Showing papers on "Gas compressor published in 2003"

Acoustic Analysis of Gas Turbine Combustors

Abstract: Combustion instability has become a major issue for gas turbine manufacturers. Stricter emission regulations, particularly on nitrogen oxides, have led to the development of new combustion methods, such as lean premixed prevaporized(LPP)combustion,to replacethetraditionaldiffusion e ame.However,LPPcombustionismuchmore liable to generate strong oscillations, which can damage equipment and limit operating conditions. As a tutorial, methods to investigate combustion instabilities are reviewed. Theemphasis is on gas turbine applications and LPP combustion. The e ow is modeled as a one-dimensional mean with linear perturbations. Calculations are typically done in the frequency domain. The techniques described lead to predictions for the frequencies of oscillations and the susceptibility to instabilities for which linear disturbances grow expotentially in time. Appropriate boundary conditions are discussed, as is the change in the linearized e ow across zones of heat addition and/or area change. Many of the key concepts are e rst introduced by considering one-dimensional perturbations. Later higher-order modes, particularly circumferential waves, are introduced, and modal coupling is discussed. The modeling of a simplie ed combustion system, from compressor outlet to turbine inlet, is described. The approaches are simple and fast enough to be used at the design stage.

Combined rankine and vapor compression cycles

Abstract: An organic rankine cycle system is combined with a vapor compression cycle system with the turbine generator of the organic rankine cycle generating the power necessary to operate the motor of the refrigerant compressor. The vapor compression cycle is applied with its evaporator cooling the inlet air into a gas turbine, and the organic rankine cycle is applied to receive heat from a gas turbine exhaust to heat its boiler within one embodiment, a common condenser is used for the organic rankine cycle and the vapor compression cycle, with a common refrigerant, R-245a being circulated within both systems. In another embodiment, the turbine driven generator has a common shaft connected to the compressor to thereby eliminate the need for a separate motor to drive the compressor.

Recuperated gas turbine engine system and method employing catalytic combustion

Abstract: A recuperated gas turbine engine system and associated method employing catalytic combustion, wherein the combustor inlet temperature can be controlled to remain above the minimum required catalyst operating temperature at a wide range of operating conditions from full-load to part-load and from hot-day to cold-day conditions. The fuel is passed through the compressor along with the air and a portion of the exhaust gases from the turbine. The recirculated exhaust gas flow rate is controlled to control combustor inlet temperature.

Refrigerating air-conditioner

Abstract: PROBLEM TO BE SOLVED: To eliminate machining for a compressor, to reduce a production cost, to dispense with high precision work for an accumulator, and to enhance productivity. SOLUTION: This air-conditioner provided with a plurality of the compressors a-d connected in parallel each other and having suction pipes 82a-82d, and an oil separator 11 for separating gaseous refrigerant from a refrigerator oil and used in common for the compressors a-d, so as to introduce the delivered refrigerant delivered from the compressors a-d to the common oil separator 11 is provided with oil returning means 51, 51a-51d for oil-returning the refrigerator oil separated by the oil separator 11 to the respective suction pipes 82a-82d of the compressors a-d, and contraction mechanisms 53a-53a for regulating a turn-back amount of the refrigerator oil to an amount required for each of the compressors, in a midway of the oil returning means. COPYRIGHT: (C)2003,JPO

Natural gas network modeling for power systems reliability studies

Abstract: The growth of power generation in Spain and several other countries is mainly based on the construction of combined-cycle power plants. As the number of this type of plants increases, the gas and electricity systems are linked together. Therefore, power system reliability studies should consider the gas supply reliability. As a consequence, the new generation of reliability models should take into account the joint operation of electrical and gas systems. This paper presents a model to compute the maximum amount of power that can be supplied by the combined-cycle power plants in a system. The gas network is modeled. The effect of compressors to enlarge the transmission capacity of the network is included. The developed model will be integrated into a higher level model that analyzes the joint reliability of the electrical and gas systems. A case study based on the Belgian high-calorific gas network is analyzed.

Microturbine engine system

Abstract: A microturbine engine that includes a compressor that is operable to provide a flow of compressed air. The compressed air flows through a recuperator where it is preheated before delivery to a combustor. The preheated compressed air mixes with a fuel and is combusted within the combustor to provide a flow of products of combustion. The flow of products of combustion pass through one or more turbines to drive the compressor and a synchronous generator. The synchronous generator is able to synchronize to a priority load, to the utility grid or to both depending on the mode of operation. A control system monitors various engine parameters as well as load and grid parameters to determine the desired mode of operation.

System and method for generation of electricity and power from waste heat and solar sources

Abstract: Recovery of electric power from low-grade waste heat/solar energy, comprising a closed-cycle charged refrigerant loop. Pressurized refrigerant fluid is pumped at ambient temperature through a heat exchanger connected to a waste heat/solar source to extract heat energy during conversion to a high pressure gas. Heated/pressurized refrigerant gas is inlet into an expander to power an output shaft during the expansion of the fluid to a cooled gas at approximately 0 psig. Cooled gaseous refrigerant is condensed to a liquid at low pressure and ambient temperature, and recycled under pressure to the heat exchanger. The expander is a reverse-plumbed gas compressor; the pressurized, hot refrigerant gas is inlet at what is ordinarily its outlet, and the normal inlet becomes the expander end. The refrigerant gas mass flow pressure/temperature drop spins the expander shaft for direct mechanical power take-off, or coupling to a synchronous or inductive generator to produce electricity.

Dual and hybrid EGR systems for use with turbocharged engine

Abstract: EGR systems for an internal combustion engine configured to operate using multiple-staged turbochargers, or a pair of single stage turbochargers, to provide exhaust gas recirculation to meet emissions requirements while not affecting engine performance. One or two EGR loops operating at low, intermediate, or high pressures may be employed. EGR exhaust gases may be taken directly from the exhaust manifold, or after the exhaust stream has passed through a turbocharger turbine. EGR exhaust gases may be injected at an intermediate pressure between stages of a multiple stage turbocharger, or alternatively between a low pressure turbocharger compressor and high pressure turbocharger compressor, before being boosted to a pressure high enough to ensure the desired mass flow to the engine and delivered to the intake manifold. Intake air may be pressurized prior to mixing with the EGR exhaust gases.

Integrated bypass turbojet engines for aircraft and other vehicles

Abstract: A turbo jet engine comprises a fan unit (10a) which combines a fan (11a), centrifugal compressor cells (11b), and turbine blades (11c). Air flowing through the centrifugal compressor cells (11b) is supplied to a peripheral combustor (12), and air flowing through the fan (11a) cools the air flowing through the compressor cells (11b) and bypasses the combustor (12). Turbine exhaust and bypass air are then ejected through a common nozzle (9).

Active Flow Separation Control of a Stator Vane Using Embedded Injection in a Multistage Compressor Experiment

Abstract: Micro-flow control actuation embedded in a stator vane was used to successfully control separation and improve near stall performance in a multistage compressor rig at NASA Glenn. Using specially designed stator vanes configured with internal actuation to deliver pulsating air through slots along the suction surface, a research study was performed to identify performance benefits using this microflow control approach. Pressure profiles and unsteady pressure measurements along the blade surface and at the shroud provided a dynamic look at the compressor during microflow air injection. These pressure measurements lead to a tracking algorithm to identify the onset of separation. The testing included steady air injection at various slot locations along the vane. The research also examined the benefit of pulsed injection and actively controlled air injection along the stator vane. Two types of actuation schemes were studied, including an embedded actuator for on-blade control. Successful application of an online detection and flow control scheme will be discussed. Testing showed dramatic performance benefit for flow reattachment and subsequent improvement in diffusion through the use of pulsed controlled injection. The paper will discuss the experimental setup, the blade configurations, and preliminary CFD results which guided the slot location along the blade. The paper will also show the pressure profiles and unsteady pressure measurements used to track flow control enhancement, and will conclude with the tracking algorithm for adjusting the control.

Study on a direct-expansion solar-assisted heat pump water heating system

Abstract: Analytical and experimental studies were performed on a direct-expansion solar-assisted heat pump (DX-SAHP) water heating system, in which a 2 m2 bare flat collector acts as a source as well as an evaporator for the refrigerant. A simulation model was developed to predict the long-term thermal performance of the system approximately. The monthly averaged COP was found to vary between 4 and 6, while the collector efficiency ranged from 40 to 60%. The simulated results were used to obtain an optimum design of the system and to determinate a proper strategy for system operating control. The effect of various parameters, including solar insolation, ambient temperature, collector area, storage volume and speed of compressor, had been investigated on the thermal performance of the DX-SAHP system, and the results had indicated that the system performance is governed strongly by the change of solar insolation, collector area and speed of compressor. The experimental results obtained under winter climate conditions were shown to agree reasonably with the computer simulation. Copyright © 2003 John Wiley & Sons, Ltd.

Hardware accelerated compression

Abstract: A compression system is arranged to use software and/or hardware accelerated compression techniques to increase compression speeds and enhance overall data throughput. A logic circuit is arranged to: receive a data stream from a flow control processor, buffer the data stream, select a hardware compressor (e.g., an ASIC), and forward the data to the selected hardware compressor. Each hardware compressor performs compression on the data (e.g., LZ77), and sends the compressed data back to the logic circuit. The logic circuit receives the compressed data, converts the data to another compressed format (e.g., GZIP), and forwards the converted and compressed data back to the flow control processor. History associated with the data stream can be stored in memory by the flow control processor, or in the logic circuit.

Oil free screw compressor

Abstract: A screw compressor includes a compressor main body, a male rotor having a screw-like male tooth shape and a female rotor having a screw-like female tooth shape meshing with the screw-like male tooth shape or the male rotor. The male and female motors are provided within the compressor main body. A motor casing is operably connected to the compressor main body, and a high speed electric motor provided within the motor casing. The motor includes a motor rotor, a motor stator and a motor shaft for driving at least one of the male and female rotors. A speed ratio of the motor shaft and the at least one of the male and female rotors driven by the motor shaft is in a range of 2:1 to 1:2.

Supercharger for internal combustion engine

Abstract: A first compressor (1 a) which supercharges intake air is provided in the intake passage (6, 20, 21) of an internal combustion engine (12). The first compressor (1 a) is driven by the exhaust gas energy of the engine (12). A second compressor (2 a) driven by an electric motor (2 b), and a bypass valve (3) which bypasses the second compressor (2 a), are provided in the intake passage (7, 20, 21) between the first compressor (1 a) and the engine (12). The bypass valve (3) shifts from the open state to the closed state according to the operation of the second compressor (2 a). At this time, the bypass valve (3) starts closing at some time after startup of the second compressor (2 a) so that the intake air amount of the engine (12) is not deficient.

Systems and methods for generating electrical power from solar energy

Abstract: Systems and methods capable of producing electrical power from solar energy through the use of air cycles without fossil fuel combustion. The system includes a solar receiver, a generator, a compressor, and an expander. The expander is coupled to the generator to drive the generator and coupled to the compressor to drive the compressor. The system uses solar generated heat from the solar receiver to heat compressed air from the compressor. The solar generated heat can be directly transferred from the solar receiver to the compressed air as the compressed air flows through receiver tubes of the solar receiver, or the solar receiver can transfer the solar generated heat to a liquid metal, with the liquid metal transferring thermal energy to the compressed air. The expander receives and expands the heated compressed air to drive the generator to produce electricity, and to drive the compressor to compress air.

Boosted air source heat pump

Abstract: A heat pump system is presented having a primary compressor, a booster compressor, a multi-step thermostat, an indoor coil, an outdoor coil, a refrigerant flow conduit connecting these elements is a closed loop system, and at least one pressure sensor positioned to always sense the refrigerant system low side pressure, which is commensurate with outdoor ambient air temperature in all heating modes of operation. The pressure sensor functions as an override and safety control to prevent or permit operation of the compressors, and also other system components, depending on outside air temperature. The primary compressor is preferably a multi-capacity compressor. A defrost energy transfer fluid is used in a defrost cycle.

Gas turbine apparatus

Abstract: A gas turbine apparatus is provided wherein a turbine is driven or rotated by burning a mixture of a fuel and compressed air and supplying a combustion gas generated by the combustion. A flameout determination unit is provided in the apparatus which is adapted to calculate the air/fuel ratio in the air/fuel mixture, correct the calculated air/fuel ratio to calculate a corrected air/fuel ratio which is substantially constant, compare the calculated corrected air/fuel ratio with a predetermined reference air/fuel ratio, and generate a signal indicative of occurrence of a flameout when the corrected air/fuel ratio is smaller than the reference air/fuel ratio. The corrected air/fuel ratio is calculated by calculating a deviation of a compressor discharge pressure of the compressed air from an air compressor, from a predetermined reference pressure, multiplying the pressure deviation by a predetermined constant, and adding the pressure deviation multiplied by the predetermined constant to the calculated air/fuel ratio. In this way, the corrected air/fuel ratio can be maintained substantially constant even if a load increases in steps.

Using Hydrogen as Gas Turbine Fuel

Abstract: This paper addresses the possibility to burn hydrogen in a large size, heavy–duty gas turbine designed to run on natural gas, as a possible short-term measure to reduce greenhouse emissions of the power industry. The process used to produce hydrogen is not discussed here: we mainly focus on the behavior of the gas turbine, by analyzing the main operational aspects related to switching from natural gas to hydrogen. We will consider the effects of variations of volume flow rate and of thermo-physical properties on the matching between turbine and compressor and on the blade cooling of the hot rows of the gas turbine. In the analysis we will keep into account that those effects are largely emphasized by the abundant dilution of the fuel by inert gases (steam or nitrogen), necessary to control the NOx emissions. Three strategies will be considered to adapt the original machine, designed to run on natural gas, to operate properly with diluted hydrogen (VGV operations, increased pressure ratio, re-engineered machine). The performance analysis, carried out by a calculation method including a detailed model the cooled gas turbine expansion, shows that moderate efficiency decays can be predicted with elevated dilution rates (nitrogen is preferable to steam under this point of view). The combined cycle power output substantially increases if not controlled by VGV operations. It represents an opportunity if some moderate re-design is accepted (turbine blade height modifications or HP compressor stages addition).© 2003 ASME

Integrated starter/generator for a turbomachine

Abstract: The invention relates to a turbomachine of axis X including a compressor and an integrated starter/generator. The field magnetic circuit of the starter/generator is mounted in the bore of at least one disk of the compressor and surrounds the secondary magnetic circuit which is secured to a cylindrical shroud provided on the support structure for the bearing of the compressor. The invention applies in particular to single-shaft or multi-shaft turbomachines.

Impact of Geometric Variability on Axial Compressor Performance

Abstract: A probabilistic methodology to quantify the impact of geometric variability on compressor aerodynamic performance is presented. High-fidelity probabilistic models of geometric variability are derived using a Principal-Component-Analysis (PCA) of blade surface measurements. This probabilistic blade geometry model is then combined with a compressible, viscous blade-passage analysis to estimate the impact on the passage loss and turning using a Monte Carlo simulation. Finally, a mean-line multi-stage compressor model, with probabilistic loss and turning models from the blade-passage analysis, is developed to quantify the impact of the blade variability on overall compressor efficiency and pressure ratio. The methodology is applied to a flank-milled Integrally-Bladed Rotor (IBR). Results demonstrate that overall compressor efficiency can be reduced by approximately 1% due to blade-passage effects arising from representative manufacturing variability.Copyright © 2003 by ASME

Vehicle air conditioner

Abstract: In a vehicle air conditioner, a compressor is driven by a vehicle engine, and a displacement of the compressor is controlled based on a cooling load. When a post-evaporator air temperature (TE) is higher than a predetermined value (TEO+β), it is determined that the cooling load is large, and the compressor is forcibly controlled at maximum displacement that is larger than a control value controlled based on the cooling load. Accordingly, the post-evaporator air temperature (TE) can be rapidly reduced to be lower than the predetermined value (TEO+β), so that a driving time of the vehicle engine can be made shorter. As a result, fuel consumption efficiency of the vehicle engine can be effectively improved.

Humid air turbine cycle with carbon dioxide recovery

Abstract: Carbon dioxide (152) is removed following compressor (130) which compresses a mixture of compressed air (132) and recirculated exhaust gas (118’) from a gas turbine (120). The carbon dioxide depleted gas (136) is humidified (180, 114) and fed to the combustor (110).

Development of an axial microturbine for a portable gas turbine generator

Abstract: A miniature gas turbine is under development with the aim of generating electrical energy from fuel. This system consists of a compressor, combustion chamber, turbine and generator. The turbine is a single-stage axial impulse turbine (Laval turbine) with a rotor diameter of 10 mm, made of stainless steel using die-sinking electro-discharge machining. It has been tested with compressed air to speeds up to 160 000 rpm and generates a maximum mechanical power of 28 W with an efficiency of 18.4%. When coupled to a small generator, it generates 16 W of electrical power, which corresponds to an efficiency for the total system of 10.5%. The power density is mainly limited by the maximal speed of the ball bearings. The main losses are the blade profile losses and the exit losses. Higher speeds can considerably reduce the exit losses and therefore increase efficiency and power density. An improved turbine has been tested at temperatures up to 360 °C and generates up to 44 W of electrical energy with a total efficiency of 16%. A 20 mm diameter centrifugal compressor matching the pressure and flow characteristics of the turbine has been designed and is currently under construction.

The ICER Progressive Wavelet Image Compressor

Abstract: ICER is a progressive, wavelet-based image data compressor designed to meet the specialized needs of deep-space applications while achieving state-of-the-art compression effectiveness. ICER can provide lossless and lossy compression, and incorporates an error-containment scheme to limit the effects of data loss during transmission. The Mars Exploration Rover (MER) mission will rely primarily on a software implementation of ICER for image compression. This article describes ICER and the methods it uses to meet its goals, and explains the rationale behind the choice of methods. Performance results also are presented.

Integrated turbine power generation system with catalytic reactor

Abstract: The invention provides integrated turbogenerators having a turbine wheel, a compressor impeller, and a motor generator mounted to or mechanically constrained to a common shaft, and improved components and configurations thereof.

Transcritical vapor compression system and method of operating including refrigerant storage tank and non-variable expansion device

Abstract: A transcritical vapor compression system includes a fluid circuit circulating a refrigerant in a closed loop. The fluid circuit has operably disposed therein, in serial order, a compressor, a first heat exchanger, at least one non-variable expansion device and a second heat exchanger. The compressor compresses the refrigerant from a low pressure to a supercritical pressure. The first heat exchanger is positioned in a high pressure side of the fluid circuit. The second heat exchanger is positioned in a low pressure side of the fluid circuit. The at least one non-variable expansion device reduces the pressure of the refrigerant from a supercritical pressure to a relatively lower pressure. A refrigerant storage vessel is in fluid communication with the fluid circuit and contains a variable mass of refrigerant whereby the capacity of the system may be controlled.

Exhaust gas turbocharger in an internal combustion engine

Abstract: In an exhaust-gas turbocharger of an internal combustion engine including an exhaust-gas turbine coupled to a compressor by a shaft and having a relatively large and a relatively small turbine inlet flow passage, the relatively large turbine inlet flow passage is arranged adjacent to the shaft and the relatively small turbine inlet flow passage facing away from the shaft and a switching device is provided via which the exhaust gas of the cylinders can be selectively supplied either to the small or to the large or to both of turbine inlet flow passages and furthermore, an exhaust gas recirculation line connected to the exhaust gas line leading to the small turbine inlet flow passage is in communication with the engine intake tract.

Advanced hybrid coal gasification cycle utilizing a recycled working fluid

Abstract: A power generating system having a hybrid gasification cycle (10), in which CO2 is recycled to a gasifier (12) to be used as a gasification reactant and working fluid. The power generating system includes a source of fresh, pure oxygen (20), a gasifier, a particle separator (16) arranged in flow connection with the gasifier, a syngas combustor (48), a gas turbine (50) arranged in flow connection with the outlet of the gas turbine, and a gas compressor system (36) which discharges a stream of compressed exhaust gas. A first portion (34) of the stream of compressed exhaust gas is conducted to the gasifier to control the temperature in the gasifier, to provide CO2 and steam for gasification, and to decrease the demand for fresh, pure oxygen therein.