Glossary

What are transonic airfoils, and what is the active clearance control? Check out our technical dictionary and find out more about engine technology terms – from active clearance control to velocity triangle.

Active clearance control (ACC) Adaptive HSC milling Afterburner Airfoil bitangent line Airfoil chord Aluminizing and chromizing Aluminum oxide dry blasting Aluminum oxide wet blasting Annular combustion chamber Anodizing Atmospheric plasma spraying (APS) ATFI Axial-flow compressor

Active clearance control (ACC)

Active clearance control serves to adjust the radial gap, i.e. the distance between blade tips and casing inner wall. In aero engines the expansion behavior of rotors differs from that of the casings. Since it is hardly possible to change the rotor behavior the casings are impingement cooled from the outside to limit thermal expansion and thus maintain the specified radial gap.