A Design Approach of CMC RAM-Combustor Wall

Paper number

IAC-05-C2.P.03

Author

Dr. Tetsuya Morimoto, Japan Aerospace Exploration Agency (JAXA), Japan

Year

2005

Abstract

Ceramic matrix composite (CMC) is a candidate material for the combustor wall of a conceptual RAM jet engine studied in Japan Aerospace Exploration Agency (JAXA).  The application, two-stage to orbit (TSTO) type future launch vehicle, may enable an orbital access with improved pay-load capacity of reduced cost through utilizing atmospheric oxygen at the first stage hypersonic flight.    The RAM-jet operation has been estimated to complete in limited time, and the reusability maybe commercially acceptable with some ten times.  Then, the lifetime of CMC RAM-combustor wall may be acceptable within only few hours, which enables the design standard focus less on the time-dependent factors such as creep and high-cycle fatigue.  
Thermal stress, however, remains an important design factor as unstable RAM combustion leads to heat-spot formation, which causes thin wall to serious in-plane thermal gradient.  Therefore, a data sheet is essential in designing a CMC RAM-combustor on the in-plane parameters such as strength and critical fracture toughness.
  In this work, Tyrannohex SiC/SiC CMC (UBE Industry Co.) was selected as a candidate material for the RAM-combustor wall application due to the reported excellence on the high-temperature strength.  Three-point bending was used to collect the data of in-plane bending strength and the critical fracture toughness.
Using the datasheet, the relationship between critical flaw size and in-plane thermal gradient was estimated to modify the RAM-combustor wall initial design.

Abstract document

IAC-05-C2.P.03.pdf

Manuscript document

IAC-05-C2.P.03.pdf (🔒 authorized access only).

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