Design and Development of an Advanced Two-Stage Centrifugal Compressor

1995 ◽  
Vol 117 (2) ◽  
pp. 205-212 ◽  
Author(s):  
D. L. Palmer ◽  
W. F. Waterman
Keyword(s):  
Centrifugal Compressor ◽  
High Performance ◽  
Low Cost ◽  
Pressure Ratio ◽  
Tip Clearance ◽  
Development Effort ◽  
Design And Development ◽  
Two Stage ◽  
Surge Margin ◽  
The Impact

This paper describes the aeromechanical design and development of a 3.3 kg/s (7.3 lb/sec), 14:1 pressure ratio two-stage centrifugal compressor, which is used in the T800-LHT-800 helicopter engine. The design employs highly nonradial, splitter bladed impellers with swept leading edges and compact vaned diffusers to achieve high performance in a small and robust configuration. The development effort quantified the effects of impeller diffusion and passive inducer shroud bleed on surge margin as well as the effects of impeller loading on tip clearance sensitivity and the impact of sand erosion and shroud roughness on performance. The developed compressor exceeded its performance objectives with a minimum of 23 percent surge margin without variable geometry. The compressor provides a high-performance, rugged, low-cost configuration ideally suited for helicopter applications.

scholarly journals Design and Development of an Advanced Two-Stage Centrifugal Compressor

1994 ◽  
Author(s):  
D. L. Palmer ◽  
W. F. Waterman
Keyword(s):  
Centrifugal Compressor ◽  
High Performance ◽  
Low Cost ◽  
Pressure Ratio ◽  
Tip Clearance ◽  
Development Effort ◽  
Design And Development ◽  
Two Stage ◽  
Surge Margin ◽  
The Impact

This paper describes the aero-mechanical design and development of a 3.3 kg/sec (7.3 lb/sec), 14:1 pressure ratio two-stage centrifugal compressor which is used in the T800-LHT-800 helicopter engine. The design employs highly nonradial, splitter bladed impellers with swept leading edges and compact vaned diffusers to achieve high performance in a small and robust configuration. The development effort quantified the effects of impeller diffusion and passive inducer shroud bleed on surge margin as well as the effects of impeller loading on tip clearance sensitivity and the impact of sand erosion and shroud roughness on performance. The developed compressor exceeded its performance objectives with a minimum of 23-percent surge margin without variable geometry. The compressor provides a high performance, rugged, low-cost configuration ideally suited for helicopter applications.

Study of the Flow in Centrifugal Compressor

2009 ◽  
Author(s):  
C. Xu ◽  
R. S. Amano
Keyword(s):  
High Pressure ◽  
Centrifugal Compressor ◽  
High Efficiency ◽  
Design Method ◽  
Pressure Ratio ◽  
Pressure Rise ◽  
Tip Clearance ◽  
Low Flow ◽  
High Pressure Ratio ◽  
Surge Margin

An unshrouded centrifugal compressor would give up clearance very large in relation to the span of the blades, because centrifugal compressors produce a sufficiently large pressure rise in fewer stages. This problem is more acute for a low flow high-pressure ratio impeller. The large tip clearance would cause flow separations, and as a result it would drop both the efficiency and surge margin. Thus a design of a high efficiency and wide operation range for a centrifugal compressor is a great challenge. This paper describes a new development of high efficiency and a large surge margin flow coefficient of 0.145 centrifugal compressor. A viscous turbomachinery optimal design method developed by the authors for axial flow machine was further extended and used in this centrifugal compressor design. The new compressor has three main parts: impeller, a low solidity diffuser and volute. The tip clearance is under a special consideration in this design to allow impeller insensitiveness to the clearance. A three-dimensional low solidity diffuser design method is proposed and applied to this design. This design demonstrated to be successful to extend the low solidarity diffusers to high-pressure ratio compressor. The design performance range showed the total to static efficiency of the compressor being about 85% and stability range over 35%. The experimental results showed that the test results are in good agreement with the design.

Development of a Low Flow Coefficient Single Stage Centrifugal Compressor

2005 ◽  
Author(s):  
C. Xu ◽  
R. S. Amano
Keyword(s):  
Centrifugal Compressor ◽  
High Efficiency ◽  
Design Method ◽  
Pressure Ratio ◽  
Tip Clearance ◽  
Flow Coefficient ◽  
Low Flow ◽  
High Pressure Ratio ◽  
Surge Margin ◽  
Low Flow Coefficient

A low flow coefficient unshrouded centrifugal compressor would give up clearance very large in relation to the span of the blades, because centrifugal compressors produce a sufficiently large pressure rise in fewer stages. This problem is more acute for a low flow high-pressure ratio impeller. The large tip clearance would cause flow separations, and as a result it would drop both the efficiency and surge margin. Thus a design of a high efficiency and wide operation range for a low flow coefficient centrifugal compressor is a great challenge. This paper describes a new development of high efficiency and large surge margin low flow coefficient (0.145) centrifugal compressor. A viscous turbomachinery optimal design method developed by the authors for axial flow machine was further extended and used in this centrifugal compressor design. The new compressor has three main parts: impeller, a low solidity diffuser and volute. The tip clearance is under a special consideration in this design to allow impeller insensitiveness to the clearance. A three-dimensional low solidity diffuser design method is proposed and applied to this design. This design is successful to extend the low solidarity diffusers to high-pressure ratio compressor. It is demonstrated that the design is in a great success. The design performance range of the total to static efficiency of the compressor is about 85% and stability range is over 35%. The experimental results showed that the test results are in good agreement with the design.

Numerical Study on the Range Enhancement of a Centrifugal Compressor With a Ring Groove System

2011 ◽  
Author(s):  
ChiYong Park ◽  
YoungSeok Choi ◽  
KyoungYong Lee ◽  
JoonYong Yoon
Keyword(s):  
Centrifugal Compressor ◽  
High Performance ◽  
High Efficiency ◽  
Numerical Study ◽  
Pressure Ratio ◽  
Low Flow ◽  
Ring Groove ◽  
Guide Vanes ◽  
Operating Range ◽  
Surge Margin

This paper presents a numerical study of casing treatments on a centrifugal compressor in order to improve stability and the surge margin. High efficiency, a high pressure ratio, and a wide operating range are required for a high-performance centrifugal compressor. A ring groove casing treatment is effective for flow range enhancement in centrifugal compressors. In the present study, compressor performance was analyzed according to the ring groove location and the results were compared with the case without a ring groove. The effect of guide vanes in the ring groove was also investigated. Four more variants of grooves were modeled and simulated using computational fluid dynamics (CFD) in order to optimize the groove location. The numerical analysis was carried out using a commercial code ANSYS-CFX program. The simulation results showed that the ring groove increased the operating range of the compressor. The ring groove with guide vanes improved both the compressor’s performance at low flow rates and improved the compressor’s surge margin.

A Study of a Single Stage Centrifugal Compressor

2006 ◽  
Author(s):  
C. Xu ◽  
R. S. Amano
Keyword(s):  
Centrifugal Compressor ◽  
High Efficiency ◽  
Design Method ◽  
Pressure Ratio ◽  
Tip Clearance ◽  
Flow Coefficient ◽  
Low Flow ◽  
High Pressure Ratio ◽  
Surge Margin ◽  
Low Flow Coefficient

A low flow coefficient unshrouded centrifugal compressor would give up clearance very large in relation to the span of the blades, because centrifugal compressors produce a sufficiently large pressure rise in fewer stages. This problem is more acute for a low flow high-pressure ratio impeller. The large tip clearance would cause flow separations, and as a result it would drop both the efficiency and surge margin. Thus a design of a high efficiency and wide operation range for a low flow coefficient centrifugal compressor is a great challenge. This paper describes a new development of high efficiency and large surge margin low flow coefficient (0.145) centrifugal compressor. A viscous turbomachinery optimal design method developed by the authors for axial flow machine was further extended and used in this centrifugal compressor design. The new compressor has three main parts: impeller, a low solidity diffuser and volute. The tip clearance is under a special consideration in this design to allow impeller insensitiveness to the clearance. A three-dimensional low solidity diffuser design method is proposed and applied to this design. This design is successful to extend the low solidarity diffusers to high-pressure ratio compressor. It is demonstrated that the design is in a great success. The design performance range of the total to static efficiency of the compressor is about 85% and stability range is over 35%. The experimental results showed that the test results are in good agreement with the design.

scholarly journals Engineered tunneling layer with enhanced impact ionization for detection improvement in graphene/silicon heterojunction photodetectors

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Jun Yin ◽  
Lian Liu ◽  
Yashu Zang ◽  
Anni Ying ◽  
Wenjie Hui ◽  
...  
Keyword(s):  
High Performance ◽  
Impact Ionization ◽  
Low Cost ◽  
Atomic Layer ◽  
Light Illumination ◽  
Insulation Material ◽  
Defect States ◽  
Uv Illumination ◽  
Layer Deposition ◽  
The Impact

AbstractHere, an engineered tunneling layer enhanced photocurrent multiplication through the impact ionization effect was proposed and experimentally demonstrated on the graphene/silicon heterojunction photodetectors. With considering the suitable band structure of the insulation material and their special defect states, an atomic layer deposition (ALD) prepared wide-bandgap insulating (WBI) layer of AlN was introduced into the interface of graphene/silicon heterojunction. The promoted tunneling process from this designed structure demonstrated that can effectively help the impact ionization with photogain not only for the regular minority carriers from silicon, but also for the novel hot carries from graphene. As a result, significantly enhanced photocurrent as well as simultaneously decreased dark current about one order were accomplished in this graphene/insulation/silicon (GIS) heterojunction devices with the optimized AlN thickness of ~15 nm compared to the conventional graphene/silicon (GS) devices. Specifically, at the reverse bias of −10 V, a 3.96-A W−1 responsivity with the photogain of ~5.8 for the peak response under 850-nm light illumination, and a 1.03-A W−1 responsivity with ∼3.5 photogain under the 365 nm ultraviolet (UV) illumination were realized, which are even remarkably higher than those in GIS devices with either Al2O3 or the commonly employed SiO2 insulation layers. This work demonstrates a universal strategy to fabricate broadband, low-cost and high-performance photo-detecting devices towards the graphene-silicon optoelectronic integration.

scholarly journals Preface

2021 ◽  
Vol 2125 (1) ◽  
pp. 011001
Keyword(s):  
High Performance ◽  
Direct Reduction ◽  
Low Cost ◽  
Committee Member ◽  
Scientific Information ◽  
Main Research ◽  
University Of Technology ◽  
The World ◽  
Oral Presentations ◽  
The Impact

We are glad to introduce you that the 2021 4th International Conference on Mechanical, Electrical and Material Application (MEMA 2021) was successfully held on October 29-31, 2021. In light of worldwide travel restriction and the impact of COVID-19, MEMA 2021 was carried out in the form of virtual conference to avoid personnel gatherings. Because most participants were still highly enthusiastic about participating in this conference, we chose to carry out MEMA 2021 via online platform according to the original schedule instead of postponing it. MEMA 2021 is to bring together innovative academics and industrial experts in the field of Mechanical, Electrical and Material Application to a common forum. The primary goal of the conference is to promote research and developmental activities in Mechanical, Electrical and Material Application and another goal is to promote scientific information interchange between researchers, developers, engineers, students, and practitioners working all around the world. The conference will be held every year to make it an ideal platform for people to share views and experiences in Mechanical, Electrical and Material Application and related areas. We were greatly honored to invited Prof. Kun Li, from Chongqing University, China and Assoc. Prof. Wei Wei, from Xi’an University of Technology, China as our Conference Chairmen. This scientific event brings together more than 100 national and international researchers in mechanical, electrical and material application. During the conference, the conference model was divided into three sessions, including oral presentations, keynote speeches, and online Q&A discussion. In the first part, some scholars, whose submissions were selected as the excellent papers, were given about 5-10 minutes to perform their oral presentations one by one. Then in the second part, keynote speakers were each allocated 30-45 minutes to hold their speeches. We were pleased to invite four distinguished experts to present their insightful speeches. Our first keynote speaker, Prof. Shahid Hussain, Jiangsu University, China. His research interests include MOS-MOF-MXene Nanomaterials, Gas-Sensors, Electrochemical Supercapacitors, Li-S batteries. And then we had Prof. Jie Huang, from Southwest University, China. His research includes RF/Microwave circuits and sensors. Prof. Qiyan Xu, Anhui University of Technology, China. His main research directions are: New process and technology of low cost steel making, Direct reduction and melting reduction, Development of new metallurgical technology - comprehensive utilization of waste resources. Lastly, we were glad to invite Prof. Kun Li, Chongqing University, China. He mainly engaged in additive manufacturing, intelligent 3D net forming, high performance materials and phase transformation, material computing and other research. In the last part of the conference, all participants were invited to join in a WeChat group to discuss and explore the academic issues after the presentations. The online discussion was lasted for about 30-60 minutes. We are glad to share with you that we still received lots of submissions from the conference during this special period. Hence, we selected a bunch of high-quality papers and compiled them into the proceedings after rigorously reviewed them. These papers feature following topics but are not limited to: Mechanical Dynamics and its Applications, Material Physics, Electrical and Electronic Systems and other related topics. All the papers have been through rigorous review and process to meet the requirements of International publication standard. Lastly, we would like to express our sincere gratitude to the Chairman, the distinguished keynote speakers, as well as all the participants. We also want to thank the publisher for publishing the proceedings. May the readers could enjoy the gain some valuable knowledge from the proceedings. We are expecting more and more experts and scholars from all over the world to join this international event next year. The Committee of MEMA 2021 List of Committee member is available in this pdf.

scholarly journals LiFePO4-Graphene Composites as High-Performance Cathodes for Lithium-Ion Batteries: The Impact of Size and Morphology of Graphene

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 842 ◽  
Author(s):  
Yanqing Fu ◽  
Qiliang Wei ◽  
Gaixia Zhang ◽  
Yu Zhong ◽  
Nima Moghimian ◽  
...  
Keyword(s):  
Electrochemical Performance ◽  
High Performance ◽  
Lithium Iron Phosphate ◽  
Low Cost ◽  
Lithium Ion ◽  
Iron Phosphate ◽  
Full Potential ◽  
Active Materials ◽  
Size And Morphology ◽  
The Impact

In this work, we investigated three types of graphene (i.e., home-made G, G V4, and G V20) with different size and morphology, as additives to a lithium iron phosphate (LFP) cathode for the lithium-ion battery. Both the LFP and the two types of graphene (G V4 and G V20) were sourced from industrial, large-volume manufacturers, enabling cathode production at low cost. The use of wrinkled and/or large pieces of a graphene matrix shows promising electrochemical performance when used as an additive to the LFP, which indicates that the features of large and curved graphene pieces enable construction of a more effective conducting network to realize the full potential of the active materials. Specifically, compared to pristine LFP, the LFP/G, LFP/G V20, and LFP/G V4 show up to a 9.2%, 6.9%, and 4.6% increase, respectively, in a capacity at 1 C. Furthermore, the LFP combined with graphene exhibits a better rate performance than tested with two different charge/discharge modes. Moreover, from the economic and electrochemical performance view point, we also demonstrated that 1% of graphene content is optimized no matter the capacity calculated, based on the LFP/graphene composite or pure LFP.

scholarly journals The Effect of Variable Geometry on the Operating Range and Surge Margin of a Centrifugal Compressor

1976 ◽  
Author(s):  
A. Whitfield ◽  
F. J. Wallace ◽  
R. C. Atkey
Keyword(s):  
Centrifugal Compressor ◽  
Peak Pressure ◽  
Pressure Ratio ◽  
Variable Geometry ◽  
Vaneless Diffuser ◽  
Flow Rates ◽  
Lower Flow ◽  
Operating Range ◽  
Surge Margin ◽  
Isentropic Efficiency

Two variable geometry techniques have been applied to a small turbocharger compressor, with the objective of trying to move the peak pressure ratio operating point to lower flow rates, thereby yielding a broad flow range map. Variable prewhirl guide vanes and variable vaneless diffuser passage height have been studied separately. The results obtained with both techniques are compared and the relative merits and demerits with respect to improved flow range and isentropic efficiency penalties are considered.

Experimental and Numerical Investigation of Tip Clearance and Bleed Effects in a Centrifugal Compressor Stage With Pipe Diffuser

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Robert Kunte ◽  
Philipp Schwarz ◽  
Benjamin Wilkosz ◽  
Peter Jeschke ◽  
Caitlin Smythe
Keyword(s):  
Numerical Investigation ◽  
Centrifugal Compressor ◽  
Tip Clearance ◽  
Compressor Stage ◽  
Local Flow ◽  
Centrifugal Compressor Stage ◽  
Centrifugal Stage ◽  
Flow Phenomena ◽  
Fundamental Insight ◽  
The Impact

The subject of this paper is the experimental and numerical investigation of a state-of-the-art high pressure centrifugal compressor stage with pipe diffuser for a jet engine application. This study shows the impact of impeller tip clearance- and bleed-variation on the centrifugal stage. The purpose of this paper is threefold. In the first place, it investigates the effects on the stage performance. Secondly, it seeks to explain local flow-phenomena, especially in the diffuser. Finally, it shows that steady CFD simulations are capable of predicting these phenomena. Experimental data were gathered using conventional pitot and three-hole-probes as well as particle-image-velocimetry. Numerical simulations with the CFD solver TRACE were conducted to get fundamental insight into the flow. Thus, this study contributes greatly towards understanding the principle of the flow phenomena in the pipe diffuser of a centrifugal compressor.

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