Showing papers on "Turbine published in 1989"

Redistribution of an inlet temperature distortion in an axial flow turbine stage

Abstract: The results of an experimental program aimed at determining the extent of the redistribution of an inlet temperature distortion in an axial flow turbine stage are presented. The program was conducted in a large-scale, low-speed, single-stage turbine where air, seeded with CO2, was introduced at one circumferential location upstream of the inlet guide vane. The migration of the seeded air through the turbine was determined by sensing CO2 concentration inside the stage. A temperature distortion was introduced by heating the seeded air. The CO2 concentration contours measured downstream of the vane showed h'ttle change with heating, indicating that the vane flowfield was relatively unaffected by the introduction of the temperature distortion. However, the CO2 contours observed on the rotor airfoil surfaces for the case with inlet heating indicated segregation of hot and cold gas with the higher temperature gas migrating to the pressure side and the lower temperature gas migrating to the suction side. Significant increases in rotor secondary flow were also observed. Two separate physical mechanisms are postulated to explain the observed experimental trends. Calculations performed by using a three-dimensional Euler solver show qualitative agreement with the experimental data.

Geared counterrotating turbine/fan propulsion system

Abstract: High by-pass fan jet engine includes counterrotating turbine blade sets for receiving hot combustion gases from a core engine portion and driving the fan blades through a planetary gear-type reduction gear assembly. Lightweight, highspeed, concentric, counterrotating shafts transmit power from both turbine blade sets to the fan via the reduction gear assembly. A pair of planetary gear assemblies with fixed fing gears and a rotatable common planetary gear carrier is used to drive a single set of fan blades via the carrier, and a pair of planetary gear assemblies with a fixed common planetary gear carrier and rotatable ring gears is used to drive two or more counterrotating fan blade sets via the ring gears. A low pressure "booster" compressor feeding the core engine portion can be directly driven from one of the two high speed shafts.

Doubly fed generator variable speed generation control system

Abstract: Disclosed is a device and method to control the conversion of an arbitrary resource energy into mechanical energy and subsequently into electric energy with a variable-speed generation system utilizing a turbine and a doubly-fed generator, to be connected directly to a power grid of a certain grid frequency. Via electronic control of the rotor speed by controlling the rotor winding excitation frequency, the device has the capability of providing an optimum tradeoff in maximum turbine efficiency and minimal generator losses to secure maximum efficiency of the total conversion process, irrespective of varying resource and electric load conditions. The excitation requirements of the generator are confined to moderate levels and yet a wide rotor-speed variation margin, starting from zero speed, is permitted. An integrated strategy is implemented which effectively coordinates the execution of these tasks and the independent control of the generator terminal voltage as well as the active and reactive electric power output. All signal processing as required correspondingly is carried out without the need for cumbersome measurements of turbine input and output power or generator losses.

Thermal barrier coatings for gas turbine use

Abstract: The use of thermal barrier coatings on high-pressure turbine components can improve gas turbine efficiency through reduction of cooling airflow. However, the risk involved in reducing cooling airflow requires a highly reliable thermal barrier coating. This increased reliability will be achieved through several complementary approaches; material and process development, life prediction method development and engine service experience. The two processes available for deposition of thermal barrier coatings (plasma spray and physical vapor deposition) are compared, and the advantages and disadvantages of each discussed as they apply to gas turbine components. The results of bond coat material development which has increased the thermal cycle life of plasma spray thermal barrier coatings are presented. Improvements were achieved by two methods: (1) the use of creep-resistant bond coat compositions and (2) overaluminiding of the bond coat. Results of engine testing of thermal barrier coatings in an environment that produces hot corrosion are also presented.

Combined cycle engine

Abstract: The purpose of the Wicks Combined Cycle Engine (WCCE) is to provide a very substantial fuel efficiency improvement relative to the liquid cooled, internal combustion, piston engines that are now utilized by virtually all automobiles, trucks, and buses, and most trains and ships. The method is to recover virtually all of the internal combustion engine heat that is normally rejected through the engine coolant radiator and through the engine exhaust, by a Rankine Cycle that is comprised of a feed pump, feed heater, boiler, superheater, turbine or other type of mechanical power producing expander and air cooled condenser. The reference analysis shows a potential efficiency increase from 25% for existing practice engines to 41.8% for the WCCE.

Heat shield for gas turbine engine frame

Abstract: A heat shield assembly for use in a turbine engine frame includes inner and outer flowpath liners for shielding the inner and outer turbine frame members from hot exhaust gasses flowing through the turbine engine. The flowpath liners are supported on the turbine frame members with a support structure which allows the flowpath liners to freely expand and contract under thermally induced forces. In this manner thermal stresses are minimized. The flowpath liner support structure also provides uniform support for the flowpath liners and allows for the even and unobstructed flow of cooling air through the flowpath liners.

High pressure ratio turbocharger

Abstract: A turbocharger for an internal combustion engine can provide a two-stage compressor with movable stator blades to shift the compressor performance and match the air output of the turbocharger to varying air requirements of an internal combustion engine. The turbocharger can also be provided with a generally optimum boost pressure ratio of about 4.5:1 to 4.6:1. Such a compressor comprises a first axial-compressor stage, typically providing a 1.3:1 pressure boost ratio, and a second radial-compressor stage, typically providing a pressure ratio of 3.5:1. The turbine of such a turbocharger can be a combination flow turbine and can be provided with closure means to vary the turbine geometry and provide more efficient turbine operation at low-engine speeds. The turbocharger includes a roller bearing system adapted to accommodate imbalance. A control system operating in response to engine-operating conditions can operate the compressor-stator vanes and, if present, the turbine closure means.

Turbine system having more failure resistant rotors and repair welding of low alloy ferrous turbine components by controlled weld build-up

Abstract: System for repairing worn surfaces of steam turbine components and especially high pressure turbine rotors, are disclosed. These systems include depositing a first layer of weld metal on a worn surface of the component, whereby a heat-affected zone is created. A second layer of weld metal is then deposited over the first layer using a greater amount of heat to temper at least a portion of the heat-affected zone produced by the first layer. The preferred embodiments include the use of gas tungsten arc welding for providing fine-grain size and more creep resistance, especially in the weld and heat-affected zone. The resulting build-up can be machined, for example into a blade fastening to produce a component having properties equal to or better than the base-metal alloy. The invention also provides a longer lasting turbine system, including rotors which have serrated steeples that are more resistant to failure.

More creep resistant turbine rotor, and procedures for repair welding of low alloy ferrous turbine components

Abstract: A more creep resistant turbine rotor and novel methods for repairing worn surfaces of Cr-Mo-V steam turbine components are disclosed. These methods include specified alloy compositions and welding procedures that minimize weld stresses and cracking. These alloys exhibit improved creep and fatigue properties and are preferably deposited using a gas tungsten arc welding procedure. Bead sequencing, cooling side plates and the use of run-off tabs are also disclosed for minimizing welding defects in turbine rotors and discs.

Aircraft engine starting and emergency power generating system

Abstract: The problem of excessive weight in an aircraft 10 powered by at least one turbine engine 12 as a result of the incorporation of both a starter for the turbine engine 12 and a source of emergency power is avoided by utilizing a turbine wheel 62 to alternatively start the engine 12 or drive an emergency power generator 102 The turbine wheel 62 may be driven either by compressed air from a ground source 34 or an engine bleed 32 or, in the alternative, by hot gases of combustion from a stored energy source 36 in an emergency situation

Power recovery pump turbine

Abstract: The invention is directed to an energy recovery pump turbine for use in industrial processes where a fluid is pumped at a high pressure to the process and at least a portion of the fluid is discharged from the process at a high pressure. A turbine is positioned to receive the high pressure discharge from the process. The turbine has an impeller positioned on a shaft and the discharged fluid engages the impeller and causes the impeller and shaft to rotate. A pump is position adjacent to the turbine to receive the fluid being pumped to the process. The pump has an impeller mounted on a shaft and the shaft of the pump is operatively connected to the shaft of the turbine. Rotation of the turbine shaft causes the impeller and the shaft of the pump to rotate whereby the pump assists in supplying the fluid under pressure to the process and to recover energy from the high pressure fluid discharged from the process. Also disclosed is a method for recovering energy from an industrial process where a fluid is pumped at a high pressure into the process and at least a portion of the fluid is discharged from the process at a high pressure. The high pressure discharged fluid is directed into the inlet of a turbine. The inlet of the turbine is caused to rotate by the high pressure discharged fluid. The turbine impeller is mounted on a rotatable shaft. An impeller of a pump that is mounted on the shaft is caused to rotate by the rotation of the shaft that is caused by the rotation of the turbine impeller. The fluid that is to be pumped to the process is directed to the inlet of the pump. The rotating impeller of the pump raises the pressure of the fluid supplied under high pressure to the process and recovers energy from the high pressure fluid discharged from the process.

Segmented seal plate for a turbine engine

Abstract: The clearance between a seal assembly (48) and a turbine wheel (16) in an engine of the type having a radial outflow compressor (24) and a radial inflow turbine (16) is minimized by forming the seal assembly (48) in part out of a plurality of segments (74) disposed in a circular array and which are relatively movable but sealed to each other. The thermal stress in the segments (74) will be less than in a single ring resulting in an extended life before the onset of cracking and eventual mechanical failure.

Fully Scaled Transonic Turbine Rotor Heat Transfer Measurements

Abstract: The heat transfer to an uncooled transonic singlestage turbine has been measured in a short-duration facility, which fully simulates all the nondimensional quantities of interest for fluid flow and heat transfer (Reynolds number, Prandtl number, Rossby number, temperature ratios, and corrected speed and weight flow). Data from heat flux gages about the midspan of the rotor profile, measured from d-c to more than 10 times blade passing frequency (60 kHz), are presented in both time-resolved and mean heat transfer form. These rotating blade data are compared to previously published heat transfer measurements taken at Oxford University on the same profile in a two-dimensional cascade with bar passing to simulate blade row interaction effects. The results are qualitatively quite similar at midspan. The data are also compared to a two-dimensional Navier–Stokes calculation of the blade mean section and the implications for turbine design are discussed.

High bypass turbofan engine having a partially geared fan drive turbine

Abstract: The present invention provides a high bypass turbofan engine configuration wherein a fan drive turbine is divided into first and second turbine sections mounted for independent rotation within the engine frame. The first, higher pressure, higher speed turbine section is coupled to the fan section drive shaft via a gear box which reduces the rotational speed of the power delivered by the higher pressure first turbine section to match the design rotational speed of the fan section. The second turbine section, having a larger diameter and lower rotational speed as compared to the first turbine section, is directly connected to the fan section and drives the fan section at the same rotational speed as that of the second turbine section. In this manner, the fan drive shaft horsepower is provided while reducing the weight and size of the necessary gearing between the fan drive turbine and the fan. The weight and size of the fan drive turbine and the booster compressor are also reduced.

Hand-held oral irrigating device

Abstract: The hand-held oral irrigating device of the invention is substantially self-contained and powered solely by an input stream of continuous flow treatment liquid, such as water from a conventional supply line. The device includes a internal turbine that is rotated by one portion of the input stream and which generates a pulsatile flow of the treatment liquid from a second portion of the stream by interruptedly passing the second portion through apertures defined in the rotating turbine. The rotating turbine concurrently operates a gear pump for mixing a stored medicament, at a rate controlled by the rotation of the turbine, with the pulsatile flow of treatment liquid at a predetermined and substantially constant volumetric ratio. The resulting combined pulsatile flow of treatment liquid and medicament is discharged through a releasably mounted appliance head or tip for use, by way of example, in cleaning the teeth and stimulating the gums of the user.

Vertical axis sail bladed wind turbine

Abstract: A vertical axis turbine is provided which comprises a plurality of flexible sail blades attached to a vertically extending, rotatable shaft by upper and lower blade attachment devices, and a power absorbing load device coupled to the rotatable shaft. The flexible sail blades are deployed and stabilized in operation by the centrifugal forces produced in response to rotation of the blades about the vertical axis of the shaft, whereby, in operation, aerodynamic forces acting on the sail blades can be transmitted to shaft without generating bending movements. The sail blades comprise plural elongate flexible sail panels, with flyweights being disposed between and secured to the ends of pairs of the sail panels. In different embodiments, passive flyweights, active flyweights (secondary turbines) and combinations of both types are used.

Low voltage aircraft engine starting system

Abstract: In a system for starting an aircraft turbine from a low voltage direct current power supply, the low voltage power supply is coupled by an invertor to the turbine's a.c. generator. The generator operates as a motor during starting. The invertor is initially coupled directly to the generator during starting, and to the generator via a step-up transformer after the speed of the generator increases. In a preferred embodiment of the invention, the transformer is an autotransformer used to step down the output of the generator when operating as a generator after the turbine has been started.

Development of Rotational Speed Control Systems for a Savonius-Type Wind Turbine

Abstract: An attempt is made here to increase the output of a Savonius rotor by using a flow deflecting plate. When the deflecting plate is located at the optimum position, the rotor power increases nearly 30 percent over that when no deflecting plate is present. The rotor torque was found to become almost zero, when the plate is placed just in front of the rotor. In addition, two systems to control the rotational speed of a Savonius rotor are developed. These permit the rotor to be stopped in strong wind. Operating characteristics of the two control systems are investigated.

Combined air-hydrogen turbo-rocket power plant

Abstract: A combined air-hydrogen turbo-rocket engine is disclosed having a simplified construction in which the hydrogen driven turbine is formed integrally with the rotor wheel of the axial air compressor stages. The rotor stages are located downstream of a stator vane structure and are driven by gaseous hydrogen passing across the turbine blades. The hydrogen is subsequently injected into an air duct surrounding the axial air compressor and defining an airflow path having an air inlet. The hydrogen-air mixture is ignited and the burned gases are expanded through a converging-diverging exhaust nozzle.

Turbulence Measurements in a Multistage Low-Pressure Turbine

Abstract: The flow in the rotor blades of a five-stage low-pressure turbine was investigated experimentally using hot-film probes. Time averaging, Fourier transforms, and ensemble averaging are applied for data reduction. The techniques prove to be a very helpful instrument for the assessment of the flow characteristics in the relative frame. A strong interaction is identified between two successive rows of rotor blades. A physical model, developed from velocity and turbulence results, gives a comprehensive understanding of the phenomenon. The main parameter is the nonuniformity of the flow entering the downstream blade row. Separation occurs when the wake of the upstream rotor blades enters the blade passage near the leading edge, preferably on the pressure side. The interaction is quasi-steady in the relative frame and rotates with the rotor speed. It was observed only in one of three investigated blade rows. Further studies are necessary to identify the mechanism correlating the nonuniformity to the separation. (orig.).

Apparatus and method for optimizing the air inlet temperature of gas turbines

Abstract: A heat exchanger is disclosed for heating air entering a combustion gas turbine to increase the power output of the turbine when the turbine operates in a cold environment. The heat exchanger may be used also as a cooler to cool air entering the turbine to increase the power output of the turbine when the turbine operates in a hot environment.

Turbocharged compound cycle ducted fan engine system

Abstract: A turbocharged, compounded cycle ducted fan engine system includes a conventional internal combustion engine drivingly connected to a fan enclosed in a duct. The fan provides propulsive thrust by accelerating air through the duct and out an exhaust nozzle. A turbocharger is disposed in the duct and receives a portion of the air compressed by the fan. The turbocharger compressor further pressurizes the air and directs it to the internal combustion engine where it is burned and exits as exhaust gas to drive the turbine. A power turbine also driven by exhaust gas is also drivingly connected through the engine to the fan to provide additional power. The size and weight of the turbocharger are reduced since the compressor's work is partially achieved by the compression effect of the fan. The total propulsive thrust includes the fan generated thrust which bypasses the turbocharger and the thrust of exhaust gases exiting the turbine.

The Influence of Turbine Clearance Gap Leakage on Passage Velocity and Heat Transfer Near Blade Tips: Part II—Source Flow Effects on Blade Suction Sides

Abstract: A study has been conducted to investigate influences of tip leakage flow on heat transfer and flow development along the pressure side of a gas turbine blade. An analysis of the sink character of the flow situation indicates that high velocities and accelerations are generated very near the gap, and an apparatus was specifically designed to model the phenomena and to permit resolution of the expected localized near-gap heat transfer enhancement

Investigation of coatings at high temperature for use in turbomachinery

Abstract: Aircraft gas turbines, steam turbines and coal utilization turbines operating under particulate flows are exposed to erosion and performance deterioration. Almost all advanced aircraft turbines today are manufactured with a protective coating on the blades. The particulates in the steam turbines are produced in the boiler from exfoliated oxide scales and carried in the steam to the turbine. In coal utilization turbines, the particulates are by-products of the combustion process. There are many problem areas which need future research to be able to produce better and more durable high-temperature coatings. However, this paper will present only some of the work done at the University of Cincinnati on erosion testing at high temperatures and velocities for different materials and coatings. The testings have been performed with a special high-temperature erosion wind tunnel which simulates the aerodynamic conditions on the blades.

Turbofan engine having a counterrotating partially geared fan drive turbine

Abstract: A high bypass ratio turbofan engine having a fan section, a booster compressor disposed aft of the fan section relative to the flow of combustion gases through the engine, and a core section disposed aft of the booster compressor. A low pressure counterrotating turbine, disposed aft of the core section, is used for driving the fan section and the booster compressor. The counterrotating turbine includes at least one set of rotating turbine blades and at least one set of oppositely rotating counterrotating turbine blades. A twin spool shaft is provided for coupling the turbine blades to the booster compressor and for coupling the counterrotating turbine blades to the fan section. A reduction gear is disposed in the drive shaft for coupling the turbine blades to the fan section and for reducing the rotational speed of the turbine output power to match the rotational speed of the fan section thereby splitting the usable work of the turbine blades between the fan section and the booster.

System for cooling in a gas turbine

Abstract: A gas turbine is provided in which the quantity of cooling air required to cool the turbine is reduced by the evaporative cooling of air bled from the compressor discharge for cooling purposes. The evaporative cooling is accomplished by spraying pressurized water into a bleed pipe which diverts the cooling air from the compressor discharge to the turbine.

Active clearance control

Abstract: The invention relates to a control system which controls the diameter of a turbine shroud which surrounds a turbine in a gas turbine aircraft engine. The invention seeks to minimize the clearance (33) between the turbine rotor blades (123) and the shroud (36). Air is bled from the compressor (18) in the engine and ducted (98,112) to the shroud in order to heat or cool the shroud in order to, respectively, either expand or shrink the shroud to a proper diameter. The air temperature which is required is computed based on compressor speed and other engine parameters, but not necessarily upon rotor temperature as such, despite the fact that rotor temperature has a significant influence upon rotor diameter, and thus upon the shroud diameter needed. In a preferred embodiment, air at two different temperatures is bled from two different compressor stages (83,89) in the engine and mixed together (98) in a ratio which is determined (by valve 94) according to flight conditions, in order to provide air of the required temperature for the shroud, and then ducted to the shroud in order to modify shroud size. Further, during accelerations and decelerations of the engine, a different air temperature is provided, as compared with that provided during steady state operation. In the event of system failure shroud diameter can be controlled by back up systems, e.g. one for use during steady state, and the other for use during accelerations and decelerations.

The theory and operation of evaporative coolers for industrial gas turbine installations

Abstract: This paper discusses the theory of evaporative cooling and describes the application of wetted rigid media evaporative coolers to gas turbines. Calculations of parameters used to predict evaporative cooler performance are included. Also included are discussions of evaporative cooler design, installation, operation, feedwater quality, and the causes and prevention of water carryover.