How to Design and Operate Quiet Centrifugal Compressor System

2000 ◽  
Author(s):  
Roman W. Motriuk
Keyword(s):  
Centrifugal Compressor ◽  
Dynamic Performance ◽  
Point Of View ◽  
Design Parameters ◽  
Clear Understanding ◽  
System Failures ◽  
Performance Point ◽  
Vibration Problems ◽  
And Performance ◽  
Fatigue Failures

Historically, designs of centrifugal compressor systems focused on the aerodynamic and performance aspects. Noise, pulsation, and vibration phenomena were rarely considered. Recent applications of high flow and high power centrifugal compressors require that this approach be changed. Several transmission system failures, in different gas transmission companies, were documented. They included fatigue failures of the compressor components, piping attachments, and, in some instances, pipework shell failures. As a result, numerous investigations were carried out. While the compressors were adequately designed from the aerodynamic performance point of view, they appeared to act as dynamic generators, producing excessive noise, pulsation, and vibration levels even when operated well within their design parameters. It was found that neither the designers nor equipment users had a clear understanding on how to practically analyse and mitigate such dynamic phenomena. The objective of this study is to briefly explain possible sources of the observed problems in the hope that such explanation might provide a means for preventing or minimising noise and pulsation generation in centrifugal machines. The study is based on the author’s experience in mitigating pulsation/noise and vibration problems mainly in the single stage natural gas centrifugal compressor systems. The study briefly describes differences in operation between vaned and vaneless diffuser compressors. It considers pipework and its influence on the compressor dynamic performance, and addresses some aspects of the compressor design in both aerodynamic and acoustic areas. Furthermore, it gives several practical methods to mitigate high frequency pulsation and vibration problems. Most of the approaches suggested here were implemented in the field and evaluated either by the author or others.

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.

New Steps to Improve Rotordynamic Stability Predictions of Centrifugal Compressors

2008 ◽  
Vol 130 (2) ◽  
Author(s):  
Manoj K. Gupta ◽  
Thomas A. Soulas ◽  
Dara W. Childs
Keyword(s):  
Centrifugal Compressor ◽  
Flow Model ◽  
Aerodynamic Performance ◽  
Magnetic Bearing ◽  
Point Of View ◽  
Test Results ◽  
Performance Point ◽  
Pressure Test ◽  
Full Pressure ◽  
Rotor Model

Improved rotordynamic stability is desired by end users, and centrifugal compressor manufacturers are expected to meet, if not exceed, this expectation. Compressor manufacturers are required to design and build machines that are rotordynamically stable on the test stand and in the field. Confidence has been established in predicting the excitation forces from seals and bearings, but impeller aerodynamic excitation forces continue to be a challenge. While much attention is paid to impellers from an aerodynamic performance point of view, more efforts are needed from a rotordynamic standpoint. A high-pressure, reinjection centrifugal compressor is analyzed in order to predict rotordynamic stability using the best available resources for seals and bearings. Impeller shroud forces are predicted using the bulk-flow model developed by Gupta and Childs (Gupta, M., and Childs, D., Proc. of ASME Turbo Expo 2000, Power for Land, Sea, and Air). Each impeller stage is analyzed and an attempt is made to improve the estimation of impeller aerodynamic excitation forces. Logarithmic decrement (log dec) predictions for the full rotor model consisting of all the stages and seals are compared to the full-load full-pressure test measured values using a magnetic bearing exciter. A good correlation is obtained between the measured test results and analytical predictions.

Renewable Biodiesel From CSO: A Fuel Option for Diesel Engines

Solar Energy ◽  
2006 ◽  
Author(s):  
B. Murali Krishna ◽  
J. M. Mallikarjuna
Keyword(s):  
Diesel Fuel ◽  
Direct Injection ◽  
Point Of View ◽  
Ethyl Esters ◽  
Second Phase ◽  
Performance Point ◽  
Alternate Fuel ◽  
Two Phases ◽  
And Performance ◽  
Conventional Diesel Fuel

The petroleum-based fuels are limited reserve fuels, with our present known reserves and the growing rate of consumption, it is feared that they are not going to last long. These finite resources of petroleum and highly concentrated in certain regions of the world has given rise to frequent disruptions and uncertainties in its supply and as well as price. This situation has created a problem to increase the prices of these oils. The growing dependence on oil has created great scarcities and hardships with serious economic imbalance. A part from the problem of fast vanishing reserves, Petroleum fueled vehicles discharge significant amount of pollutants. In view of these problems attempts must be made to develop the technology of alternate clean burning fuels. The alternative, which satisfies all these requirements, is bio-diesel. Bio-diesel is methyl or ethyl ester of fatty acid made from virgin or used vegetable oils (both edible and non-edible) and animal fat, by converting the triglyceride oils to methyl (or ethyl) esters with a process known as transesterification. Bio-fuels are important now and offer increase in potential for the future. This paper consists two phases. The phase one dealt with preparation of bio-diesel from Cotton Seed Oil (C.S.O), which is available at cheaper price, as it is byproduct from cotton industries. Its properties were determined experimentally and compared with the conventional diesel fuel. The second phase dealt with conduction of experiments on a single cylinder, 4-stroke, direct injection Diesel Engine without modifications at constant speed 1500 rpm for various loads using 100% bio-diesel and conventional diesel fuel. It noticed that, the performance of the engine is not severely deviated by the substituted renewable biodiesel inaddition considerable decrease in smoke level. It is concluding that the biodiesel is superior fuel from the environmental and performance point of view, addition to this reducing the import of oil and consequentially improving energy security as a renewable alternate fuel.

Dynamic Simulation of Hydro-Mechanical Differential Turning Hydraulic System of Tracked Vehicle

2009 ◽  
Vol 628-629 ◽  
pp. 77-82 ◽  
Author(s):  
Zhi Li Zhou ◽  
F.Y. Cao ◽  
L.Y. Xu
Keyword(s):  
Hydraulic System ◽  
Optimization Design ◽  
Structural Parameters ◽  
Dynamic Performance ◽  
System Optimization ◽  
Design Parameters ◽  
Tracked Vehicle ◽  
And Performance ◽  
The Mathematical Model ◽  
Turning System

Being an important subsystem of hydro-mechanical differential turning system of tracked vehicle, the turning hydraulic system plays the crucial role on turning and running performance of tracked vehicle. The mathematical model and simulated model of turning hydraulic system are established. The dynamic performance of different running parameters and structural parameters of certain tracked vehicle is simulated and analyzed adopting Runge-Kutta four, five step arithmetic in this paper. The theory basis of system optimization design, parameters match and performance analysis of hydro-mechanical differential turning system is provided.

Parametric Performance of a Class of Standard Discharge Scrolls for Industrial Centrifugal Compressors

2014 ◽  
Author(s):  
Marco Giachi ◽  
Vidyasagar Ramalingam ◽  
Elisabetta Belardini ◽  
Fabio De Bellis ◽  
Chanukya Reddy
Keyword(s):  
Centrifugal Compressor ◽  
Point Of View ◽  
Experimental Results ◽  
The Other ◽  
Delivery Time ◽  
Centrifugal Compressors ◽  
Performance Point ◽  
Engineering Solution ◽  
Other Hand

For many reasons, the discharge volute of a centrifugal compressor is becoming more and more critical for the performance of the machine. The most important are the need to reduce the size of the casing and to minimize the delivery time and cost of the compressor. A database of standard geometries represents a good engineering solution to both these requirements. In fact, it is possible, from a mechanical point of view, to design a class of similar volutes to fit different casings and stages. On the other hand, from the performance point of view, very little has been done to describe families of similar scrolls and how the performance of a baseline geometry can be adapted to take into account the differences which exist in the scrolls of the same family. A lot of data are available in literature but they refer to single specific geometries and to optimized individual designs. In this paper, a description of the analysis which has been done to investigate which may be the most convenient parameters to describe the volute performance is presented together with some experimental results which have been used to validate the analysis.

scholarly journals Privacy-Preserving Analytics, Processing and Data Management

2021 ◽  
pp. 157-168
Author(s):  
Kalmer Keerup ◽  
Dan Bogdanov ◽  
Baldur Kubo ◽  
Per Gunnar Auran
Keyword(s):  
Machine Learning ◽  
Homomorphic Encryption ◽  
Point Of View ◽  
Public And Private ◽  
Performance Point ◽  
Public Data ◽  
Private And Public ◽  
Privacy Enhancing Technologies ◽  
And Performance ◽  
Public And Private Sector

AbstractTypically, data cannot be shared among competing organizations due to confidentiality or regulatory restrictions. We present several technological alternatives to solve the problem: secure multi-party computation (MPC), trusted execution environments (TEE) and multi-key fully homomorphic encryption (MKFHE). We compare these privacy-enhancing technologies from deployment and performance point of view and explain how we selected technology and machine learning methods. We introduce a demonstrator built in the DataBio project for securely combining private and public data for planning of fisheries. The secure machine learning of best catch locations is a web solution utilizing Intel® Software Guard Extensions (Intel® SGX)-based TEE and built with the Sharemind HI (Hardware Isolation) development tools. Knowing where to go fishing is a competitive advantage that a fishery is not interested to share with competitors. Therefore, joint intelligence from public and private sector data while protecting secrets of each contributing organization is an important enabler. Finally, we discuss the wider business impact of secure machine learning in situations where data confidentiality is a concern.

Redundant Robot: A Dynamic Performance Point of View

1992 ◽  
Author(s):  
Vittorio Marchis ◽  
Rosario Sinatra
Keyword(s):  
Dynamic Performance ◽  
Time History ◽  
Point Of View ◽  
Geometrical Parameters ◽  
Objective Functions ◽  
Redundant Robot ◽  
Redundant Robots ◽  
Performance Point ◽  
Performance Map ◽  
Principal Directions

Abstract Redundant robots find important applications in non structured environment, particularly in presence of obstacles. The number of degree of freedom (DOF) allow a choice of the configuration over range, even when the path has been planned and the constraints have been taken into account. Optimization of the time history, to be planned for the robot, can be achieved with respect to several objective functions. Following to a previous work by the Authors, the present paper analyzes the vibration eigenfrequencies, and their oscillation principal directions applied to a plane 3R manipulator, over its entire workspace. A dynamic performance map, correlated to the robot geometrical parameters, has been calculated via Monte Carlo method.

New Steps to Improve Rotordynamic Stability Predictions of Centrifugal Compressors

2007 ◽  
Author(s):  
Manoj K. Gupta ◽  
Thomas A. Soulas ◽  
Dara W. Childs
Keyword(s):  
Centrifugal Compressor ◽  
Flow Model ◽  
Aerodynamic Performance ◽  
Magnetic Bearing ◽  
Point Of View ◽  
Test Results ◽  
Performance Point ◽  
Pressure Test ◽  
Full Pressure ◽  
Rotor Model

Improved rotordynamic stability is desired by end users, and centrifugal compressor manufacturers are expected to meet, if not exceed, this expectation. Compressor manufacturers are required to design and build machines that are rotordynamically stable on the test stand and in the field. Confidence has been established in predicting the excitation forces from seals and bearings, but impeller aerodynamic excitation forces continue to be a challenge. While much attention is paid to impellers from an aerodynamic performance point of view, more efforts are needed from a rotordynamic standpoint. A high-pressure, re-injection centrifugal compressor is analyzed in order to predict rotordynamic stability using the best available resources for seals and bearings. Impeller shroud forces are predicted using the bulk-flow model developed by Gupta and Childs [1]. Each impeller stage is analyzed and an attempt is made to improve the estimation of impeller aerodynamic excitation forces. Logarithmic decrement (log dec) predictions for the full rotor model consisting of all the stages and seals are compared to the full-load full-pressure test measured values using a magnetic bearing exciter. A good correlation is obtained between the measured test results and analytical predictions.

Principles of Thermodynamic Preliminary Design of Civil Turbofan Engines

2009 ◽  
Author(s):  
Vasileios E. Kyritsis ◽  
Pericles Pilidis
Keyword(s):  
Mathematical Problem ◽  
Engine Performance ◽  
Optimal Solution ◽  
Thermodynamic Cycle ◽  
Point Of View ◽  
Design Parameters ◽  
Preliminary Design ◽  
Performance Point ◽  
Component Design ◽  
Direction Component

The design process of a civil turbofan engine is a continuous iteration among a variety of disciplines. From the performance point of view, its main target is the accomplishment of a specified thermodynamic cycle, which is optimised in terms of block fuel for a specified airframe and typical mission, while meeting a variety of multidisciplinary restrictions. Engine performance and component areas are engaged in an interactive collaboration. Performance provides component designers with precious information regarding component operating points and boundary conditions at critical flight conditions and power levels. In the opposite direction, component design is revised to provide performance with the most up-to-date overall component behaviour. Such an iterative process is initiated based on fundamental assumptions regarding the engine architecture, the available proven technology and the customer demands. Scope of the current work is to investigate the effect of engine architecture, component related restrictions and aircraft requirements on engine performance during the preliminary design phase. Given the multi-disciplinary nature of engine design, the conflicting interaction of various design parameters is discussed considering aerodynamic, mechanical and lifing issues. The parameters selected to form the mathematical problem all reflect a level of compromise among the various disciplines. The study aims at justifying the result of an optimal solution, which satisfies the requirements and restrictions set.

scholarly journals A modular design method based on TRIZ and AD and its application to cutter changing robot

2021 ◽  
Vol 13 (7) ◽  
pp. 168781402110343
Author(s):  
Mei Yang ◽  
Yimin Xia ◽  
Lianhui Jia ◽  
Dujuan Wang ◽  
Zhiyong Ji
Keyword(s):  
Modular Design ◽  
Design Method ◽  
Idea Generation ◽  
Design Parameters ◽  
Problem Analysis ◽  
Concept Design ◽  
Functional Requirements ◽  
Shield Tunneling ◽  
Structural Hierarchy ◽  
And Performance

Modular design, Axiomatic design (AD) and Theory of inventive problem solving (TRIZ) have been increasingly popularized in concept design of modern mechanical product. Each method has their own advantages and drawbacks. The benefit of modular design is reducing the product design period, and AD has the capability of problem analysis, while TRIZ’s expertise is innovative idea generation. According to the complementarity of these three approaches, an innovative and systematic methodology is proposed to design big complex mechanical system. Firstly, the module partition is executed based on scenario decomposition. Then, the behavior attributes of modules are listed to find the design contradiction, including motion form, spatial constraints, and performance requirements. TRIZ tools are employed to deal with the contradictions between behavior attributes. The decomposition and mapping of functional requirements and design parameters are carried out to construct the structural hierarchy of each module. Then, modules are integrated considering the connections between each other. Finally, the operation steps in application scenario are designed in temporal and spatial dimensions. Design of cutter changing robot for shield tunneling machine is taken as an example to validate the feasibility and effectiveness of the proposed method.

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