The sealing device is a key component in aero-engines used for sealing the gaps between the compressor rotor and stator (such as between the rotor blade tips and the casing, between the rectifier inner ring and the rotor drum, and between the rotor's front and rear end faces and the casing). It reduces gas leakage losses and improves compressor efficiency by decreasing the leakage area and pressure difference.
This device is divided into two categories: contact and non-contact. Contact seals include structures such as expanding ring seals and graphite thrust plates fitting the end faces, achieving sealing through spring preload. Non-contact seals primarily use grate seals, employing multi-stage cavity pressure differentials, utilizing blade-like thin tooth tips to control the gap, and incorporating graphite blocks to optimize radial clearance. Modern technology introduces brush seals, where fine steel wire brushes form a stator ring that contacts and rubs against the rotating shaft, combined with a ceramic coating to improve durability. Other sealing forms include the labyrinth seal's zigzag structure and the floating ring seal's oil film throttling. Studies have shown that a 1% reduction in sealing leakage can increase engine thrust by 1%.
