Life Cycle Prediction Of A Liquid Propellant Rocket Engine Thrust Chamber Using Unified Chaboche Viscoplastic Model
- Paper number
IAC-18,C4,IP,24,x44436
- Author
Mr. A.K. Asraff, India, Indian Space Research Organization (ISRO)
- Coauthor
Mr. ROZAN MANZOOR, India
- Coauthor
Mr. Krishnajith Jayamani, India, Liquid Propulsion Systems Centre(LPSC), Indian Space Research Organization (ISRO)
- Coauthor
Mr. Sarath Chandran Nair, India, Liquid Propulsion Systems Centre(LPSC), Indian Space Research Organization (ISRO)
- Coauthor
Dr. E JAYAKUMAR, India
- Year
2018
- Abstract
High thrust liquid propellant rocket engines are used in space technology to power heavy lift satellite launch vehicles. The engine investigated in this paper works on liquid oxygen and kerosene propellants. The thrust chamber of the engine is of double walled construction and regeneratively cooled. A high conductivity copper alloy is selected for the inner wall in regions of high heat flux and for other regions an austenitic stainless steel is used. Outer wall is of a high strength stainless steel throughout the chamber which is brazed on to the inner wall by vacuum brazing at elevated temperature. Combustion of propellants occurring inside the thrust chamber induces high thermal and pressure loads on inner wall while the passage of coolant through coolant channels imparts shrinkage and pressure loads. Materials at high temperatures are sensitive to strain rate effects and thus exhibit viscoplastic behaviour. Viscoplasticity in metals is observed at temperatures above half the melting point temperature. The main aim of this work is to evaluate the cyclic life of the thrust chamber using the Chaboche unified viscoplastic material model for the inner wall austenitic stainless steel. The model parameters are calibrated by matching finite element simulations with test results, by trial and error. Elevated temperature low cycle fatigue tests are conducted on smooth specimens at ±1.5% strain range with a hold time equal to that of the steady state operating duration of the engine, to evaluate the cyclic as well as stress relaxation characteristics of the material. Tests are conducted in an INSTRON-8862 UTM in an environmental chamber. Constitutive model chosen is a combination of Chaboche cyclic plasticity and Chaboche viscoplasticity models available in ANSYS (Version 18.0) software. Finally, using these parameters, viscoplastic cyclic stress analysis of the thrust chamber is carried out to evaluate its cyclic life.
- Abstract document
- Manuscript document
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