Interference Shrink Fit Shroud

Increased tip chord, tip speed, and use of sweep have long been recognized as beneficial to fan and compressor aero designs. However, significant increases in blade stress, blade weight, disk weight, and cost result from higher tip speed and longer tip chord. An innovative design concept is presented that reduces blade stress, weight, and cost while increasing possible forward sweep and blade natural frequency. This concept uses a self supporting 360 degrees rotating shroud ring with an interference shrink fit between the shroud ring and the blade tip. The radial deflection of the ring and blade tip are nearly matched and the ring provides a positive clamp force at all steady-state and transient operating conditions. MMC and OMC materials are used in shroud ring design for 400 degrees F to 500 degrees F applications at corrected tip speed (UT/0) up to 1650 ft/sec. An analytical feasibility study of the Interference Shrink Fit Shroud (Tip Ring) concept is proposed for the Forward Swept JTDE subscale fan with MMC and OMC ring materials. A tip shroud ring is added to the existing Finite Element Model and the feasibility of each shroud ring will be determined, as well as, ring weight, blade weight, blade frequencies and live disk weight. A comparison will be made to the baseline enshrouded rotor.