performance characteristics of single and multistage axial compressors in rotating stall. The correlation is derived from new measurements of stalled compressor performance which have been obtained using a series of different compressor builds. In these experiments the compressor design parameters were systematically varied so that the influence of each could be clearly seen. It is shown that the stall cell blockage is an important parameter for correlating the flow regimes in stall, and hence the overall compressor performance. The resulting correlation, which has been developed based on a heuristic model of the stalled flow, can be applied to predict whether a given compressor will exhibit full-span or part-span stall, as well as the extent of the stall-unstall hysteresis loop. In particular, it is shown that as the number of stages and/or the design value of axial velocity parameter increases, the trend is toward both full-span stall and large hysteresis loops.

The Effects of Water Ingestion on the Tip Clearance Flow in Compressor Rotors

2018 ◽  
Author(s):  
Lu Yang ◽  
Xiaocui Wu ◽  
Desheng Qin ◽  
Qun Zheng ◽  
Hai Zhang
Keyword(s):  
Mass Flow ◽  
Pressure Ratio ◽  
External Disturbance ◽  
Rotating Stall ◽  
Droplet Breakup ◽  
Tip Clearance ◽  
Tip Clearance Flow ◽  
Water Ingestion ◽  
Clearance Flow ◽  
Wet Compression

As the first core component of commercial aviation engines, compressor is likely to ingest a serious amount of liquid water into its path flow during the situation of heavy rain. Under the influence of centrifugal force, the tip region of compressor rotors may be filled with water. Unfortunately, the instability of tip clearance flow is a major reason for rotating stall. In order to explore the effects of water ingestion on the steady operating boundary of compressor, the change characteristics of tip clearance flow have been investigated in this research by using numerical simulation method. In reality, the compression process after water ingestion can be regarded as a special wet compression. Therefore, on the basis of existing wet compression study, the ingested mass flow and the mean droplet diameters were set as 1% of inlet air flow as well as 100 μm respectively to investigate how does water ingestion affects the flow field at the tip clearance of rotors. The typical trajectory of water droplet in compressor has been researched firstly to simply understand the situation of water ingestion and to verify the reliability of some special droplet breakup models. Then, the compressor performance in two states of dry and wet have been compared to indicate that the pressure ratio and adiabatic efficiency of compressor will decrease after water ingestion. Among them, the compression efficiency drops by 1∼2% as a whole compared with the dry condition, the operating point moves forward and the surge margin reduces slightly. The simulation results show that the presence of water droplets will change the distribution of airflow parameters along span direction, which leads to the decreases of mass flow rate and flow capacity of blade row, the increase of attack angel at tip region, and the separation of boundary layer in suction surface. Furthermore, the momentum losses caused by droplet impingement and breakup cause a sharp increase in the static entropy at the blade tip region as well. On the other hand, the ingestion of droplet brings an external disturbance to the flow, although it has some dissipated effects on the turbulence kinetic energy, it aggravates the unsteady characteristic of turbulent flow seriously at the tip region of blade.

Compressor Rotating Stall in Uniform and Nonuniform Flow

1980 ◽  
Vol 102 (4) ◽  
pp. 762-769 ◽  
Author(s):  
B. F. J. Cossar ◽  
W. C. Moffatt ◽  
R. E. Peacock
Keyword(s):  
Structural Damage ◽  
Static Pressure ◽  
Pressure Ratio ◽  
Flow Characteristics ◽  
Rotating Stall ◽  
Maximum Pressure ◽  
Flow Distortion ◽  
Inlet Flow ◽  
Pressure Profiles ◽  
Compressor Performance

Rotating stall in axial compressors consists of regions or cells of retarded flow moving around the annulus relative to the blades. Planar symmetry is destroyed, resulting in stalled blades in part of the annulus and unstalled blades in the remainder. The stall cell moves in the direction opposite to the rotor, relative to the blades, but since the relative speed of propagation is usually less than the rotor speed, the cell is seen to move in the same direction as the rotor from an absolute reference frame. The presence of the stall cells results in a deterioration of compressor performance since the maximum pressure ratio is not achieved in regions of retarded flow. Furthermore, since this self-induced distortion is periodic, the forced frequencies generated may coincide with the natural harmonics of the blading, tending to cause structural damage. This paper describes a series of experiments in which a single-stage, lightly loaded compressor operated under stall-free conditions and with rotating stall, both with uniform inlet flow and with distortions generated by an upstream screen of uniform porosity. Not only was the overall compressor performance determined in the traditional manner, but the distribution of static pressure over the rotor suction and pressure surfaces was measured with high response instrumentation. The rotor pressure profiles measured in both undistorted and distorted flow are presented for operation before and after the onset of rotating stall and the latter are compared with the steady flow results. It is observed that two distinctly different types of rotating stall exist depending upon whether or not an inlet flow distortion is present. These cells differ not only in macroscopic properties—rotational speed, circumferential extent, mass-averaged flow conditions, etc.—but also in detailed flow characteristics as evidenced by the rotor blade static pressure distributions. It is further observed that not all inlet distortion geometries lead to the development of rotating stall.

Effects of Asymmetric Radial Clearance on Performance of a Centrifugal Compressor

2017 ◽  
Vol 140 (5) ◽  
Author(s):  
Cheng Xu ◽  
Ryoichi S. Amano
Keyword(s):  
Pressure Ratio ◽  
Industrial Applications ◽  
Radial Clearance ◽  
Centrifugal Compressors ◽  
Numerical Studies ◽  
Compressor Design ◽  
Compressor Performance ◽  
Manufacturing Tolerances ◽  
And Performance ◽  
Design Pressure

The centrifugal compressors are widely used in industrial applications. The design, manufacturing, and installation are all critical for the compressor performance. Many studies have been carried out in the past to optimize the compressor performance during compressor design. The manufacturing tolerances and installation errors can cause the performance drop. There are many compressor performance distortions that are not fully understood due to manufacturing and facilities. In this paper, an asymmetrical radial clearance of the impeller due to manufacturing and installation is studied in detail for the performance impacts. The numerical studies and experiments indicated that the asymmetric radial clearance impacts the compressor flow field structure and performance. Experimental results suggested that the manufacturing and installation cause asymmetric radial clearance which decreased the compressor performance in whole operating range. The numerical analysis demonstrated that the impeller asymmetric clearance impacts performance near the design pressure ratio more than other pressure ratios. The numerical studies showed that the maximum clearance location of asymmetric clearance might impact the compressor performance. The proper asymmetricity of diffuser verse the volute may benefit the compressor performance. The excellent compressor performances for centrifugal compressors especially for small centrifugal compressors not only need to have a good aerodynamic design but also need to control manufacturing and installation carefully.

Design and Development of Diesel Turbocharger Compressor With Low-Pressure Ratio for Low BMEP Engines

2019 ◽  
Author(s):  
Franklin Praveen Simonradha ◽  
Dhinagaran Ramachandran ◽  
Balamurugan Mayandi ◽  
Tamilarasan Kashirajan ◽  
Alagarsamy Vengidasamy ◽  
...  
Keyword(s):  
Peak Power ◽  
Internal Combustion Engines ◽  
Pressure Ratio ◽  
Peak Torque ◽  
Low Pressure ◽  
Computational Effort ◽  
Geometrical Parameters ◽  
Performance Requirements ◽  
Compressor Design ◽  
Compressor Performance

Abstract As Indian OEMs are marching towards to meet the latest emission norms set by Government, the automotive industry is improving the performance of turbocharged internal combustion engines in terms of improved low-end torque, peak torque, peak power, fuel economy and reduced emissions. This, in turn, raises the demand for highly efficient turbocharging technology. The key strategy to improve turbocharger performance is to tailor the performance characteristics of the compressor. The type of turbocharger application governs the performance requirements of the compressor. Certain Indian commercial vehicle manufacturers in LCV segment especially tractor manufacturers apply low BMEP engines to have good durability and such applications require low-pressure ratio and wide flow compressors with peak efficiency island below the pressure ratio 1.3 to 1.4. A careful investigation is required to study the influence of compressor design features to design a low-pressure ratio compressor. However, the number of geometrical parameters influencing the compressor performance is high and investigating all the parameters may take a lot of time and computational effort. Furthermore, the trade-off between efficiency at low-end torque, peak torque, peak power and part-load efficiencies dictates the need for a multi-disciplinary optimization tool to design the compressor stage. The computational effort required to perform optimization through 3D CFD is also quite high. Hence, in this paper, we are introducing an approach to optimize the compressor design at multiple operating points through streamline calculations with the help of AxStream and validating the selected designs numerically through CFD and FEA calculations. This approach helps to design tailor-made compressors based on customer requirements and deliver the proto samples in a shorter period.

scholarly journals Influence of Seal Cavity Leakage Flow on Compressor Performance Investigated with a Circumferentially Averaged Method

2021 ◽  
Vol 11 (2) ◽  
pp. 780
Author(s):  
Dong Liang ◽  
Xingmin Gui ◽  
Donghai Jin
Keyword(s):  
Flow Field ◽  
Pressure Ratio ◽  
Interaction Mechanism ◽  
Main Flow ◽  
Leakage Flow ◽  
Destructive Effect ◽  
Through Flow ◽  
Compressor Performance ◽  
Overall Performance ◽  
Flow Blockage

In order to investigate the effect of seal cavity leakage flow on a compressor’s performance and the interaction mechanism between the leakage flow and the main flow, a one-stage compressor with a cavity under the shrouded stator was numerically simulated using an inhouse circumferentially averaged through flow program. The leakage flow from the shrouded stator cavity was calculated simultaneously with main flow in an integrated manner. The results indicate that the seal cavity leakage flow has a significant impact on the overall performance of the compressor. For a leakage of 0.2% of incoming flow, the decrease in the total pressure ratio was 2% and the reduction of efficiency was 1.9 points. Spanwise distribution of the flow field variables of the shrouded stator shows that the leakage flow leads to an increased flow blockage near the hub, resulting in drop of stator performance, as well as a certain destructive effect on the flow field of the main passage.

Roles of vanes in diffuser on stability of centrifugal compressor

2019 ◽  
Vol 233 (14) ◽  
pp. 5380-5392
Author(s):  
Wangzhi Zou ◽  
Xiao He ◽  
Wenchao Zhang ◽  
Zitian Niu ◽  
Xinqian Zheng
Keyword(s):  
High Pressure ◽  
Centrifugal Compressor ◽  
Dynamic Pressure ◽  
Pressure Ratio ◽  
Pressure Rise ◽  
Rotating Stall ◽  
Centrifugal Compressors ◽  
Compression System ◽  
The Stability ◽  
Rotating Instability

The stability considerations of centrifugal compressors become increasingly severe with the high pressure ratios, especially in aero-engines. Diffuser is the major subcomponent of centrifugal compressor, and its performance greatly influences the stability of compressor. This paper experimentally investigates the roles of vanes in diffuser on component instability and compression system instability. High pressure ratio centrifugal compressors with and without vanes in diffuser are tested and analyzed. Rig tests are carried out to obtain the compressor performance map. Dynamic pressure measurements and relevant Fourier analysis are performed to identify complex instability phenomena in the time domain and frequency domain, including rotating instability, stall, and surge. For component instability, vanes in diffuser are capable of suppressing the emergence of rotating stall in the diffuser at full speeds, but barely affect the characteristics of rotating instability in the impeller at low and middle speeds. For compression system instability, it is shown that the use of vanes in diffuser can effectively postpone the occurrence of compression system surge at full speeds. According to the experimental results and the one-dimensional flow theory, vanes in diffuser turn the diffuser pressure rise slope more negative and thus improve the stability of compressor stage, which means lower surge mass flow rate.

Modeling of Discrete Tip Injection in a Two-Dimensional Streamline Curvature Method

2012 ◽  
Author(s):  
Roland Matzgeller ◽  
Richard Pichler
Keyword(s):  
Rotating Stall ◽  
Streamline Curvature ◽  
Measurement Results ◽  
Compressor Design ◽  
Multistage Compressor ◽  
Physical Effects ◽  
Tip Injection ◽  
Stability Enhancement ◽  
Good Agreement ◽  
Streamline Curvature Method

Fluid injection at the tip of highly loaded compressor rotors is known to be effective in suppressing the onset of rotating stall and eventually compressor instability. However, using such stability enhancement methods in a multistage compressor might not only stabilize certain stages but has also an impact on radial and axial matching. In order to account for tip injection during the early stages of compressor design, this paper focuses on the development of a method to model the physical effects underlying tip injection within a streamline curvature method. With the help of system identification it could be shown that a rotor subject to the discrete jets of tip injection adapts to the varying flow conditions according to a first order model. This information was used to generate a time-dependent input for the steady equations used with a streamline curvature method and eventually to model the unsteady response of the rotor to tip injection. Comparing the results obtained with the enhanced streamline curvature model to measurement results, good agreement could be shown which raised confidence that the influence of tip injection on axial and radial matching was sufficiently captured.

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