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Full-Text Articles in Engineering
Time-Dependent Deposition Characteristics Of Fine Coal Fly Ash In A Laboratory Gas Turbine Environment, Robert Laycock, Thomas H. Fletcher
Time-Dependent Deposition Characteristics Of Fine Coal Fly Ash In A Laboratory Gas Turbine Environment, Robert Laycock, Thomas H. Fletcher
Faculty Publications
Time-dependent deposition characteristics of fine coal fly ash were measured in the Turbine Accelerated Deposition Facility (TADF) at Brigham Young University. Two samples of subbituminous coal fly ash, with mass mean diameters of 3 and 13 microns, were entrained in a hot gas flow with a gas temperature of 1288 C and Mach number of 0.25. A nickel-based, superalloy metal coupon approximately 0.3 cm thick was held in a hot particle-laden gas stream to simulate deposition in a gas turbine. Tests were conducted with deposition times of 20, 40, and 60 min. Capture efficiencies and surface roughness characteristics (e.g., Ra) …
Effect Of Hole Spacing On Deposition Of Fine Coal Flyash Near Film Cooling Holes, Weiguo Ai, Nathan Murray, Thomas H. Fletcher, Spencer Harding, Elizabeth Bonsignore, Jeffrey P. Bons
Effect Of Hole Spacing On Deposition Of Fine Coal Flyash Near Film Cooling Holes, Weiguo Ai, Nathan Murray, Thomas H. Fletcher, Spencer Harding, Elizabeth Bonsignore, Jeffrey P. Bons
Faculty Publications
Particulate deposition experiments were performed in a turbine accelerated deposition facility to examine the nature of flyash deposits near film cooling holes. Deposition on both bare metal and thermal barrier coating (TBC) coupons was studied, with hole spacing (s/d) of 2.25, 3.375, and 4.5. Sub-bituminous coal ash particles (mass mean diameter of 13 microns) were accelerated to a combustor exit flow Mach number of 0.25 and heated to 1183°C before impinging on a target coupon. The particle loading in the 1 h tests was 310 ppmw. Blowing ratios were varied in these experiments from 0 to 4.0 with the density …
Computational Analysis Of Conjugate Heat Transfer And Particulate Deposition On A High Pressure Turbine Vane, Weiguo Ai, Thomas H. Fletcher
Computational Analysis Of Conjugate Heat Transfer And Particulate Deposition On A High Pressure Turbine Vane, Weiguo Ai, Thomas H. Fletcher
Faculty Publications
Numerical computations were conducted to simulate flash deposition experiments on gas turbine disk samples with internal impingement and film cooling using a computational fluid dynamics (CFD) code (FLUENT). The standard k-epsilon turbulence model and Reynoldsaveraged Navier–Stokes were employed to compute the flow field and heat transfer. The boundary conditions were specified to be in agreement with the conditions measured in experiments performed in the BYU turbine accelerated deposition facility (TADF). A Lagrangian particle method was utilized to predict the ash particulate deposition. Userdefined subroutines were linked with FLUENT to build the deposition model. The model includes particle sticking/rebounding and particle …
Deposition Near Film Cooling Holes On A High Pressure Turbine Vane, Weiguo Ai, Nathan Murray, Thomas H. Fletcher, Spencer Harding, Scott Lewis, Jeffrey P. Bons
Deposition Near Film Cooling Holes On A High Pressure Turbine Vane, Weiguo Ai, Nathan Murray, Thomas H. Fletcher, Spencer Harding, Scott Lewis, Jeffrey P. Bons
Faculty Publications
Deposition on film-cooled turbine components was studied in an accelerated test facility. The accelerated deposition facility seeds a natural-gas burning combustor with finely ground coal ash particulate at 1180 C and 180 m/s (M=0.25). Both cylindrical and shaped holes, with and without thermal barrier coating, were studied over a range of blowing ratios from 0.5 to 4.0. Coolant density ratios were maintained at values from 2.1 to 2.4. Deposition patterns generated with the cylindrical film cooling holes indicated regions of low deposition in the path of the coolant with heightened deposition between film holes. This distinctive pattern was more accentuated …
Effect Of Particle Size And Trench Configuration On Deposition From Fine Coal Flyash Near Film Cooling Holes, Weiguo Ai, Robert G. Laycock, Devin S. Rappleye, Thomas H. Fletcher
Effect Of Particle Size And Trench Configuration On Deposition From Fine Coal Flyash Near Film Cooling Holes, Weiguo Ai, Robert G. Laycock, Devin S. Rappleye, Thomas H. Fletcher
Faculty Publications
Particulate deposition experiments were performed in a turbine accelerated deposition facility to examine the effects of flyash particle size and trench configuration on deposits near film cooling holes. Deposition on two bare metal Inconel coupons was studied, with hole spacings (s/d) of 3.4 and 4.5. Two sizes of sub-bituminous coal ash particles were used, with mass mean diameter of 4 and 13 μm, respectively. The effect of a cooling trench at the exit of the cooling holes was also examined in this deposition facility. Experiments were performed at different angles of impaction. Particles were accelerated to a combustor exit flow …
Film Cooling Effectiveness And Heat Transfer Near Deposit-Laden Film Holes, Scott Lewis, Brett Barker, Jeffrey P. Bons, Weiguo Ai, Thomas H. Fletcher
Film Cooling Effectiveness And Heat Transfer Near Deposit-Laden Film Holes, Scott Lewis, Brett Barker, Jeffrey P. Bons, Weiguo Ai, Thomas H. Fletcher
Faculty Publications
Experiments were conducted to determine the impact of synfuel deposits on film cooling effectiveness and heat transfer. Scaled up models were made of synfuel deposits formed on film-cooled turbine blade coupons exposed to accelerated deposition. Three distinct deposition patterns were modeled: a large deposition pattern (maximum deposit peak = 2 hole diameters) located exclusively upstream of the holes, a large deposition pattern (maximum deposit peak = 1.25 hole diameters) extending downstream between the cooling holes, and a small deposition pattern (maximum deposit peak = 0.75 hole diameter) also extending downstream between the cooling holes. The models featured cylindrical holes inclined …
Evolution Of Surface Deposits On A High-Pressure Turbine Blade—Part Ii: Convective Heat Transfer, Jeffrey P. Bons, James Edward Wammack, Jared M. Crosby, Daniel Fletcher, Thomas H. Fletcher
Evolution Of Surface Deposits On A High-Pressure Turbine Blade—Part Ii: Convective Heat Transfer, Jeffrey P. Bons, James Edward Wammack, Jared M. Crosby, Daniel Fletcher, Thomas H. Fletcher
Faculty Publications
A thermal barrier coating (TBC)-coated turbine blade coupon was exposed to successive deposition in an accelerated deposition facility simulating flow conditions at the inlet to a first stage high pressure turbine (T=1150 C, M=0.31). The combustor exit flow was seeded with dust particulate that would typically be ingested by a large utility power plant. The turbine coupon was subjected to four successive 2 h deposition tests. The particulate loading was scaled to simulate 0.02 parts per million weight (ppmw) of particulate over 3 months of continuous gas turbine operation for each 2 h laboratory simulation (for a cumulative 1 year …
High-Pressure Turbine Deposition In Land-Based Gas Turbines From Various Synfuels, Thomas H. Fletcher
High-Pressure Turbine Deposition In Land-Based Gas Turbines From Various Synfuels, Thomas H. Fletcher
Faculty Publications
Ash deposits from four candidate power turbine synfuels were studied in an accelerated deposition test facility. The facility matches the gas temperature and velocity of modern first-stage high-pressure turbine vanes. A natural gas combustor was seeded with finely ground fuel ash particulate from four different fuels: straw, sawdust, coal, and petroleum coke. The entrained ash particles were accelerated to a combustor exit flow Mach number of 0.31 before impinging on a thermal barrier coating (TBC) target coupon at 1150°C. Postexposure analyses included surface topography, scanning electron microscopy, and x-ray spectroscopy. Due to significant differences in the chemical composition of the …
Observations Of Flame Behavior In A Laboratory-Scale Premixed Natural Gas/Air Gas Turbine Combustor From Planar Laser Induced Fluorescence Measurements Of Oh, Laser Doppler Anemometer Velocity Measurements, And Coherent Anti-Stokes Roman Spectrometer Temperature Measurements, Thomas H. Fletcher
Faculty Publications
Instantaneous planar laser induced fluorescence (PLIF) images of OH, simultaneous axial/radial and axial/tangential velocity measurements with an LDA (laser Doppler anemometer), and instantaneous gas temperature measurements using a coherent anti- Stokes Raman spectrometer (CARS) were obtained in a pre-mixed, swirl-stabilized laboratory-scale combustor, fired with natural gas. Four operating conditions were examined (two swirl conditions and equivalence ratios of 0.80 and 0.65). The instantaneous PLIF images of OH illustrate the chaotic nature of the turbulent flame eddies. Mean and standard deviations of each variable were measured at different locations in the flame, along with probability density functions. Stability of the flame …
Simulated Land-Based Turbine Deposits Generated In An Accelerated Deposition Facility, Jared W. Jensen, Sean W. Squire, Jeffrey P. Bons, Thomas H. Fletcher
Simulated Land-Based Turbine Deposits Generated In An Accelerated Deposition Facility, Jared W. Jensen, Sean W. Squire, Jeffrey P. Bons, Thomas H. Fletcher
Faculty Publications
This report presents a validation of the design and operation of an accelerated testing facility for the study of foreign deposit layers typical to the operation of land-based gas turbines. This facility was designed to produce turbine deposits in a 4-h test that would simulate 10,000 h of turbine operation. This is accomplished by matching the net foreign particulate throughput of an actual gas turbine. Flow Mach number, temperature and particulate impingement angle are also matched. Validation tests were conducted to model the ingestion of foreign particulate typically found in the urban environment. The majority of this particulate is ceramic …