scholarly journals Self-Recirculating Casing Treatment Concept for Enhanced Compressor Performance

2002 ◽  
Author(s):  
Michael D. Hathaway
Keyword(s):  
High Speed ◽  
Flow Characteristics ◽  
Treatment Concept ◽  
Casing Treatment ◽  
Compressor Performance ◽  
And Performance ◽  
The Stability ◽  
The Impact ◽  
Compressor Efficiency ◽  
Transonic Rotor

A state-of-the-art CFD code (APNASA) was employed in a computationally based investigation of the impact of casing bleed and injection on the stability and performance of a moderate speed fan rotor wherein the stalling mass flow is controlled by tip flow field breakdown. The investigation was guided by observed trends in endwall flow characteristics (e.g., increasing endwall aerodynamic blockage) as stall is approached, and based on the hypothesis that application of bleed or injection can mitigate these trends. The “best” bleed and injection configurations were then combined to yield a self-recirculating casing treatment concept. The results of this investigation yielded: 1) identification of the fluid mechanisms which precipitate stall of tip critical blade rows, and 2) an approach to recirculated casing treatment which results in increased compressor stall range with minimal or no loss in efficiency. Subsequent application of this approach to a high speed transonic rotor successfully yielded significant improvements in stall range with no loss in compressor efficiency.

Application of a Multistage Casing Treatment in a High Speed Axial Compressor Test Rig

2011 ◽  
Author(s):  
T. Kroeckel ◽  
S. J. Hiller ◽  
P. Jeschke
Keyword(s):  
High Speed ◽  
Flow Analysis ◽  
Axial Compressor ◽  
Aircraft Engine ◽  
Test Rig ◽  
Local Flow ◽  
Casing Treatment ◽  
And Performance ◽  
The Impact ◽  
Casing Treatments

The subject of this paper is the experimental investigation of the overall performance and local aerodynamics of a 2.5 stage axial compressor test rig with a two stage casing treatment. Casing treatments are a well known method to aerodynamically stabilize the near stall compressor aerodynamics. However, in the past, casing treatments have only been applied to high aspect ratio front stages. This investigation puts the focus on the impact of advanced casing treatments applied to both rotors of a high speed compressor test rig. The rotors’ geometric and aerodynamic features are identical to those seen in the rear stages of aircraft engine high pressure compressors. Based on experimental results, we explain the casing treatment’s effect on the local flow phenomena as well as its influence on the compressor operability and performance. In order to clearly quantify the casing treatment’s influence, all measurements are conducted twice: for the rig without casing treatments and for an identical rig with casing treatments. The analysis of experimental data confirms that multistage casing treatments are able to significantly push the surge line towards higher pressure ratios and lower mass flow rates without any significant degradation of the peak efficiency. However, detailed flow analysis and the comparison of the configurations with and without casing treatments reveal that the flow is significantly redistributed by the effect of the casing. The present effort was conducted as part of the EU integrated program for New Aero Engine Core Concepts (NEWAC).

scholarly journals Influence of Whey Protein Micro-Gel Particles and Whey Protein Micro-Gel Particles-Xanthan Gum Complexes on the Stability of O/W Emulsions

Polymers ◽  
2021 ◽  
Vol 13 (14) ◽  
pp. 2301
Author(s):  
Man Zhang ◽  
Bin Liang ◽  
Hongjun He ◽  
Changjian Ji ◽  
Tingting Cui ◽  
...  
Keyword(s):  
Oxidative Stability ◽  
Whey Protein ◽  
High Speed ◽  
Xanthan Gum ◽  
Physical Stability ◽  
Theoretical Support ◽  
Gel Particles ◽  
Oil In Water ◽  
The Stability ◽  
The Impact

Appropriate pretreatment of proteins and addition of xanthan gum (XG) has the potential to improve the stability of oil-in-water (O/W) emulsions. However, the factors that regulate the enhancement and the mechanism are still not clear, which restricts the realization of improving the emulsion stability by directional design of its structure. Therefore, the effects of whey protein micro-gel particles (WPMPs) and WPMPs-XG complexes on the stability of O/W emulsion were investigated in this article to provide theoretical support. WPMPs with different structures were prepared by pretreatment (controlled high-speed shear treatment of heat-set WPC gels) at pH 3.5–8.5. The impact of initial WPC structure and XG addition on Turbiscan Indexes, mean droplet size and the peroxide values of O/W emulsions was investigated. The results indicate that WPMPs and XG can respectively inhibit droplet coalescence and gravitational separation to improve the physical stability of WPC-stabilized O/W emulsions. The pretreatment significantly enhanced the oxidative stability of WPC-stabilized O/W emulsions. The addition of XG did not necessarily enhance the oxidative stability of O/W emulsions. Whether the oxidative stability of the O/W emulsion with XG is increased or decreased depends on the interface structure of the protein-XG complex. This study has significant implications for the development of novel structures containing lipid phases that are susceptible to oxidation.

Map Width Enhancement Technique for a Turbocharger Compressor

2013 ◽  
Vol 136 (6) ◽  
Author(s):  
Subenuka Sivagnanasundaram ◽  
Stephen Spence ◽  
Juliana Early
Keyword(s):  
Performance Improvement ◽  
Peak Pressure ◽  
Pressure Ratio ◽  
Comparison Study ◽  
Heavy Duty ◽  
Recirculating Flow ◽  
Heavy Duty Diesel ◽  
And Performance ◽  
The Stability ◽  
The Impact

This paper presents an investigation of map width enhancement and the performance improvement of a turbocharger compressor using a series of static vanes in the annular cavity of a classical bleed slot system. The investigation has been carried out using both experimental and numerical analysis. The compressor stage used for this study is from a turbocharger unit used in heavy duty diesel engines of approximately 300 kW. Two types of vanes were designed and added to the annular cavity of the baseline classical bleed slot system. The purpose of the annular cavity vane technique is to remove some of the swirl that can be carried through the bleed slot system, which would influence the pressure ratio. In addition to this, the series of cavity vanes provides a better guidance to the slot recirculating flow before it mixes with the impeller main inlet flow. Better guidance of the flow improves the mixing at the inducer inlet in the circumferential direction. As a consequence, the stability of the compressor is improved at lower flow rates and a wider map can be achieved. The impact of two cavity vane designs on the map width and performance of the compressor was highlighted through a detailed analysis of the impeller flow field. The numerical and experimental study revealed that an effective vane design can improve the map width and pressure ratio characteristic without an efficiency penalty compared to the classical bleed slot system without vanes. The comparison study between the cavity vane and noncavity vane configurations presented in this paper showed that the map width was improved by 14.3% due to a significant reduction in surge flow and the peak pressure ratio was improved by 2.25% with the addition of a series of cavity vanes in the annular cavity of the bleed slot system.

Stability and Control of Tooling System for High-Speed Machining

2014 ◽  
Vol 684 ◽  
pp. 375-380
Author(s):  
Deng Sheng Zheng ◽  
Jian Chen ◽  
D.F. Tao ◽  
L. Lv ◽  
Gui Cheng Wang
Keyword(s):  
Natural Frequency ◽  
High Speed ◽  
System Stability ◽  
Finite Model ◽  
High Speed Machining ◽  
Cnc Machine ◽  
And Performance ◽  
The Stability ◽  
Tooling System ◽  
And Control

Tooling system for high-speed machining is one of the key components of high-end CNC machine , its stability and reliability directly affects the quality and performance of the machine. Based on the finite element method, developing a 3D finite model of high-speed machining tool system, studying on the stability of the high Speed machining tool from the natural frequency by the method of modal analysis. Analysis the amount of the overhang and clamping of the tooling , different shank taper interference fit and under different speed conditions, which affects the natural frequency of high-speed machining tool system. Proposed to the approach of improving system stability, which also provides a theoretical basis for the development of new high-speed machining tool system.

Effects of Circumferential Inlet Distortion on the Performance of a Transonic Fan Together With the Impact of Tip Injection

2016 ◽  
Author(s):  
Hossein Khaleghi ◽  
Reza Jalaly
Keyword(s):  
Flow Field ◽  
Axial Flow ◽  
Test Case ◽  
Inlet Distortion ◽  
Distorted Region ◽  
And Performance ◽  
Tip Injection ◽  
The Stability ◽  
Transonic Fan ◽  
The Impact

Half-annulus unsteady numerical simulations have been conducted with a 60-deg total pressure circumferential distortion in a transonic axial-flow fan. The effects of inlet distortion on the performance, stability and flow field of the test case are investigated and analyzed. Results show that the incidence angles are reduced when the blades are entering into the distorted region. Conversely, distortion increases the incidence angles onto the blades when they are leaving the distorted section. Results further reveal that the time-averaged flow field at the tip of the blade is similar with and without distortion. However, the distortion applied is found to have detrimental effects on both the stability and performance. The impacts of both annular and discrete tip injection on the endwall flow field are further studied in the current work. It is shown that endwall injection reduces the incidence angles onto the blades. Consequently, the passage shock and the leakage flow are pushed rearward, which postpones stall initiation.

Impact of Impeller Casing Treatment on the Acoustics of a Small High Speed Centrifugal Compressor

2018 ◽  
Author(s):  
Sidharath Sharma ◽  
Jorge García-Tíscar ◽  
John M. Allport ◽  
Martyn L. Jupp ◽  
Ambrose K. Nickson
Keyword(s):  
Centrifugal Compressor ◽  
High Speed ◽  
Pressure Fluctuations ◽  
Operating Conditions ◽  
Aerodynamic Noise ◽  
Noise Sources ◽  
Casing Treatment ◽  
Active Research ◽  
Ported Shroud ◽  
The Impact

Ported shroud casing treatment is widely used to delay the onset of surge and thereby enhancing the aerodynamic stability of a centrifugal compressor by recirculating the low momentum fluid in the blade passage. Performance losses associated with the use of recirculation casing treatment are well established in the literature and this is an area of active research. The other, less researched aspect of the casing treatment is its impact on the acoustics of the compressor. This work investigates the impact of ported shroud casing treatment on the acoustic characteristics of the compressor. The flow in two compressor configurations viz. with and without casing treatment operating at the design operating conditions of an iso-speed line are numerically modelled and validated with experimental data from gas stand measurements. The pressure fluctuations calculated as the flow solution are used to compute the spectral signatures at multiple locations to investigate the acoustic phenomenon associated with each configuration. Propagation of the frequency content through the ducts has been estimated with the aid of method of characteristics to enhance the content coming from the compressor. Expected tonal aerodynamic noise sources such as monopole (buzz-saw tones) and dipole (Blade Pass Frequency) are clearly identified in the acoustic spectra of the two configurations. The comparison of two configurations shows higher overall levels and tonal content in the case of a compressor with ported shroud operating at design conditions due to the presence of ‘mid-tones’.

Enhancing the Centrifugal Compressor Performance Map Measurements Through a Developed One–Dimensional Calculation Tool to Analyse Local Flow Phenomena

2014 ◽  
Author(s):  
Matthias Hamann ◽  
Elias Chebli ◽  
Markus Müller ◽  
Alexander Krampitz
Keyword(s):  
Centrifugal Compressor ◽  
Static Pressure ◽  
Flow Characteristics ◽  
Local Flow ◽  
One Dimensional ◽  
Casing Treatment ◽  
Surge Margin ◽  
Performance Map ◽  
Flow Phenomena ◽  
Compressor Performance

Centrifugal compressors for automotive turbochargers have large influence on the operation characteristic of combustion engines. Especially the improvement of the surge margin is one of the most important development targets. Thereby, a reliable detection of local flow phenomena within the compressor stage is necessary and a procedure to gain this information from standard measurement data is discussed in this paper. A one–dimensional calculation methodology for a single-stage centrifugal compressor with a vaneless diffuser and casing treatment is presented. The tool calculates the flow properties at the impeller inlet and exit as well as at diffuser exit, based on the measured inlet and outlet data and the geometry information of the compressor. The calculated flow characteristics are plotted within the measured compressor performance map to show local flow parameters. The unsteady recirculation flow within the casing treatment, the inflow angle and the total pressure losses are considered. The tool is validated on different compressor sizes. Thereby the compressor is equipped with static pressure measuring points at the impeller inlet and exit as well as at the diffuser exit. The calculated static pressure correlated well with the measured data with an accuracy of 2 % to 5 % on 95 % of the operating range. In this paper an experimental parameter study is executed in order to improve the surge margin. Thereby the geometry of the diffuser and the casing treatment is varied and the compressor performance is measured on a turbocharger test rig. The calculation of the flow angles and other flow characteristics within the diffuser enables one to find out whether surge is triggered through the diffuser or the impeller.

The Impact of Bleeding on Compressor Stator Corner Separation

2011 ◽  
Author(s):  
Bin Zhao ◽  
Shaobin Li ◽  
Qiushi Li ◽  
Sheng Zhou
Keyword(s):  
Radial Flow ◽  
Single Stage ◽  
Corner Separation ◽  
Transonic Compressor ◽  
High Pressure Compressor ◽  
Compressor Performance ◽  
The Impact ◽  
Large Flow ◽  
Compressor Efficiency ◽  
Pressure Compressor

Bleed air from the high pressure compressor has taken up 3–5% in the air system. However, there are not many studies on the compressor performance after bleeding. By analyzing a low-speed single-stage compressor and a transonic single-stage compressor, this paper presents several plans with different bleeding rates on the casing near stator corner, in order to study the influence of bleeding rates on the compressor stator corner separation. The results showed that for the stators of subsonic compressor with large flow separation in the corner, there is an optimum value in the stator casing bleed air amount. The flow field is better at resisting the radial flow caused by bleed air in the transonic compressor stator. The more the bleeding rates of the stator, the more the compressor efficiency improves.

On the Development and Performance Test of Combined Packing Integrated Device for Treating Domestic Sewage Aboard Ships

2011 ◽  
Vol 66-68 ◽  
pp. 2153-2157
Author(s):  
Zhi Li Chen ◽  
Kai Sheng Xiong ◽  
Wan Tu Zhang ◽  
Wen Biao Wang ◽  
Wen Ping Chen ◽  
...  
Keyword(s):  
High Speed ◽  
Performance Test ◽  
Simulation Experiment ◽  
Sewage Treatment ◽  
High Specific Surface Area ◽  
Domestic Sewage ◽  
Raw Water ◽  
And Performance ◽  
Integrated Device ◽  
The Impact

This paper elaborates on the development of elastic combined packing and an integrated device for treating domestic sewage aboard ships, analyzes the growth of combined packing microorganisms, the speed of membrane forming as well as the impact of raw water quality on membrane forming, and conducts a simulation experiment of treating domestic sewage by membrane bio-reactors. Researches show that elastic combined packing features high specific surface area and high speed of membrane forming and that this integrated domestic sewage treatment device performs well and can be widely applied.

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