Abstract: The present invention relates to a gas turbine engine jet noise suppressor which does not appreciably adversely impact engine thrust and performance. The jet noise suppressor includes a nozzle, having an arrangement thereon of tabs disposed on the downstream end of the nozzle, the tabs having a length and the angular offset with respect to the engine flow such that mixing occurs primarily at the interface of the engine flow and the ambient air. In addition, various construction details are developed for the tabs including tabs that are trapezoidal with tapered sides such that the tabs minimize adverse impact to engine performance.

Abstract: A control system for controlling the compressor stall margin during acceleration in a gas turbine engine includes means for sensing signals indicative of the gas flow temperature and gas pressure. The control system further includes signal processing means, responsive to the sensed signals, for synthesizing and providing a processed signal indicative of a measure of compressor destabilization due to heat transfer effects. The control system also includes means, responsive to the processed signal, for providing an output to initiate corrective action to increase compressor stall margin if needed. The engine control means, which is a part of the control system, increases the compressor stall margin by either adjusting the compressor variable vanes, reducing fuel flow or modulating the compressor bleed.

Abstract: A control system for operating a compressor bleed valve in a gas turbine engine to prevent compressor operation in surge region determines engine stability in response to a plurality of sensed engine parameters, and calculates and stores engine parameters to estimate compressor performance relative to a stability limit which is indicative of a surge operation. The control system further maintains a rolling average of the estimate of compressor performance for up to a predetermined number of engine flights. This rolling average of the estimate of compressor performance is indicative of engine usage and associated engine degradation. The control system determines a bias for the bleed valve in response to calculated engine parameters and adjusts the operation of the bleed valve in response to the compressor performance so as not to exceed the stability limit.

Abstract: An apparatus for supporting a rotatable shaft within a gas turbine engine during a high rotor imbalance condition includes a first bearing and a fixed support frame. One of the support frame or shaft includes a one-piece flange that has a first portion, a second portion and a failure region with a predetermined load capacity, which connects the first and second portion together. The bearing is radially disposed between the rotatable shaft and the fixed support frame, and is supported by the second portion of the flange. The bearing provides a load path between the fixed support frame and the rotatable shaft until a high rotor imbalance condition when the failure region fails in response to the application of loads that exceed the load capacity of the failure region. The failure of the failure region then provides for the separation of the first portion of the flange from the second portion and the elimination of the load path through the bearing.

Abstract: A vibration damper 38 for a fuel nozzle 24 having a central axis about which are disposed an inner 34 and outer 36 concentric fuel tubes. The damper includes a sleeve 40 and at least two legs 42, each leg having a radial portion extending from the sleeve and a resilient, longitudinally extending portion 46. The sleeve engages the inner tube while the longitudinally extending portions of the legs bear against the inner surface 37 of the outer tube to dampen vibrations between the concentric tubes. Besides damping objectionable vibratory forces experienced by the fuel tubes in the fuel nozzle, the present invention offers minimal fuel flow blockage in the concentric fuel tubes.

Abstract: A turbine (18) of a gas turbine engine includes erosion energy dissipaters (44) which comprise of a plurality of inlet orifices (46) and a large diameter outlet orifice (48). The erosion energy dissipater reduces erosion of associated structure due to impingement of particulates entrained in airstreams. Various construction details are described to provide cooling air containing entrained particulates to the high pressure turbine case of a gas turbine engine without eroding the case.

Abstract: A swirler 50 for a gas turbine engine combustor 10 has an outer wall 54, groupings 52 of vanes 42 attached to the outer wall, a centerbody 60 mechanically decoupled from the outer wall via the groupings of vanes so that the swirler can accommodate differential rates of thermal growth between the outer wall and the inner centerbody and vanes. Alternatively, the centerbody may be attached to one of the groupings of vanes to keep the centerbody from vibrating.

Abstract: A stator assembly for reducing noise in the outermost portion of the working medium flow path is disclosed. Various construction details are developed which relate to the reduction in noise within the outer twenty percent (20%) of the working medium flow path. In one particular embodiment, an annular channel extends rearwardly from a location between the blades and the vanes for capturing a significant portion of the wake turbulent flow from the tip region of the rotor blades. The annular channel is bounded by a pair of circumferentially extending walls, at least one of which has acoustic treatment to absorb tonal and broadband noise.

Abstract: A process for controllably applying thermal spray coating onto substrates is described. The process includes positioning rotor blades in a fixture rotatable about an axis, forming a spray of particles of softened coating medium in an apparatus for propelling the coating medium towards the blade tips and coating the blade tips by passing the blades through the spray of particles of coating medium. Various process details, including process parameters, are developed.

Abstract: A stator assembly for reducing noise in the outer most portion of the working medium flow path is disclosed. Various construction details are developed which relate to the reduction to noise within the outer twenty percent (20%) of the working medium flow path. In one particular embodiment, the number of radially extending surfaces in the outermost portion of the working medium flow path is reduced.

Abstract: The present invention relates to a fan blade in an axial gas turbine engine. The blade platform is constructed to fracture adjacent the airfoil portion of the blade so as to locate the fractured edge of the platform in the root portion. As a result of this benign platform, damage to successive fan blades during a blade loss condition is reduced. In addition, various construction details are developed in the airfoil and root portion of the fan blade to reduce damage to fan blades during impact with adjacent blades.

Abstract: A coolable airfoil having a passage for discharging particulates entrained in cooling air is disclosed. Various construction details are developed to provide clean cooling air to the leading edge of the airfoil. In one embodiment, a chordwise duct extends past a spanwisely extending supply passage to the inlet of a spanwisely extending rear passage such that momentum effects direct the flow of a portion of cooling air and particulates from the duct, past the entrance of the supply passage and into the rear passage and a larger portion of the flow of cooling air into the supply passage for cooling the leading edge of the airfoil.

Abstract: The present invention relates to a seal interposed between platforms of blades for a fan in an axial gas turbine engine. Modern impact resistant fan blades have larger interplatform gaps. As a result, the interplatform seals have to seal a large gap. The seal is stiffened such that it can withstand centrifugal forces due to fan operation. In addition, various construction derails are developed for the stiffened seal.