Print to pdf application sdk technology highlights. Cdc guidance for evaluating healthcare personnel for. Pdf systemlevel design of a shape memory alloy actuator. A fast response active clearance control fracc system has been designed, prototyped and characterized based on stateoftheart medium temperature 220 c shape memory alloy mtsma wire as primary muscle and 2d flextensional actuator. Airway clearance techniques are regarded as an integral component of management. Aircraft engine performance improvement by active clearance control in low pressure turbines. Sma wires contract upon heating flextensional amplifier deflection to close clearance. The presentation describes active tip clearance control research being conducted by nasa to improve turbine engine systems. Prevention, treatment, and clearance of anaplasmosis using drugs. Engine monitoring and controls development at mtu aero engines. Mar 10, 1987 an active clearance control system for a twin spool gas turbine power plant operating over an engine operating envelope including a cruise mode having a plurality of stages of axial flow compressors defining the high pressure compressor spool and the low pressure compressor spool powering aircraft, each compresor stage having a stator including. During phase 1, the sensors and measurement electronics will be optimized for the specific requirements of an active control system. Evaluation of an active clearance control system concept steinetz, bruce m.
The active clearance control acc of aeroengine turbine tip clearance is evaluated in a lapserate takeoff transient, along with the comparative and quantitative analysis. Active tipclearance control wikipedia republished wiki 2. Active clearance control systems may be categorized as mechanical, thermal, and pneumatic. Active cycle of breathing technique acbt is widely advocated4 comprising breathing control, thoracic expansion exercises and forced expiratory technique which may be used with postural drainage pd. In an active clearance control for controlling clearance between a shroud and turbine blades in a gas turbine engine, the improvement comprising. Active predictive control of turbine tip clearance for aero. Acc speed control state a substate of acc active state in which no forward vehicles are present such that the acc system is controlling vehicle speed to the set speed as is typical with conventional cruise control systems. The target application for this effort is commercial aircraft engines. A radar system attached to the front of the vehicle is used to detect whether slower moving vehicles are in the acc vehicles path. An active clearance control as in claim 1 including labyrinth seals having lands on the inner diameter of the stator vanes and cooperating depending members extending from the outer diameter of said discs defining therebetween a gap, said control means for controlling said selective bleeding means for admitting compressed air to said bore area by said feeding means to heat said disc so as to.
Clearance confirmed by inoculating splenectomizedcalves 83 days after treatment. Tb usually affects the lungs, but it can also affect other parts of the body, such as the brain, the kidneys, or. Security clearance levels are used as part of a method to control access to information that should not be freely available to all personnel the different organizations in the united states federal government use different terminology and lettering, as is discussed below. Active control of tip clearance flow in axial compressors by jinwoo bae b. Controls considerations for turbine active clearance.
Jun 16, 2014 clearance control is the harsh and hostile environment surrounding the turbine blade. The active clearance control acc of aeroengine turbine tip clearance is evaluated in a lapserate takeoff transient, along with the comparative and quantitative analysis of the stability and. Active generalized predictive control of turbine tip clearance for aero. One common active clearance control consists of the acc valve which mixes hot and cold air from the compressor exit and the bypass duct, respectively, to a desired temperature. Us20050149274a1 method and system for active tip clearance. Tuberculosis tb is a disease caused by a germ called mycobacterium tuberculosis that is spread from person to person through the air. Jun 26, 2012 american institute of aeronautics and astronautics 12700 sunrise valley drive, suite 200 reston, va 201915807 703. Phase i will also involve the initial design of a control methodology capable of adjusting the tip clearance of the specific engine sections. The clearance was confirmed in splenectomized calves by inoculating them with blood from the treated cattle 412 months posttreatment.
Knipser, christian, horn, wolfgang, and staudacher, stephan. Ambient temperature performance tests of this first. Evaluation of an active clearance control system concept. Pdf pdf icon 149 kb the difference between latent tb infection and tb disease what is tb. Seal investigations of an active clearance control system concept bruce m. In a system which controls clearance between turbine blades and a shroud in a gas turbine engine, the improvement comprising. When implemented, it can optimize engine performance in all the flight segments by actively maintaining. This causes expansion of certain components and alters the gap between the turbine casing and tips of the spinning turbine.
Acc to increase hpt efficiency throughout the engine operation range. Electrothermally active seal for fast response tip clearance. In an active clearance control for a turbine in a gas turbine engine, the improvement comprising. Us5012420a active clearance control for gas turbine engine. Active clearance control system for gas turbine engines download pdf info. The primary clearance control found in large stateoftheart turbine engines is an. Adaptive cruise control system overview 1 introduction adaptive cruise control acc is an automotive feature that allows a vehicles cruise control system to adapt the vehicles speed to the traffic environment. Jun 19, 2012 american institute of aeronautics and astronautics 12700 sunrise valley drive, suite 200 reston, va 201915807 703. The clearances change with the operating point external loads component deterioration the concept of active clearance control is to identify the current condition to react with clearance adjustment. Acbt is a set of breathing exercises that loosens and moves the sputum from your airways. Roby, et al, 1978, gave two injections of 200 mgml oxytetracycline, 9 mglb, 7 days apart.
Taylor and others published further characterization of an active clearance control concept find, read and cite all the. Specifically, the plasma force was oriented perpendicular to the camber line in order to resist the leakage flow through the tip gap. Active clearance control acc is a method used in gas turbines to improve fuel efficiency. Pcc is any system that sets the desired clearance at one operating point.
The achievable overall performance improvement is evaluated for different control loops. Passive clearance control systems may be categorized as thermal or pneumatic. Department of health and human services, atlanta, ga 30333. Clearance adjudicators use a documented guide and formula to determine whether or not the individual is eligible for a security clearance. Tip clearance management categorized by 2 control schemes. Background figure 1 shows the high pressure hpt blade tip seal location in a modern gas turbine engine. Propensity matched analysis of 697 consecutive patients who underwent cardiac surgery at a single center. Active clearance of chest tubes is associated with reduced. Controls considerations for turbine active clearance control. In an active clearance control for a gas turbine, the improvement comprising.
An active clearance control for a gas turbine engine powering aircraft over and operating envelope including high powered and low powered conditions, said engine having a compressor section comprising a plurality of stages of axial compressors rotatably supported in the bore area of the compressor section, each of said stages including a plurality of blades supported in a disc and each. Acc is defined as active clearance control somewhat frequently. Preliminary evaluation of an active clearance control. The invention concerns an active clearance control for controlling clearance between a turbine and a casing in a gas. Active clearance control united technologies corporation.
Pdf further characterization of an active clearance control. Acc active state the acc system is in active control of the vehicles speed. This is achieved by dynamically controlling the turbine tip clearance during normal cruise flight, the engine is exposed to many loads such as intense heat and centrifugal force. Active control to improve the aerodynamic performance and reduce the tip clearance noise of axial turbo machines. Active clearance control how is active clearance control. Active clearance control the clearances between rotating and stationary parts are a dominant source of losses in turbomachines. Aircraft engine performance improvement by active clearance. Us7491029b2 active clearance control system for gas. An active clearance control as in claim 1 including labyrinth seals having lands on the inner diameter of the stator vanes and cooperating depending members extending from the outer diameter of said discs defining therebetween a gap, said control means for controlling said selective bleeding means for admitting compressed air to said bore area. Active control of turbine blade tip clearance continues to be a concern in design and control of gas turbines.
However, formatting rules can vary widely between applications and fields of interest or study. Active, expires 202601 application number us11251,374 other versions us20070086887a1 en inventor. Active generalized predictive control of turbine tip. The invention relates generally to tip clearance control and in particular to active tip clearance control in turbines. Control image and graphic options, such as resolution, colors, downsampling, and more. Seal investigations of an active clearance control system. The active cycle of breathing techniques acbt is one way to help you to clear sputum from your chest. Benefits of improve hp turbine active clearance control. Develop a highpressure turbine hpt active clearance control system. The air is routed to flow through tubes surrounding the casing at each turbine stage.
A novel generalized predictive control and its application on. Pdf electrothermally active seal for fast response tip. Request pdf controls considerations for turbine active clearance control this presentation discusses active control of turbine tip clearance from a control systems perspective. Toward a fastresponse active turbine tip clearance control. A randomized evaluation of the acute efficacy, acceptability. The active flow control was design to act as a plasma squealer. Server enables you to print to pdf from any windowsbased application that can print to paper.
Very few approaches having moving parts are considered viable for active tip clearance control. The active clearance control acc of aeroengine turbine tip clearance is evaluated in a lapserate takeoff transient, along with the comparative and quantitative analysis of the stability and robustness of the active tip clearance control system. Front macpherson struts, longtravel coil springs, 1piece aluminum, lower control arms and stabilizer bar rear 4link rear suspension with trailing arm. Nasa aeronautics research institute electrothermally active. The results show that the resultant active tip clearance control system has favorable steadystate and dynamic performance and benefits of increased efficiency, reduced. The system utilizes independent actuators, a segmented shroud structure, and clearance measurement feedback to provide fast and precise active clearance control throughout engine operation. Request pdf active control of tip clearance flow in axial compressors control of compressor tip clearance flows is explored in a linear cascade using three types of fluidic actuators. Pdf high temperature evaluation of an active clearance control. In an applicant, they look for honesty, trustworthiness, character, loyalty, financial responsibility, and reliability. Pdf a mechanically actuated blade tip clearance control concept was evaluated in a nonrotating test rig to quantify secondary seal leakage. The mmwr series of publications is published by the center for surveillance, epidemiology, and laboratory services, centers for disease control and prevention cdc, u. Preliminary evaluation of an active clearance control system. The temperature between gas turbine engine case and its shrouds typically exceeds 1200 f, and the actuation. A tip clearance sensor allows the acc to adapt to an individual engine.
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