Film Cooling

Film cooling is the introduction of a secondary fluid (coolant or injected fluid) at one or more discrete locations along a surface exposed to a high temperature environment to protect that surface not only in the immediate region of injection, but also in the downstream region. This chapter discusses film cooling with both the mainstream fluid and the secondary fluid being gases, although not necessarily the same gas and with a turbulent boundary layer downstream of injection. Both the two-dimensional and the three-dimensional secondary flow geometries are considered. In addition, film cooling in compressible flows as well as in incompressible flows is examined. Although the emphasis is on adiabatic wall temperatures and uniform mainstreams, the effects of heat transfer and variable free stream velocity are discussed.