scholarly journals Heat Transfer Characterization Methodology for an Oxy-Fuel Direct Power Extraction Combustion System

2018 ◽  
Vol 34 (5) ◽  
pp. 1313-1322
Author(s):  
Luisa Cabrera Maynez ◽  
Ahsan Choudhuri ◽  
Norman Love
Author(s):  
Luisa A. Cabrera ◽  
Jad Aboud ◽  
Manuel J. Hernandez ◽  
Brian Lovich ◽  
Ahsan R. Choudhuri ◽  
...  

2018 ◽  
Vol 141 (2) ◽  
Author(s):  
Tao Ren ◽  
Michael F. Modest

With today's computational capabilities, it has become possible to conduct line-by-line (LBL) accurate radiative heat transfer calculations in spectrally highly nongray combustion systems using the Monte Carlo method. In these calculations, wavenumbers carried by photon bundles must be determined in a statistically meaningful way. The wavenumbers for the emitting photons are found from a database, which tabulates wavenumber–random number relations for each species. In order to cover most conditions found in industrial practices, a database tabulating these relations for CO2, H2O, CO, CH4, C2H4, and soot is constructed to determine emission wavenumbers and absorption coefficients for mixtures at temperatures up to 3000 K and total pressures up to 80 bar. The accuracy of the database is tested by reconstructing absorption coefficient spectra from the tabulated database. One-dimensional test cases are used to validate the database against analytical LBL solutions. Sample calculations are also conducted for a luminous flame and a gas turbine combustion burner. The database is available from the author's website upon request.


Author(s):  
Omar Vidana ◽  
Mariana Chaidez ◽  
Brian Lovich ◽  
Jad Aboud ◽  
Manuel J. Hernandez ◽  
...  

1970 ◽  
Vol 92 (4) ◽  
pp. 351-358 ◽  
Author(s):  
F. J. Bayley ◽  
A. B. Turner

This paper describes a program of experimental and analytical research designed to evaluate the aerodynamic and thermodynamic performance of transpiration-cooled porous surfaces in the high-temperature gas turbine. The aerodynamic penalties of effusing coolant through a set of nozzle blades are shown to be small, particularly when compared with the thermodynamic advantages which accrue from the effective cooling obtained. Although the effusing coolant can in certain circumstances increase gas to blade heat transfer rates by destabilizing a laminar boundary layer, in the turbulent boundary layers which predominate in turbine practice there is inevitably a reduction in heat transfer which can be satisfactorily predicted theoretically. In the combustion system of the gas turbine, transpiration cooling appears also to be very attractive, but much work remains to be done on heat transfer rates in the flame-tube.


Author(s):  
J. Zelina ◽  
D. T. Shouse ◽  
J. S. Stutrud ◽  
G. J. Sturgess ◽  
W. M. Roquemore

An aero gas turbine engine has been proposed that uses a near-constant-temperature (NCT) cycle and an Inter-Turbine Burner (ITB) to provide large amounts of power extraction from the low-pressure turbine. This level of energy is achieved with a modest temperature rise across the ITB. The additional energy can be used to power a large geared fan for an ultra-high bypass ratio transport aircraft, or to drive an alternator for large amounts of electrical power extraction. Conventional gas turbines engines cannot drive ultra-large diameter fans without causing excessively high turbine temperatures, and cannot meet high power extraction demands without a loss of engine thrust. Reducing the size of the combustion system is key to make use of a NCT gas turbine cycle. Ultra-compact combustor (UCC) concepts are being explored experimentally. These systems use high swirl in a circumferential cavity about the engine centerline to enhance reaction rates via high cavity g-loading on the order of 3000 g’s. Any increase in reaction rate can be exploited to reduce combustor volume. The UCC design integrates compressor and turbine features which will enable a shorter and potentially less complex gas turbine engine. This paper will present experimental data of the Ultra-Compact Combustor (UCC) performance in vitiated flow. Vitiation levels were varied from 12–20% oxygen levels to simulate exhaust from the high pressure turbine (HPT). Experimental results from the ITB at atmospheric pressure indicate that the combustion system operates at 97–99% combustion efficiency over a wide range of operating conditions burning JP-8 +100 fuel. Flame lengths were extremely short, at about 50% of those seen in conventional systems. A wide range of operation is possible with lean blowout fuel-air ratio limits at 25–50% below the value of current systems. These results are significant because the ITB only requires a small (300°F) temperature rise for optimal power extraction, leading to operation of the ITB at near-lean-blowout limits of conventional combustor designs. This data lays the foundation for the design space required for future engine designs.


1996 ◽  
Vol 22 (6) ◽  
pp. 1281-1288
Author(s):  
Hiroshi Miyama ◽  
Hitoshi Kaji ◽  
Yasuo Hirose ◽  
Norio Arai

Author(s):  
Forrest E. Ames ◽  
Pierre A. Barbot ◽  
Chao Wang

Vane endwall heat transfer distributions are documented for a mock aeroderivative combustion system and for a low turbulence condition in a large-scale low speed linear cascade facility. Inlet turbulence levels range from below 0.7 percent for the low turbulence condition to 14 percent for the mock combustor system. Stanton number contours are presented at both turbulence conditions for Reynolds numbers based on true chord length and exit conditions ranging from 500,000 to 2,000,000. Low turbulence endwall heat transfer shows the influence of the complex three-dimensional flow field, while the effects of individual vortex systems are less evident for the high turbulence cases. Turbulent scale has been documented for the high turbulence case. Inlet boundary layers are relatively thin for the low turbulence case while inlet flow approximates a nonequilibrium or high turbulence channel flow for the mock combustor case. Inlet boundary layer parameters are presented across the inlet passage for the three Reynolds numbers and both the low turbulence and mock combustor inlet cases. Both midspan and 95 percent span pressure contours are included. This research provides a well-documented database taken across a range of Reynolds numbers and turbulence conditions for assessment of endwall heat transfer predictive capabilities.


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