Showing papers on "Ram air turbine published in 2015"

Dual dissimilar engines for an aircraft

Abstract: A system and method for controlling a tail-sitter aircraft, includes determining a mode of operation for the aircraft; operating each of a large turbine engine and a small turbine engine to provide total aircraft power during hover or high-power mode of operation; and selectively providing aircraft power from the small turbine engine to a plurality of rotors during a long-range endurance cruise mode of operation.

Transient Simulations of a T100 Micro Gas Turbine Converted Into a Micro Humid Air Turbine

Abstract: Micro Gas Turbines (mGTs) have arisen as a promising technology for Combined Heat and Power (CHP) thanks to their overall energy efficiencies of 80% (30% electrical + 50% thermal) and the advantages they offer with respect to internal combustion engines. The main limitation of mGTs lies in their rather low electrical efficiency: whenever there is no heat demand, the exhaust gases are directly blown off and the efficiency of the unit is reduced to 30%. Operation in such conditions is generally not economical and can eventually lead to shutdown of the machine. To address this issue, the mGT cycle can be modified so that in moments of low heat demand the heat in the exhaust gases is used to warm up water which is then re-injected in the cycle, thereby increasing the electrical efficiency. The introduction of a saturation tower allows for water injection in mGTs: the resulting cycle is known as a micro Humid Air Turbine (mHAT).The static performance of the mGT Turbec T100 working as an mHAT has been characterised through previous numerical and experimental work at Vrije Universiteit Brussel (VUB). However, the dynamic behaviour of such a complex system is key to protect the components during transient operation. Thus, we have modelled the Turbec T100 mHAT with the TRANSEO tool in order to simulate how the cycle performs when the demanded power output fluctuates. Steady-state results showed that when operating with water injection, the electrical efficiency of the unit is incremented by 3.4% absolute. The transient analysis revealed that power increase ramps higher than 4.2 kW/s or power decrease ramps lower than 3.5 kW/s (absolute value) lead to oscillations which enter the unstable operation region of the compressor. Since power ramps in the controller of the Turbec T100 mGT are limited to 2kW/s, it should be safe to vary the power output of the T100 mHAT when operating with water injection.Copyright © 2015 by ASME

T100 Micro Gas Turbine Converted to Full Humid Air Operation: A Thermodynamic Performance Analysis

Abstract: Waste heat recovery has become more and more important for the profitability of small-scale Combined Heat and Power (CHP) plants like micro Gas Turbines (mGTs). Adding a saturation tower to the mGT unit is such a waste heat recovery route. The cycle includes the saturation tower after the compressor to humidify the compressed air. Simulations show that this cycle, known as the micro Humid Air Turbine (mHAT), increases mGT electric efficiency by 7% relatively (2% absolute), improving the general economic performance. The mHAT concept with saturation tower was however never tested experimentally. To show the potential of the cycle, the Turbec T100 mGT of the University of Brussels was converted into a mHAT cycle by adding a spray saturation tower to the system. In this paper, we present the results of several water injection tests in the T100 mGT at part and nearly nominal load. The water injection experiments resulted in stable mGT operation at reduced rotational speed and pressure ratio and increased electric efficiency. Experimental results showed a reduced fuel mass flow rate by 4.3% and a relative electric efficiency increase of 4.8% for the different experiments. In addition, the impact of the water on the other turbine parameters has been studied.Copyright © 2015 by ASME

Floating breakwater doubling as wave power generation device

Abstract: The invention relates to the technical field of breakwater engineering and wave power generation, in particular to a floating breakwater generation device arranged in open sea. The floating breakwater generation device comprises floating members, air turbine generator sets, air chambers, airflow passages, mooring systems and signal transmission devices, and is characterized in that the floating members are respectively connected with concrete anchor blocks at the sea bottom through anchor chains; a plurality of wave dissipating perforations penetrating through a floating body are formed in the head-sea face of each floating member; the air turbine generator sets are respectively arranged in the airflow passages; the floating bodies are driven by waves to vertically move, so that water in the air chambers vibrates and air in the air chambers is pushed to move, and the air turbine generator sets are further driven to generate electricity. The floating breakwater generation device disclosed by the invention has the characteristics of being stable in structure, low in erection cost, high in generation conversion efficiency, convenient to maintain, and the like, and can be applied to sea areas with deep water, high waves and complex terrain; while wave impacts are weakened and a steady water area environment is provided for surrounding water areas, the waves can be converted into electric energy, and the electric power supply problem of harbor district or island residents is effectively solved.

Design and evaluation of a high-speed and precision microspindle

Abstract: This study presents the design and evaluation of a high-speed and precision microspindle used for micromechanical machining. A radial impulse turbine with two rows of nozzles was designed to realize the high-speed performance. A monolithic flexible coupling was used to decouple the turbine shaft and the tool, and then, the tool shank was directly supported by aerostatic bearings, which can minimize the run-out of the tool at high speeds. Additionally, a shape memory alloy (SMA)-based clamp was designed for tool clamping. It can avoid the assembly error caused by stack-up tolerances. The microspindle has simple configuration and compact design with a 30-mm outer diameter and a 95-mm length. The prototype microspindle has a maximum speed of over 240,000 rpm and a tool radial run-out of 2.79 μm. The evaluation results show the feasibility and potential application of the new design concept of the microspindle proposed in this study.

Method for assisting a turboshaft engine in standby of a multiple-engine helicopter, and architecture of a propulsion system of a helicopter comprising at least one turboshaft engine that can be in standby

Abstract: The invention relates to an architecture of a propulsion system of a multiple-engine helicopter comprising turboshaft engines (5, 6), characterised in that it comprises: at least one hybrid turboshaft engine (5) that is capable of operating in at least one standby mode during a stable flight of the helicopter, the other turboshaft engines (6) operating alone during this stable flight; an air turbine (30) that is mechanically connected to the gas generator (17) of the hybrid turboshaft engine (5) and is suitable for rotating said gas generator (17); means for withdrawing pressurised air from the gas generator (27) of a running turboshaft engine (6); and a duct (31) for routing this withdrawn air to said air turbine (30).

Combined circulating energy supply system

Abstract: The invention provides a combined circulating energy supply system and belongs to the technical field of heat energy utilization and heat pumps. An air turbine device forward circulating system is formed by an air compressor, a boiler and an air turbine mechanism. A compressing type reverse circulating system is formed by a compressor, a second compressor, a second condenser, an evaporator, a low-temperature throttling valve, a second low-temperature throttling valve and a low-temperature heat exchanger. An absorbing type reverse circulating system is formed by an absorber, a generator, a condenser, the evaporator, a throttling valve, a solution pump and a solution heat exchanger. Air turbine device forward circulation supplies power to compressing type reverse circulation, and supplies driving heat loads to absorbing type reverse circulation. Compressing type reverse circulation obtains low-temperature heat loads, supplies heat outwards through the second condenser and supplies heat to absorbing type reverse circulation through the evaporator. Absorbing type reverse circulation supplies heat outwards through the absorber and the condenser, and the combined circulating energy supply system is formed.

The One-Dimensional Meanline Design of Radial Turbines for Small Scale Low Temperature Organic Rankine Cycles

Abstract: This paper presents a complete radial turbine design methodology intended for the design of a small scale organic Rankine cycle (ORC) turbo expander. The design methodology is comprised of 1D meanline design, coupled with REFPROP for real fluid properties, and 3D geometrical construction of the turbine rotor, stator and volute. A novel method to predict the rotor passage velocity distribution also enables the rotor passage to be effectively designed to ensure a smooth expansion without requiring CFD analysis. The design method is used to construct two test turbines with target isentropic total-to-static efficiencies of 85%. The first expands air from 282.3kPa and 1073K with a total-to-static pressure ratio of 3 and mass flow rate of 0.1kg/s. The ORC turbine expands R245fa from 350K and 623kPa, with a pressure ratio of 2.5 and mass flow of 0.7kg/s. Comparison with design point CFD validates the turbine design program, predicting a mass flow rate of 0.104kg/s for the air turbine at the design point with a total-to-static isentropic efficiency of 84.73%. At the design mass flow rate and rotational speed, the ORC turbine achieves a total-to-static pressure ratio of 2.51 and a total-to-static isentropic efficiency of 84.87%.

Humid Air Turbine Power, Water Extraction, and Refrigeration Cycle

Abstract: Various embodiments relate to combined heat and power (CHP) systems. A CHP system can include a turbine system, a turbocharger system, and a refrigeration system. The refrigeration system can receive combustion products from the turbine system and compressed air from the turbocharger system. The refrigeration system can cool the combustion products and the compressed air to generate a cooled combustion product mixture that is provided to the turbine system.

Over-rating control of a wind turbine generator

Abstract: A method is disclosed for controlling a wind turbine generator to provide power above a rated level. The wind turbine includes one or more electrical components that conduct current from the internal generator to supply the external grid. The control method calculates the maximum current that the electrical components can carry at the ambient temperature. The calculated current is combined with a measurement of the voltage and an estimate of reactive power in the system to give a maximum power at which the wind turbine can operate without the maximum allowable current being exceeded for the electrical components. The electrical components may be housed in the main electrical panel of the wind turbine.

Numerical modelling and control of an oscillating water column wave energy converter

Abstract: An oscillating water column (OWC) wave energy converter (WEC) is a device designed to extract energy from waves at sea by using the water to move trapped air and thus drive an air turbine. Because the incident waves and the force caused by the power take-off (PTO) interact, control of the power take off (PTO) system can increase the total energy converted. A numerical model was developed to study the interaction of an OWC with the water and other structures around it. ANSYS TM AQWA R © is used here to find the effects on the water surface in and around the central column of a five-column, breakwater-mounted OWC. For open OWC structures, coupled modes were seen which lead to sensitivity to incident wave period and direction. The frequency-domain displacements of the internal water surface of the central column were turned into a force-displacement, time-domain model in MATLAB R © Simulink R © using a state space approximation. The model of the hydrodynamics was then combined with the thermodynamic and turbine equations for a Wells turbine. A baseline situation was tested for fixed turbine speed operation using a wave climate for a region off the north coast of Devon. A linear feedforward controller and a controller based on maximising turbine efficiency were tested for the system. The linear controller was optimised to find the combination of turbine speed offset and proportional constant that gave maximum energy in the most energy abundant sea state. This increased the converted energy by 31% in comparison to the fixed speed case. For the turbine efficiency control method, the increase was 36%. Energy conversion increases are therefore clearly possible using simple controllers. If increased converted energy is the only criterion for controller choice, then the turbine efficiency control is the best method, however the control action involves using very slow turbine speeds which may not be physically desirable.

Air turbine starter systems including gearbox-integrated clutch modules and gas turbine engines employing the same

Abstract: Air Turbine Starter (ATS) systems are provided, as gas turbine engines including ATS systems. In one embodiment, a gas turbine engine includes an accessory gearbox (AGB) and an integrated Air Turbine Starter (ATS) system. The AGB includes a gearbox gear train within a gearbox housing. The integrated ATS system is removably installed on the AGB and includes an ATS having an air turbine and an output shaft coupled thereto. An ATS clutch module is coupled to the ATS output shaft. The ATS clutch module is further within the gearbox housing and mechanically couples the ATS output shaft to the gearbox gear train when the integrated ATS system is installed on the AGB.

Floating breakwater doubling as wave energy power generation device

Abstract: The utility model relates to the technical field of breakwater engineering and wave power generation. A floating breakwater doubling as a wave energy power generation device comprises a floating member, an air turbine generating set, an air chamber, an air flow passage, an anchoring system and a signal transmission device, and is characterized in that the floating member is connected with a concrete anchor block at the sea bottom through an anchor chain, wherein a wave approach side of the floating member is provided with a plurality of wave dissipating holes penetrating through a floating body; the air turbine generator is arranged in the air flow passage; the floating body is driven by wave to move up and down, so water in the air chamber oscillates and pushes air in the air chamber to move so as to push the air turbine generating set to generate power. The floating breakwater has the characteristics of stable structure, low construction cost, high power generation conversion efficiency, convenience in maintenance and the like, and can be applied to deep sea areas with huge wave and complex terrain, the wave energy can be converted into electric energy while the influence of wave is reduced to provide a stable water area environment for the surrounding sea area, and the problem of power supply of harbor area or island residents is effectively solved.

Utilize the generator of wave energy

Abstract: The utility model provides an utilize the generator of wave energy, includes air slide room (2), empty air turbine (9) and generator (10), its characterized in that, air slide room (2) are including triumph ejector pad (1), connecting rod (12), piston (5), last valve body (3), lower valve body (4), ejector pad (1) the bottom with connecting rod (12) fixed connection, connecting rod (12) bottom fixed connection said piston (5), piston (5) and air slide room (2) phase-match, a go up valve body (3) is provided on the piston (5), air slide room (5) inside bottom is equipped with down valve body (4), air slide room (2) bottom is equipped with air collecting box (7), air collecting box (7) one side is equipped with sky air turbine (9), empty air turbine (9) one side electric connection generator (10). The utility model relates to an utilize the generator of wave energy can simultaneously through the air check valve, can utilize the potential energy electricity generation of wave through the high-efficient electricity generation of wave potential energy completely, and in addition, the instability of traditional oscillating water column type generator has been avoided to the indoor spring that is equipped with of air slide.

Air inlet structure for fuel nozzle of gas turbine

Abstract: The invention relates to the technical field of gas turbines, and provides an air inlet structure for a fuel nozzle of a gas turbine. The air inlet structure comprises a center air channel and a fuel cavity which are communicated with each other, and the center air channel is used for connecting the air into the fuel cavity. A nozzle hanging flange is arranged at one end of the center air channel, the nozzle hanging flange is provided with a plurality of air inlet channels used for connecting the air into the center air channel, and the air inlet channels are evenly distributed in the circumferential direction of the nozzle hanging flange. Each air inlet channel is provided with an adjusting mechanism, and each adjusting mechanism is used for limiting the size of the minimum flow area of the corresponding air inlet channel. Each adjusting rod can be adjusted independently, the speed distribution of the air on the head portion of a combustion chamber is effectively improved, the mixing effect of fuel and the air is improved, hence, tempering can be effectively prevented from happening at a nozzle outlet, and the reliability of the nozzle is improved. The air flow can be steplessly adjusted, stepless speed change of the air turbine can also be achieved, and the fuel can be fully burnt ultimately.

A control system for a wind turbine generator

Abstract: The invention relates to a control system for a wind turbine generator, WTG. The control system defines reactive limits for a reactive power reference for the WTG. The reactive limits are defined as a function of a physical parameter, e.g. the output voltage of the WTG. In case the reactive power reference exceeds the predefined limits, the reactive power reference is limited. By limiting the reactive power reference output voltages which exceed certain output voltage limits may be avoided and, thereby, a disconnection of the WTG from the grid may be avoided.

Magneto-aerostatic bearing for miniature air turbine

Abstract: Under the circumstance of pursuing high speed and miniaturization, mini-type air turbines have been widely applied to high-speed dental handpieces in recent years. Among all the components of a mini-type air turbine, bearing is the most important part which significantly affects its efficiency. Friction, collision, and wear are the main causes to make the ball bearing unable to reach higher efficiency. Though very small sliding friction can be realized by the aerostatic bearing, its poor bearing capacity limits the application. This research combines the magnetic and aerostatic levitation principle to develop a magneto-aerostatic hybrid bearing for miniature air turbine. The aerostatic bearing undertakes the main function of the radial and the axial bearings. However, the air bearing also possesses a drawback, which is pneumatic hammer effect induced by the air compressibility. In order to eliminate the pneumatic instability, an axial passive magnetic bearing is integrated into the aerostatic bearing. With the magnetic bearing, not only the bearing capacity can be improved, but also the pneumatic hammer effect can be significantly damped. Both theoretical calculation and finite element method (FEM) are used to study the cause and elimination solution of the pneumatic instability. Through experimental testing, the performance of our developed magneto-aerostatic bearing is also verified. The magneto-aerostatic bearing suppresses the axial vibration over 57%, and also enhances its axial bearing capacity by 50%.

Floating type offshore wind plant wave energy auxiliary power generation device

Abstract: The invention relates to a device for generating power through natural energy, in particular to a floating type offshore wind plant wave energy auxiliary power generation device The floating type offshore wind plant wave energy auxiliary power generation device is structurally characterized in that a plurality of gas chambers are formed in inner cavities of floating platforms and are sequentially connected with the gas inlet chamber as the head and the gas outlet chamber as the tail, a vent hole is formed between every two adjacent gas chambers and provided with a ventilation check gas valve, and a water chamber is arranged below each gas chamber and communicated with seawater; two ventilation holes are formed between each gas chamber and the corresponding water chamber, and the floating platforms are connected; a gas outlet of the floating platform in the front is connected and communicated with a gas inlet of the floating platform behind through a pipeline; compressed gas flow is connected to an air turbine through a gas flow channel, and the air turbine is connected with a rotating shaft of an AC power generator The floating type offshore wind plant wave energy auxiliary power generation device has the advantages that the offshore wind power generation type and the wave energy power generation type are comprehensively utilized, the wave energy is effectively combined into deep sea wind power, the power compensation under the complex environment is achieved, the power output stability is ensured, and the grid connection is facilitated

Design of an Air-Starter Turbine and Starting Performance Prediction Through the Numerical Analysis

Abstract: To get the required power, a procedure for starting an engine is required For an engine of the large ship or land-based power plant, two kinds of mechanisms exist: one is to use an electric motor and the other air-starter As one of the starting methods of heavy-duty engines, the air-starter gives rotating power from the blade lifting force by the compressed air flow through the turbine to rotate the stopped engine Since the air turbine has a large weight-to-power ratio, simple structure and is spark-free, many heavy-duty engine are equipped with this device for their starting process In order to get high enough power required to rotate the engine up to sufficient speed in a short time, high instantaneous torque is required An impulsive supersonic turbine can be applied for this purpose In this case, an one-stage air turbine with a minimum length convergent-divergent nozzle and transition arc shaped rotor was utilized to reduce shock loss The performance of the desired turbine is evaluated numerically and compared with experimental results The spin-down test is performed to estimate the performance of the designed turbine and numerical analysis is performed using the commercial tool ANSYS CFX© 2015 ASME

Solar moist air circulating electricity-water cogeneration system

Abstract: The invention discloses a solar moist air circulating electricity-water cogeneration system which comprises an immersion bubbling distiller, a fed seawater pipeline, a condenser, a low-pressure compressor, an intercooler, a high-pressure compressor, a heat regenerator, a tower type solar superheater, a high-pressure moist air turbine, a tower type solar reheater, a low-pressure moist air turbine and an electric generator Original seawater is subjected to two-level preheating through the intercooler and the condenser and then is conveyed into the immersion bubbling distiller; external air is subjected to two-level compressor and then enters the heat regenerator to be warmed, and then the external air is sprayed into the seawater to be heated and mixed; formed moist and hot air is heated by the tower type solar superheater and then sent to the moist air turbine for acting and power generation; waste heat of exhausted steam is discharged through the heat regenerator and the condenser, and water steam in moist air is condensed into fresh water which is then output The Brayton cycle and the immersion bubbling distilling technology are coupled, and the solar moist air circulating electricity-water cogeneration system has the characteristics of being good in distilling performance, high in overall power generating efficiency, high in circulating heat efficiency and wide in application range, and can be widely applied to the field of solar electricity-water cogeneration

Solar thermal power generation method and device

Abstract: The invention relates to a solar thermal power generation method and device. The method adopts an operation mode of overlapping top Britten circulation and bottom Britten circulation, and adopts air as a circulation working medium. After the air is pressurized by a top circulation air compressor, the air is fed into a cavity type receiver of a solar heat collecting device for absorbing heat; and the air, with higher temperature, discharged by a high-temperature air turbine in the top Britten circulation is used as a heat source of the bottom Britten circulation, thereby to forming an overlapped solar thermal power generation system. The device can effectively improve the solar thermal power generation efficiency, is excellent in unit safety and economy, and is specifically suitable for water-deficient areas.