CMC blade with pressurized internal cavity for erosion control and corresponding method

A ceramic matrix composite blade (30) for use in a gas turbine engine having an airfoil (23) with leading (11) and trailing edges (12) and pressure and suction side surfaces, a blade shank (15) secured to the lower end of each airfoil (23), one or more interior fluid cavities (13,24) within the airfoil (23) having inlet flow passages (17,18) at the lower end which are in fluid communication with the blade shank (15), one or more passageways in the blade shank corresponding to each one of the interior fluid cavities (13,24) and a fluid pump (or compressor) that provides pressurized fluid (nominally cool, dry air) to each one of the interior fluid cavities (13,24) in each airfoil (23). The fluid (e.g., air) is sufficient in pressure and volume to maintain a minimum fluid flow to each of the interior fluid cavities (13,24) in the event of a breach due to foreign object damage. A corresponding method is also provided.