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ABSTRACT
Because natural gas resources continue to be depleted for usage of gas turbines, it becomes important to search for alternate fuels. Coal-derived synthetic fuels contain traces of ash and other contaminants that result in deposition on vane and turbine surfaces. The present research shows a comparison of simulated results with and without a deposition configuration. Film cooling effectiveness distribution after the deposition was obtained to investigate the effects of various deposition heights and widths under the blowing ratios of 0.5, 0.75, and 1.0. The results indicated that the deposition near the hole exit can weaken the cooling performance. Moreover, it is revealed that the film cooling effectiveness deteriorates with increased deposition heights. The deposition width study revealed that a narrow deposition shows a good attachment of the coolant jet to the wall surface. It is found that an improvement of the film cooling effectiveness can be obtained by decreasing the blowing ratio.
Nomenclature
| d | = | film hole throat diameter (mm) |
| h | = | height of deposition (mm) |
| k | = | turbulence kinetic energy (m2/s2) |
| M | = | blowing ratio (= ρjVj/ρ∞V∞) |
| P | = | pressure (N/m2) |
| T | = | temperature (K) |
| u | = | streamwise velocity component (m/s) |
| V | = | velocity magnitude (m/s) |
| w | = | width of deposition (mm) |
| x, y, z | = | coordinate direction distance (m) |
| α | = | inclination angle (°) |
| ϵ | = | turbulence dissipation rate |
| η | = | adiabatic film cooling effectiveness (= Taw − Ti)/(Tj − Ti) |
| λ | = | heat conductivity (W/mK) |
| θ | = | nondimensional temperature (= T − Ti)/(Tj − Ti) |
| ρ | = | density (kg/m3) |
| τ | = | stress tensor (kg/m s2) |
| Subscripts | = | |
| a | = | area average value |
| aw | = | adiabatic wall |
| c | = | centerline |
| i | = | mainstream flow |
| j | = | coolant jet |
| t | = | turbulent |
Nomenclature
| d | = | film hole throat diameter (mm) |
| h | = | height of deposition (mm) |
| k | = | turbulence kinetic energy (m2/s2) |
| M | = | blowing ratio (= ρjVj/ρ∞V∞) |
| P | = | pressure (N/m2) |
| T | = | temperature (K) |
| u | = | streamwise velocity component (m/s) |
| V | = | velocity magnitude (m/s) |
| w | = | width of deposition (mm) |
| x, y, z | = | coordinate direction distance (m) |
| α | = | inclination angle (°) |
| ϵ | = | turbulence dissipation rate |
| η | = | adiabatic film cooling effectiveness (= Taw − Ti)/(Tj − Ti) |
| λ | = | heat conductivity (W/mK) |
| θ | = | nondimensional temperature (= T − Ti)/(Tj − Ti) |
| ρ | = | density (kg/m3) |
| τ | = | stress tensor (kg/m s2) |
| Subscripts | = | |
| a | = | area average value |
| aw | = | adiabatic wall |
| c | = | centerline |
| i | = | mainstream flow |
| j | = | coolant jet |
| t | = | turbulent |
