Showing papers on "Gas compressor published in 2005"

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 thermophysical 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 take 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 NO x emissions. Three strategies will be considered to adapt the original machine, designed to run on natural gas, to operate properly with diluted hydrogen: variable guide vane (VGV) operations, increased pressure ratio, re-engineered machine. The performance analysis, carried out by a calculation method including a detailed model of 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 high-pressure compressor stages addition).

Gas Pipeline Hydraulics

Abstract: GAS PROPERTIES Mass and Weight Volume Density, Specific Weight, and Specific Volume Specific Gravity Viscosity Ideal Gases Real Gases Natural Gas Mixtures Pseudo-Critical Properties from Gas Gravity Impact of Sour Gas on Non-Hydrocarbon Components Compressibility Factor Heating Value Summary Problems References PRESSURE DROP DUE TO FRICTION Bernoulli's Equation Flow Equations General Flow Equation Effect of Pipe Elevations Average Pipe Segment Pressure Velocity of Gas in a Pipeline Erosional Velocity Reynolds Number of Flow Friction Factor Colebrook-White Equation Transmission Factor Modified Colebrook-White Equation American Gas Association (AGA) Equation Weymouth Equation Panhandle A Equation Panhandle B Equation Institute of Gas Technology (IGT) Equation Spitzglass Equation Mueller Equation Fritzsche Equation Effect of Pipe Roughness Comparison of Flow Equations Summary Problems References PRESSURE REQUIRED TO TRANSPORT Total Pressure Drop Required Frictional Effect Effect of Pipeline Elevation Effect of Changing Pipe Delivery Pressure Pipeline with Intermediate Injections and Deliveries Series Piping Parallel Piping Locating Pipe Loop Hydraulic Pressure Gradient Pressure Regulators and Relief Valves Temperature Variation and Gas Pipeline Modeling Line Pack Summary Problems References COMPRESSOR STATIONS Compressor Station Locations Hydraulic Balance Isothermal Compression Adiabatic Compression Polytropic Compression Discharge Temperature of Compressed Gas Horsepower Required Optimum Compressor Locations Compressors in Series and Parallel Types of Compressors-Centrifugal and Positive Displacement Compressor Performance Curves Compressor Station Piping Losses Compressor Station Schematic Summary Problems References PIPE LOOPS VERSUS COMPRESSION Purpose of a Pipe Loop Purpose of Compression Increasing Pipeline Capacity Reducing Power Requirements Looping in Distribution Piping Summary Problems References PIPE ANALYSIS Pipe Wall Thickness Barlow's Equation Thick-Walled Pipes Derivation of Barlow's Equation Pipe Material and Grade Internal Design Pressure Equation Class Location Mainline Valves Hydrostatic Test Pressure Blowdown Calculations Determining Pipe Tonnage Summary Problems References THERMAL HYDRAULICS Isothermal versus Thermal Hydraulics Temperature Variation and Gas Pipeline Modeling Review of Simulation Model Reports Summary Problems References TRANSIENT ANALYSIS AND CASE STUDIES Unsteady Flow Case Studies Summary Problems References VALVES AND FLOW MEASUREMENTS Purpose of Valves Types of Valves Material of Construction Codes for Design and Construction Gate Valve Ball Valve Plug Valve Butterfly Valve Globe Valve Check Valve Pressure Control Valve Pressure Regulator Pressure Relief Valve Flow Measurement Flow Meters Venturi Meter Flow Nozzle Summary Problems References PIPELINE ECONOMICS Components of Cost Capital Costs Operating Costs Determining Economic Pipe Size Summary Problems References APPENDIX A: UNITS AND CONVERSIONS APPENDIX B: PHYSICAL PROPERTIES OF VARIOUS GASES APPENDIX C: PIPE PROPERTIES-US CUSTOMARY SYSTEM OF UNITS APPENDIX D: GASMOD OUTPUT REPORT APPENDIX E: SUMMARY OF FORMULAS INDEX

Methods and apparatus for operating gas turbine engines

Abstract: A method for operating a gas turbine engine (10), including a first compressor (14), a second compressor (16), and a turbine (20), coupled together in serial flow arrangement. The method includes channeling compressed airflow (53) discharged from the first compressor through an intercooler (50) having a cooling medium flowing therethrough, operating the intercooler such that condensate is formed in the intercooler from the compressed airflow, and channeling the condensate to an inlet (26,30) of the first or second compressor to facilitate reducing an operating temperature of the gas turbine engine.

Turbomachinery flow physics and dynamic performance

Abstract: I Turbomachinery Flow Physics.- Introduction, Turbomachinery, Applications, Types.- Kinematics of Turbomachinery Fluid Motion.- Differential Balances in Turbomchinery.- Integral Balances in Turbomachinery.- Theory of Turbomachinery Stages.- Turbine and Compressor Cascade Flow Forces.- II Turbomachinery Losses, Efficiencies, Blades.- Losses in Turbine and Compressor Cascades.- Efficiency of Multi-stage Turbomachines.- Incidence and Deviation.- Simple Blade Design.- Radial Equilibrium.- III Turbomachinery Dynamic Performance.- Nonlinear Dynamic Simulation of Turbomachinery Components and Systems.- Generic Modeling of Turbomachinery Components and Systems.- Modeling of Inlet, Exhaust, and Pipe Systems.- Modeling of Heat Exchangers, Combustion Chambers, Afterburners.- Modeling Compressor Component, Design, Off-Design.- Turbine Aerodynamic Design and Off-design Performance.- Gas Turbine Engines Design and Off-deign Dynamic Performance.

The effect of turbine blade cooling on the cycle efficiency of gas turbine power cycles

Abstract: A thermodynamic cycle analysis computer code for the performance prediction of cooled gas turbines has been used to calculate the efficiency of plants with varying combustor outlet temperature, compressor pressure ratio, and turbomachinery polytropic efficiency. It is shown that the polytropic efficiency exerts a major influence on the optimum operating point of cooled gas turbines: for moderate turbomachinery efficiency the search for enhanced combustor outlet temperature is shown to be logical, but for high turbomachinery efficiency, this is not necessarily so. The sensitivity of the cycle efficiency to variation in the parameters determining the cooling flow rates is also examined. While increases in allowable blade metal temperature and film cooling effectiveness are more beneficial than improvements in other parameters, neither is as important as increase in turbomachinery aerodynamic efficiency.

Compressor diagnostic and protection system

Abstract: A system includes a compressor, processing circuitry, a first sensor detecting high-side data indicative of an operating condition of a high-pressure side of the refrigeration circuit, and a second sensor detecting low-side data indicative of an operating condition of a low-pressure side of the refrigeration circuit. The processing circuitry receives the high-side data and the low-side data from the first and second sensors and processes at least one of the high-side data and low-side data to select an operating mode for the compressor. The operating modes include a normal mode, a reduced-capacity mode, and a shutdown mode.

Systems and methods for power generation and hydrogen production with carbon dioxide isolation

Abstract: A power generation system includes a first gas turbine system. The first turbine system includes a first combustion chamber configured to combust a first fuel stream of primarily hydrogen that is substantially free of carbon-based fuels, a first compressor configured to supply a first portion of compressed oxidant to the first combustion chamber and a first turbine configured to receive a first discharge from the first combustion chamber and generate a first exhaust and electrical energy. The power generation system further includes a second gas turbine system. The second turbine system includes a second combustion chamber configured to combust a second fuel stream to generate a second discharge, wherein the first compressor of the first gas turbine system is configured to supply a second portion of compressed oxidant to the second combustion chamber and a second turbine configured to receive the second discharge from the second combustion chamber to generate a second exhaust and electrical energy. A second compressor is configured to receive the second exhaust comprising carbon dioxide and to discharge a recycle stream to the second combustion chamber and a split stream to a separator system adapted to recover carbon dioxide. The power generation system also includes a hydrogen generation system configured to receive a third fuel and steam to generate the first fuel and a third exhaust gas, wherein the third exhaust gas is recycled into the second combustion chamber.

System and method for controlling the working line position in a gas turbine engine compressor

Abstract: A system for actively controlling the working line location within a low pressure compressor. The system includes a plurality of variable inlet guide vanes that are adjusted to maintain the working line at a constant level as the low pressure compressor rotates at a constant speed.

Thermal control system and method

Abstract: A system and method for controlling the temperature of a process tool uses the vaporizable characteristic of a refrigerant that is provided in direct heat exchange relation with the process tool. Pressurized refrigerant is provided as both condensed liquid and in gaseous state. The condensed liquid is expanded to a vaporous mix, and the gaseous refrigerant is added to reach a target temperature determined by its pressure. Temperature corrections can thus be made very rapiday by gas pressure adjustments. The process tool and the operating parameters will usually require that the returning refrigerant be conditioned and processed for compatibility with the compressor and other units, so that cycling can be continuous regardless of thermal demands and changes.

Conjugate Flow and Heat Transfer Investigation of a Turbo Charger

Abstract: In this paper a three-dimensional conjugate calculation has been performed for a passenger car turbo charger. The scope of this work is to investigate the heat fluxes in the radial compressor, which can be strongly influenced by the hot turbine. As a result of this, the compressor efficiency may deteriorate. Consequently, the heat fluxes have to be taken into account for the determination of the efficiency. To overcome this problem a complex three-dimensional model has been developed. It contains the compressor, the oil cooled center housing, and the turbine. Twelve operating points have been numerically simulated composed of three different turbine inlet temperatures and four different mass flows. The boundary conditions for the flow and for the outer casing were derived from experimental test data (Bohn et al.). Resulting from these conjugate calculations various one-dimensional calculation specifications have been developed. They describe the heat transfer phenomena inside the compressor with the help of a Nusselt number, which is a function of an artificial Reynolds number and the turbine inlet temperature.

Air-conditioning apparatus including motor-driven compressor for idle stopping vehicles

Abstract: A low-cost vehicle air-conditioning apparatus for idle stopping vehicles is capable of performing both cooling and heating operations throughout the year. The air-conditioning apparatus includes an engine-driven compressor and engine-driven pump for a heating unit. The air-conditioning apparatus includes a motor-driven compressor and pump. A control unit drives the motor such that the motor-driven compressor is operated when there is a need for cooling and the motor-driven pump is operated when there is a need for heating when the engine is stopped. Battery power is conserved through various methods.

Combined cooling and power plant with water extraction

Abstract: A turbine engine system and a method for using the turbine engine system that includes at least one low-pressure compressor, at least one high-pressure compressor, at least one low-pressure turbine, and at least one high-pressure turbine. In addition, the turbine engine system includes an absorption refrigeration system that is used to pre-cool an air-gas mixture before it enters the high-pressure compressor. As such, the pre-cooled mixture is easier to compress, thereby increasing the thermal efficiency of the turbine engine. Additionally, the exhaust heat from the air-gas mixture that is pre-cooled may be used to drive the absorption refrigeration system. Lastly, water, may be extracted from the evaporator of the absorption refrigeration cycle.

Computational Fluid Dynamics Study of Wake-Induced Transition on a Compressor-Like Flat Plate

Abstract: Recent experimental work has documented the importance of wake passing on the behavior of transitional boundary layers on the suction surface of axial compressor blades. This paper documents computational fluid dynamics (CFD) simulations using a commercially available general-purpose CFD solver, performed on a representative case with unsteady transitional behavior. The study implements an advanced version of a three-equation eddy-viscosity model previously developed and documented by the authors, which is capable of resolving boundary layer transition. It is applied to the test cases of steady and unsteady boundary layer transition on a two-dimensional flat plate geometry with a freestream velocity distribution representative of the suction side of a compressor airfoil. The CFD results are analyzed and compared to a similar experimental test case from the open literature. Results with the model show a dramatic improvement over more typical Reynolds-averaged Navier-Stokes (RANS)-based modeling approaches, and highlight the importance of resolving transition in both steady and unsteady compressor aerosimulations.

Vapor-compression evaporation system and method

Abstract: According to one embodiment of the invention, a vapor-compression evaporation system includes a plurality of vessels in series each containing a feed having a nonvolatile component. A first set of the plurality of vessels includes vapor-compression evaporators and a second set of the plurality of vessels includes multi-effect evaporators. A mechanical compressor is coupled to the last vessel in the series of vapor-compression evaporators and is operable to receive a vapor therefrom. A turbine is coupled to, and operable to drive, the mechanical compressor. A pump is operable to deliver a cooling liquid to the mechanical compressor, and a tank is coupled to the mechanical compressor and is operable to separate liquid and vapor received from the mechanical compressor. A plurality of heat exchangers is coupled inside respective ones of the vessels, wherein the heat exchanger in the first vessel in the first set is operable to receive the vapor from the tank, and at least some of the vapor condenses therein. The heat of condensation provides the heat of evaporation to the first vessel in the first set, and at least some of the vapor inside the first vessel in the first set is delivered to the heat exchanger in the next vessel in the first set, whereby the condensing, evaporating, and delivering steps continue until the last vessel in the second set is reached.

Axial Compressor Deterioration Caused by Saltwater Ingestion

Abstract: Gas turbine performance deterioration can be a major economic factor. An example is within offshore installations where a degradation of gas turbine performance can mean a reduction of oil and gas production. This paper describes the test results from a series of accelerated deterioration tests on a General Electric J85-13 jet engine. The axial compressor was deteriorated by spraying atomized droplets of saltwater into the engine intake. The paper presents the overall engine performance deterioration as well as deteriorated stage characteristics. The results of laboratory analysis of the salt deposits are presented, providing insight into the increased surface roughness and the deposit thickness and distribution. The test data show good agreement with published stage characteristics and give valuable information regarding stage-by-stage performance deterioration.

Multi-stage turbocharging system utilizing VTG turbine stage(s)

Abstract: Multi-stage turbocharging, and more particularly, an advanced multi-stage turbocharging system using the variable turbine power of one or more variable turbine geometry (VTG) turbochargers to adjust compressor boost and exhaust back pressure to engine operating demands. The invention further relates to a turbocharged internal combustion engine, in particular a turbocharged internal combustion engine with at least one high-pressure turbine stage and one downstream low-pressure turbine stage, wherein the high-pressure turbine may be a single-flow or double-flow type, wherein the high pressure or low pressure compressor may be variable geometry, wherein the high pressure or low pressure compressor may be variably bypassed, and wherein the high pressure or low pressure turbine may be provided with an active control variable bypass or wastegate.

Detailed thermodynamic characterization of hermetic reciprocating compressors

Abstract: The aim of this paper is the detailed analysis of different well-known thermodynamic efficiencies usually used to characterize hermetic compressors. Attention is focussed on the volumetric efficiency, the isentropic efficiency, and the combined mechanical–electrical efficiency. A procedure is presented to detach these efficiencies into their main components (physical sub-processes) to get deeper insight on the overall behavior. The volumetric efficiency is split into partial efficiencies related to pressure drop and heat transfer effects, supercharging effects, superdischarging effects, leakages, etc. The isentropic efficiency is detached using two different points of view: the work associated to the individual sub-processes (compression, discharge, expansion, suction), and the work associated to the underpressures, overpressures, and between the inlet and outlet mean compressor pressures. Finally, the combined mechanical–electrical efficiency is related to the heat transfer losses/gains, and to the exergy transfers and exergy destroyed. Even though some of the concepts introduced in the paper can be applied to different kinds of compressors, the discussion is specially focussed on hermetic reciprocating compressors. An advanced simulation model developed by the authors has been used to generate data to illustrate the possibilities of the detailed thermodynamic characterization proposed. The criteria developed are useful tools for comparison purposes, to characterize compressors, and to assist designers during the optimization process.

Systems and methods for power generation with carbon dioxide isolation

Abstract: A power generation system and method includes a first gas turbine system comprising a first combustion chamber configured to combust a first fuel stream of primarily hydrogen that is substantially free of carbon-based fuels The first gas turbine system also includes a first compressor configured to supply a first portion of compressed oxidant to the first combustion chamber and a first turbine configured to receive a first discharge from the first combustion chamber and generate a first exhaust and electrical energy The power generation system further includes a second gas turbine system comprising a second combustion chamber configured to combust a second fuel stream to generate a second discharge The first compressor of the first gas turbine system is configured to supply a second portion of compressed oxidant to the second combustion chamber The second turbine system also includes a second turbine configured to receive the second discharge from the second combustion chamber to generate a second exhaust and electrical energy and a second compressor configured to receive the second discharge comprising carbon dioxide The second compressor is also configured to discharge a recycle stream to the second combustion chamber and a split stream to a separator system adapted to recover carbon dioxide

Multi-Objective Optimization of Transonic Compressor Blade Using Evolutionary Algorithm

Abstract: In this work we perform multi-objective optimization of the NASA rotor67 transonic compressor blade. Our objectives are to maximize the stage pressure ratio as well as to minimize the compressor weight. The backbones of the optimization approach consist of a genetic algorithm, a gradient-based method, and a response surface model. The genetic algorithm is used to facilitate the multi-objective optimization and to flnd the global optima of high-dimensional problems. The gradient-based method accelerates the optimization convergence rate. The response surface model, constructed to replace the computationally expensive analysis tool, reduces the computational cost. Representative solutions are selected from the Pareto-optimal front to verify against the CFD tool. Comparing with the baseline design some optimal solutions increase the stage pressure ratio by 1.8% and decrease the weight by 5.4%. A detailed study of ∞ow structure near peak e‐ciency is presented by means of pressure distribution and streamlines inside boundary layers. Our results show that the optimized blade favors a lighter weight by a thinner blade shape. The stage pressure rise is attributed to a reduced separation zone and a weaken shock wave.

Apparatus and method for controlling operation of compressor

Abstract: An apparatus for controlling an operation of a compressor includes: a back electromotive force calculator for calculating a back electromotive force of a compressor based on a value of a current applied to a motor of the compressor and a value of a voltage applied to the motor of the compressor; an operation frequency reference value determining unit for detecting a mechanical resonance frequency of the compressor based on the back electromotive force value and the current value and determining the detected mechanical resonance frequency as an operation frequency reference value; and a controller for varying an operation frequency of the compressor according to the determined operation frequency reference value.

Emissions Reduction Technologies for Military Gas Turbine Engines

Abstract: Future military gas turbine engines will have higher performance than current engines, resulting in increased compressor and combustor exit temperatures, combustor pressures, and fuel-air ratios with wider operating limits. These combustor characteristics suggest undesirable exhaust emission levels of nitrogen oxides and smoke at maximum power and higher carbon monoxide and unburned hydrocarbons at low power. To control emission levels while improving performance, durability and cost, requires major advances in combustor technology. Current emissions control approaches as applied to conventional swirl-stabilized combustors include rich- and lean-burn strategies, together with staged combustion. These approaches, even in fully developed form, may not be sufficient to satisfy the projected design requirements. Unconventional combustor configurations may become necessary. Different engine cycles other than the standard Brayton cycle may also be used for special applications in order to avoid the use of excessive combustion temperatures. The paper presents an overview of the currently utilized emissions control approaches, comparing their performances and likely potential for meeting future requirements. Experimental results are presented for two non-conventional combustor configurations that have shown promise for advanced engine applications. A brief discussion is offered on cycle changes that could result in lower peak temperatures while maintaining advanced performance.

Mobile gas turbine engine and generator assembly

Abstract: A method for supplying power to a remote load includes coupling a gas turbine engine to a vessel that is not used to provide propulsion for the vessel, coupling a generator to the gas turbine engine, coupling an intercooler system downstream from a first compressor such that compressed air discharged from the first compressor is channeled therethrough, the intercooler system includes an intercooler and a first heat exchanger, channeling a first working fluid through the intercooler to facilitate reducing an operating temperature of air discharged from the intercooler to a second compressor, channeling a second working fluid flowing through the first heat exchanger to extract energy from the first working fluid to facilitate reducing an operating temperature of the first working fluid, and operating the gas turbine engine and generator to supply power to a load that is located remotely from the vessel.

Electrically coupled supercharger for a gas turbine engine

Abstract: A gas turbine engine, in particular a turboshaft engine, includes a spool having a turbine and a gas generator compressor mounted thereto, a source of heat positioned between the turbine and the compressor, a first shaft and a free turbine mounted to the first shaft, and a control system for transferring power between the spool and the shaft. The operating speed of the gas generator compressor is re-matched in order to improve the efficiency and surge margin of the gas generator compressor and to improve the transient performance of the gas turbine engine.

Method for compensating compressor lag of a hybrid powertrain

Abstract: A method for compensating for the torque response of an internal combustion engine having a compressor coupled thereto for boosting cylinder air amount is presented. According to the method, a motor of a hybrid vehicle may assist the internal combustion engine to improve vehicle response. The method may improve driver perception of vehicle response and may reduce lag that can be associated with operating an engine having a compressor.

Heat-activated heat-pump systems including integrated expander/compressor and regenerator

Abstract: Heat-activated heat-pump systems and related methods are disclosed that include a power cycle coupled to a vapor-compression refrigeration cycle both utilizing the same working fluid. The power cycle comprises a boiler, an expander receiving superheated vapor and producing work from the superheated vapor, a condenser, and a pump. A regenerator conducts a first stream of working fluid from the pump to the boiler and a second stream of the working fluid from the expander to the condenser while transferring heat from the second stream to the first stream. The refrigeration cycle comprises a compressor that compresses the working fluid from the evaporator and delivers the compressed working fluid to a condenser. The expander and compressor are coupled together such that at least a portion of the work produced by the expander is utilized for running the compressor.

Heat Transfer and Film-Cooling Measurements on a Stator Vane With Fan-Shaped Cooling Holes

Abstract: In a typical gas turbine engine, the gas exiting the combustor is significantly hotter than the melting temperature of the turbine components. The highest temperatures in an engine are typically seen by the turbine inlet guide vanes. One method used to cool the inlet guide vanes is film cooling, which involves bleeding comparatively low-temperature, high-pressure air from the compressor and injecting it through an array of discrete holes on the vane surface. To predict the vane surface temperatures in the engine, it is necessary to measure the heat transfer coefficient and adiabatic film-cooling effectiveness on the vane surface. This study presents heat transfer coefficients and adiabatic effectiveness levels measured in a scaled-up, two-passage cascade with a contoured endwall. Heat transfer measurements indicated that the behavior of the boundary layer transition along the suction side of the vane showed sensitivity to the location of film-cooling injection, which was simulated through the use of a trip wire placed on the vane surface. Single-row adiabatic effectiveness measurements without any upstream blowing showed jet lift-off was prevalent along the suction side of the airfoil. Single-row adiabatic effectiveness measurements on the pressure side, also without upstream showerhead blowing, indicated jet lifted-off and then reattached to the surface in the concave region of the vane. In the presence of upstream showerhead blowing, the jet lift-off for the first pressure side row was reduced, increasing adiabatic effectiveness levels.