The Development and Application of Improved Combustor Wall Cooling Techniques

Abstract

The continuing emphasis over the past few years on the development of lower sfc, long on-wing life and low emission engines for commercial transportation has put a premium on combustor liner cooling techniques employing less cooling flow. Rolls-Royce pioneered the fully machined ring and impingement cooling concepts which formed the basis for the RB211 combustor design. Further improvement of the impingement cooling technique has led to the development of a laminated, psuedo-transpiration material. It exploits the high impingement heat transfer coefficients and provides an extended internal surface area for heat transfer. Rolls-Royce has developed this material primarily for combustor applications. A major milestone has now been achieved with the certification by the CAA of a Spey combustor variant incorporating this material for limited release for commercial operations. These combustors are now entering service in the BAe1-11 with a number of UK airlines.