Within gas turbine engines, the combustors direct hot exhaust gas over the blade rows of the turbine section. The temperatures are usually hotter than the melting point of these blades, so the blades need to be cooled directly to prevent them from being damaged. This is usually done by redirecting cooler air from the compressor to the inside of each blade, and then out through an array of small holes to create a film of cool air over the blade surface.