scholarly journals Experiments in Active Control of Stall on an Aeroengine Gas Turbine

1997 ◽  
Author(s):  
Christopher Freeman ◽  
Alexander G. Wilson ◽  
Ivor J. Day ◽  
Malcolm A. Swinbanks
Keyword(s):  
Control System ◽  
Control Strategies ◽  
Pressure Rise ◽  
Pressure Transducers ◽  
Operating Range ◽  
Stable Operating ◽  
Response Pressure ◽  
All Speeds ◽  
Stall Control ◽  
And Control

This paper describes work carried out between 1989 and 1994 to investigate the application of ‘Active Stall Control’ to a Rolls-Royce Viper turbojet. The results demonstrate that stall control is feasible and can increase the stable operating range by up to 25% of pressure rise. Stall disturbances were detected using rings of high response pressure transducers positioned at different axial planes along the compressor, and processed using a PC-based data acquisition and control system. Actuation was provided by six hydraulically operated sleeve valves positioned to recirculate air over all or part of the compressor. Stall was artificially induced using combinations of inbleed into the combustor outer casing, fuel spiking, hot gas ingestion and inlet pressure spoiling, thus replicating many of the transient conditions commonly observed to make a compressor prone to stall. Results are compared from a number of stall control strategies including those demonstrated at low speed by Paduano et al [1993] and Day [1993]. Best results were obtained with detection of non-axisymmetric disturbances coupled with axisymmetric control action. A control system of this type is demonstrated to be capable of extending the stable engine operating range at all speeds and with each method of inducing stall.

Experiments in Active Control of Stall on an Aeroengine Gas Turbine

1998 ◽  
Vol 120 (4) ◽  
pp. 637-647 ◽  
Author(s):  
C. Freeman ◽  
A. G. Wilson ◽  
I. J. Day ◽  
M. A. Swinbanks
Keyword(s):  
Control System ◽  
Control Strategies ◽  
Pressure Rise ◽  
Pressure Transducers ◽  
Operating Range ◽  
Stable Operating ◽  
Response Pressure ◽  
All Speeds ◽  
Stall Control ◽  
And Control

This paper describes work carried out between 1989 and 1994 to investigate the application of “Active Stall Control” to a Rolls-Royce Viper turbojet. The results demonstrate that stall control is feasible and can increase the stable operating range by up to 25 percent of pressure rise. Stall disturbances were detected using rings of high response pressure transducers positioned at different axial planes along the compressor, and processed using a PC-based data acquisition and control system. Actuation was provided by six hydraulically operated sleeve valves positioned to recirculate air over all or part of the compressor. Stall was artificially induced using combinations of in-bleed into the combustor outer casing, fuel spiking, hot gas ingestion, and inlet pressure spoiling, thus replicating many of the transient conditions commonly observed to make a compressor prone to stall. Results are compared from a number of stall control strategies including those demonstrated at low speed by Paduano et al. (1993) and Day (1993). Best results were obtained with detection of nonaxisymmetric disturbances coupled with axisymmetric control action. A control system of this type is demonstrated to be capable of extending the stable engine operating range at all speeds and with each method of inducing stall.

scholarly journals Study and Control of a Radial Vaned Diffuser Stall

2012 ◽  
Vol 2012 ◽  
pp. 1-12 ◽  
Author(s):  
Aurélien Marsan ◽  
Isabelle Trébinjac ◽  
Sylvain Coste ◽  
Gilles Leroy
Keyword(s):  
Boundary Layer ◽  
Skin Friction ◽  
Suction Side ◽  
Boundary Layer Separation ◽  
Point Of View ◽  
Vaned Diffuser ◽  
Operating Range ◽  
Stable Operating ◽  
And Control ◽  
Friction Line

The aim of the present study is to evaluate the efficiency of a boundary layer suction technique in case of a centrifugal compressor stage in order to extend its stable operating range. First, an analysis of the flow pattern within the radial vaned diffuser is presented. It highlights the stall of the diffuser vanes when reaching a low massflow. A boundary layer separation in the hub-suction side corner grows when decreasing the massflow from the nominal operating point to the surge and finally leads to a massive stall. An aspiration strategy is investigated in order to control the stall. The suction slot is put in the vicinity of the saddle that originates the main separating skin-friction line, identified thanks to the analysis of the skin-friction pattern. Several aspiration massflow rates are tested, and two different modelings of the aspiration are evaluated. Finally, an efficient control is reached with a removal of only 0,1% of the global massflow and leads—from a steady-state calculations point of view—to an increase by 40% of the compressor operating range extent.

Design of Bioreactor Control System for Ligament Tissue Engineering

2011 ◽  
Vol 130-134 ◽  
pp. 430-433
Author(s):  
Xiu De Wu ◽  
Xiong Wang
Keyword(s):  
Tissue Engineering ◽  
Control System ◽  
Culture Medium ◽  
Control Strategies ◽  
Mechanical Strain ◽  
Coordinated Control ◽  
Loading Frequency ◽  
Measuring Device ◽  
And Control ◽  
Ligament Tissue Engineering

An electromechanical control system of a novel bioreactor for ligament tissue engineering, combined with culture medium perfusion control, cyclic mechanical loading and displacement coordinated control, strains and temperature measure and control, based on programmable logical controller (PLC), was designed and implemented. Well-controlled mechanical stimulations (resolution of <0.01mm for translational and <0.1° for rotational strains, cyclic loading frequency of up to 1 Hz) could be applied to the growing tissue, especially to the tissue engineered anterior cruciate ligaments (ACLs). The novel control system could complete detection and control functions of multi-dimensional mechanical strain in the same axis (resolution of 0.01N for tension and 0.01Nm for torsion strains). An online parameter measuring device of PO2 ，which did not consume oxygen and independent of flow rate, and were incorporated into the culture medium recirculation loop, was designed. The displacement and mechanical stimulate coordinated control strategies were achieved. The aim of this control system is to meet the functions of bioreactor for the ACLs tissue engineering in both research and clinical applications.

scholarly journals Experimental Study on Active Control of Surge in a Centrifugal Compression System

2000 ◽  
Vol 6 (5) ◽  
pp. 383-392
Author(s):  
Nie Chaoqun ◽  
Chen Jingyi ◽  
Chen Naixing
Keyword(s):  
Experimental Study ◽  
Control System ◽  
Active Control ◽  
Nonlinear Interaction ◽  
Compression System ◽  
Operating Range ◽  
Stable Operating ◽  
Control Scheme ◽  
On Line

An experimental study has been carried out on the active control of surge in a centrifugal compression system. With a computerized on-line control scheme, the surge phenomenon is suppressed and the stable operating range of the system is extended. In order to design the active control scheme and choose the desired parameters of the control system inputs, special emphases have been placed on the development of surge inception and the nonlinear interaction between the system and the actuator. By use of the method designed in the present work, the results of active control onsurge have been demonstrated for the different B parameters, different prescribed criteria and different control frequencies.

scholarly journals Operation of Shared Systems via a Common Control System in a Multi-Modular Plant

2014 ◽  
Vol 2014 ◽  
pp. 1-9
Author(s):  
Jia Qianqian ◽  
Huang Xiaojin ◽  
Zhang Liangju
Keyword(s):  
Control System ◽  
Human Performance ◽  
Control Strategies ◽  
Modular System ◽  
Concept Design ◽  
Integral Type ◽  
Common Control ◽  
Plant Site ◽  
Different Characteristics ◽  
And Control

Integral type reactors may need to be grouped to produce as much energy as a utility demands due to the small electrical output of an individual reactor. Sharing of systems among modules at a nuclear plant site is economically beneficial. Operation of systems shared between modules in a multi-modular plant is an issue never met in current NPPs, which may impact human performance. A design of operation of the shared systems via a common control system is presented as a technical approach to solve the problem. Modules and shared systems are controlled in independent network domains, respectively. Different from current NPPs, a limitation of operation authorities corresponding to certain modules and shared systems is defined to minimize the operation confusion between modules by one operator and to minimize the operation confusion of shared systems by different operators. Different characteristics of the shared system are analyzed, and different operation and control strategies are presented. An example is given as an application of the operation strategies. The operation design of the multi-modular system is in the preliminary stage, and, as an concept design, more verification and validation is needed in further works.

scholarly journals Application of an energy management and control system to assess the potential of different control strategies in HVAC systems

2010 ◽  
Vol 42 (11) ◽  
pp. 2258-2267 ◽  
Author(s):  
Guillermo Escrivá-Escrivá ◽  
Isidoro Segura-Heras ◽  
Manuel Alcázar-Ortega
Keyword(s):  
Control System ◽  
Energy Management ◽  
Control Strategies ◽  
Hvac Systems ◽  
And Control

Fuzzy Control for Variable Cooling Water Flow System

2012 ◽  
Vol 461 ◽  
pp. 105-108 ◽  
Author(s):  
Jin Ming Yang
Keyword(s):  
Control System ◽  
Water Flow ◽  
Frequency Conversion ◽  
Control Strategies ◽  
Water System ◽  
Cooling Water ◽  
Variable Flow ◽  
Control Loops ◽  
Cooling Water System ◽  
And Control

The variable flow cooling water system can achieve energy saving benefits just like variable primary flow chilled water system for central air conditioning system. How to design the control system with appropriate control algorithms and control strategies is particularly important. We can clarify the basic control principle of variable cooling water flow technology based on the analysis on DOF (degree of freedom) of cooling water systems, it is important for control system design. The article pointed out explicitly that the realization of variable flow technology for cooling water system must construct two control loops, one for cooling water supply temperature the other for return temperature, further more discussed control strategies for two control loops. In the end the article illustrated the synchronous frequency conversion technology for multiple cooling water pumps system to avoid overload when part of pumps put in operation

Review of Vehicle Active Safety Systems and their coordinated control

2020 ◽  
Vol 13 ◽  
Author(s):  
Zixiang Zhao ◽  
Xiaobin Fan
Keyword(s):  
Control System ◽  
Angular Velocity ◽  
Control Strategy ◽  
Sliding Mode ◽  
Control Strategies ◽  
Slip Rate ◽  
Coordinated Control ◽  
Active Safety ◽  
Vehicle Active Safety ◽  
And Control

Background: All the time, the safety of the vehicle has been valued by all the world's parties, whether it is now or in the future, the automobile safety issue is the hotspot and focus of the research by experts and scholars. The continuous increase of car ownership brings convenience to people's life and also poses a threat to people's life and property security. Vehicle active safety system is the hotspot of current research and development, which plays an important role in automobile safety. Firstly, the vehicle active safety technology and its development situation was introduced, then Ref. review was carried out about Anti-Lock Brake System (ABS), Electronic Brake force Distribution (EBD/CBC), Brake Assist System (BAS/EBA/BA), Traction Control System (TCS/ASR), Vehicle Stability Control (VSC/ESP/DSC), etc. At present, there are many patents on the control of each subsystem, but few patents on the integrated control for the active safety of vehicles. Objective: The main contents of this paper are as follows: the control strategies and methods of different active safety systems, how to improve the stability of vehicle control and ensure the effectiveness of active safety system control. It provides a reference for the development of active safety control technology and patent. Methods: Through the analysis of different control algorithms and control strategies of Anti-lock and braking force distribution systems, it is pointed out that the switching of EBD/ABS coordinated control strategy according to slip rate can make full use of slip rate and road adhesion coefficient to improve the safety of the system. For the BAS, the slip problem is solved through the combination of Mechanical Assistant Braking System (MABS) and Electronic Braking Assistant (EBA) system by measuring the distance of the vehicle ahead and the speed of the vehicle ahead. The optimal slip rate control is realized by different control algorithms and control strategies of traction control system. It is pointed out that the adaptive fuzzy neural controller should be used to control the yaw angular velocity and centroid side angle of Electronic Stability Program (ESP), which has a good effect on maintaining vehicle stability. A sliding mode variable structure controller combined with constant speed control and approach law control is used to control the yaw moment. Results: Through the coordinated control strategy of EBD/ABS, the slip rate and road adhesion coefficient were fully utilized by switching according to slip rate. The problem of sliding slope is solved by MABS with EBA system. The ESP should use adaptive fuzzy neural controller to control the yaw angular velocity and centroid side angle, and adopt the joint sliding mode variable structure controller which combines the ABS control and the yaw moment control. Through the optimal control theory, the coordinated control of each subsystem can significantly improve the driving stability, riding comfort, fuel economy and so on. Conclusion: This adopt different control strategy and control algorithm for different active safety control system and make full use of tire-road friction coefficient and slip ratio optimal slip ratio, then it realized accurate control of control variables such as yawing angular velocity, centroid side-slip angle, yawing moment and finally ensure the vehicle braking stability, robustness of the controller and the lateral stability of vehicle.

Investigation of the Effect of Injection and Control Strategies on Combustion Instability in Reactivity Controlled Compression Ignition (RCCI) Engines

2014 ◽  
Author(s):  
David T. Klos ◽  
Sage L. Kokjohn
Keyword(s):  
Control Strategies ◽  
Combustion Instability ◽  
Pressure Rise ◽  
Operating Conditions ◽  
Combustion Stability ◽  
Cfd Modeling ◽  
Surface Model ◽  
Injection Timing ◽  
Reactivity Controlled Compression Ignition ◽  
And Control

This paper uses detailed CFD modeling with the KIVA-CHEMKIN code to investigate the influence of injection timing, combustion phasing and operating conditions on combustion instability. Using detailed computational fluid dynamics (CFD) simulations, a large design of experiments (DOE) is performed with small perturbations in the intake and fueling conditions. A response surface model (RSM) is then fit to the DOE results to predict cycle-to-cycle combustion instability. Injection timing had significant tradeoffs between engine efficiency, emissions and combustion instability. Near TDC injection timing can significantly reduce combustion instability, but the emissions and efficiency drop to close to conventional diesel combustion (CDC) levels. The fuel split between the two DI injections has very little effect on combustion instability. Increasing EGR rate, while making adjustments to maintain combustion phasing, can significantly reduce PPRR variation until the engine is on the verge of misfiring. Combustion phasing has a very large impact on combustion instability. More advanced phasing is much more stable, but produces high peak pressure rise rates, higher NOx levels, and can be less efficient due to increased heat transfer losses. The results of this study identify operating parameters that can significantly improve the combustion stability of dual-fuel RCCI engines.

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