Showing papers on "Turbine published in 1987"

Current status of thermal barrier coatings — An overview

Abstract: The science and technology of thermal barrier coatings has advanced considerably since reports of the first test on turbine blades in a research engine in 1976. Today thermal barrier coatings are flying in revenue service in a low risk location within the turbine section of certain gas turbine engines. The state-of-the-art coating system for gas turbine applications is currently a plasma-sprayed ZrO 2 -(6%–8%) Y 2 O 3 ceramic layer over an MCrAlY (M ≡ Ni, Co or NiCo) bond coat layer plasma sprayed at low pressure. Although the potential for meeting current and short-term goals is high, longer-range goals may not be attainable with current coating concepts. These longer-range goals will involve high risk designs where coating loss could lead directly to component loss. Several steps must be taken to help meet these goals. Improved understanding of coating failure mechanisms is required. Models are needed to predict lifetimes. Process automation and quality control procedures must be instituted. Finally, new concepts in plasma-sprayed coatings must be developed and alternatives to the plasma- spraying process may be required. The current status of thermal barrier coatings and prospects for future progress in the above areas are summarized.

Ceramic coatings for advanced heat engines - A review and projection

Abstract: This report assesses the current status and future potential for the application of ceramic coatings in advanced diesel and turbine engines A previous report describes the authors findings in greater detail Ceramics, in contrast with metals, generally exhibit better structural and thermal capabilities at high temperatures In general, ceramics are more resistant to creep, oxidation, corrosion, erosion, and wear, as well as being better thermal insulators The benefits of thermal barrier coatings on the hotter side of diesel or turbine engine components are well-documented, and thermal barrier coatings are one of several applications of ceramics that are being pursued actively for heat engines Ceramic coatings are being considered for diesel engine cylinder liners, piston caps, valve faces and seats, piston rings, and other parts and for turbine components such as combustors, blades, stators, seals, and bearings

Three-Dimensional Flow in a Low-Pressure Turbine Cascade at Its Design Condition

Abstract: This paper describes an experimental study of the three-dimensional flow within a high-speed linear cascade of low-pressure turbine blades. Data were obtained using pneumatic probes and a surface flow visualization technique. It is found that in general, the flow may be described using concepts derived from previous studies of high-pressure turbines. In detail, however, there are differences. These include the existence of a significant trailing shed vortex and the interaction of the endwall fluid with the suction surface flow. At an aspect ratio of 1.8, the primary and secondary losses are of equal magnitude.

Turbofan gas turbine engine

Abstract: An improved arrangement of a turbofan engine comprises a core engine, an upstream fan, a downstream fan and a booster compressor. The upstream fan and downstream fan are both positioned upstream of the core engine, and are arranged to be driven in opposite directions by a gear assembly. The gear assembly is positioned axially between the upstream fan and downstream fan. The booster compressor is positioned upstream of the upstream fan and downstream fan, and comprises a first rotor carrying blades and a second rotor carrying blades. The first rotor is driven with the upstream fan and the second rotor is driven by the turbine of the core engine in opposite direction to the first rotor.

Turbine cooling for gas turbine engine

Abstract: A gas turbine engine cooling system has cooling air cooling in order, the first stage disk (50) and blades (22), the second stage vanes (24), and the second stage air seal (82). Air passes to the second stage vane from the rotor through a reaction nozzle (62) effecting a reaction stage adding energy to the rotor and cooling the air.

Wind turbine blade attachment methods

Abstract: A rotor blade for a horizontal axis wind turbine wherein a multiplicity of sucker rods are utilized internally of the blade root for securing the blade to the rotating hub of the turbine including the method of attaching the blade root to the hub and the method of making the blade root.

Gas turbine combustion apparatus

Abstract: A gas turbine cooling apparatus is disclosed in which a flow sleeve is provided to surround a combustor liner and a tail pipe substantially over their full length. A group of small holes for impinge-cooling an outer wall of the tail pipe are formed in a region of the flow sleeve close to a turbine. Further, opening portion for introducing cooling air are provided closer to the combustor liner than the small holes. Thus, the outer wall of the tail pipe and the wall of the combustor liner are cooled by the cooling air flowing between the tail pipe, the combustor liner and the flow sleeve.

Variable geometry turbocharger turbine

Abstract: A variable geometry turbine system for internal combustion engine turbochargers is provided which comprises a turbine wheel and a meridionally divided volute having first and second volute passageways defining first and second turbine inlet openings for the flow of exhaust gas from the passageways into the turbine wheel. The system further includes closure means movable betwen a first position in which both from both volute passageways to flow into the turbine turbine inlet openings are open to permit exhaust gas wheel to provide a mixed-flow turbine during periods of high engine speed; and a second position closing the first turbine inlet opening to permit exhaust gas from only the second volute passageway to flow into the turbine wheel to provide an axial-flow turbine during periods of reduced engine speed. The closure means of the system can further include valve means for diverting during periods of reduced engine speed. The turbine all exhaust gas flow into the second volute passageway system is simple in construction, durable, low in cost and provides efficient engine operation over a full range of engine speeds.

Aircraft engine frame construction

Abstract: A gas turbine engine of the type having generally cylindrical casings defining concentric bypass and turbine discharge passages including a support structure in the turbine discharge passage. The support structure is cooled with low pressure compressor discharge air through a scoop located in the bypass gas passage. The support structure includes a plurality of radial fairings, each of which includes a discharge chute which is approximately perpendicular to its respective fairing. The discharge chutes each communicate with the compressor discharge cool air flow in its respective fairing so as to provide a discharge flow in the form of a stratified annulus to cool downstream members which are aligned with the discharge chutes. The cooling air further reduces the temperature of the downstream gases so as to reduce the potential for flashback in the engine. The aerodynamic form and placement of the discharge chutes provide enhancements to the operation of the diffuser, of which the support structure is a part.

Compressed air turbomachinery cycle with reheat and high pressure air preheating in recuperator

Abstract: A peaking/intermediate power plant is disclosed having a compression mode in which air is compressed and stored in a storage device and an expansion mode in which such stored compressed air is initially pre-heated by exhaust gas in a recuperator, expanded without combustion in a high pressure turbine, combined with fuel and combusted in a low pressure combustor, expanded in a low pressure turbine, and supplied to the recuperator as exhaust gas of sufficient temperature to heat the compressed air enough to eliminate the need for is combustion prior to supply to the high pressure turbine.

Flow pulsing apparatus with axially movable valve

Abstract: Flow pulsing apparatus is adapted to be connected in a drill string above a drill bit. The apparatus includes a housing providing a passage for a flow of drilling fluid toward the bit. A turbine in the housing is rotated about an axis by the flow of drilling fluid. A valve is operated by the turbine to periodically restrict the flow through the passage to create pulsations in the flow and a cyclical water hammer effect to vibrate the housing and the drill bit during use. A cam is provided for effecting reciprocation of the valve along the axis of rotation of the turbine to effect the periodic restriction of flow.

Inverter operated turbine engine starting system

Abstract: Engine start capability may be added to an aircraft generating system including a variable speed, constant frequency inverter (34) by placing transistors (48) in shunt relation to diodes (22) forming part of a full wave rectifier for rectifying A.C. power from a brushless generator output winding (10) which is normally supplied to the inverter (34) for conversion to constant frequency A.C. power. A source of D.C. power (60) may be connected to the diodes (22) and transistors (48) and the latter are operated by an inverter controller (52) to convert the D.C. power so provided to alternating current to be fed to the brushless generator output windings (10) and cause the brushless generator to operate as an A.C. motor for the starting of a turbine engine (18) or the like.

Governed vane wind turbine

Abstract: Wind energy converting machine comprising a solid rotating ring carrying airfoils which are governed to have an optimal angle of attack to the wind approaching each of them when the wind velocity is below a chosen limit In stronger wind the angles of attack are decreased to limit the power uptake The ring is supported by stationary rollers which act as friction wheels to transfer the power to electric generators or the like An example is described in which 90 airfoils, 30 meters high and with 36 meters root chord, perform a track of 200 meters diameter, at a speed of 8 m/sec This turbine is calculated to produce 375 megaWatt in a wind of a velocity of 10 m/sec or higher

The effects of inlet turbulence and rotor/stator interactions on the aerodynamics and heat transfer of a large-scale rotating turbine model, volume 1

Abstract: A combined experimental and analytical program was conducted to examine the effects of inlet turbulence on airfoil heat transfer. Heat transfer measurements were obtained using low conductivity airfoils with miniature thermocouples welded to a thin, electrically heated surface skin. Heat transfer data were acquired for various combinations of low or high inlet turbulence intensity, flow coefficient (incidence), first-stator/rotor axial spacing, Reynolds number, and relative circumferential position of the first and second stators. Aerodynamic measurements include distributions of the mean and fluctuating velocities at the turbine inlet and, for each airfoil row, midspan airfoil surface pressures and circumferential distributions of the downstream steady state pressures and fluctuating velocities. Analytical results include airfoil heat transfer predictions and a examination of solutions of the unstead boundary layer equipment.

Wind energy convertor

Abstract: Apparatus for converting the energy of the wind into mechanical energy for use in the generation of electricity comprises an upstanding column a fan which is freely rotatably mounted on the column and which comprises circumferentially spaced, radially extending blades and, supported by and freely rotatable about the axis of the column, a turbine which surrounds and is radially spaced from the column and which comprises circumferentially spaced blades extending lengthwise with respect to the column. Preferably, an annular body is supported by the column and has an upper surface of such a shape as to encourage laminar flow of the wind over its surface. Preferably, also, over an upper part of its length immediately below the fan the column has circumferentially spaced, helically extending fins 4 defining passages wind being caused to flow upwardly within the passages to form a vortex. Circumferentially spaced blades depending from the annular body define, between adjacent blades, venturi through which wind is directed on to the blades of the turbine.

Turbo-machine with device for automatically controlling the rate of flow of turbine ventilation air

Abstract: A device for automatically controlling the rate of flow of turbine ventilation air in a turbo-machine comprises two superimposed ceramic rings which are split and are each fixed at a single point to a metal support so that differential expansion of the support and the two rings in response to the operating conditions of the turbo-machine causes the registry of peripherally disposed slots in the ceramic rings to vary and thereby control the rate of ventilation air flow therethrough in accordance with the turbo-machine operating conditions.

Starter-generator for engines

Abstract: Inefficiencies in electrical starter-generator systems for turbine engines are avoided in a construction including a dynamoelectric machine 16 operable as a motor or as a generator and having a rotor 26, a hydraulic torque converter 70 including an impeller 80 connected to the rotor 26 and a turbine 86. A system 94, 96 is provided for selectively providing hydraulic fluid to the torque converter 70 and a constant speed drive 112, 142, 144 is included. Overrunning clutches 108 and 158 interconnect the turbine 86 and an input for the constant speed drive for allowing the input to overrun the turbine 86 but not the reverse, and for interconnecting the rotor 26 and an output 130 of the constant speed drive for allowing the rotor 26 to overrun the output 130.

Exergy Analysis of Combined Cycles: Part 1—Air-Cooled Brayton-Cycle Gas Turbines

Abstract: Quantitative analytical tools based on the second law of thermodynamics provide insight into the complex optimization tradeoffs encountered in the design of a combined cycle. These tools are especially valuable when considering approaches beyond the existing body of experience, whether in cycle configuration or in gas turbine cooling technology. A framework for such analysis was provided by the author [1-3] using simplified, constant-property models. In this paper, this theme is developed to include actual chemical and thermodynamic properties as well as relevant practical design details reflecting current engineering practice. The second-law model is applied to calculate and provide a detailed breakdown of the sources of inefficiency of a combined cycle. Stage-by-stage turbine cooling flow and loss analysis calculations are performed using the GASCAN program and examples of the resulting loss breakdowns presented. It is shown that the dominant interaction governing the variation of cycle efficiency with turbine inlet temperature is that between combustion irreversibility and turbine cooling losses. Compressor and pressure-drop losses are shown to be relatively small. A detailed analysis and loss breakdown of the steam bottoming cycle is presented in Part 2 of this paper.

Combined auxiliary and emergency power unit

Abstract: Weight and spatial concerns in aircraft are alleviated or minimized through a combined auxiliary and emergency power unit including a gear box 10 adapted to drive a generator 16 and a hydraulic pump 18 as auxiliary to emergency power supplies for the aircraft. The system includes a pair of turbine wheels 22 and 24 along with a pair of motion transmitting paths 12, 26, 42; 14, 68, each including a selectively operable clutch 42, 68 so as to connect the turbine wheels 22, 24 to the gear box 10 in mechanical parallel. A rotary compressor 28 is connected to one of the turbine wheels 22 and an associated combustor 46 provides combustion gas to the turbine wheel 22 for auxiliary power unit operation. A pressure tank 56 for compressed oxidant and an additional combustor 60 are utilized to provide combustion gas to the other turbine wheel 24 in an emergency power unit mode of operation.

Methods and apparatus for ocean thermal energy conversion using metal hydride heat exchangers

Abstract: Methods and apparatus for ocean thermal energy conversion using metal hydride heat exchangers to power a turbine by desorbing and absorbing hydrogen gas. Heat exchangers are alternatively floated to the ocean surface to warm the metal hydride bed or sunk to the bottom to cool the bed. The turbine powers an electric generator which produces electricity which may be utilized directly, stored in a superconducting magnet, used to desalinate water, or used to power the electrolysis of water in order to produce hydrogen for use as a fuel.

Axial flow turbine

Abstract: In an axial flow gas turbine with reaction blading, whose outlet rotor blades (14) are followed by a diffuser with axial outlet into an exhaust gas pipe (13), the kink angles of the diffuser inlet both at the hub (10) and at the cylinder (9) are fixed exclusively for the purpose of evening out the energy profile over the duct height at the outlet from the last rotor blade row in order to shorten the diffuser system and to optimise it in part load operation. In addition, a mechanism provided to remove swirl from the swirling flow in the form of profile ribs (17). Where the outlet rotor blades have a high Mach number flow, which leads to a large opening angle of the blading, the diffuser is subdivided into several partial diffusers (16) via sheet metal guides (15).

Method and apparatus for controlling temperatures of turbine casing and turbine rotor

Abstract: A method and apparatus for controlling a temperature of a turbine casing and a turbine rotor in a gas turbine, which method and apparatus enables a maintaining of an optimum gap at a tip end of the rotor blades of the gas turbine over an entire operating range by independently controlling the amounts of heat energy supplied to a space of the turbine casing and the turbine rotor.

Turbine monitoring apparatus

Abstract: A turbine monitoring device is provided for interfacing the control panel of a gas turbine with a standard personal computer. The interface device includes a plurality of isolation circuits for isolating the personal computer from the turbine control panel to prevent ground faults. The interface device also includes scaling circuits to allow a selectable scaling factor to be provided to prefetermined operating signals. The interface device is adapted to receive operating signals from the control panel of the turbine and convert the operating signals into data signals which are suitable for use by the data processor. The interface device of the present invention may be used in conjunction with a variety of data processors which are readily available.

Flexible tethered wind turbine

Abstract: This invention relates to a flexible tethered wind turbine useful, among other things, for generating electricity. A flexible shaft supported by guy wires is provided at its upper end with a flexible rotor and an airfoil assembly. Rotation of the airfoils in response to wind creates centrifugal force and tension which causes the rotor to become rigid during use. The light flexible shaft easily follows the rotating sails, which permits the entire turbine to automatically track the wind as it changes direction. As the rotor spins, its rotational energy is transferred to the shaft, which rotates along its entire flexible length.

Nonlinear Dynamics of Rotor/Blade/Casing Rub Interactions

Abstract: This paper considers the transient analysis of rub problems in high-speed rotating equipment that involve interactions between the rotor, blades, and casing. Special emphasis is given to ascertaining the participation characteristics of turbine/impeller blades during the overall rub event. To generalize the scope of the work, single and multiple blade rub events are considered including the effect of such system parameters as imbalance magnitude, blade/rotor stiffness, system damping, and rub interface friction characteristics.

Performance of a High-Efficiency Radial/Axial Turbine

Abstract: This paper presents the test performance of a lightly loaded, combination radial/axial turbine for a 420-hp, two-shaft gas turbine. This two-stage turbine configuration which included an interstage duct and an exhaust duct discharging vertically to ambient pressure conditions, was shown to be capable of attaining an overall isentropic efficiency of 89.7 percent. The influence of exhaust diffuser struts on the turbine performance under stalled power turbine conditions was shown to significantly affect compressor and turbine matching.

Method and apparatus for automatically index testing a kaplan turbine

Abstract: Method and apparatus for automatically determining the set of optimal operating angles for the variable pitch blades of a Kaplan-type turbine which has movable gates and is controlled by a governor and an electronic 3D cam. The governor controls the gates so as to maintain the turbine at a predetermined setpoint power generation level, and on-cam values of particular operating parameters of the turbine are measured. When evaluation of the measured data indicates that the turbine is in a steady-state condition, the blades are moved through a series of incremental off-cam variations in pitch. Following each incremental pitch variation of the blades, the governor repositions the gates to return the turbine to the predetermined setpoint power generation level. The operation of the turbine is then monitored, and values of particular operating parameters are measured at the new gate-blade operating point once the turbine has returned to steady-state. An efficiency value is computed for each of the measured operating points and are compared to identify a peak efficiency value.

Tubocharger with variable vane

Abstract: A turbocharger having a plurality of adjustable vanes for varying gas flow to the turbine impeller of the turbocharger so as to vary the output power of the turbine. In a preferred embodiment, the turbocharger comprises a turbine empeller and a compressor impeller mounted for rotation on a common shaft. The turbocharger also includes a inlet turbine housing defining a volute shaped toroid about the periphery of the turbine impeller and having a generally circular opening forming a mating surface. An outlet turbine housing is secured to the turbine inlet housing and projects into the opening of the turbine inlet housing so as to define at least one bore. The turbocharger includes at least one vane comprising an airfoil portion, and integral shaft portion projecting from the airfoil portion, and an actuating arm portion extending from the shaft portion and having an integral pin portion. The airfoil portion is located between the volute shaped toroid and the periphery of the turbine impeller and the shaft portion is rotatably mounted in the bore. An actuating ring having a slot engaging the pin portion is provided to rotate the vane shaft portion so as to vary the orientation of the airfoil portion.

Turbine nozzle mounting arrangement

Abstract: The invention comprises a turbine nozzle and nozzle support assembly in which a turbine nozzle support seating flange is positioned adjacent to a turbine nozzle mounting flange and pins are used to affix the turbine nozzle to the nozzle support. Retainer strips are installed into the nozzle support to trap the pins in engagement with the mounting and seating flanges. In the preferred embodiment of the invention seal means is provided for restricting the airflow through the completed turbine nozzle and nozzle support assembly.