Reasons for Centrifugal Compressor Surging and Surge Control

1979 ◽  
Vol 101 (1) ◽  
pp. 79-86 ◽  
Author(s):  
A. Kolnsberg
Keyword(s):  
Reynolds Number ◽  
Control System ◽  
Control Systems ◽  
Polytropic Index ◽  
Suction Pressure ◽  
Flow Conditions ◽  
Radial Compressor ◽  
Bypass Valve ◽  
Surge Control ◽  
The Right

The paper discusses conventional modes of presenting axial and radial compressor operating envelopes and the conditions under which changes of factors such as the polytropic index n and the Reynolds number Re are negligible. It is shown on the basis of operating envelopes under what conditions compressors will surge (erratic flow conditions or stalling). In axial or radial compressor installations, surging can only be controlled by shifting the operating point in the operating envelope to the right away from the surge limit line. One method of doing this is to open the bypass valve to recycle part of the gas from the discharge piping to the suction piping. The paper describes in detail the control system required and discusses universal and simplified control systems. Modifications of control systems to fit, for example, wide suction pressure ranges are studied. The paper concludes with an investigation of methods of providing for high surge control reliability.

Development of a Guideline for the Design of Surge Control Systems

2008 ◽  
Author(s):  
Marybeth G. Nored ◽  
Klaus Brun ◽  
Rainer Kurz
Keyword(s):  
Control System ◽  
System Design ◽  
Control Systems ◽  
Control System Design ◽  
Compressor Station ◽  
System Designer ◽  
Common Reference ◽  
Southwest Research Institute ◽  
Critical Issues ◽  
Surge Control

Under the Gas Machinery Research Council 2007 program, Southwest Research Institute has developed an application guideline to be used in the design and selection of centrifugal compressor surge control systems. The surge control system guideline provides a common reference on the required functionality of the surge control system components. The guideline benefits the user, system designer, and compressor manufacturer by enhancing the understanding of surge control system design to improve performance and reduce unnecessary cost. The guideline also provides methods of evaluating surge control system performance against recommended design criteria. This allows the operating company to determine if the surge control system will meet expectations. This paper highlights the critical issues of surge control system design based on the recommendations of the GMRC guideline. Due to the competing factors in the design of the compressor station, the optimal measurement instrumentation, piping layout and recycle valve are not always available. The surge control system designer must overcome these factors by designing against the limitations of the compressor station, the selected measurement instrumentation, and the various components of the control system.

SET-VALUED DYNAMICS IN PROBLEMS OF MATHEMATICAL THEORY OF CONTROL PROCESSES

2012 ◽  
Vol 26 (25) ◽  
pp. 1246010 ◽  
Author(s):  
TATIANA FILIPPOVA
Keyword(s):  
Control System ◽  
Differential Equations ◽  
Nonlinear Control ◽  
Control Systems ◽  
Mathematical Theory ◽  
Quadratic System ◽  
Nonlinear Control System ◽  
Reachable Sets ◽  
The Right ◽  
Differential Control

The dynamics and properties of set-valued states of differential control systems with uncertainties in initial data are studied. It is assumed that the dynamical system has a special structure, in which nonlinear terms in the right-hand sides of related differential equations are quadratic in state coordinates. We construct external and internal ellipsoidal estimates of reachable sets of nonlinear control system and find differential equations of proposed ellipsoidal estimates of reachable sets of nonlinear control system. The results obtained for quadratic system nonlinearities are extended to other types of control systems under uncertainty.

Reliability Assessment of Control Systems

2011 ◽  
Vol 467-469 ◽  
pp. 174-180
Author(s):  
Salvatore Distefano
Keyword(s):  
Control System ◽  
Control Systems ◽  
Reliability Assessment ◽  
Critical Systems ◽  
Monitoring And Control ◽  
Dynamic Reliability ◽  
Reliability Block Diagrams ◽  
Safety Critical Systems ◽  
The Right ◽  
And Control

Actually modern systems have to ensure higher and higher operating standards, thus including monitoring and control subsystems for their achievement. In safety critical systems control is a crucial task in order to satisfy strict reliability requirements. But it is also necessary that the control system is itself reliable. As a consequence, adequate techniques are necessary in order to perform reliability evaluation of both the controlled and the control systems. Techniques that therefore should avoid over-simplistic assumptions and/or approximations that, for example, are usually introduced when dependencies, interferences and other dynamic reliability aspects are not taken into the right consideration. In this paper, a technique for carefully evaluating the reliability of such systems, also considering dynamic aspects and behaviors, is proposed. Firstly the technique is detailed through the specification of the dynamic reliability block diagrams notation, and therefore in order to demonstrate its effectiveness, it is applied to an example of a computing-based control system taken from literature, thus providing guidelines for the reliability representation and evaluation through DRBD.

Thirty years of research on salesforce control systems and sales territory designs: An update on progress and research gaps

2019 ◽  
Vol 19 (1) ◽  
pp. 3-16
Author(s):  
Zoha Fatima
Keyword(s):  
Job Satisfaction ◽  
Control System ◽  
Control Systems ◽  
Strong Impact ◽  
Sales Managers ◽  
Research Gaps ◽  
Territory Design ◽  
The Right ◽  
The Impact ◽  
Overall Effectiveness

Sales territory design is an important component of a sales organisation as it is associat ed with salesperson incentives, performance, job satisfaction and overall effectiveness of the organisation. Sales literature suggests that salesforce control systems are likely to have a strong impact on sales territory design. Therefore, this study makes an attempt to analyse the impact of two types of salesforce control system, behaviour-based and outcome-based salesforce control systems, on sales territory design and also the impact of sales territory design on salesforce performance and sales organisation effectiveness. The paper is based on a review of studies published between 1987 and 2018, and reveals that a behaviour-based control system is more positively related to satisfaction with sales territory design than an outcome-based salesforce control system. These findings hold important implications for sales organisations as they will help sales managers in choosing the right kind of salesforce control system.

scholarly journals Touching the Right Nerve

1999 ◽  
Vol 121 (02) ◽  
pp. 54-56
Author(s):  
Gale Morrison
Keyword(s):  
Nervous System ◽  
Control System ◽  
The Netherlands ◽  
Control Systems ◽  
Motion Control ◽  
Field Of Vision ◽  
The Right ◽  
The University ◽  
And Control ◽  
A Current

De Ruyter from the University of Groningen in the Netherlands has been studying nervous system of blowflies. These insects have extremely sophisticated visual and tactile perception that is much more sophisticated than our own. De Ruyter placed a tiny tungsten probe into the fly’s head, near one of its motion-sensitive neurons to understand motion control system. With the necessary second probe that acts as a ground (and allows for a current), a nearby oscilloscope feeds the air with an audible indication of voltage. When de Ruyter runs his hand across the fly’s field of vision, the oscilloscope’s output becomes loud and continuous, like old radio static. Davidowitz illustrated how sophisticated these sensory systems are and, therefore, why they would be studied in order to model sense and control systems. Roaches run—when they can—along a wall, with one antenna touching that wall for positioning information. This system checks, feeds information, and makes the control corrections for positioning 25 times a second.

Pengaruh Sistem Pengendalian Internal Pemerintah dan Kompetensi Pegawai Terhadap Kinerja Instansi Pemerintah Kabupaten Karimun

2020 ◽  
Vol 5 (1) ◽  
pp. 101-106
Author(s):  
Doni Putra Utama
Keyword(s):  
Control System ◽  
Control Systems ◽  
Internal Control ◽  
Statistical Tests ◽  
Government Agencies ◽  
Government Performance ◽  
Significant Positive Effect ◽  
Internal Control System ◽  
Employee Competencies ◽  
Positive Effect

This research is a causality study with the title "Effect of Government Internal Control Systems and Employee Competence on the Performance of Government Agencies in Karimun Regency." The purpose of this study was to determine the effect of the implementation of the Government's Internal Control System on the performance of Karimun Regency government agencies and to determine the effect of employee competence on the performance of Karimun Regency government agencies. Data collection using a questionnaire where the questionnaire contained questions about the Government's Internal Control System, employee competencies and agency performance. Data were tested using multiple linear regression statistical tests. Based on the results of the study, it can be concluded that the governmental internal control system has a significant positive effect on Government Agency Performance with the results of statistical tests that show a sig value of 0.016 <0.05 (alpha 5%). Employee Competency has a significant positive effect on Government Performance with the results of statistical tests showing a sig value of 0,000.

scholarly journals Coordination of Lateral Vehicle Control Systems Using Learning-Based Strategies

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1291
Author(s):  
Balázs Németh
Keyword(s):  
Control System ◽  
Control Systems ◽  
Coordinated Control ◽  
Front Wheel ◽  
Steering Angle ◽  
Conventional Model ◽  
Linear Parameter Varying ◽  
Coordination Strategy ◽  
Torque Vectoring ◽  
Performance Specifications

The paper proposes a novel learning-based coordination strategy for lateral control systems of automated vehicles. The motivation of the research is to improve the performance level of the coordinated system compared to the conventional model-based reconfigurable solutions. During vehicle maneuvers, the coordinated control system provides torque vectoring and front-wheel steering angle in order to guarantee the various lateral dynamical performances. The performance specifications are guaranteed on two levels, i.e., primary performances are guaranteed by Linear Parameter Varying (LPV) controllers, while secondary performances (e.g., economy and comfort) are maintained by a reinforcement-learning-based (RL) controller. The coordination of the control systems is carried out by a supervisor. The effectiveness of the proposed coordinated control system is illustrated through high velocity vehicle maneuvers.

The Control of the Eye's Intrinsic Muscles: A Multivariable Optimum Performance Control System

1968 ◽  
Vol 1 (8) ◽  
pp. T.129-T.132 ◽  
Author(s):  
F. M. Toates
Keyword(s):  
Control System ◽  
Control Systems ◽  
Pupil Diameter ◽  
Control Model ◽  
Point Of View ◽  
Theoretical Point ◽  
Pupil Control ◽  
Performance Control ◽  
A Value ◽  
Intrinsic Muscles

The reciprocal interaction between the accommodation and pupil control systems of the human eye is examined from a theoretical point of view. The system, which is responsible for maintaining pupil diameter at a value which is a compromise between conflicting requirements, is represented by a control model, and is considered in terms of the concept of a performance index.

scholarly journals Net-exergetic, hydraulic and thermal optimization of coaxial heat exchangers using fixed flow conditions instead of fixed flow rates

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Tobias Blanke ◽  
Markus Hagenkamp ◽  
Bernd Döring ◽  
Joachim Göttsche ◽  
Vitali Reger ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Laminar Flow ◽  
Mass Flow ◽  
Flow Rate ◽  
Heat Exchangers ◽  
Circular Ring ◽  
Flow Conditions ◽  
Flow Rates ◽  
Mass Flow Rates ◽  
Pipe Radius

AbstractPrevious studies optimized the dimensions of coaxial heat exchangers using constant mass flow rates as a boundary condition. They show a thermal optimal circular ring width of nearly zero. Hydraulically optimal is an inner to outer pipe radius ratio of 0.65 for turbulent and 0.68 for laminar flow types. In contrast, in this study, flow conditions in the circular ring are kept constant (a set of fixed Reynolds numbers) during optimization. This approach ensures fixed flow conditions and prevents inappropriately high or low mass flow rates. The optimization is carried out for three objectives: Maximum energy gain, minimum hydraulic effort and eventually optimum net-exergy balance. The optimization changes the inner pipe radius and mass flow rate but not the Reynolds number of the circular ring. The thermal calculations base on Hellström’s borehole resistance and the hydraulic optimization on individually calculated linear loss of head coefficients. Increasing the inner pipe radius results in decreased hydraulic losses in the inner pipe but increased losses in the circular ring. The net-exergy difference is a key performance indicator and combines thermal and hydraulic calculations. It is the difference between thermal exergy flux and hydraulic effort. The Reynolds number in the circular ring is instead of the mass flow rate constant during all optimizations. The result from a thermal perspective is an optimal width of the circular ring of nearly zero. The hydraulically optimal inner pipe radius is 54% of the outer pipe radius for laminar flow and 60% for turbulent flow scenarios. Net-exergetic optimization shows a predominant influence of hydraulic losses, especially for small temperature gains. The exact result depends on the earth’s thermal properties and the flow type. Conclusively, coaxial geothermal probes’ design should focus on the hydraulic optimum and take the thermal optimum as a secondary criterion due to the dominating hydraulics.

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