FILM COOLING OPTIMIZATION FOR MINIMUM COOLING AIRFLOW IN AIRCRAFT GAS-TURBINES

Publisher Summary This chapter discusses film cooling optimization for minimum cooling airflow in aircraft gas turbines. A simple, one-parameter optimization on the basis of local matching of velocity ratio for maximum potential core length produces a worthwhile reduction in the total amount of coolant flow required to limit the maximum flametube temperature to a specified value. The amount of this reduction depends very much on the individual slot design used, but such an optimization apparently offers greater air savings than likely material improvements. By optimizing the cooling system, more air is available for mixing in the dilution zone, thus easing considerably the design problems associated with this zone. The drawbacks to the optimized cooling system are that its complexity increases considerably, together with a likely doubling of cost. A significant weight penalty can be incurred for an optimized system, but the extent of this again depends very much on the design of the individual slots.