Effect of cooling hole configurations on combustion and heat transfer in an aero-engine combustor

A numerical model is developed to investigate the combustion and cooling performance of an aero-engine combustor. Cylindrical holes, conical holes, fan-shaped holes and console holes are introduced to reduce the thermal load of thermal barrier coatings (TBCs) in combustor, respectively. To reduce the coolant consumption, the number of film cooling holes in the first and second row at outer liner is decreased by 20% for comparison. The adoption of the four types holes leads to following results: the peak gas temperature increases from 2459.36 K to 2473.39 K, 2485.76 K, 2491.15 K, and 2464.57 K; the NOx emission increases from 3.2306 g/kg to 3.4762 g/kg, 3.5197 g/kg, 3.5341 g/kg and 3.3494 g/kg; the peak working temperature of TBCs decreases by 149.01 K, 208.12 K, 248.64 K and 257.78 K respectively. Fan-shaped holes have the highest coolant discharge coefficient and correspond to the highest peak gas temperature and NO,, emission. The decrease of cooling hole number has very slight effect on TBCs peak working temperature, while it will reduce the peak gas temperature and the NO,, emission in the meanwhile. The cooling effectiveness of the console hole is the highest followed by the fan-shaped hole and the conical hole.

Automated summary

By introducing different types of cooling holes to reduce the thermal load of thermal barrier coatings in the combustor, it is possible to increase the peak gas temperature and reduce NOx emissions. Decreasing the number of cooling holes has minimal impact on the peak working temperature of thermal barrier coatings, but can lower peak gas temperatures and NOx emissions. Cooling effectiveness is highest for console holes, followed by fan-shaped holes and conical holes.