The Advanced Low-Emissions Catalytic-Combustor Program: Phase I — Description and Status

The Advanced Low-Emissions Catalytic-Combustor Program ia an ongoing three-phase contract contract effort with the primary objective of evolving the technology required for incorporating catalytic combustors into advanced aircraft gas-turbine engines. Phase I is corrently in progress. At the present time, analytical evaluation is being conducted on advanced catalytic combustor concepts — including variable geometry — with their known inherent potential advantages of low level pollutant emission, widened combustion at ability limits, and reduced pattern factor for longer turbine life. Phases II and III will consist of experimental evaluation of the most promising concepts.

Low Frequency Gas Turbine Noise

British Gas have experienced problems at some installations from low frequency turbine noise. The paper describes how the low frequency noise problems were investigated and then resolved by aerodynamic modifications and a silencer extension.

Effects of the Combustion Products of Coal-Derived Fuels on Gas Turbine Hot-Stage Hardware

This paper reports a DOE-sponsored program to evaluate the effect of the combustion products of coal-derived fuels on current and potential materials used in gas turbine hot-section components and on the plugging of cooling holes in air-cooled airfoils. Atmospheric-pressure small burner rigs and a combustor operating at elevated pressures and design air flows, equipped with a segment of a first-stage nozzle (turbine simulator), were used in these evaluations.

Account of Film Turbulence for Predicting Film Cooling Effectiveness in Gas Turbine Combustors

The paper deals with a small but important part of the overall gas turbine engine combustion system and continues earlier published work on turbulence effects in film cooling to cover the case of film turbulence. Film cooling of the gas turbine combustor liner imposes certain geometric limitations on the coolant injection device. The impact of practical film injection geometry on the cooling is one of increased rates of film decay when compared to the performance from idealized injection geometries at similar injection conditions. It is important to combustor durability and life estimation to be able to predict accurately the performance obtainable from a given practical slot. The coolant film is modeled as three distinct regions, and the effects of injection slot geometry on the development of each region are described in terms of film turbulence intensity and initial circumferential non-uniformity of the injected coolant. The concept of the well-designed slot is introduced and film effectiveness is shown to be dependent on it. Only slots which can be described as well-designed are of interest in practical equipment design. A prediction procedure is provided for well-designed slots which describes growth of the film downstream of the first of the three film regions. Comparisons of predictions with measured data are made for several very different well-designed slots over a relatively wide range of injection conditions, and good agreement is shown.

Wind Tunnel Model Study of the Hot Exhaust Plume From the Compressor Research Facility at Wright-Patterson Air Force Base, OH

This paper presents the results of a wind tunnel model study to determine temperatures at various locations generated by the hot exhaust air from the Compressor Research Facility [CRF] which is being built at Wright-Patterson Air Force Base, Ohio. The study was designed to provide data at the inlet to the CRF and at other nearby locations where pedestrians, building ventilation systems, and vegetation might be affected. The test program, which was conducted in the Calspan Atmospheric Simulation Facility, included flow visualization studies and quantitative concentration measurements of a tracer gas from which full-scale temperature could be calculated. The concentration measurements were performed for a number of wind speeds at each of twelve different wind directions. Two exhaust flows and two exhaust stack configurations were studied.

Alternate Fuels and the Gas Turbine Catalytic Combustor

Inasmuch as conventional gas turbine combustors often produce soot even with the present low aromatic content fuels, the production of acceptable liquid turbine fuels from hydrogen deficient raw materials such as coal and tar sands requires large quantities of high cost hydrogen if conventional combustors are to be used. The economics of producing alternate turbine fuels would be improved if high aromatic content fuels could be burned in gas turbines without soot formation. Gas turbines using the catalytic combustor not only can efficiently burn highly aromatic fuels without soot formation but can meet all existing or proposed regulations on emissions of hydrocarbons, carbon monoxide, and nitrogen oxides. Under certain conditions, high fuels can be burned with as little as 10 to 15 percent conversion of the fuel nitrogen to nitrogen oxides. In view of the potential savings, any program for alternate fuels should take into account the opportunities offered by the catalytic combustor.

Radiative Heat Transfer From Gas Turbine Flames

Measurements have been made of the normal component of the radiative heat flux to the wall of a model gas turbine combustor with and without a mirrored background. Measurements have also been made of the centerline soot concentration. The data show that the heat flux correlated with the soot concentration but not universally, since JET A fuel yielded a different curve 1han DIESEL fuel. A theoretical analysis of the heat flux from a soot suspension was formulated. A criterion was established for the use of a small particle analysis. Finally, it is shown that there is no correspondence between theory and these experiments. It is speculated that turbulent fluctuations need to be modeled.

Electrocoalescer Comparison Performance Tests

Validation tests were carried out based upon tests specified in Military Specification MIL-F-8901. The Electrocoalescer has demonstrated excellent performance, has passed the validation test, and showed an improved performance over that of the Military Standard Filter Separator. When tested with diesel fuel, the improvement was on the order of a factor of 10 or more. Moreover, it demonstrated a lower overall pressure drop. Use of the Electrocoalescer in fuels decontamination service is expected to result in cleaner fuels and longer filter life.

Design of Pressurized Fluid-Bed Combustor/Particulate Control System for Reliable Turbine Operation

The commercial operation of coal-fired pressurized fluid-bed combustion-gas turbine plants for central station electric power generation or for industrial cogeneration applications depends on the reliable operation of the gas turbine. Reliable operation of the turbine is related to the particulate and chemical composition of the gases that it expands. This study is limited to an evaluation of particulates as they limit turbine life by erosion. Pressurized fluid-bed combustor design and operation trade-offs exist that affect the particle concentration and size ranges presented to the gas cleaning equipment. Gas cleaning equipment choices will subsequently effect the particulates going to the turbine. The development of a particle profile model permits an assessment of the effect of these decisions on the particles that enter the turbine. Turbine tolerance models previously developed by Westinghouse are then used to estimate turbine life and the incremental energy cost penalty. The scope of the evaluation procedure is presented and selected parametric cases presented to illustrate available trade-offs for design, operation, and cost.

The Base Pressure Problem in Transonic Turbine Cascades

Base pressure data were systematically collected at VKI during recent years on a great variety of cascades operated over a wide range of outlet March numbers. An attempt is made to correlate these data by relating the base pressure to important cascade and flow parameters. Details about the trailing edge flow are obtained by using an enlarged model simulating the overhang section of convergent turbine cascades. The experimental cascade and model test results are compared with theoretical calculations using base pressure calculation methods.