Turbine abradable layer with nested loop groove pattern

Abstract

Turbine and compressor casing abradable component embodiments for turbine engines, with nested loop pattern abradable surface ridges and grooves. The nested loops comprise nested fully closed loops or a spiraling maze pattern loop. Some embodiments include distinct forward upstream and aft downstream composite multi orientation groove and vertically projecting ridges planform patterns, to reduce, redirect and/or block blade tip airflow leakage downstream into the grooves rather than from turbine blade airfoil high to low pressure sides. Ridge or rib embodiments have first lower and second upper wear zones. The lower zone optimizes engine airflow characteristics while the upper zone is optimized to minimize blade tip gap and wear by being more easily abradable than the lower zone.