Abstract: A rocket engine fluid-flow system includes a pump fluidly interconnecting a fluid source to a combustion chamber. A nozzle is in fluid communication with the combustion chamber and includes coolant tubes fluidly arranged between the pump and the combustion chamber. An orifice has a throat and is fluidly arranged between the pump and the coolant tubes. The orifice has entrance and exit ramps arranged on either side of the throat. The exit ramp has an exit ramp surface with a divergent angle that is less than a right angle. The entrance ramp provides a smooth approach to the orifice throat. In one example, the exit ramp includes an exit ramp surface having a divergent angle of 20-60°. The exit ramp radius is less than twice the throat radius in one example.

Abstract: The current invention comprises tubes that can be constrained and expanded by either axial or torsional strain. By torsionally displacing the tube in a direction counter to the biased helices and angularly displacing the lower angle helix to an angle equal to, but opposite, the starting angle, the tube is expanded diametrically with no significant change in length after expansion of the tube. These tubes find utility in medical and non medical applications.

Abstract: A deployment sheath for medical devices is provided that includes one or more pleats in its pre-deployment state that are allowed to open during deployment so as to facilitate easier device deployment and sheath removal. Preferably, the sheath is removed by everting it over itself during the delivery process. By orienting the pleats along the length of the sheath, preferably helically around the sheath, the sheath undergoes a predictable enlargement during deployment so as to relieve friction of the everted sheath sliding along itself during deployment. This allows the sheath to be removed with less tension than previous everting sheath constructions and assures more accurate device placement in a patient.

Abstract: A method of synthesizing rotor inlet temperature in a turbine comprising the steps of determining a burner fuel flow (WFGG), a burner inlet pressure (PS32), and a compressor discharge temperature (T3) of a turbine, calculating a ratio unit parameter from the burner fuel flow, the burner inlet pressure, and the compressor discharge temperature, and calculating a synthesized rotor inlet temperature from the ratio unit parameter.

Abstract: A method of synthesizing rotor inlet temperature in a turbine comprising the steps of determining a burner fuel flow (WFGG), a burner inlet pressure (PS32), and a compressor discharge temperature (T3) of a turbine, calculating a ratio unit parameter from the burner fuel flow, the burner inlet pressure, and the compressor discharge temperature, and calculating a synthesized rotor inlet temperature from the ratio unit parameter.

Abstract: A method and an apparatus for determining the clearance between the rotor blades of a rotor assembly and a shroud disposed radially outside of the rotor assembly is provided that calculates steady-state operating conditions for a given power engine setting and utilizes those steady-state conditions to determine a steady-state clearance at the given power setting. The method and apparatus further calculate instantaneous thermal conditions for the rotor disk, rotor blades, and shroud. The instantaneous thermal conditions are subsequently used to determine the amount of instantaneous thermal expansion of the rotor disk, rotor blades, and shroud. A clearance transient overshoot is determined using the calculated instantaneous thermal expansions. The actual clearance is determined using the steady-state clearance and the clearance transient overshoot.

Abstract: A method and an apparatus for determining the clearance between the rotor blades of a rotor assembly and a shroud disposed radially outside of the rotor assembly is provided that calculates steady-state operating conditions for a given power engine setting and utilizes those steady-state conditions to determine a steady-state clearance at the given power setting. The method and apparatus further calculate instantaneous thermal conditions for the rotor disk, rotor blades, and shroud. The instantaneous thermal conditions are subsequently used to determine the amount of instantaneous thermal expansion of the rotor disk, rotor blades, and shroud. A clearance transient overshoot is determined using the calculated instantaneous thermal expansions. The actual clearance is determined using the steady-state clearance and the clearance transient overshoot.

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 method and an apparatus for use with a gas turbine engine receive a signal indicative of an engine operating condition, generate signals representative of thermal conditions of a rotor, blades, and a case, and in response to each of the signals above, determine a signal indicative of a difference between a instantaneous clearance for the thermal conditions and a steady state clearance for the engine operating condition. The determination includes effects related to a temporary difference that results from a difference between the steady state clearance for the engine operating condition and a steady state clearance for a preceding engine operating condition, but does not require computation of the actual temperatures or the steady state temperatures of the rotor, the blades, and the case. A signal indicative of the difference between a instantaneous clearance for the thermal conditions and a steady state clearance for the engine operating condition may be provided to various augmentation schedules.

Abstract: An improved integral composite cable jacket or tubing is disclosed wherein a fluoropolymer fiber array is disposed between a first and second elastomer jacket layer. At least one of the elastomer jacket layers is comprised of silicone. The first and second elastomer jacket layers are bonded together through predetermined open spaces defined by the fiber array.

Abstract: A transition assembly for directing the gas flow from a combustor to an axial turbine includes a transition liner having a shroud disposed about its outer surface and abutting thereto at a plurality of points to defining a plurality of cooling air passages therebetween. The downstream end of the assembly is circumscribed by the first stage stator and extends axially to just upstream of the first stage turbine rotor. At this end a plurality of circumferentially spaced struts are mounted between the liner and the shroud to define a plurality of axially facing nozzles which are angled to impart a pre-swirl to the cooling air exiting therefrom.

Abstract: Non-destructive evaluation of a ceramic nozzle is accomplished by generating a thermal gradient across the nozzle while it is mounted in a test rig. The thermal gradient is then measured and compared to a preselected gradient that is representative of the harshest condition to which the nozzle will be exposed during its operating life. The thermal gradient is adjusted until it approximates the preselected gradient. The nozzle is then observed for any cracks which reveal a weakness in the ceramic.

Abstract: A stator vane assembly for a gas turbine engine that includes a plurality of circumferentially spaced ceramic vanes, each of which has an inner and outer ceramic shroud, and a ceramic post extending from one of the shrouds, and a metallic platform having a plurality of circumferentially spaced recesses. The posts are inserted into a metallic sleeve and then brazed. The brazed sleeves are then mounted in the recesses. A method for assembling these components to form the stator assembly is also described.

Abstract: The invention provides a pressure transducer with two mainly identical ceramic members located opposite each other in a housing. Substantially cylindrical recesses are provided in each of the ceramic members, the innermost delimiting walls of each recess forming a thin diaphragm. Each diaphragm is provided with a conductive coating, and contact elements electrically connect each conductive coating with circuitry for determining differential capacitance. The recesses and the housing form first and second pressure chambers which are connected via a channel provided through the two ceramic members. Spacing material maintains the ceramic members at a constant spacing and also seals their periphery. Together with the inner walls of the diaphragms, the sealing material delimits an inner pressure chamber. A first port connects the first pressure chamber with a first external pressure source. A second channel connects the inner pressure chamber with a second external pressure source.