University of California, Irvine
The UCI Combustion Laboratory (UCICL) is engaged in both fundamental and applied studies in gas turbine combustion. Emphasis is placed on stationary, aeroengine, and advanced propulsion applications. The UCICL is addressing the challenges associated with gas turbine combustion by developing and applying advanced laser diagnostics and numerical tools to practical hardware and model combustors under conditions ranging from atmospheric to practical engine conditions. A key component of the activity is collaboration with industry to more effectively design the experiments and to more effectively transfer the technology developed into practical reality.
The UCICL is currently supported with six permanent technical staff, eleven graduate students, and seven undergraduate students.
The research is presently funded at the federal level by the U.S. Department of Energy. In addition, industrial contracts and grants are provided by Catalytica, CFD Research Corporation, Kaiser Marquardt, Parker Hannifin, Southern California Edison, Siemens-Westinghouse, Solar Turbines, Southern California Gas Company, and Tokyo Gas. State and local agency support includes that provided by the California Energy Commission, California Air Resources Board, Lawrence Berkeley National Lab, and the South Coast Air Quality Management District.
The UCICL is housed in research facilities that include five high-bay test cells, and gas turbine cell, and support laboratories. One test cell is designed specifically for high-pressure experiments in two independent rooms. The facility has an independent air factory which can provide 4 lbs/sec of air and preheat to 1200F. The test facilities include model and practical burners and gas turbine combustors, a variety of spray test stands, and a variable geometry reactor for the study of turbulent transport in jet and recirculating flows. Diagnostics include both conventional diagnostics (e.g., extractive probes, thermocouple probes, emission consoles), and laser diagnostics (e.g., laser anemometry, laser diffraction, sheet lighting, Rayleigh scattering, intensity ratioing, coherent anti-Stokes Raman spectroscopy, degenerate four-wave mixing, phase Doppler interferometry, optical patternation, laser-induced fluorescence, planar liquid laser-induced fluorescence, and particle image velocimetry). In addition, a variety of imaging diagnostics are available, including high magnification high-speed video, digital cameras, and microCCD cameras. The facility features the ability to provide various blends of gaseous fuels to reflect variation in natural gas composition, medium-BTU content, and low BTU content fuels. To support this facility, a dedicated on-line gas analysis system is utilized to monitor the composition of the natural gas coming into the building. A gas compressor boosts the pressure of the natural gas or desired blend of gaseous fuels to pressures up to 500 psia. In addition, a wide variety of liquid fuels are available including DF-2, Jet-A, Calibration Fluids, and several pure blends. Two Independent fuel delivery circuits provide up to 500 lb/hr of fuel at pressures up to 1000 psia to a manfold which services the test cells.
Of particular importance is gaining an understanding of the extent to which inlet and boundary conditions affect both the detailed flow structure and the overall performance of the system. The objective is to optimize the coupling between the introduction of the fuel and the air flow into which the fuel is injected and mixed. The goal is to optimize combustion efficiency and overall combustor stability, and to minimize the emission of air pollutants. An important contribution of this program has been the development of surrogate fuels to provide compositional control in the development of the required data bases, and a numerical code to predict the performance of these systems.
With the increasing understanding of the association between fuel/air mixing and combustor performance, programs have been initiated to monitor and optimize combustor performance through the use of direct performance sensors and a feedback control system. A key component of this multidisciplinary effort is the development of a control system that can minimize and assure the maintenance of minimum pollutant emission. This application of control technology to gas turbine engines will improve the performance of present-day engines and expand combustor technology for future designs. Control methodologies are being developed for the use of active controls in the management of combustor performance including the provision of engine flexibility by expanding the range of efficient operation. Both dynamic control and quasi-steady control (active optimization) are believed to be necessary to meet future demands of combustion systems.
Another program is underway to examine flashback and autoignition behavior in geometries representative of practical devices at conditions of interest to gas turbine applications. The goal is to develop design guidelines for premixing devices. To this end, CFD is being applied to evaluate novel mixer geometries for aerodynamic qualities and perturbations. In parallel, data are being acquired for gaseous and liquid fuels to establish correlations for ignition behavior in light of the observed aerodynamic perturbations.
Another program currently underway examines the relationship between lean combustion processes and the emissions of ozone precursors and hazardous air pollutants. To this end, sampling systems and protocols have been established to characterize very small quantities of these air toxics in the exhaust stream of combustion sources.
The UCICL also benefits from extensive interaction with the National Fuel Cell Research Center, which is co-located in the Engineering Laboratory Facility. Fuel cells offer an alternative to traditional combustion for the provision of power. Of particular interest, however, are hybrid cycles one of which involves the combination of a fuel cell and a gas turbine which can offer significant efficiency gains relative to each technology independently. Combustion methods are likely necessary as enabling technologies for some of the fuel cell applications, possibly including start-up, auxiliary power, and fuel processing. |