Speaker
Description
Numerous studies are currently being carried out on a global scale to develop advanced technological solutions for Single Stage To Orbit (SSTO) and hypersonic flights. These technologies are highly demanding and challenging due to the technical requirements involved especially the design of the propulsion system for the spacecraft and aircraft. Synergetic engine, which uses Rocket Based Combined Cycle (RBCC) technology with air-breathing propulsion in combination with rocket propulsion is proposed to have the potential for SSTO and hypersonic travel. This engine works in two different modes - Air-breathing mode and Rocket mode. In the air-breathing mode, the engine makes use of the oxygen present in the atmosphere rather than using a separate oxidizer tank starting from the takeoff itself. Despite efforts to minimize its usage, a certain quantity of onboard oxygen is required to sustain the necessary thrust. Once it gains sufficient velocity and altitude, the engine switches from the air-breathing mode to the rocket mode where the onboard oxygen supply is utilised at higher rates. In the air-breathing mode, the air taken in through the intake section of the engine is utilised as the oxidiser in the combustion chamber of the rocket and gaseous hydrogen is used as the fuel. The combustion products are then expanded through the rocket nozzle to generate thrust. Once a predetermined velocity as well as altitude is reached, the intake starts to close. As the intake is closing, the demand for the separate oxygen supply gradually increases to maintain the thrust. Eventually, the engine will be purely switched into the rocket mode. The air intake is eventually shut down and only the onboard oxygen will be used for the combustion process.
This engine technology under development, makes use of cryogenic propellants hydrogen and oxygen along with an intelligent, calibrated and timely supply of the intake air to propel. The basic thermodynamic cycle of this multifluid system is available in the open literature, but the detailed analysis of this engine technology is limited. The present study is devoted to investigating the multifluid thermodynamic lines of the synergetic engine in its air-breathing configuration by incorporating the possibility of regenerative cooling of the nozzle. A flight condition with an altitude of 25 km and Mach number 4 is being considered for the analysis. The existing thermodynamic circuit is modified and redesigned to incorporate the changes. The different fluid lines involving air, helium, hydrogen, oxygen and pre-burned exhaust gas are being analysed. For each of these lines, the temperature, pressure, specific heat at constant pressure, specific enthalpy, mass flow rate, heat transfer rate, and work transfer rate are calculated at different stations. The stations of the loop are analysed based on the physics and reference literature, with suitable assumptions to reduce the complexity. Governing equations of flow - conservation of energy and isentropic relations have been used across the steady flow devices for calculations. Darcy-Weisbach equation with the Swamee-Jain equation for the friction factor is being considered for calculating the pressure drop in the regenerator coil. The combustion chambers of the system are analysed using NASA CEARUN rev4. Finally, the rocket nozzle thrust is determined, and a simplified computer model of the system is created. This work proposes an interlinked thermodynamic loop towards the development of a synergetic engine with cryogenic propellants that can find mutual property variations at each location corresponding to different inlet conditions and component specifications.
Keywords: Rocket Based Combined Cycle (RBCC), Synergetic Air-Breathing Rocket Engine (SABRE), Single Stage To Orbit (SSTO), Air-breathing rocket engine
| Submitters Country | INDIA |
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