This thesis presents CFD predictions of gas turbine film and effusion cooling. The dearth of detailed experimental adiabatic effusion cooling data led to the validation of the computational procedures against the experimental adiabatic cooling effectiveness data for a single row of inclined round film cooling holes. This showed that the overall best agreement of the CFD predictions with experimental data was for the realizable k-e turbulence model with enhanced wall function. This was also shown to give good predictions of experimental results for trench outlet film cooling. This film cooling CFD work was extended .to demonstrate trench outlet lip geometries that could further improve the cooling effectiveness. The limitation of the CFD model was at higher blowing rates, M, when the film jet lifted off from the surface, where the CFD did not accurately predict the adiabatic cooling effectiveness close to the hole. For attached jets at lower M the agreement was good. The same CFD procedures were used for all the effusion cooling conjugate heat transfer (CHT) predictions. The hot metal wall effusion cooling experimental data base of Andrews and co-workers (1983-1995) was used to validate the CHT effusion cooling predictions. This database was for combustor flat wall cooling with mainly 90° injection holes. The overall effusion cooling effectiveness was measured and this required conjugate heat transfer CFD predictions. The adiabatic film cooling effectiveness was also predicted, by using a gas tracer in the cooling air and predicting its concentration at the effusion wall. For each effusion hole configuration, the coolant mass flow rate, G kg/srrr2bar, was varied from 0.1 to 1.5 and each G required a separate computation. The influence of the number of holes at a constant X!D of 4.6 and the hole size at fixed X were investigated. The agreement between the predictions and experimental data was good. Finally, the influence of the effusion coolant jets flow direction to the hot-gas crossflow on effusion cooling performance was investigated. This included 30° inclined opposed-flow jets effusion wall, which was predicted to be the best effusion jets flow pattern. The addition of the filleted shape trench outlet to effusion cooling was predicted to improve the cooling performance with reduced coolant mass flow rate, due to the improved adiabatic film cooling.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:581946 |
| Date | January 2012 |
| Creators | Oguntade, Habeeb Idowu |
| Publisher | University of Leeds |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
Page generated in 0.002 seconds