PSI - Issue 71

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ScienceDirect

Procedia Structural Integrity 71 (2025) 287–294

ISRO is developing a 2000kN thrust Semi-cryogenic engine works on oxidizer rich staged combustion cycle using LOX as oxidiser and special grade Kerosene as fuel for use in expandable and reusable launch vehicles to increase payload capability. The engine is designed to operate in 3 thrust levels – Nominal level (100% thrust), throttled level (60% thrust), and up rated level (105% thrust). It will be tested in the qualification test range of 57% and 110% thrust conditions to evaluate the stability of the engine at the designed extremes. The engine's major primary sub-systems are the feed circuits, flow control components, thrust chamber, preburner, turbo pump, thrust, and mixture ratio control system. The thrust chamber generates propulsive force by combustion of fuel in the presence of oxidizer rich hot gas 1. Introduction Keywords: Semi-cryo; injector head; finite element analysis; acceptance test; proof pressure; thermo-structural; non-linear; LOX; kerosene Semi-cryo engine is designed to operate with LOX (oxidiser) and special grade kerosene (fuel) as propellant. The engine generates thrust by converting the chemical energy of this propellant into kinetic energy of hot gas in the thrust chamber assembly. Thrust chamber assembly comprises of injector head assembly, the combustion chamber, and the convergent divergent nozzle assembly. In the injector head assembly, proper injection of propellant in the desired mixture ratio takes place, and the resultant product is injected into the combustion chamber through injector elements. Injector head assembly consists of the Gas duct, Diffuser, and Mixer assembly, which are welded together. During operating condition, the injector head assembly is subjected to high pressure and high temperature loads. The response of the structure under these loads is non linear. Therefore, finite element analysis is called upon to check the structural integrity before putting it into actual engine hot test conditions. An acceptance pressure test at room temperature is devised to screen the quality of the assembly. The response of the structure to this test is evaluated by means of finite element simulations. The FE simulations are performed using the ANSYS FEA package, and a material model based on test data is used to account for their non-linear behaviour at service conditions. Based on the results of FE simulations, necessary modification in the configuration of the gas duct was carried out so that they conform to the requirements spelt out for launch vehicle systems as per relevant standards. Subsequently, analysis was done to ensure the structural integrity of the modified configuration for acceptance pressure test condition and maximum operating condition. Abstract © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SICE 2024 organizers a Mechanical Design and Analysis Entity, Liquid Propulsion Systems Centre, Indian Space Research Organisation, Thiruvananthpuram b Structures Entity, Vikram Sarabhai Space Centre, Indian Space Research Organisation, Thiruvananthpuram Anoop Kumar A. a* , Krishnajith Jayamani a , Vinayaravi R. a ,Vasudevan R. a , Asraff A.K. b Structural Integrity Assessment of An Indigenously Developed Semi-Cryogenic Engine Component Based on FE Stress Analysis 5 th International Structural Integrity Conference & Exhibition (SICE 2024)

* Corresponding author. Mob.: +91-9496311479 E-mail address: a_anoopkumar@lpsc.gov.in; anoopkumarcet@gmail.com

2452-3216 © 2025 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of SICE 2024 organizers 10.1016/j.prostr.2025.08.039