Showing papers in "Journal of Energy in 1982"
TL;DR: In this article, the pyroelectric effect has been used for the conversion of heat to electricity by means of pyro-electric effect and the basic thermal-electrical cycle is described.
Abstract: The conversion of heat to electricity by means of the pyroelectric effect is demonstrated here. The basic thermal-electrical cycle is described. The production of 100 mj of electrical energy per cubic centimeter of ferroelectric material (PZST) per thermal cycle (with a temperature span of 20°C) has been observed. This observation is discussed in terms of using regeneration to approach Carnot efficiency. The staging of ferroelectrics to increase the temperature range (and hence efficiency) is also explained.
84 citations
TL;DR: In this paper, the double-multiple-streamtube model was used for determining the aerodynamic blade loads and roto performance on the Darrieus vertical-axis wind turbine with curved blades.
Abstract: The double-multiple-streamtube model was used for determining the aerodynamic blade loads and roto performance on the Darrieus vertical-axis wind turbine with curved blades. This analytical model i capable of predicting the difference in the induced velocities at the upstream and downstream passes. The upwind and downwind interference factors are calculated by a double iteration, one for each half of the rotor and vertical variations in the freestream velocity are accounted for. Under local aerodynamic conditions a closed-form analytical solution is obtained for two functions, one for the upwind and one for the downwind hal of the turbine. Thus the local aerodynamic loads on the blade and the rotor performance are calculated more accurately than by other streamtube methods. Comparison of the analytical results obtained with the doublemultiple-streamtube model and the available field test data for the Sandia 17-m machine shows good agreement. This method can therefore be used for generating a suitable aerodynamic-load model for structural-design analysis of the Darrieus rotor.
75 citations
TL;DR: In this paper, a mathematical model of the three-dimensional two-phase reacting flows in gas turbine combustors has been developed which takes into account the mass, momentum, and energy coupling between the phases.
Abstract: A mathematical model of the three-dimensional two-phase reacting flows in gas turbine combustors has been developed which takes into account the mass, momentum, and energy coupling between the phases. The fundamental equations of motion of the droplets are solved numerically in a Lagrangian frame of reference, using a finite-difference solution of the governing equations of the gas. Well-known relations are used to model the heat and mass transfer processes and the initial droplet heat-up is allowed for. The entire fuel spray is constructed using a finite number of size ranges obeying a two parameter droplet size distribution. The results are found to be in close agreement with experimental data. An important feature of this analytical technique is that it permits the rational selection or specification of fuel nozzle design.
50 citations
43 citations
TL;DR: In this article, the authors investigated the Wells turbine and its difficulty in running up to operational speed when started from rest (known as "crawling") and showed that a high solidity and a low hub-to-tip ratio rotor is required to avoid crawling.
Abstract: The Wells turbine is investigated, as well as its difficulty in running up to operational speed when started from rest (known as ''crawling''). A schematic is presented of: the Wells turbine; a typical graph of the tangential force coefficient (C /SUB r/ )-angle of incidence curve for a symmetrical airfoil; and graphs showing the influence of hub-to-tip ratio and solidity on starting and efficiency. In order to avoid crawling, a high solidity and a low hub-to-tip ratio rotor is required.
37 citations
35 citations
TL;DR: In this paper, the development of the three-dimensional flow and temperature fields in an MHD channel is studied, where partial differential equations for the three momenta, the enthalpy, and the electrical fields are solved by a finitedifference calculation procedure.
Abstract: The development of the three-dimensional flow and temperature fields in an MHD channel is studied. The partial-differential equations for the three momenta, the enthalpy, and the electrical fields are solved by a finitedifference calculation procedure. The turbulence phenomenon is represented by a two-equation turbulence model, in which additional equations are solved for the kinetic energy of turbulence and its dissipation rate. Calculations have been made for typical MHD channel conditions in the subsonic flow regime. Interesting secondary flow patterns have been observed to develop along the duct as the flow and electrical fields interact with each other. The detailed development of the three-dimensional flow, temperature, and electrical fields is presented.
32 citations
TL;DR: In this paper, an integral method is proposed where spatial profiles of pressure and flow rate are assumed which satisfy the boundary conditions, and two procedures have been employed: sensitivity tests including systematic variations of profile families, and mathematical analysis of the PDE based on an iterative approach carried out to second order.
Abstract: A sudden rupture of a high-capacity gas transmission line will result in a massive release of combustible material. To assess this hazard it is necessary to know the rate of outflow at the breakpoint as a function of time. The time required to empty a long pipeline is of the order of several hours, and the major part of the outflow occurs in a time period for which wave processes and inertial effects are shown to be of little importance. The flow rate is governed by a nonlinear PDE expressing the balance between friction and pressure forces. The initial distribution of pressure is of considerable importance, the most difficult case being a break at the high-pressure end. To solve the boundary-value problem, an integral method is proposed where spatial profiles of pressure and flow rate are assumed which satisfy the boundary conditions. Simple solutions are developed for flow cases of prime interest. To check the validity and accuracy of the integral method, two procedures have been employed: 1) sensitivity tests including systematic variations of profile families, and 2) mathematical analysis of the PDE based on an iterative approach carried out to second order. The integral method is shown to have adequate accuracy for engineering studies.
21 citations
TL;DR: In this article, the effect of wing drag on the static profile and force transmission efficiency of a tether connected to a kite-like system was considered, assuming that the velocity and density fields due to the wind do not vary with altitude.
Abstract: N a tethered wind energy conversion system, usually the tether is designed with the assumption that the tether static profile is a catenary.1"4 The catenary behavior is assumed because the equations of a catenary are well known and can be obtained analytically without much difficulty. However, a catenary cannot accurately represent the tether profile in situations where the wind drag is of the same order of magnitude as the weight of the tether. The tether drag varies as the tether diameter, while the tether weight is proportional to the square of the diameter. Consequently, for smalldiameter tethers or when the tethers are made of materials with high strength-to-weight ratios, the deviation from a catenary behavior may become appreciable. In this study, we have considered the effect of wing drag on the static profile and force transmission efficiency of a tether connected to a kite-like system. Calculations have been made assuming that the velocity and density fields due to the wind do not vary with altitude.
21 citations
TL;DR: In this article, the authors explained that two major concerns in the development of the methanol-to-gasoline (MTG) process are heat removal from the reactor and the formation of durene (1-,2-,4-,5-tetramethylbenzene).
Abstract: This paper explains that 2 major concerns in the development of the methanol-to-gasoline (MTG) process are heat removal from the reactor and the formation of durene (1-,2-,4-,5-tetramethylbenzene). Conversion of methanol to gasoline is highly exothermic (about 1510-1740 kJ/kg of methanol converted) and the adiabatic temperature rise would be almost 600C. Within Mobil, 2 types of reactor configurations were adopted for development: an adiabatic fixed-bed and a fluid-bed reactor. The fixed-bed reactor is ready for immediate commercialization and is more suitable for smaller scale operation. The fluid-bed reactor is under development and possesses the following potential advantages over the fixed-bed reactor: reaction heat removal is simplified by using the superior heat transfer characteristics of a fluid bed; when coupled with alkylation, the fluid bed gives a higher gasoline yield than the fixed bed; and constant catalyst activity, gasoline selectivity, and gasoline quality can be maintained with the fluid-bed operation. Fixed-bed is cyclic.
19 citations
TL;DR: In this article, the authors describe the computation of the flow, reaction, and heat transfer in the combustion chamber region of a typical industrial glass producing furnace, and demonstrate the value of such computations to furnace designers.
Abstract: The paper describes the computation of the flow, reaction, and heat transfer in the combustion chamber region of a typical industrial glass producing furnace. The economy of the computation is considerably enhanced by the use of special grids; by the separate calculation of the burner and bulk combustion chamber regions in a manner which takes into account the differing physical nature of their flows; and by a novel technique for the handling of the thermal radiation. Predictions which demonstrate the value of such computations to furnace designers are shown for a range of operating parameters.
TL;DR: In this paper, the authors presented a study of a porous flat plate solar air heater, which was modified by using appropriate boundary conditions and also considering the realistic case of different air and matrix temperatures.
Abstract: This communication presents a study of a porous flat plate solar air heater. An earlier theory use to analyze such a system has been modified by using 1) appropriate boundary conditions and also 2) by considering the realistic case of different air and matrix temperatures. Numerical calculations have been performed to bring out the difference between the earlier theory and the present theory. The results of the present theory are found to be in excellent agreement with the measurements of an experiment. The yearly performance of the system has also been evaluated for Delhi-type climates.
TL;DR: In this article, a model for calculating cross-plane current and electric field distributions in MHD generator channels is formulated and numerically solved, which can be implemented on the IBM 3033 digital computer in less than 1 CPU second and thus the model can be conveniently coupled to a full three dimensional gasdynamics analysis.
Abstract: A model for calculating cross-plane current and electric field distributions in MHD generator channels is formulated and numerically solved. The chief advantage of this model is that its solution can be implemented on the IBM 3033 digital computer in less than 1 CPU second and thus the model can be conveniently coupled to a full three-dimensional gasdynamics analysis. The model is equally valid for Faraday, diagonal-insulating-sidewall, and diagonal-conducting-sidewall channels. Accuracy of the model is calibrated by comparing its predictions with the results of three-dimensional finite-segmentation analyses. The model is found to perform best for channels with low wall temperatures and low electrode pitch-to-height ratios and when the boundary layers are thick. A discussion is given of the roles of the nonuniformity in normal current density, as predicted by the model, leading to velocity overshoots in the boundary layers, and of the transverse nonuniformity in Hall current density, generating secondary flows.
TL;DR: In this paper, the characteristic time model for ignition is used to describe the spark ignition of liquid fuel sprays in gas turbine combustors, which states that for ignition to occur, the energy of a spark must heat up an initial volume such that the heat release rate within that volume is greater than the loss rate.
Abstract: The characteristic time model for ignition is used to describe the spark ignition of liquid fuel sprays in gas turbine combustors. The model states that for ignition to occur, the energy of a spark must heat up an initial volume such that the heat release rate within that volume is greater than the loss rate. Heat generation is limited first by a droplet evaporation time and then a kinetic time; heat loss (for gas turbine applications) is due to turbulent diffusion and, hence, is controlled by a mixing time. Data from two can-type combustors and seventeen fuels are correlated by a single ignition limit curve. The key to applying the model to engine data is the estimation of drop sizes and equivalence ratios at the spark gap.
TL;DR: In this article, the influence of air velocity and liquid properties on drop-size distribution was examined using an airblast atomizer in which a flat liquid sheet is exposed to high velocity air on both sides.
Abstract: The influence of air velocity and liquid properties on drop-size distribution is examined using an airblast atomizer in which a flat liquid sheet is exposed to high velocity air on both sides. Both photographic and lightscattering techniques are employed to measure drop sizes. The effect of the physical properties of liquids is studied by preparing special liquid solutions to obtain wide variations in one property while keeping the others sensibly constant. The results obtained show that increases in air velocity and/or reduction in liquid flow rate lead to more uniform sprays and a lower mean drop size. Higher values of viscosity and surface tension result in coarser sprays of larger mean drop size. The effect of liquid density on spray characteristics appears to be quite small. In general, it is found that any change in liquid properties or atomizer operating conditions which tends to lower the mean drop size will also tend to narrow the range of drop sizes produced.
TL;DR: In this article, the influence of a horizontal air jet on the performance of a fluidized bed coal combustor was investigated using cold flow model studies as a basis, and the importance of the synergistic influence of bed solids blending rate, elutriation rate, superficial velocity, and chemical reaction rate in realizing high combustion efficiencies was demonstrated.
Abstract: Experiments have been conducted to investigate the influence of a horizontal air jet on the performance of a fluidized bed coal combustor. Cold flow model studies were first made to visually and photographically study the effect of jet penetration on bed solids circulation patterns and mixing characteristics. Using these cold flow model studies as a basis, the influence of jet penetration and jet induced solids circulation on the combustion characteristics of a high sulfur coal has been investigated in an identical fluidized bed combustor. The experiments show that the combustion efficiency and bed temperature are usually higher at low jet air mass flow rates. The importance of the synergistic influence of bed solids blending rate, the elutriation rate, the superficial velocity, and the chemical reaction rate in realizing high combustion efficiencies is demonstrated. Pf PP Nomenclature = nozzle diameter, m = mean particle diameter, m = gravitational constant jet penetration depth from end of nozzle, m = jet air velocity, m/s = bed void fraction = gas density, kg/m3 = bed solid particle density, kg/m3
TL;DR: In this article, the authors derived a simple expression to determine the rate of desorption of water if it is assumed that the temperature, concentration, and vapor pressure of the weak absorbent solution are constant at the arithmetic average of these values at the beginning and end of the regenerator.
Abstract: This paper reports on the derivation of a simple expression to determine the rate of desorption of water if it is assumed that the temperature, concentration, and vapor pressure of the weak absorbent solution are constant at the arithmetic average of these values at the beginning and end of the regenerator. Thermal performance depends on the rate of evaporation of water from the weak solution, which will vary along the flow length of the regenerator. Factors to be considered include climatic variables such as insolation, wind velocity, ambient temperature, and the flow rates and initial parameters of the absorbent solution and air. Calcium chloride is analyzed as the absorbent, while the forced convective heat transfer coefficient between the solution film and airstream is evaluated for laminar and turbulent conditions. Figures are presented showing effect of water vapor pressure in air on rate of desorption and effect of preheating the solution and air. It is concluded that solution regeneration is more effective while preheating the air than while preheating the solution.
TL;DR: In this article, experimental data collected from coal-fired MHD generator tests conducted at the University of Tennessee Space Institute, Energy Conversion Facility are compared to theoretical predictions, and three distinct numerical, steady flow models are used in these comparisons which include one-dimensional, two-dimensional and quasi-three-dimensional techniques.
Abstract: Experimental data collected from coal-fired MHD generator tests conducted at the University of Tennessee Space Institute, Energy Conversion Facility are compared to theoretical predictions. Three distinct numerical, steady flow models are used in these comparisons which include one-dimensional, two-dimensional, and quasi three-dimensional techniques. Comparisons are made between measured gasdynamic and electrical performance parameters to those predicted at a fixed set of generator operating conditions which include an experimentally inferred entrance temperature. These analyses serve to illustrate the effects of flowfield dimensionality on generator performance predictions. Discussions of the applications and limitations of each analytical model are included along with suggestions for further refinements of each to achieve a better representation of real MHD phenomena.
TL;DR: In this paper, the split cylinder test was reviewed and critically evaluated in detail to assure its applicability to the study of Green River Formation oil shale along the bedding planes, which is a mechanical property parameter important to predicting how oil shale will break.
Abstract: Ultimate tensile strength of Green River Formation oil shale along the bedding planes is a mechanical property parameter important to predicting how oil shale will break. This is particularly important to in situ fragmentation. The split cylinder test was reviewed and critically evaluated in detail to assure its applicability to this study. Test specimens representing oil shales of the Mahogany zone sections of cores taken from the Naval Oil Shale Reserve No. 1 in Colorado and from the Bonanza area in Utah were subjected to the split cylinder test. Linear regression equations relating ultimate tensile strength along the bedding planes to volume percent of organic matter in the rock were developed from the test data. The Utah and Colorado equations are statistically similar, corresponding to their identical mineralogy. A similar equation representing the clay-rich, dolomitepoor Tipton member of Wyoming's Green River formation differed sharply, demonstrating an emphatic mineralogicaS influence with major variations.
TL;DR: In this paper, an airborne high-power-density superconducting generator under construction at the authors' company is considered. But the design approach is quite different from that of any other generator.
Abstract: The application of superconductors to the field windings of synchronous ac generators has been the subject of considerable development effort over the past decade. Machines and/or components have been built and tested in more than half a dozen countries. This paper considers an airborne high-power-density superconducting generator under construction at the authors' company. The unique requirements of this application include high power density, fast startup capability, and high terminal voltage. As a consequence, the design approach is quite different from that of any other generator. The significant design constraints and the configuration of the generator under construction are reviewed.
TL;DR: In this paper, a columnar tungsten surface structure was developed for the distribution wick of a gravity assisted heat pipe with a 19mm-i.d. SiC heat pipe.
Abstract: Operation of heat pipes in air at temperatures above 1200/sup 0/K has been accomplished using SiC as a shell material and a chemical vapor deposit (CVD) tungsten inner liner for protection of the ceramic from the sodium working fluid. The CVD tungsten has been used as a distribution wick for the gravity assisted heat pipe through the development of a columnar tungsten surface structure, achieved by control of the metal vapor deposition rate. Wick performance has been demonstrated in tests at approximately 2 kW throughput with a 19-mm-i.d. SiC heat pipe. Operation of ceramic heat pipes in repeated start cycle tests has demonstrated their ability to withstand temperature rise rates of greater than 1.2 K/s.
TL;DR: The importance of the centrifugal force in the stabilization of flames in swirling flows is difficult to access under normal operating conditions owing to the presence of other stabilizing factors as mentioned in this paper, however, at conditions near the blowoff limit the effect of centrifugal forces tends to be predominant.
Abstract: The importance of the centrifugal force G in the stabilization of flames in swirling flows is difficult to access under normal operating conditions owing to the presence of other stabilizing factors. However, at conditions near the blowoff limit the effect of centrifugal force tends to be predominant. Results calculated from several experimental sources have shown there is little effect on flame propagation for G less than or equal to 200 g. For G greater than or equal to 600g, good agreement has been found with the ''bubble transport'' correlation: S /SUB B/ ..cap alpha..G /SUP 1/2/ No abrupt decrease in flame speed is obtained for centrifugal force G greater than or equal to 3500g as experienced by Lewis. The effect of G on flame speed is likely to be beneficial to small highly loaded combustors, where it is possible to generate high values of G in an operating range where other flame stabilization factors are also present.
TL;DR: The High Performance Demonstration Experiment (HPDE) as mentioned in this paper demonstrated that an MHD generator, simulating a commercial scale device, can convert 15% of the available thermal energy into electrical power.
Abstract: The high performance demonstration experiment (HPDE) is in progress with the objective of demonstrating that an MHD generator, simulating a commercial scale device, can convert 15% of the available thermal energy into electrical power Operation of the facility was initiated in the fall of 1979 Preliminary experimental results have been obtained with the channel in the Faraday configuration and magnetic field strengths from 15-35 T A maximum Faraday power of 23 MW has been generated which represents an enthalpy extraction of 9% A detailed analysis of the electrical power and aerodynamic characteristics of the channel, including the voltage drop in the relatively cold plasma layers near the electrode walls is presented
TL;DR: In this article, a comparison of advanced heat engines for use on the dish power module is presented in terms of the performance potential of each engine as weighed against its requirements for advanced technology development.
Abstract: A paraboloidal dish solar thermal power plant produces electrical energy by a two-step conversion process. The collector subsystem is composed of a two-axis tracking paraboloidal concentrator and a cavity receiver. The concentrator focuses intercepted sunlight (direct, normal insolation) into a cavity receiver whose aperture encircles the focal point of the concentrator. At the internal wall of the receiver the electromagnetic radiation is converted to thermal energy. A heat engine/generator assembly, which is mounted directly behind th receiver, then converts the thermal energy captured by the receiver to electricity. Developmental activity has been concentrated on relatively small power modules which employ 11- to 12-m-diam dishes to generate nominal power levels of approximately 20 kW. A comparison of advanced heat engines for use on the dish power module is presented in terms of the performance potential of each engine as weighed against its requirements for advanced technology development. Three advanced engine possibilities are considered. These are the Brayton (gas turbine), Brayton/Rankine combined cycle, and Stirling engines. All three engine candidates are attractive in terms of overall system performance potential.
TL;DR: In this paper, a 60 deg diagonal conducting wall generator with vitiation-heated oxidizer was tested at the University of Tennessee Space Institute, Energy Conversion Division, in support of technology development of coal-fired MHD generator systems.
Abstract: Tests were conducted at the University of Tennessee Space Institute, Energy Conversion Division, in support of technology development of coal-fired MHD generator systems. The primary objectives of the test series were to evaluate the overall electrical performance of the 60 deg diagonal conducting wall generator with vitiationheated oxidizer, to study the thermal behavior of capped vs solid frame electrodes, and to investigate various power takeoff schemes. Results of these areas of investigation are presented and discussed.
TL;DR: In this article, a permanent magnet (PM) excited synchronous generator was proposed to be integrated into a modern jet engine to replace the mechanical accessory power drive system; thus all secondary power supplied from the engine to the aircraft is supplied by the electrical generator.
Abstract: The paper presented discusses the design of a permanent magnet (PM) excited synchronous generator to be integrated into a modern jet engine. The electrical machine is to replace the mechanical accessory power drive system; thus all secondary power supplied from the engine to the aircraft is supplied by the electrical generator. The generator is also to double as starter motor for the engine, a job which can easily be handled at the required total secondary power level. It has been found that an integrated generator is technically feasible. It is heavier than its conventional counterpart, but offers significant reliability and maintenance benefits. This paper describes part of the work done for a study to investigate the feasibility of integrating a PM generator into a jet engine. IR Force and industry have recognized the potential value of integrating secondary-power-generation devices and engine accessory components into the basic engine structure. The objective of this design approach is to minimize the propulsion system envelope. Provided that a suitable configuration can be defined, the propulsion system should then provide improved installed performance, in two respects: drag will be reduced, and reliability will be improved by eliminating the complex mechanical secondary-power- generating equipment and accessory drive system. A program was undertaken to study the practicality of an integrated jet engine generator and its potential benefits. Experience with conventional aircraft alternators had proven that only solid rotor type electrical machines such as a per- manent magnet (PM) machine would meet the stringent reliability and maintainability requirements which would allow the integration of the alternator into an engine. The program encompassed a detailed study and design effort to determine applicability, location, and configuration of the engine structure. This paper describes the tradeoff and design studies un- dertaken to obtain an electrical machine design suitable for the application. The major goals were to achieve high reliability, low maintenance, and low life cycle costs for the electrical system. These goals can best be served by PM ex- cited electrical machines, since their rotors have a reliability potential which is higher than that for industrial induction motors and only surpassed by solid rotor machines. The PM generator is part of a variable speed constant- frequency-generating system which consists of the high frequency generator and a cycloconverter. The cycloconverter allows power flow in both directions. Thus the cycloconverter generator system is also capable of operating as an elec- tronically commutated motor-drive to start the engine. The cycloconverter will provide for all electrical controls, in- cluding frequency and voltage control, since an ac-PM machine does not allow for a simple reliable voltage control within the machine itself.
TL;DR: In this article, a diagonal generator with shuffle power and current control was shown to be identical to a uniform electrode current Faraday generator under all loading conditions, and the generator performance was compared to the Faraday and diagonal configurations with reduced control and power conditioning requirements.
Abstract: Current controllers developed for regulating the electrode currents of the diagonal generator against the effect of slag-driven cathode wall nonuniformities can also be used as power shufflers that force the electrode currents to be proportional to the generator load current. Power shufflers eliminate axial currents in the plasma, being driven by the mismatches between the isopotentials of the uncontrolled diagonal generator and its load current requirements. The generator performance with shuffle power is shown to be identical to a uniform electrode current Faraday generator under all loading conditions. Analysis shows that diagonal generators with current control and power shufflers may embody the advantages of both Faraday and diagonal configurations with reduced control and power conditioning requirements.
TL;DR: In this article, the authors examined the flow characteristics and power production capabilities of the Tornado Wind Energy Conversion System (TWECS) by fitting a plastic shroud 360 deg around the tower from the top of the bottom inlet to the tower exit level.
Abstract: The flow characteristics and power production capabilities of the Tornado Wind Energy Conversion System (TWECS) are examined. Experimental results indicate that the confined vortex in the tower of TWECS rotates approximately as a solid body and only supplements total power production, most of which comes from the tower acting as a bluff body. Wrapped tower experiments were performed by fitting a plastic shroud 360 deg around the tower from the top of the bottom inlet to the tower exit level which transformed the TWECS into a hollow, raised cylinder. Coefficient of power is compared for louvered towers vs. wrapped tower. The fact that the wrapped tower performs as well as the louvered tower suggests that it is the pressure difference between the bottom inlet region and the region above the tower (where the pressure of the ambient flow will be somewhat reduced owing to its acceleration over the bluff body of the tower) which determines the vertical force on the fluid within the tower.
TL;DR: In this article, a single-cylinder AGT-1500 and T-63 engines were evaluated using the equivalence ratio of the primary and secondary swirler air at the spark gap.
Abstract: The extension of the ignition model to an annular combustor was successful and a single ignition limit curve for three engines was developed. The correlation also includes 4 geometries and 2 plug locations for the AGT-1500, 30 fuels covering a wide range of volatilities from gasoline to No. 6 fuel oil and viscosities of 0.3-75 x 10/sup -6/ m/sup 2//s, inlet air temperatures of 240-330 K, and pressures of 30-140 kPa. One significant difference that developed in examining the F101 data is that the primary zone equivalence ratio was the proper equivalence ration for the F101 as opposed to the assumption of a constant equivalence ratio at the spark gap for the AGT-1500 and T-63. This may indicate better mixing of the fuel spray with the primary zone air in the F101 due to the injection of the fuel into the primary and secondary swirler air. The critical features of applying the ignition model to gas turbine combustors are the drop size estimates via empirical equations and the equivalence ratio evaluations based on the fuel spray and spark plug locations.