Showing papers on "Gas compressor published in 1992"

Power plant utilizing compressed air energy storage and saturation.

Abstract: An improved power plant employing a combination of compressed air storage and saturation (simultaneous heating and humidification) of compressed air is disclosed. The power plant (20A) includes a combustor (26) which provides hot gas for driving a turbine (24). The turbine (24) is used in conjunction with a generator (34) to generate electrical power. The power from the turbine (24) is accessible by a compressor system (40) during low power demand periods. The compressor system (40) is used to compress air which is stored in an air storage chamber (52). The compressed air from the air storage chamber (52) is used by the combustor (26) during high power demand periods, while the compressor system (40) is shut down, to provide compressed combustion gas to the turbine (24). To enhance the efficiency of the plant, while further lowering the capital cost of the plant, a saturator (60) is positioned between the storage chamber (52) and the combustor (26). The saturator (60) receives compressed air from the storage chamber (52) and simultaneously heats and humidifies it. The resultant heated and humidified compressed air is then conveyed to the combustor (26), typically after further heating by a recuperator (70).

Surge Dynamics in a Free-Spool Centrifugal Compressor System

Abstract: Turbocharger surge has been investigated in a radial impeller-vaneless diffuser free-spool system. Several different aspects are addressed. First, two very different compression systems, one with a large downstram volume and one with the smallest possible downstram voluem, are employed to examine stall initiation phenomena as well as the behavior of the compressor characteristics when operating in surge. The measurements show impeller stall at the inducer tips to be a key phenomena in initiating surge. The inducer stall is stationary and asymmetric, due to the presence of the volute, and is most severe near the volute tongue angular position

Fast data compressor with direct lookup table indexing into history buffer

Abstract: A cooperating data compressor, compressed data format, and data decompressor The compressor compresses an input data block (HB) to a compressed data block having the format The decompressor decompresses the compressed data block to restore the original data block The compressor has a direct lookup table (DLT) of 28×N entries, each indexable by N bytes at a current HB location and identifying a target HB location The compressor determines whether a target string at the target HB location matches a current string at the current HB location If they do not match, the compressor outputs a literal representing a datum at the current location If they match, the compressor outputs a vector from the current location to the target string Compression speed is maximized by the direct addressing of the DLT by the current N bytes in the HB Decompression speed is maximized by state machine operation according to literal/vector indicators, special case string length codes, and special case offset codes in the compressed data format

Air-conditioning apparatus

Abstract: An air-conditioning apparatus forms a refrigerating cycle with a coolant heater (43) and a compressor (17) having two cylinders. The apparatus simultaneously carries out a coolant heating operation and a heat pump operation when a required heating capacity is high, and when the required heating capacity is low, only the heat pump operation. This operation technique helps reduce the size of the apparatus and expand a variable width of heating capacity. The apparatus also has a defrosting unit for defrosting an outdoor heat exchanger (47) during the heat pump operation.

Simplified Mathematical Representations of Single Shaft Gas Turbines in Mechanical Drive Service

Abstract: There have been several recent applications of large single shaft, heavy duty gas turbines in mechanical drive service, powering high horsepower, multi-casing compressors. This variable speed application of a traditional constant speed driver, with a more limited operating speed range, has created a need for simplified but accurate mathematical representations that can be incorporated into overall process simulations to allow interactive dynamic evaluation of the complete system.This paper presents simplified mathematical representations of four gas turbines covering the horsepower range from 26,000 HP to 108,000 HP. The models incorporate both the control and fuel system characteristics as well as those of the turbomachinery. Although gas fuel is assumed, listed references can be used to accomodate liquid fuel. The models are suitable for a wide range of ambient temperatures, and the influence of axial flow compressor variable inlet guide vanes is included in the models as appropriate to the actual machinery configuration.Copyright © 1992 by ASME

Methods and apparatus for operating a refrigeration system

Abstract: A refrigeration system of the type having an economizer cycle is provided with a null cycle, in addition to heating and cooling cycles, without shutting a compressor prime mover down, to preserve air flow in a conditioned space. First, second and third controllable valves respectively: (1) select main and auxiliary condensers, (2) open and close a liquid line, and (3) open and close a line which provides a warm liquid to an economizer heat exchanger. The valves are controlled in at least one predetermined open/close pattern during a null cycle, and preferably in a plurality of selectable predetermined open/close patterns, to provide a null cycle at any instant which substantially matches the net heat gain or loss taking place in the conditioned space. Thus, the temperature of the served space will be more apt to remain in a null temperature range close to set point, providing smoother and more accurate control over the temperature of the conditioned space for longer shelf life of perishables stored therein. The system achieves the latter by controlling a bypass value according to the load of the compressor.

Air conditioning system suitable for use in an electric vehicle

Abstract: An air conditioning system suitable for use in an electric vehicle. In the air conditioning system, a refrigerant gas circulatory system of the heat pump type for selectively effecting cooling and heating is disposed inside the electric vehicle and comprises lines which interconnect three heat exchangers, a directional control valve, a compressor and an expansion valve to one another. A control device is provided so as to activate and inactivate the heat exchanger, the directional control valve and the compressor. Before the expected running of the vehicle, at least a portion of the refrigerant gas circulatory system can be operated by the control device using a drive source different from the drive source used for running the vehicle. Accordingly, a comfortable room environment can be established for the expected time on riding by activating the air conditioning system in an unmanned state.

Intercooled turbine blade cooling air feed system

Abstract: A gas turbine engine having a compressor and an air-cooled turbine is provided with a cooling system for decreasing the temperature of the turbine cooling air. A heat exchanger, mounted on the compressor casing, receives a portion of the pressurized air which is bled from the compressor. A heat sink medium is pumped through the heat exchanger into heat exchange relationship with the pressurized air, thereby cooling the air. The cooled air is then further pressurized and routed to and circulated through the turbine rotor blades to provide improved cooling thereof. The intercooling of the compressor bleed air permits a reduction in the quantity of compressor air required for turbine rotor blade cooling or allows an increase in turbine entry temperature and thus provides an improvement in engine power and performance. In the case where the heat sink medium is engine fuel, the heat extracted from the compressor bleed air is returned to the engine operating cycle in the form of heated engine fuel.

Single grating laser pulse stretcher and compressor

Abstract: A single-grating method and apparatus is described for a laser pulse stretcher and compressor. The method and apparatus exploits a two-layer vertical structure. One layer for the stretcher, and the other, for the compressor. Such a stretch-compressor is particularly suitable for using in a chirped-pulse or regenerative laser amplifier where laser wavelength tuning is desirable. When a change in the wavelength is applied, only one rotational adjustment is required to resume the alignment of the whole stretcher and compressor. This apparatus shows significant simplification in structure and alignment over the existing stretcher and compressor systems.

Scroll machine with overheating protection

Abstract: A thermally responsive valve assembly (134) for scroll motor-compressor high temperature protection, which causes a high-side to low-side leak when excessive discharge gas temperatures are encountered, thereby causing the motor protector (35) to trip and de-energize the motor. The valve assembly (134) includes means for ducting (200) the excessive temperature discharge gas to the lower portion of the motor/compressor shell (10) to the motor to circulate the high temperature gas throughout the motor cavity. The excessive temperature discharge gas heats the motor stator (20) and windings (32) which will in turn cause the motor protector (35) to trip and de-energize the motor.

Process for producing and utilizing an oxygen enriched gas

Abstract: This invention comprises a method and apparatus for obtaining from air (2) an oxygen enriched gas mixture containing at least 40 mole % nitrogen The apparatus comprises a gas turbine, an oxygen separation unit which is in fluid communication with the turbine air compressor (28) and means for maintaining a proper mass balance tolerance between the turbine compressor/unit and the turbine energy production unit (26) This invention comprises a method and apparatus for recovering large quantities of an oxygen enriched gas from the volume of a compressed air stream (10) produced by a gas turbine by compensation of the mass loss to the energy production unit section (26) thereof by providing means for maintaining the turbine in proper mass and thermal balance as the turbine is utilized to provide the duty/power requirements of a process which utilizes the oxygen enriched gas stream as a reactant

Airconditioner having selectively operated condenser bypass control

Abstract: A heater core is connected with an engine to receive a hot engine-coolant, which operates as a main heater. An evaporator in a refrigerating cycle operates as an auxiliary heater. A condenser is connected to an outlet of the compressor, and the evaporator is connected to an inlet of the compressor. A bypass conduit is provided, one end of which is connected to the outlet side of the compressor and another end of which is connected to an inlet side of the evaporator. A expansion valve is disposed in the bypass conduit. In heating stage, the compressed hot refrigerant discharged from the compressor flows into the bypass conduit. The refrigerant is expanded by the expansion valve and radiates the heat in the evaporator.

Control system for preventing compressor damage in a refrigeration system

Abstract: A microprocessor based device which monitors the operation of a compressor in a refrigeration system and automatically shuts the compressor down if a monitored condition is abnormal Sensors in the refrigeration system sense conditions such as refrigerant pressure and temperature, superheat, oil pressure and motor current draw If a sensed condition is outside of a safety range and remains there for a time out period, an alarm condition is indicated and the device generates a alarm signal and shuts down the compressor A detachable display module includes a keypad for carrying out field programming and a LCD screen for displaying the refrigerant conditions and programming prompts and commands A rest button permits resetting twice before a service call is required

A Simplified Cycle Simulation Model for the Performance Rating of Refrigerants and Refrigerant Mixtures

Abstract: A simulation program, CYCLE11, which is useful for the preliminary evaluation of the performance of refrigerants and refrigerant mixtures in the vapour compression cycle is described. The program simulates a theoretical vapour-compression cycle and departures from the theoretical cycle that occur in a heat pump and in a refrigerator. The cycles are prescribed in terms of the temperatures of the external heat-transfer fluids with the heat exchangers generalized by an average effective temperature difference. The isethalpic expansion process is assumed. The program includes a rudimentary model of a compressor and a representation of the suction line and liquid line heat exchange. Refrigerant thermodynamic properties are calculated by using the Carnahan-Starling-DeSantis equation of state. Refrigerant transport properties are not included in the simulations. The program can generate merit ratings of refrigerants for which limited measured data are available. An example of simulation results stresses the need for careful application of simplified models and consideration for the assumptions involved.

Unsteady Aerodynamics and Gust Response in Compressors and Turbines

Abstract: A comprehensive series of experiments and analyses was performed on compressor and turbine blading to evaluate the ability of current, practical, engineering/analysis models to predict unsteady aerodynamic loading of modern gas turbine blading. This is part of an ongoing effort to improve methods for preventing blading failure. The experiments were conducted in low-speed research facilities capable of simulating the relevant aerodynamic features of turbomachinery. Unsteady loading on compressor and turbine blading was generated by upstream wakes and, additionally for compressors, by a rotating inlet distortion. Fast-response hot-wire anemometry and pressure transducers embedded in the airfoil surfaces were used to determine the aerodynamic gusts and resulting unsteady pressure responses acting on the airfoils. This is the first time that gust response measurements for turbines have been reported in the literature. Several different analyses were used to predict the unsteady component of the blade loading: (1) a classical flat-plate analysis, (2) a two-dimensional linearized flow analysis with a frozen gust model, (3) a two-dimensional linearized flow analysis with a distorted gust model, (4) a two-dimensional linearized Euler analysis, and (5) a two-dimensional nonlinear Euler analysis. Also for the first time, a detailed comparison of these analyses methods is made and the importancemore » of properly accounting for both vortical and potential disturbances is demonstrated. The predictions are compared with experiment and their abilities assessed to help guide designers in using these prediction schemes.« less

Variable displacement compressor

Abstract: A variable displacement compressor includes a housing having therein a space, a rotor eccentrically disposed in the space of the housing so as to define a compression chamber and an intake chamber in the housing, a bypass passage formed in the housing for establishing fluid communication between the compression chamber and the intake chamber and being in the form of a slot, and a device for opening and closing the bypass passage which is movable depending on a pressure in the intake chamber in a direction perpendicular to the bypass passage.

Investigation of the influence of oil injection upon the screw compressor working process

Abstract: Some results of mathematical modelling and experimental investigation of the influence of oil injection upon the screw compressor working process are presented. Several parameters that characterize oil injection were varied over ranges that were initially determined from a computer model. These include: oil flowrate, inlet temperature, droplet atomization, positions in the casing at which the oil was injected, oil jet speed and angle, and time of oil retention in the working volume. The compressor performances were evaluated from measurements of all important bulk parameters: delivery rate, power consumption, power utilization efficiency, specific power, as well as the instantaneous pressure and temperature at several positions along the working volume, from which the indicator diagram was worked out. In addition to the information about the influence of each oil parameter upon the compressor performances, the collected data served to verify and complement the mathematical model of the influence of oil upon the screw compressor working process developed earlier, which has subsequently been employed for computer-aided design of two different screw-compressor oil systems. The experimental results and the application of the computer simulation helped in modifying the oil injection system, which resulted in a saving in compressor energy consumption up to 7%.

Inlet distortion effects in aircraft propulsion system integration

Abstract: A tutorial survey of inlet flow distortion effects on engine performance and stability is presented. Inlet distortions in aero engines arise through a variety of causes. They can be essentially steady, due to non-axisymmetric intake duct geometry, or time varying, for example from flow separation off the lip of the inlet during maneuvers or shock-induced separation during supersonic flight. Whatever the cause, the result is generally a decrease in performance and, more importantly, a lessening of the stable flow range of the compressor. The distortions are generally three-dimensional. It is an extremely useful simplification to break them, at least conceptually, into radial and circumferential non-uniformities and approach each separately. Purely radial distortions can be treated by the methods that were developed for designing compressors in nominally axisymmetric inlet flow, and this type of distortion will be only briefly discussed. Circumferential non-uniformities, however, introduce additional fluid dynamic features into the analysis of compressor behavior and often have the larger impact on performance and stability. Thus we concentrate mainly on the effects of steady circumferential inlet flow distortion.

Thermal Energy Analysis in Reciprocating Hermetic Compressors

Abstract: In this paper the thermal energy analysis of a reciprocating hermetic compressor is performed using a computational program The simulation model employed in the program is based on energy balances For the refrigerant gas inside the compressor cylinder use was made of the first law of thermodynamics including time variations of the mass and energy fluxes The required temperatures at the suction chamber, cylinder walls, discharge chamber, discharge muffler, compressor shell, and ambient inside the compressor shell are obtained from steady state energy balances at various locations within the compressor Effective overall heat transfer coefficients were determined experimentally, except for the heat transfer between the refrigerant and the cylinder walls which was obtained from existing correlations A companion simulation program which represents the compressor working features was used to calculate the mass fluxes at the suction, discharge, and the leakage flux Simulation results are presented for a small compressor and compared with experimental results Good agreement prevails indicating that the major effects affecting the thermal performance of the compressor have been considered by the proposed model INTRODUCTION There are several reports in the literature concerning numerical models to predict the performance of hermetic refrigeration compressors Those models require thermodynamic relationships to describe the behavior of the gas inside the cylinder These relationships can be obtained either through a polytropic transformation or through an energy balance A furth-er aspect to be considered is the heat transfer to and from the refrigerant as it passes through the compressor The models described in the literature differ mainly on how the two aforementioned issues are addressed On the next paragraphs some of the major works done on compressor modelling will be reviewed Qvale eta/ [l] indicated some areas where research should be done to improve the current knowledge on compressor modelling Heat transfer on the suction and discharge lines, on the valves, and between the gas and the cylinder walls are the most important points mentioned by the authors According to [l] the numerical models dealing with the cylinder of hermetic compressors have frequently employed the assumption of perfect gas in a polytropic process The exponent of the polytropic equation is usually adjusted to fit experimental results In this regard the polytropic index incorporates the combined effect of the heat transfer between gas and cylinder, friction, and deviations from the perfect gas behavior Therefore, the influence of these effects separately cannot be detected Karl! [2] investigated through the first law of thermodynamics the process described by a real gas inside the cylinder He considered the cylinder as a close system undergoing exchange of heat and work with the surroundings Prakash and Singh [3] also employed the first law of thermodynamics but assumed perfect gas behavior The heat transfer between the cylinder walls and the gas was predicted using the correlation given by Adair et a/ [4]· Rottger and Kruse [5] verified through their model that for the compressor performance it is important to use the equation of state for real gas but for the valve performance suffices to use the perfect

Case treatment for compressor blades

Abstract: The outer shroud of an axial flow compressor is treated to remove the low momentum flow adjacent the tips of the compressor blades in a judiciously located and sized passageway that removes the low momentum flow relative to the rotor blades at a location downstream of the blades' leading edge and returned at a location upstream of the point of removal. It being critical that no more than 12% of the total flow in the compressor rotor is removed for treatment. Anti-swirl vanes in the passageway serve to remove or reverse the swirl component from the removed low momentum flow. The intake is so designed that it selectively removes only the weak low momentum flow relative to the rotor and encourages the strong mainstream flow to remain in the main gas stream.

Petroleum engineering handbook for the practicing engineer

Abstract: Principles of transient test analysis - characteristics of various flow regimes, the radial-diffusivity equation, principle of superposition, gas flow through porous media transient testing of oil and gas wells - productivity index tests, pressure build-up tests, estimating average reservoir pressure, gas well build-up test analysis pressure drawdown testing, analysis of well tests using type curves, gas well backpressure tests, other well tests, use of pressure derivative in well test analysis, pressure analysis for horizontal wells drilling technology - rotary drilling, drillstring design, casing design, drilling hydraulics, drilling fluid selection, directional drilling and deviation control, hole problems, kick control and blowout precvention, cementing production technology - length and force changes in tubing, well stimulation-hydraulic fracturing and acidizing, well performance evaluation, gas lift design, sucker rod pumping, gas compression, oil and gas separators, handling and treatment of gas, water and gas coning.

Three-Dimensional Flow and Mixing in an Axial Flow Compressor With Different Rotor Tip Clearances

Abstract: The effect of difference in rotor tip clearance on the mean flow fields and unsteadiness and mixing across a stator blade row were investigated using hot-wire anemometry, pressure probes, flow visualization, and the ethylene tracer-gas technique on a single- stage axial flow compressor. The structure of the three-dimensional flow fields was discussed based on results of experiments using the 12-orientation single slanted hot- wire technique and spectrum analysis of velocity fluctuation

Operation controller for air conditioner

Abstract: An operation controller for an air conditioner designed to decrease a difference between an ambient temperature and a set temperature by varying the number of revolutions of a compressor (4), includes: a means (21) for calculating an operation ratio of the compressor; and a means (23) for determining the range of varying an operation frequency of the compressor (4) in accordance with the operation ratio.

Control system for refrigerating apparatus

Abstract: There is disclosed a control system for controlling a refrigerating apparatus in which a control unit is arranged to calculate a super heat amount of a discharge gas of a compressor at the time immediately before starting operation of the compressor, on the basis of a difference between temperatures detected by a discharge gas temperature sensor and a condenser temperature sensor and to control an opening degree of an electronic expansion valve to a completely open state. After starting operation of the compressor, the control unit constantly measures the super heat amount of the discharge gas and controls the valve opening degree to the usual degree when the super heat amount becomes higher than the preset value.

Gas liquefaction process control system

Abstract: A method for controlling the operation of a liquefied natural gas (LNG) process which utilizes gas turbine-driven refrigeration compressors (205) is disclosed. A feedforward control system (207) compensates for the effects of changes in ambient air temperature on the plant operating efficiency by periodically predicting a new temperature and resetting the set points of key feedback controllers in anticipation of this new temperature, thereby optimizing the operation of the plant and minimizing the specific fuel consumption at a given LNG production rate.

Epicyclic speed reducer designed for fitment to the transmission between the gas turbine and air compressor of an aircraft engine

Abstract: A speed reducer has a sun gear for connection to a turbine of an engine and a planet carrier supporting a number of planetary gears meshing with the sun gear and with the ring gear fitted to the engine mounting. According to the present invention, the planet carrier has a first annular element having pairs of seats for pins on each of which rotates one of the planetary gears. A second annular element for connection to a compressor of the engine has a number of axial arms fitted inside respective cavities of the first annular element. An end of each axial arm is connected to a portion of the first annular element that is substantially equidistant between to the seats of each of the pairs of seats.

Roof-mounted air conditioning system with built-in compressor

Abstract: A roof-mounted air conditioning system (10) has a built-in compressor compartment (18) between the condensor and evaporator sections (12,14), the fans (23) in the condensor section (12) inducing the flow of air through the compressor compartment (18) and into the condensor section (12) through lowered vents (42) in the partition wall (35) between the compressor and condensor sections (12,14), and the air flowing from the compressor compartment (18) is confined to flow directly across the condensor coils (22) so as to satisfy the normal cooling requirements in the condensor section (12).

Multi-stage cold accumulation type refrigerator and cooling device including the same

Abstract: In a multi-stage cold accumulation type refrigerator including a compressor disposed at an ordinary temperature, a helium gas as a common operating fluid to be compressed by the compressor, and one or more expansion chambers and cold accumulators of different temperature levels; a cold accumulating member of the cold accumulators is formed of an alloy or compound containing a rare earth metal, so that the efficiency of the refrigerator can be improved. Further, a heat generation quantity due to sliding resistance of a seal is set to be smaller than a theoretical generated refrigeration quantity to be obtained on the assumption of isothermal expansion in the expansion chambers, so that the refrigerating capacity can be improved. The refrigerator is applied to a cooling device for cooling a superconducting magnet, SQUID, superconducting computer, infrared telescope, etc.