Rocket engine altitude test facility design and 1D altitude simulation of IoX/LH2 propellant rocket engine

Abstract

The interest in space and development studies started in B.C. for humanity. Astronomical observations began to understand the dynamics between planets and stars. Reaching space and flying around the world have been the most considered areas over the years. Before the 20th century, theoretical and experimental studies were conducted; however, scientific research increased after the 20th century. Tsiolkovsky and Goddard contributed to rocketry both theoretically and experimentally. During World War II, the Germans developed V2 rockets, which were the predecessors of space rockets in the following years. The Saturn V rocket was launched in 1967, and it remained the most powerful rocket for humankind up to the 21st century before Starship Heavy. In today's world, the development of liquid-fueled rocket engines is progressing rapidly. Many companies and agencies are designing launch vehicles, payloads, and rocket engines all over the world. Today, NASA, ESA, SpaceX, JAXA, and others have numerous studies on rocket engines and their components. Nowadays, research and development of rocket engines have reached the most powerful rocket engine, the Raptor Engine by SpaceX. Test system designs and test facility setups are constructed even for the most powerful rocket engine designs. Various test setups and infrastructures are being established for testing numerous subcomponents and equipment as part of pre-flight verification for liquid-fueled rocket engines. It is worth noting that rocket engines with turbopump feed systems undergo ground tests and altitude simulation tests before launch in many industrial and academic studies. Today, there is ongoing development of various test infrastructures for the feed systems of turbopumps, including valve characterization test setups, cryogenic valve test setups, injector test setups, turbine test setups, pump test setups for oxidizer and fuel, leak test setups, gas generator and combustion chamber test setups, and more. Test setups for altitude testing of first-stage and second-stage rocket engines have been developed and are used to verify thrust and turbopump efficiency during the rocket's flight. Altitude test setups for rocket engines are available in various countries such as France, the United Kingdom, the United States, Germany, and South Korea, and they are used for altitude tests of rocket engines with different thrust capacities. Due to various factors such as different types of oxidizer and fuel feed systems, thrust capacities, rocket engine sizes, exit temperatures, and flow rates, unique system developments have been made and continue to be pursued. The primary sub-components of the rocket altitude test setup, as described in the literature, include motor feed tanks, rocket engines, vacuum chambers, diffusers, cooling water injectors, deflectors, ejector structures, and condensing equipment. In addition to these components, instruments such as pressure sensors, flow meters, temperature sensors, accelerometers, and load cells are used during performance testing to measure and verify performance values. Design considerations for the 1D modeling of the rocket engine followed established processes from the literature in this study. The most common programs for 1D modeling are EcosimPro and Simcenter Amesim. Simcenter Amesim was preferred for studying 1D system modeling for both the rocket engine and the altitude test facility design. In the first step, a 1D model of the rocket engine was created. A 1D model of the LOX/LH2 liquid-fueled Expander Cycle Rocket Engine VINCI's full model was developed, and a simplification method was used to reduce system unknowns. For the simplification method, the boundary conditions at the system inlet were kept the same, while the outlet conditions of the pump and turbine became the new inlet conditions for the thrust chamber. The pressurized oxidizer and fuel conditions remained stable with the addition of orifices, and the performance of the combustion chamber and nozzle was monitored. After completing the rocket engine design, the design of the altitude test facility was undertaken. Piping, chambers, divergent-convergent structures, steam ejectors, and steam feeding boundary conditions were added to the system to control the results. A vacuum system model was created to observe the VINCI rocket engine's performance under vacuum conditions lower than 50 mbarA. In this thesis study, the performance of the VINCI rocket engine and the altitude test facility were considered. The desired version of the VINCI was the 180 kN thrust in vacuum. It was observed that the thrust levels and performance data produced by the VINCI rocket engine were satisfactory during simulation. The thrust of the 1D modeled VINCI engine was found to be nearly 178 kN. The combustion chamber pressure manufacturer data was given as 60 barA, and the 1D model of the VINCI simulation result was found to be 59.78 barA. The feeding lines of the fuel and oxidizer mass flow rates were given as 5.59 kg/s and 34.11 kg/s according to the manufacturer. Simulation results for the fuel and oxidizer were found to be 5.5 kg/s and 34.31 kg/s, respectively. The manufacturer's specific impulse data was given as 457.2 s, and the 1D model of the VINCI simulation result was found to be 456.17 s. The main consideration for the vacuum conditions was set at 50 mbarA, and the 1D simulation results were found to be 42.93 mbarA with an increased steam inlet mass flow rate of the second-stage steam ejector. For the first stage of the steam ejector, literature information was followed, and a 110 kg/s steam condition was satisfied. For the second ejector, 141 kg/s of steam was supplied, creating a vacuum of 42.93 mbarA. The manufacturer's second-stage steam mass flow rate was given as 118 kg/s, suggesting that better vacuum conditions could be achieved according to the simulation results. Future work includes creating a digital twin with the 1D model, conducting 3D model-based CFD analysis for the altitude test facility design, comparing real-time test data between altitude test facilities and 1D simulation models, and running performance scenarios in the 1D altitude test model before conducting tests.