An Innovative Device for Passive Control of Surge in Industrial Compression Systems

2000 ◽  
Author(s):  
Gianmario L. Arnulfi ◽  
Pietro Giannattasio ◽  
Diego Micheli ◽  
Piero Pinamonti
Keyword(s):  
Passive Control ◽  
Experimental Tests ◽  
Control Device ◽  
Operating Conditions ◽  
Compression System ◽  
Multi Stage ◽  
Lumped Parameter ◽  
Wide Range ◽  
Optimal Values ◽  
Parameter Approach

The present paper reports a numerical-experimental study on the dynamic behaviour of a compression system based on a multi-stage centrifugal blower and fitted with an innovative device for the dynamic suppression of surge instability. The control device is of passive type and is based on the aeroelastic coupling of the basic compression system with a hydraulic oscillator. The controlled system is modelled at first by using a non-linear lumped parameter approach. The simulated system dynamics within a wide range of operating conditions allows a parametric analysis to be performed and the optimal values of the control parameters to be singled out. Such optimal values are then used to design the hydraulic oscillator, which results in a technically feasible and very simple configuration. Finally, experimental tests are carried out on the compression plant with and without the passive control device, which demonstrate the effectiveness of the proposed control system in suppressing surge instabilities, at least within the limits predicted by the numerical simulation.

An Innovative Device for Passive Control of Surge in Industrial Compression Systems

2000 ◽  
Vol 123 (3) ◽  
pp. 473-482 ◽  
Author(s):  
Gianmario L. Arnulfi ◽  
Pietro Giannattasio ◽  
Diego Micheli ◽  
Piero Pinamonti
Keyword(s):  
Passive Control ◽  
Experimental Tests ◽  
Control Device ◽  
Operating Conditions ◽  
Controlled System ◽  
Compression System ◽  
Lumped Parameter ◽  
Wide Range ◽  
Optimal Values ◽  
Parameter Approach

The present paper reports a numerical–experimental study on the dynamic behavior of a compression system based on a multistage centrifugal blower and fitted with an innovative device for the dynamic suppression of surge instability. The control device is of passive type and is based on the aeroelastic coupling of the basic compression system with a hydraulic oscillator. The controlled system is modeled at first by using a nonlinear lumped parameter approach. The simulated system dynamics within a wide range of operating conditions allows a parametric analysis to be performed and the optimal values of the control parameters to be singled out. Such optimal values are then used to design the hydraulic oscillator, which results in a technically feasible and very simple configuration. Finally, experimental tests are carried out on the compression plant with and without the passive control device, which demonstrate the effectiveness of the proposed control system in suppressing surge instabilities, at least within the limits predicted by the numerical simulation.

scholarly journals A Wide-Range Axial-Flow Compressor Stage Performance Model

1992 ◽  
Author(s):  
Gregory S. Bloch ◽  
Walter F. O’Brien
Keyword(s):  
Axial Flow ◽  
Operating Conditions ◽  
System Response ◽  
Compressor Stage ◽  
Operating Characteristics ◽  
Compression System ◽  
Axial Flow Compressor ◽  
Multi Stage ◽  
Wide Range ◽  
Flow Compressor

Dynamic compression system response is a major concern in the operability of aircraft gas turbine engines. Multi-stage compression system computer models have been developed to predict compressor response to changing operating conditions. These models require a knowledge of the wide-range, steady-state operating characteristics as inputs, which has limited their use as predicting tools. The full range of dynamic axial-flow compressor operation spans forward and reversed flow conditions. A model for predicting the wide flow range characteristics of axial-flow compressor stages was developed and applied to a 3-stage, low-speed compressor with very favorable results and to a 10-stage, high-speed compressor with mixed results. Conclusions were made regarding the inception of stall and the effects associated with operating a stage in a multistage environment. It was also concluded that there are operating points of an isolated compressor stage that are not attainable when that stage is operated in a multi-stage environment.

scholarly journals Thermal Study of Three-Phase Squirrel Cage Induction Motor with the Open-Phase Fault Operation Using a Lumped Parameter Network (LPTN)

2021 ◽  
Vol 23 (2) ◽  
pp. 87-94
Author(s):  
Mahdi Atig ◽  
Mustapha Bouheraoua ◽  
Rabah Khaldi
Keyword(s):  
Induction Motor ◽  
Convection Heat Transfer ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Thermal Network ◽  
Squirrel Cage ◽  
Lumped Parameter ◽  
Squirrel Cage Induction Motor ◽  
Three Phase ◽  
Cage Induction Motor

The aim of this paper is to estimate the induction motor temperature at both steady and transient thermal states under healthy and faulty conditions. The distribution of the temperature in the motor is calculated using thermal models based on the 2D Lumped Parameter Thermal Network (LPTN). The thermal model takes into account the heat sources, convection heat transfer and the thermal resistances in the motor. The heat flow generated by the conduction and convection in a three-phase squirrel cage induction motor is discussed. The developed model is used to study the motor thermal behavior during the opening phase situation. The results obtained by the model developed are validated by experimental tests. The tested machine is a standard three-phase, 4-pole, 2.2 kW, 380 V squirrel cage induction motor of Totally Enclosed Fan Cooled “TEFC” design manufactured in Algeria by Electro-Industries company. The simulated temperatures so obtained are in good agreement with the measured ones, and the 2D Lumped Parameter Thermal Network study seems to be appropriate to characterize the heating of the active parts of the machine under different operating conditions.

Experimental Chatter Modeling of Milling Operations

2007 ◽  
Author(s):  
Giuseppe Catania ◽  
Nicolo` Mancinelli
Keyword(s):  
Ad Hoc ◽  
Dynamical Behavior ◽  
Measurement Data ◽  
Period Doubling ◽  
Experimental Tests ◽  
Cutting Parameters ◽  
Operating Conditions ◽  
Depth Of Cut ◽  
Wide Range ◽  
Excited Vibration

This study refers to the investigation on the critical operating condition occurring on high productivity milling machines, known as chatter. This phenomenon is generated by a self-excited vibration, associated with a loss of stability of the system, causing reduced productivity, poor surface finish and noise. This study consists of the theoretical and experimental modeling of machining chatter conditions, in order to develop a real-time monitoring system able to diagnose the occurrence of chatter in advance and to dynamically modify the cutting parameters for process optimization. A prototype NC 3-axis milling machine was ad hoc realized to accomplish this task. The machine was instrumented by a dynamometer table, and a series of accelerometer sensors were mounted in the proximity of the tool spindle and the workpiece. An analytical model was developed, taking into account the periodic cutting force arising during interrupted cutting operation in milling. The system dynamical behavior was described by means of a set of delay differential equations with periodic coefficients. The stability of this system was analyzed by the semi discretization approach based on the Floquet theory. Lobe stability charts were evaluated and associated with frequency diagrams. Two chatter types were analytically and experimentally detected: period-doubling bifurcations and secondary Hopf bifurcations. Measurement data were acquired and analyzed in the time and frequency domain. Several tests were conducted in a wide range of operating conditions, such as radial immersion, depth of cut and spindle speeds and using different tools. Results are reported showing agreement between the numerical analysis and the related experimental tests.

Impact of Different Volume Sizes on Dynamic Stability of a Gas Turbine-Fuel Cell Hybrid System

2020 ◽  
Vol 142 (5) ◽  
Author(s):  
Alessio Abrassi ◽  
Alberto Traverso ◽  
David Tucker ◽  
Eric Liese
Keyword(s):  
Fuel Cell ◽  
Gas Turbine ◽  
Cell System ◽  
Open Loop ◽  
Operating Conditions ◽  
Performance Pressure ◽  
Lumped Parameter ◽  
Turbine Shaft ◽  
And Performance ◽  
Parameter Approach

Abstract A dynamic model is developed for a microgas turbine (MGT), characterized by an intrinsic free-spool configuration, coupled to large volumes. This is inspired by an experimental facility at the National Energy Technology Laboratory (NETL) called hybrid performance (Hyper), which emulates a hybrid MGT and Fuel Cell system. The experiment and model can simulate stable and unstable operating conditions. The model is used to investigate the effects of different volumes on surge events, and to test possible strategies to safely avoid or recover from unstable compressor working conditions. The modeling approach is started from the Greitzer lumped parameter approach, and it has been improved with integration of empirical methods and simulated components to better match the real Hyper plant layout and performance. Pressure, flowrate, and frequency plots are shown for the surge behavior comparing two different volume sizes, for cases where gas turbine shaft speed is uncontrolled (open loop) and controlled (closed-loop). The ability to recover from a surge event is also demonstrated.

KINEMATICS OF MULTI-STAGE MATCHING GEARBOXES FOR HYDRODINAMIC TORQUE CONVERTERS

2021 ◽  
Vol 75 (4) ◽  
pp. 33-42
Author(s):  
Agureev Igor Evgen'evich ◽  
◽  
Sergeev Alexander Leonidovich ◽  
Trushin Nikolay Nikolaevich ◽  
◽  
...  
Keyword(s):  
Torque Converter ◽  
Operating Conditions ◽  
Design Solution ◽  
Multi Stage ◽  
Wide Range ◽  
Torque Converters ◽  
Stage Matching ◽  
External Loads ◽  
Current Operating

The study offers a design solution for online capacity adjustment of hydrodynamic torque converter powertrains. It is proposed to install a step-less speed drive or multistage matching gearbox between the engine and the torque converter to adjust the powertrain properties on the move depending on the current operating conditions. We propose the matching device arrange-ments. The solutions can be used in buses, trucks, tractors, diesel locomotives, etc. that operate in a wide range of external loads.

scholarly journals Fuzzy Supervisor Approach Design Based-Switching Controller for Pumping Station: Experimental Validation

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Wael Chakchouk ◽  
Chiheb Ben Regaya ◽  
Abderrahmen Zaafouri ◽  
Anis Sellami
Keyword(s):  
Tracking Error ◽  
Experimental Tests ◽  
Operating Conditions ◽  
Pumping Station ◽  
Wide Range ◽  
Pi Controllers ◽  
Switching Controller ◽  
Hydraulic Process ◽  
Fuzzy Pd ◽  
Fuzzy Supervisor

This paper proposes a discrete-time switching controller strategy for a hydraulic process pumping station. The proposed solution leads to improving control system performances with two tests: combination of Fuzzy-PD and PI controllers and Fuzzy-PID and PI controllers. The proposed design methodology is based on accurate model for pumping station (PS), which is developed in previous works using Fuzzy-C Means (FCM) algorithm. The control law design is based on switching control; a fuzzy supervisor manages the switching from one to another and regulates the rate of participation of each order, in order to satisfy various objectives of a stable pumping station like the asymptotic stability of the tracking error. To validate the proposed solution, experimental tests are made and analyzed. Compared to the conventional PI and fuzzy logic (FL) approaches, the results show that the switching controller allows exhibiting excellent transient response over a wide range of operating conditions and especially is easier to be implemented in practice.

scholarly journals Dynamic Control of Centrifugal Compressor Surge Using Tailored Structures

1990 ◽  
Author(s):  
D. L. Gysling ◽  
J. Dugundji ◽  
E. M. Greitzer ◽  
A. H. Epstein
Keyword(s):  
Centrifugal Compressor ◽  
Structural Control ◽  
Dynamic Control ◽  
Operating Conditions ◽  
Parameter Analysis ◽  
Compression System ◽  
Lumped Parameter ◽  
Stable Operating ◽  
Compressor Surge ◽  
Structural Motion

A new method for dynamic control of centrifugal compressor surge is presented. The approach taken is to suppress surge by modifying the compression system dynamic behavior using structural feedback. More specifically, one wall of a downstream volume, or plenum, is constructed so to move in response to small perturbations in pressure. This structural motion provides a means for absorbing the unsteady energy perturbations produced by the compressor, thus extending the stable operating range of the compression system. In the paper, a lumped parameter analysis is carried out to define the coupled aerodynamic and structural system behavior and the potential for stabilization. First-of-a-kind experiments are then carried out to examine the conclusions of the analysis. As predicted by the model and demonstrated with experiment, a moveable plenum wall lowered the mass flow at which surge occurred in a centrifugal compression system by roughly 25% for a large range of operating conditions. In addition, because the tailored dynamics of the structure acts to suppress instabilities in their initial stages, this control was achieved with relatively little power being dissipated by the moveable wall system, and with no noticeable decrease in steady state performance. Although designed on the basis of linear system considerations, the structural control is shown to be capable of suppressing existing large amplitude limit cycle surge oscillations.

Mathematical Modeling of a Variable Displacement Axial Piston Pump

1999 ◽  
Author(s):  
Jeff W. Dobchuk ◽  
Richard T. Burton ◽  
Peter N. Nikiforuk ◽  
Paul R. Ukrainetz
Keyword(s):  
Mathematical Model ◽  
Operating Conditions ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Specific Effects ◽  
Lumped Parameter ◽  
Lumped Parameter Models ◽  
Wide Range ◽  
Variable Displacement ◽  
Axial Piston

Abstract The variable displacement axial piston pump has been the subject of much research, having been studied from the controls, noise reduction, and design perspectives. The resulting body of research is large and very diverse in content. A review of the available publications was conducted for this paper in order to identify those works that would be most helpful in developing a complete and accurate mathematical model of an axial piston pump. Most of the available publications can be classified into one of two general groups; those describing a small group of components to understand specific phenomena or those describing the entire pump for control or design purposes. The significant mathematical developments in various publications regarding specific phenomena, particularly those works involving nonlinear friction or pressure transients, were identified by the authors in this paper. When the mathematical developments of the phenomena specific effects are combined with the widely accepted kinematics equations for the pump, an accurate numerical model can be developed. Works on linearized lumped parameter models and parameter sensitivity were examined for this paper and the limitations of these types of models were addressed. While linearized models offer mathematical simplicity, they suffer from poor accuracy over a wide range of operating conditions and do not reflect instantaneous swashplate dynamics. This paper offers insight into the required complexity of a mathematical model that is necessary to achieve a desired accuracy as well as providing the appropriate references to develop that model.

Passive control of microclimate in museum display cases: A lumped parameter model and experimental tests

2015 ◽  
Vol 16 (4) ◽  
pp. 413-418 ◽  
Author(s):  
Francesco Romano ◽  
Luigi P.M. Colombo ◽  
Mirco Gaudenzi ◽  
Cesare M. Joppolo ◽  
Luigi P. Romano
Keyword(s):  
Passive Control ◽  
Experimental Tests ◽  
Lumped Parameter Model ◽  
Lumped Parameter ◽  
Museum Display
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