scholarly journals Experimental Investigation on the Operational Stability of Multistage Centrifugal Compression Systems

1999 ◽  
Author(s):  
Chaoqun Nie ◽  
Jingyi Chen ◽  
Haokang Jiang
Keyword(s):  
Dynamic Pressure ◽  
Stability Boundary ◽  
Maximum Amplitude ◽  
Pressure Oscillation ◽  
Operational Stability ◽  
Air Separation ◽  
Monitoring And Control ◽  
Pressure Transducers ◽  
The Stability ◽  
And Control

The operational stability of three multistage centrifugal compression systems was studied experimentally. Two of the tested machines are four-stage centrifugal compressors arranged in two cylinders and used for air separation. The third machine is a ten-stage compressor in two cylinders and used for oxygen production. The measurement features conventional probes for describing performances and per-stage pressure transducers for recording dynamic characteristics. The performance measurement was conducted for the entire machine and also per stages. The signal of dynamic pressures was analyzed in both time and frequency domains. The result of per-stage performances clearly indicated which stage is first to lose the operational stability and how far it happens before the whole system runs into the stability boundary. This result is further demonstrated by the commencing time and location of stages of the strengthened dynamic pressure oscillation which differs from the most dangerous location in terms of maximum amplitude of the pressure oscillation during surge. The knowledge thus obtained for the operational stability should serve a good basis for monitoring and control purposes when running the machine in multistage compression environment.

scholarly journals A fuzzy based parametric monitoring and control algorithm for distinctive loads to enhance the stability in rural islanded microgrids

2020 ◽  
Vol 33 (2) ◽  
pp. 227-241
Author(s):  
Fawad Azeem ◽  
Ghous Narejo
Keyword(s):  
Control Algorithm ◽  
Fuzzy Controller ◽  
Load Control ◽  
Prolonged Storage ◽  
Monitoring And Control ◽  
Skilled Manpower ◽  
Parameter Variations ◽  
Load Monitoring ◽  
The Stability ◽  
And Control

Effective monitoring and control of isolated rural microgrid in the developing world is challenging. The modern communication and monitoring is difficult to handle in such communities due to a complicated approach to the area, lack of modern facilities and unavailability of skilled manpower. Implementation of a microgrid in such areas using intermittent renewable sources and limited storage is challenging. Uncontrolled load consumption leads to the system-wide outages due to prolonged storage utilization in peak hours and is referred here as battery storage stress hours (BSSH). This research is focused to study and analyze the behavior of parametric load monitoring and control algorithm that could control the distinctive load of the microgrid during BSSH. In the proposed algorithm, the residential loads are distinctively controlled while utilizing the three locally available parameters that are the state of the charge of storage, solar irradiations and ambient temperature. In other words, the natural parameter variations have been uniquely utilized as a monitoring tool for load control. The fuzzy controller takes a decision for the activation or deactivation of any load based on the three parameters variation ranges. It is observed from the simulation and experimental results that while only utilizing locally available parameters the effective load control is possible.

Online Combustor Stability Margin Assessment Using Dynamic Pressure Data

2004 ◽  
Author(s):  
Tim Lieuwen
Keyword(s):  
Dynamic Stability ◽  
Environmental Changes ◽  
Dynamic Pressure ◽  
Stability Boundary ◽  
Stability Margin ◽  
Operating Conditions ◽  
Margin Assessment ◽  
Pressure Oscillations ◽  
Acoustic Damping ◽  
The Stability

This paper describes a strategy for determining a combustor’s dynamic stability margin. Currently, when turbines are being commissioned or simply going through day to day operation, the operator has no idea how the dynamic stability of the system is affected by changes to fuel splits/operating conditions unless, of course, pressure oscillations are actually present. We have developed a methodology for ascertaining stability margin from passive monitoring of the acoustic pressure. This method consists of signal processing and analysis that determines a real-time measure of combustor damping. When the calculated damping is positive, the combustor is stable. When the damping goes to zero, the combustor approaches its stability boundary. Changes in the stability margin of each of the combustor’s stable modes due to tuning, aging or environmental changes can then be monitored through online analysis of the pressure signal. This paper outlines the basic approach used to quantify acoustic damping and demonstrates the technique on combustor test data.

Analysis and Design of Open Remote Monitor and Control System

2013 ◽  
Vol 722 ◽  
pp. 393-396
Author(s):  
Xiang Chen ◽  
Hui Huang Pi ◽  
Lin Lin Zhou
Keyword(s):  
Control System ◽  
Real Time ◽  
Monitor System ◽  
Monitoring And Control ◽  
Time Data ◽  
Remote Monitor ◽  
Analysis And Design ◽  
Remote Monitor System ◽  
The Stability ◽  
And Control

Introduced a Web-based real-time network monitoring and control system design methods, the 3-D VR was applied in a remote monitor system based on browser/server structure, and a VRML and Java based 3-D remote monitor system was realized. Meanwhile, give possible solutions of the real-time data transmission and the stability of the system.

Robust stabilization and control using fractional order integrator

2016 ◽  
Vol 39 (10) ◽  
pp. 1559-1576 ◽  
Author(s):  
Amina Ben Hmed ◽  
Messaoud Amairi ◽  
Mohamed Aoun
Keyword(s):  
Stability Boundary ◽  
Robust Stabilization ◽  
Smith Predictor ◽  
Order System ◽  
Stabilization Problem ◽  
Stabilizing Controller ◽  
First Order ◽  
Analytic Expressions ◽  
The Stability ◽  
And Control

This paper addresses the robust stabilization problem of first-order uncertain systems. To treat the robust stabilization problem, an interval-based stabilization method using stability conditions of the non-commensurate elementary fractional transfer function of the second kind is developed. Some analytic expressions are determined to compute the set of all stabilizing controller parameters and plot the stability boundary. A robust performance control is also developed to fulfil some desired time-domain performances as the iso-overshoot property. The fractional controller can be used combined with the Smith predictor to control a first-order system with time delay and achieve desired specifications. Numerical examples are presented to illustrate the obtained results.

scholarly journals DESIGN AND TEST EVALUATION OF THE SUBSOILER EQUIPPED WITH TILLAGE DEPTH MONITORING AND CONTROL SUBSOILING ASSEMBLIES

2021 ◽  
pp. 139-152
Author(s):  
Shangyi Lou ◽  
Jin He ◽  
Hongwen Li ◽  
Qingjie Wang ◽  
Caiyun Lu ◽  
...  
Keyword(s):  
Structural Parameters ◽  
Hydraulic Cylinder ◽  
Soil Disturbance ◽  
Performance Comparison ◽  
Monitoring And Control ◽  
Magnetic Exchange ◽  
Single Row ◽  
Tillage Depth ◽  
The Stability ◽  
And Control

Aiming at solving problems that the variation of tillage depth between rows and within rows caused by the surface undulation was great, the lateral stability of tillage depth obtained by the method of adjusting at the three-point suspension was poor, and lack of subsoilers with the function of accurate detection and adjustment of single row tillage depth, a method of independent control of single row tillage depth based on ultrasonic sensor detection and hydraulic adjustment was proposed. And the tillage depth monitoring and control subsoiling assembly and the subsoiler equipped with subsoiling assemblies were designed. The key structural parameters of the hydraulic cylinder and the model of the three-position four-way magnetic exchange valve were determined. The subsoiling quality and performance comparison tests were conducted, and the results showed that the mean value of the variable coefficient of soil hardness, looseness of soil and coefficient of soil disturbance were 52.23%, 32.55% and 62.15%, respectively, and the stability coefficient of tillage depth was 92.43%, which all met the subsoiling operation requirements. The standard deviation of tillage depth belonged to the method of independent adjustment of single row and unified adjustment of each row were 38.315mm and 51.521mm, respectively. The subsoiler equipped with tillage depth monitoring and control subsoiling assemblies designed in this paper was capable of significantly improving the stability of tillage depth between rows and within rows.

Online Combustor Stability Margin Assessment Using Dynamic Pressure Data

2005 ◽  
Vol 127 (3) ◽  
pp. 478-482 ◽  
Author(s):  
Tim Lieuwen
Keyword(s):  
Environmental Changes ◽  
Dynamic Pressure ◽  
Stability Boundary ◽  
Stability Margin ◽  
Operating Conditions ◽  
Pressure Data ◽  
Pressure Oscillations ◽  
Acoustic Damping ◽  
On Line ◽  
The Stability

This paper describes a strategy for determining a combustor’s dynamic stability margin. Currently, when turbines are being commissioned or simply going through day to day operation, the operator does not know how the stability of the system is affected by changes to fuel splits or operating conditions unless, of course, pressure oscillations are actually present. We have developed a methodology for ascertaining the stability margin from dynamic pressure data that does not require external forcing and that works even when pressure oscillations have very low amplitudes. This method consists of signal processing and analysis that determines a real-time measure of combustor damping. When the calculated damping is positive, the combustor is stable. As the damping goes to zero, the combustor approaches its stability boundary. Changes in the stability margin of each of the combustor’s stable modes due to tuning, aging, or environmental changes can then be monitored through an on-line analysis of the pressure signal. This paper outlines the basic approach used to quantify acoustic damping and demonstrates the technique on combustor test data.

Rig Jacking on Soft Soil Foundations: Improvements in Safety and Speed by Monitoring Leg Loads

1983 ◽  
Vol 105 (2) ◽  
pp. 201-204
Author(s):  
P. F. Ansquer ◽  
S. A. Antalovsky
Keyword(s):  
Continuous Monitoring ◽  
Soft Soil ◽  
Soil Conditions ◽  
Soil Reaction ◽  
Monitoring And Control ◽  
Reaction Forces ◽  
Structural Stresses ◽  
The Stability ◽  
And Control ◽  
Jack Up

The stability of jack-up rigs with spud-cans, particularly during the jacking-up and preloading operations, has always been critical in soft soil conditions. In the offshore areas opened to prospection in Cameroon, unconsolidated clays and silts are frequent, and therefore the need to conduct these critical operations with maximum safety is of utmost importance. The monitoring of soil reactions at the spud-cans and of structural loads at the jack-houses enabled jacking operations to be conducted safely, in an area where other rigs previously encountered severe difficulties (capsizing). Data recorded by instrumentation have shown that leg maneuvering with soil penetrations of up 40 m (131 ft) may induce dangerous overloads to the structure. The continuous monitoring and control of soil reaction forces and structural loads during drilling ensured the safety of the rig. For jacking-down, the monitoring of the loads was necesary to control the structural stresses induced by the legs pulling out. To the authors’ knowledge, no similar measurements have been reported in the past.

scholarly journals Analysis of Construction Monitoring and Control of Tunnels Crossing Broken Faults and Water-rich Geology

2022 ◽  
Vol 2152 (1) ◽  
pp. 012019
Author(s):  
Jingang Fang
Keyword(s):  
Surrounding Rock ◽  
Monitoring Data ◽  
Monitoring And Control ◽  
Tunnel Engineering ◽  
Construction Monitoring ◽  
Construction Methods ◽  
The Poor ◽  
Secondary Lining ◽  
The Stability ◽  
And Control

Abstract In view of the poor geology such as tunnel engineering crossing faults or passing faults, the construction of surrounding rock and support is complicated. During construction, it is necessary to ensure the stability of the surrounding rock and supporting system, and ensure the timing of the secondary lining construction. For this reason, through the analysis and processing of monitoring data, the law of stratum change is mastered, and the supporting parameters and construction methods are adjusted and revised at the same time, so as to provide the best information for the tunnel surrounding rock and supporting lining construction.

Computers for data, control and simulation

1988 ◽  
Vol 46 ◽  
pp. 920-921
Author(s):  
David C. Joy
Keyword(s):  
Personal Computers ◽  
Monitoring And Control ◽  
Data Logging ◽  
Data Logger ◽  
Operational Conditions ◽  
Data Control ◽  
The Many ◽  
And Control

Personal computers (PCs) are a powerful resource in the EM Laboratory, both as a means of automating the monitoring and control of microscopes, and as a tool for quantifying the interpretation of data. Not only is a PC more versatile than a piece of dedicated data logging equipment, but it is also substantially cheaper. In this tutorial the practical principles of using a PC for these types of activities will be discussed.The PC can form the basis of a system to measure, display, record and store the many parameters which characterize the operational conditions of the EM. In this mode it is operating as a data logger. The necessary first step is to find a suitable source from which to measure each of the items of interest. It is usually possible to do this without having to make permanent corrections or modifications to the EM.

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