Blade arrangement for a gas turbine and method for operating such a blade arrangement

A method for operating a blade arrangement for a gas turbine, including blade leaves, having a leading edge, a trailing edge, a pressure side and a suction side, platforms configured as separate components, the blade leaves sealingly assembled with respective platforms, a peripheral sealing arrangement provided between the blade leaves and the respective platforms for sealing off an interspace between the blade leaves and the respective platforms against gas flowing around the blade leaves, a directed site-dependent supply of cooling air for purging the sealing arrangement provided on a side of the sealing arrangement which faces away from the hot gas, wherein the cooling air supply includes cooling ducts which run between the blade leaves and the respective platforms, the cooling ducts arranged, in each case, on the pressure side and the suction side of each blade leaf, the method comprising:

• supplying cooling air to the cooling ducts of the pressure side independently of the cooling air supplied to the suction side;
• and
• supplying cooling air for purging the sealing arrangement at a pressure which decreases from the leading edge of the blade leaves to the trailing edge.

A method for operating a blade arrangement for a gas turbine, including blade leaves, having a leading edge, a trailing edge, a pressure side and a suction side, platforms configured as separate components, the blade leaves sealingly assembled with respective platforms, a peripheral sealing arrangement provided between the blade leaves and the associated platforms for sealing off an interspace between the blade leaves and respective platforms against gas flowing around the blade leaves, a directed site-dependent supply of cooling air for purging the sealing arrangement provided on a side of the sealing arrangement which faces away from the hot gas, the method comprising:

• supplying cooling air for purging the sealing arrangement at a pressure which decreases from the leading edge of the blade leaves to the trailing edge;
• and
• supplying cooling air for purging the sealing arrangement at a pressure which allows a controlled penetration of hot gas at the sealing arrangement in a region of the leading edge.