Showing papers in "Journal of Engineering for Gas Turbines and Power-transactions of The Asme in 1990"
TL;DR: In this article, the dynamic modeling of a gas-fired combined-cycle power plant with a gas turbine, a steam turbine, and an alternator rotating on a common shaft is presented.
Abstract: Greater use is being made of dynamic simulation of energy systems as a design tool for selecting control strategies and establishing operating procedures. This paper discusses the dynamic modeling of a gas-fired combined-cycle power plant with a gas turbine, a steam turbine, and an alternator-all rotating on a common shaft. A waste-heat boiler produces steam at two pressures using heat from the gas turbine flus gas. The transient behavior of the system predicted by the model for various upset situations appears physically reasonable and satisfactory for the operating constraints
147 citations
TL;DR: In this paper, the authors describe and explain unusual constitutive behavior observed in the insulative ceramic coating layer, and present details of the ceramic cracking damage accumulation process which is responsible for spallation failure.
Abstract: Failure of a two layer plasma deposited thermal barrier coating is caused by cyclic thermal exposure and occurs by spallation of the outer ceramic layer. Spallation life is quantitatively predictable, based on the severity of cyclic thermal exposure. This paper describes and attempts to explain unusual constitutive behavior observed in the insulative ceramic coating layer, and presents details of the ceramic cracking damage accumulation process which is responsible for spallation failure. Comments also are offered to rationalize the previously documented influence of interfacial oxidation on ceramic damage accumulation and spallation life.
133 citations
TL;DR: In this paper, a second-law analysis of the combustion process in a diesel engine is presented for a single-zone model and expressions for availability and the availability balance are developed in detail from the energy and entropy balances and applied in a manner that allows the irreversibility due to combustion to be separated from that associated with heat transfer to the walls.
Abstract: A second-law analysis of the combustion process in a diesel engine is presented for a single-zone model. Expressions for availability and the availability balance are developed in detail from the energy and entropy balances and applied in a manner that allows the irreversibility due to combustion to be separated from that associated with heat transfer to the walls. Availability is divided into two components: thermomechanical and chemical availability. For the first time, chemical availability of the cylinder contents is dealt with rigorously, which allows for a correct determination of combustion irreversibilities. The analysis is applied in a parametric study of the effects of combustion timing, mass burning rate, and heat transfer rate on the irreversibility and system availability.
109 citations
TL;DR: The Kalina Cycle as mentioned in this paper utilizes a mixture of ammonia and water as the working fluid in a vapor power cycle and when the liquid mixture is heated the more volatile ammonia tends to vaporize first and at a lower temperature than does pure water.
Abstract: The Kalina Cycle utilizes a mixture of ammonia and water as the working fluid in a vapor power cycle. When the liquid mixture is heated the more volatile ammonia tends to vaporize first and at a lower temperature than does pure water. This property of ammonia-water mixtures makes possible a better match to the enthalpy-temperature curve of a hot gas heat source such as a gas turbine exhaust and also permits circulation of fluids of different composition in different parts of the cycle. Taking advantage of the latter feature, condensation (absorption) can be done at slightly above atmospheric pressure with a low concentration of ammonia, while heat input is at a higher concentration for optimum cycle performance. Computer models have been used to optimize a simplified form of the cycle and to compare results for a more complex version proposed by El-Sayed and Tribus. A method of balancing the cycle was developed and key parameters for optimizing the cycle identified.
107 citations
TL;DR: In this paper, a thermodynamic analysis of a single-cylinder, four-stroke diesel engine with a swirl prechamber is presented, under firing conditions during the open and closed part of the cycle, and the relevant characteristic velocities and lengths are calculated by setting up a zero-dimensional energy cascade turbulence model.
Abstract: This work presents a thermodynamic analysis of a naturally aspirated, four-stroke, diesel engine with a swirl prechamber, under firing conditions during the open and closed part of the cycle. For calculating the heat exchange between gas and walls in both the main chamber and (swirl) prechamber, the relevant characteristic velocities and lengths are calculated by setting up a zero-dimensional energy cascade turbulence model. One-dimensional, quasi-steady, compressible flow with heat transfer inside the throat passageway connecting the two chambers is used. Combustion in both the main chamber and the swirl prechamber is attacked by proposing a two-zone combustion model, and following the movement of the spray plume inside an air solid body rotation environment in the prechamber and its later progression into the main chamber through the connecting throat. To validate the analysis, an extensive experimental investigation is undertaken at the laboratory of the authors on a flexible Ricardo, single-cylinder, swirl chamber diesel engine, and evaluating its performance in a wide range of operating conditions. The experimental results are found to be in good agreement with the theoretical results obtained from the computer program implementing the analysis.
80 citations
TL;DR: In this paper, the impact of atmospheric conditions, such as ambient temperature, pressure, and relative humidity on gas turbine performance was studied and a fully interactive computer program based on the derived governing equations was developed.
Abstract: This paper is devoted to studying the impact of atmospheric conditions, such as ambient temperature, pressure, and relative humidity on gas turbine performance. A fully interactive computer program based on the derived governing equations is developed. The effects of typical variations of atmospheric conditions on power output and efficiency are considered. The thermal efficiency and specific network of a gas turbine were calculated at different values of maximum turbine inlet temperature and variable environmental conditions
58 citations
TL;DR: In this paper, a staged subscale turbine combustor operated at conditions of a recuperated turbine was used to conduct deposition, erosion, and corrosion (DEC) experiments using three coal-water fuels (CWF).
Abstract: Deposition, erosion, and corrosion (DEC) experiments were conducted using three coal-water fuels (CWF) in a staged subscale turbine combustor operated at conditions of a recuperated turbine. This rich-quench-lean (RQL) combustor appears promising for reducing NO{sub x} levels to acceptable levels for future turbines operating with CWF. Specimens were exposed in two test sections to the combustion products from the RQL combustor. The gas and most surface temperatures in the first and second test sections represented temperatures in the first stators and rotors, respectively, of a recuperated turbine. The test results indicate deposition is affected substantially by gas temperature, surface temperature, and unburned carbon due to incomplete combustion. The high rates of deposition observed at first stator conditions showed the need for additional tests to identify CWF coals with lower deposition tendencies and to explore deposition control measures such as hot gas cleanup.
57 citations
TL;DR: In this article, an experimental test rig was set up with a long thin shaft and several masses to represent a flexible shaft machine, and an active magnetic damper was placed in three locations: near the midspan, near one end disk, and close to the bearing.
Abstract: Many rotating machines such as compressors, turbines, and pumps have long thin shafts with resulting vibration problems. This paper describes an experimental test rig that was set up with a long thin shaft and several masses to represent a flexible shaft machine. An active magnetic damper was placed in three locations: near the midspan, near one end disk, and close to the bearing
41 citations
TL;DR: In this paper, a general analytical approach that directly determines the optimum thermodynamic and economic behavior of thermal systems is discussed and illustrated using Rankine cycles using Second Law and typical Second Law costing techniques, this method provides for the creation of mathematical models that balance a cycle's operating costs and capital expenditures.
Abstract: Optimization techniques are, in general, still not used today in the design and performance analysis of thermal systems and their components. The engineer's search for the best system configuration is based solely on rules-of-thumb and not on a systematic, analytical determination of what the optimal design or performance should be. In addition, economic factors are not directly tied to thermodynamic ones; therefore, the economic ramifications of thermodynamic changes to the system are not usually, if ever, immediately apparent. A general analytical approach that directly determines the optimum thermodynamic and economic behavior of thermal systems is discussed and illustrated using Rankine cycles. Utilizing the Second Law and typical Second Law costing techniques, this method provides for the creation of mathematical models that balance a cycle's operating costs and capital expenditures. Such models can be solved numerically, subject to various constraints, for the optimum design and performance of thermal systems.
39 citations
TL;DR: In this article, the effects of the pinch point used in the design of the heat recovery steam generator, and pressure of process steam on fuel-utilization efficiency, power-to-heat ratio, and second-law efficiency, are examined.
Abstract: The thermodynamic performance of selected combustion gas turbine cogeneration systems has been studied based on first-law as well as second-law analysis. The effects of the pinch point used in the design of the heat recovery steam generator, and pressure of process steam on fuel-utilization efficiency (first-law efficiency), power-to-heat ratio, and second-law efficiency, are examined. Results for these systems using state-of-the-art industrial gas turbines show clearly that performance evaluation based on first-law efficiency alone is inadequate. Decision makers should find the methodology contained in this paper useful in the comparison and selection of cogeneration systems.
36 citations
TL;DR: Various methods of computer simulation that have been developed are presented in summary and bird strikes on a rotating spinner and an intake blade are investigated with the finite element program DYNA3D.
Abstract: External components of aeroengines, such as casings and intake blades, must be capable of withstanding bird strikes. Various methods of computer simulation that have been developed are presented in summary. Bird and component are divided into finite elements. The component model must allow for great elastic-plastic deformation, where the yield strength is a function of the strain rate. A model shape and a homogeneous substitute material must be defined for the complicated and nonhomogeneous structure of the bird. Bird strikes on a rotating spinner and an intake blade are investigated with the finite element program DYNA3D
TL;DR: In this paper, the development of zirconia coatings, applied by the electron beam evaporation-physical vapor deposition process, that are tailored to provide superior durability in a marine engine environment is described.
Abstract: This paper describes the development of zirconia coatings, applied by the electron beam evaporation-physical vapor deposition process, that are tailored to provide superior durability in a marine engine environment
TL;DR: In this article, the performance of yttria-stabilized zirconia (YSZ), ceria stabilized (CSZ), and magnesia-stabeled (MSZ) coatings was evaluated using an atmospheric burner rig; test environment contained compounds of vanadium, sodium, and sulfur.
Abstract: The performance of yttria-stabilized zirconia (YSZ), ceria-stabilized zirconia (CSZ), and magnesia-stabilized zirconia (MSZ) coatings was evaluated using an atmospheric burner rig; test environment contained compounds of vanadium, sodium, and sulfur. The tests were designed to simulate the deposit chemistry and sulfur trioxide partial pressures expected in a marine gas turbine engine operating on contaminated fuel. YSZ, CSZ, and MSZ coatings all underwent reaction in the burner rig environment; the reaction products and their effects on spallation were varied
TL;DR: In this paper, an economic analysis of a biomass-integrated gasifier/steam-injected gas turbine (BIG/STIG) is presented for cane sugar factories, where sugar cane residues would be the fuel.
Abstract: Steam injection for power and efficiency augmentation in aeroderivative gas turbines is now commercially established for natural gas-fired cogeneration. Steam-injected gas turbines fired with coal and biomass are being developed. In terms of efficiency, capital cost, and commercial viability, the most promising was to fuel steam-injected gas turbines with biomass is via the biomass-integrated gasifier/steam-injected gas turbine (BIG/STIG). The R and D effort required to commercialize the Big/STIG is modest because it can build on extensive previous coal-integrated gasifier/gas turbine development efforts. An economic analysis of BIG/STIG cogeneration is presented for cane sugar factories, where sugar cane residues would be the fuel. A BIG/STIG investment would be attractive for sugar producers, who could sell large quantities of electricity, or for the local electric utility, as a low-cost generating option. Worldwide, the cane sugar industry could support some 50,000 MW of BIG/STIG capacity, and there are many potential applications in the forest products and other biomass-based industries.
TL;DR: In this paper, the authors investigated the influence of fuel cost on the operation of a gas turbine-waste heat boiler cogeneration plant by an optimal operational planning method and showed that the optimal operational policy is superior in economy as compared with other conventional ones.
Abstract: The influence of fuel cost on the operation is investigated for a gas turbine-waste heat boiler cogeneration plant by an optimal operational planning method. A planning method is first presented by which the operational policy of each piece of constituent equipment is determined so as to minimize the operational cost. Then, a case study is performed for a cogeneration plant used for district heating and cooling. Through the study, it is made clear how the optimal operational policy and the economic or energy conservative properties are influenced by the costs of purchased electric power and natural gas. It is also shown that the optimal operational policy is superior in economy as compared with other conventional ones.
TL;DR: In this paper, the results from an experimental investigation of the compressor casing vibration of an industrial gas turbine are presented, where it is demonstrated that statistical properties of acceleration signals can be linked with engine operating conditions.
Abstract: The results from an experimental investigation of the compressor casing vibration of an industrial gas turbine are presented. It is demonstrated that statistical properties of acceleration signals can be linked with engine operating conditions. The power content of such signals is dominated by contributions originating from the stages of the compressor, while the contribution of the shaft excitation is secondary. The transfer functions allow reconstruction of unsteady pressure signal features from the accelerometer readings
TL;DR: In this paper, a macroscopic noninteractive reliability model for ceramic matrix composites is presented, where tensorial invariant theory is used to create an integrity basis with invariants that correspond to physical mechanisms related to fracture.
Abstract: A macroscopic noninteractive reliability model for ceramic matrix composites is presented. The model is multiaxial and applicable to composites that can be characterized as orthotropic. Tensorial invariant theory is used to create an integrity basis with invariants that correspond to physical mechanisms related to fracture. This integrity basis is then used to construct a failure function per unit volume (or area) of material. It is assumed that the overall strength of the composite is governed by weakest link theory. This leads to a Weibull type model similar in nature to the principle of independent action (PIA) model for isotropic monolithic ceramics. An experimental program to obtain model parameters is briefly discussed. In addition, qualitative features of the model are illustrated by presenting reliability surfaces for various model parameters.
TL;DR: In this article, the spray characteristics of several simplex pressure-swirl nozzles are examined using water as the working fluid, and measurements of mean drop size, drop-size distribution, effective spray cone angle, and circumferential liquid distribution are carried out over wide ranges of injection pressure.
Abstract: The spray characteristics of several different simplex pressure-swirl nozzles are examined using water as the working fluid. Measurements of mean drop size, drop-size distribution, effective spray cone angle, and circumferential liquid distribution are carried out over wide ranges of injection pressure. Eight different nozzles are employed in order to achieve a wide variation in the length/diameter ratio of the final discharge orifice. Generally, it is found that an increase in discharge orifice length/diameter ratio, l(o)/d(o), increases the mean drop size in the spray and reduces the spray cone angle. The circumferential liquid distribution is most uniform when l(o)/d(o) = 2. If l(o)/d(o) is raised above or lowered below this optimum value, the circumferential uniformity of the liquid distribution is impaired. The observed effects of l(o)/d(o) on spray characteristics are generally the same regardless of whether the change in l(o)/d(o) is accomplished by varying l(o) or d(o).
TL;DR: In this paper, a hierarchy of methods used for crankshaft stress analysis with case studies is described, and a computer-based analysis system is described that combines FE and classical methods to allow optimized designs to be produced efficiently.
Abstract: The conflicting legislative and customer pressures on engine design, for example, combining low friction and a high level of refinement, require sophisticated tools if competitive designs are to be realized. This is particularly true of crankshafts, probably the most analyzed of all engine components. This paper describes the hierarchy of methods used for crankshaft stress analysis with case studies. A computer-based analysis system is described that combines FE and classical methods to allow optimized designs to be produced efficiently. At the lowest level simplified classical techniques are integrated into the CAD-based design process. These methods give the rapid feedback necessary to perform concept design iterations. Various levels of FE analysis are available to carry out more detailed analyses of the crankshaft. The FE studies may feed information to or take information from the classical methods. At the highest level a method for including the load sharing effects of the flexible crankshaft within a flexible block interconnected by nonlinear oil films is described.
TL;DR: In this article, acid dewpoints were calculated from SO 2 -to-SO 3 conversion in gas turbine exhaust, which can be used as guidelines in setting feedwater temperatures in combined-cycle systems.
Abstract: Acid dewpoints were calculated from SO 2 -to-SO 3 conversion in gas turbine exhaust. These data can be used as guidelines in setting feedwater temperatures in combined-cycle systems. Accurate settings can prevent corrosion of heat-exchanger (boiler) tubes, thus extending their life time. This study was done using gas turbine engines and a laboratory generator set. The units burned marine diesel or diesel No. 2 fuel with sulfur contents up to 1.3 percent. The exhaust from these systems contained an excess of 20 percent oxygen, and 3-10 percent water vapor. Exhaust temperatures randes from 728 to 893 K (455 to 620 o C)
TL;DR: In this article, a zero-dimensional model employs polynomial and dynamic techniques to generate cam profiles for valve event optimisation, and the model was calibrated and validated against data from a General Motors 2.5 litre engine.
Abstract: A computer simulation has been developed to study the effects of valve event parameters (lift, duration, and phasing) on spark–ignition engine performance. The zero–dimensional model employs polynomial and dynamic techniques to generate cam profiles for valve event optimisation. The model was calibrated and validated against data from a General Motors 2.5 litre engine. The simulation was then used to determine optimum valve events under different engine conditions. This insight was used to improve the cam design. Subsequent engine testing confirmed that a 3 per cent improvement in peak torque could be obtained with the optimised cam.
TL;DR: In this paper, an economic analysis of the biomass-integrated gasifier/steam-injected gas turbine (BIG/STIG) is presented for cane sugar factories, where sugar cane residues would be the fuel.
Abstract: Steam injection for power and efficiency augmentation in aeroderivative gas turbines is now commercially established for natural gas-fired cogeneration. Steam-injected gas turbines fired with coal and biomass are being developed. In terms of efficiency, capital cost, and commercial viability the most promising way to fuel steam-injected gas turbines with biomass is via the biomass-integrated gasifier/steam-injected gas turbine (BIG/STIG). The R&D effort required to commercialize the BIG/STIG is modest because it can build on extensive previous coal-integrated gasifier/gas turbine development efforts. An economic analysis of BIG/STIG cogeneration is presented here for cane sugar factories, where sugar cane residues would be the fuel
TL;DR: In this article, a staged, subscale turbine combustor based on a promising rich-quench-lean combustion approach to reduce NO x emissions was used to evaluate deposition, erosion, and corrosion from coal-water fuels (CWF).
Abstract: A staged, subscale turbine combustor based on a promising rich-quench-lean combustion approach to reduce NO x emissions was used to evaluate deposition, erosion, and corrosion (DEC) from coal-water fuels (CWF). This combustor was operated with three CWF at conditions of a recuperated turbine
TL;DR: In this article, the authors investigated the consistency of mixing between the jets, as indicated by the regularity of the temperature pattern around the crossflow annulus, and found that the degree of distortion varies in a random manner, so that each jet has its own mixing characteristics.
Abstract: Measurements have been made on a fully annular test facility, downstream of a row of heated dilution jets injected normally into a confined crossflow at a momentum flux ratio of 4. The investigation concentrated on the consistency of mixing between the jets, as indicated by the regularity of the temperature pattern around the crossflow annulus. When the heated air was supplied from a representative feed annulus, the exit velocity profile across each plunged hole was significantly altered and caused a distortion of the temperature distribution in the ensuing jet. The degree of distortion varies in a random manner, so that each jet has its own mixing characteristics, thereby producing irregularity of the temperature pattern around the annulus. With the same approach and operating conditions some of the plunged dilution holes were modified, and tests on this modified sector indicated a significant improvement in the circumferential regularity of the temperature pattern. Further tests showed that these modifications to the dilution holes had a negligible effect on the values of the discharge coefficients.
TL;DR: In this article, the authors investigated experimentally the effect of tuning the secondary-flow path length, adding a flow restrictor at the combining-cone entry station, and redesigning the combining cone itself.
Abstract: A description is given of a simple, prototype, pulse, pressure-gain combustor for a gas turbine. The work reported was targeted at alleviating problems previously observed with the prototype combustor. These were related to irreversibilities, causing a performance deficiency, in the secondary flow passage. The work consisted of investigating experimentally the effect of tuning the secondary-flow path length, adding a flow restrictor at the combining-cone entry station, and redesigning the combining cone itself. The overall result was to eradicate the previously noted performance deficiency, thereby increasing the maximum pressure gain obtained in the gas turbine from 1.6 to 4.0 percent of the compressor absolute delivery pressure.
TL;DR: In this paper, a quasi-dimensional engine-simulation program and a multidimensional engine-flow and combustion code were used to study the effect of flame propagation in lean-burn engines.
Abstract: Previous engine data suggest that slower flame propagation in lean-burn engines could be due to slower flame expansion velocity at lean conditions than at stoichiometric combustion. This paper reports on two classes of model, a quasi-dimensional engine-simulation program and a multidimensional engine-flow and combustion code, used to study this effect in detail and to assess the capabilities of the models to resolve combustion details. The computed flame-speed data from each program differed somewhat in magnitude, but the predicted trends at various equivalence ratios were quite similar. The trends include: (1) The peak in-cylinder burned-gas temperature decreases by about 300 K as the equivalence ratio is decreased from 0.98 to 0.70. (2) Both the laminar flame speed and the flame-propagation speed, the latter computed from the time derivative of flame radius, decrease with decreasing equivalence ratio.
TL;DR: In this article, the steady-state unbalance response of a Jeffcott rotor incorporating short squeeze film dampers executing circular centered whirl is obtained by a fast algorithm, where fluid inertia forces are included in the model of the dampers.
Abstract: The steady-state unbalance response of a Jeffcott rotor incorporating short squeeze film dampers executing circular centered whirl is obtained by a fast algorithm. Fluid inertia forces are included in the model of the squeeze film dampers
TL;DR: In this paper, a general method for analyzing the time-correlation and frequency-spectral structure of turbulence in IC reciprocating engines was developed and applied to the cycle-resolved turbulent velocity fluctuation and to the fluctuating motion in its more conventional sense.
Abstract: A general method for analyzing the time-correlation and frequency-spectral structure of turbulence in IC reciprocating engines was developed and applied to the cycle-resolved turbulent velocity fluctuation and to the fluctuating motion in its more conventional sense. It is based on an alternative definition of the Eulerian temporal autocorrelation coefficient so as to reduce this to an even function solely of the separation time within specific correlation periods into which the engine cycle is divided
TL;DR: This paper presents an approach to real-time turbine simulation, using a method of sequential state space linearizations that has very good accuracy for both transient and steady-state predictions.
Abstract: This paper presents an approach to real-time turbine simulation, using a method of sequential state space linearizations. The linearizations are shown to be simple enough to be computed in real time. Comparisons between simulations and experiments are presented and discussed. The approach is shown to have very good accuracy for both transient and steady-state predictions
TL;DR: In this paper, a single spool rotor bearing system is used to demonstrate the merits of the finite element method on the design of a spool bearing system, and the exterior penalty function method is used as the optimization technique to minimize the system weight.
Abstract: The constraints include restrictions on stresses, unbalance response, and/or critical speeds. The system dynamic behaviors are analyzed by the finite element method. The exterior penalty function method is used as the optimization technique to minimize the system weight. The system design variables are the cross-sectional areas of the shaft and the stiffnesses of the bearings. The example of a single spool rotor bearing system is employed to demonstrate the merits of the design algorithm