Launch Vehicle Propulsion System Research Articles

A novel kriging-improved high-dimensional model representation metamodelling technique for approximating high-dimensional problems

Aiming to address the issue of the ‘curse of dimensionality’ encountered in approximating high-dimensional problems using surrogate-based methods, high-dimensional model representation (HDMR), decomposing the high-dimensional problem into summands of different-order component functions, has been widely studied. To reduce the computational demands of the current HDMR metamodelling techniques, an improved high-dimensional model representation framework (iHDMR) is presented, taking full advantage of the relationships between the first-order and second-order component functions in the Cut-HDMR theory. then, a novel metamodelling technique, termed kriging (KRG)-iHDMR, is implemented by integrating the kriging technique and the suggested surface-axes alternating sampling strategy into the iHDMR framework. The accuracy and efficiency of KRG-iHDMR are demonstrated by various numerical and engineering examples with different dimensions. Finally, an optimization problem of the multi-stage solid launch vehicle propulsion system is introduced to verify the engineering feasibility of the KRG-iHDMR metamodelling technique.

Life Analysis of Reusable Liquid Rocket Engine Thrust Chamber

The thrust chamber’s inner wall suffers high temperature and pressure differences from the coolant channel, which limits the life of the rocket engine. Life prediction of the thrust chamber really plays an important role in reusable launch vehicle propulsion systems. The Porowski beam model is widely used in the life prediction of reusable liquid rocket engine thrust chambers, which calculates the life caused by fatigue, creep, and thinning after each firing cycle. In order to analyze the life of the thrust chamber, a LOX/Kerosene rocket engine is investigated in this paper. The life analysis consists of pressure and temperature differences and structural parameters. Two kinds of inner wall materials were chosen for comparison in this research: OFHC copper and Narloy-Z alloy. The results are presented to offer a reference for the design and manufacture of reusable rocket engine thrust chambers in the future.

A method for verifying the model of tank operational pressurization process during development of propellant supply system in liquid rocket engines of launch vehicle propulsion systems

During development of propulsion systems for launch vehicles, in order to verify the design results, standalone developmental tests of propellant supply system components were run in specially designed test setups outfitted with the required instrumentation. As an example of such work, this paper describes the experience of standalone developmental testing of operational pressurization of propellant tanks. During tests in the constructed test setups, heat and mass exchange processes were tried out with simulation of design modes of operational pressurization of propellant tanks filled with oxygen and hydrogen. As a result of these tests, a rationale was provided for selection of working mediums as the pressurization gas, design and characteristics of gas injection into propellant tanks, a method for evaluating the efficiency of the pressurization process. Empirical dependences were obtained that were used as the boundary conditions in the models for practical calculations for refining the modes and evaluating the efficiency of the propellant supply subsystem of propulsion systems. The paper calls attention to the need to use for the purpose of development of the propellant supply systems that involves computer simulations the results of such earlier work when designing advanced rocket propulsion systems. Key words: propulsion system, propellant supply system, development of pressurization process, test setup, pressurization gas, propellant components, heat and mass transfer intensity, process efficiency, liquid surface sloshing, computer simulations.

An Adaptive Dendrite-HDMR Metamodeling Technique for High-Dimensional Problems

Abstract High-dimensional model representation (HDMR), decomposing the high-dimensional problem into summands of different order component terms, has been widely researched to work out the dilemma of “curse-of-dimensionality” when using surrogate techniques to approximate high-dimensional problems in engineering design. However, the available one-metamodel-based HDMRs usually encounter the predicament of prediction uncertainty, while current multi-metamodels-based HDMRs cannot provide simple explicit expressions for black-box problems, and have high computational complexity in terms of constructing the model by the explored points and predicting the responses of unobserved locations. Therefore, aimed at such problems, a new stand-alone HDMR metamodeling technique, termed as Dendrite-HDMR, is proposed in this study based on the hierarchical Cut-HDMR and the white-box machine learning algorithm, Dendrite Net. The proposed Dendrite-HDMR not only provides succinct and explicit expressions in the form of Taylor expansion but also has relatively higher accuracy and stronger stability for most mathematical functions than other classical HDMRs with the assistance of the proposed adaptive sampling strategy, named KKMC, in which k-means clustering algorithm, k-Nearest Neighbor classification algorithm and the maximum curvature information of the provided expression are utilized to sample new points to refine the model. Finally, the Dendrite-HDMR technique is applied to solve the design optimization problem of the solid launch vehicle propulsion system with the purpose of improving the impulse-weight ratio, which represents the design level of the propulsion system.

Metallurgical failure analysis of non-separation of isolation pyro valve used in space applications

Isolation pyro valves fabricated from AISI 321 austenitic stainless steel are performance-critical components used in launch vehicle propulsion systems. These valves isolate the fuel and oxidizer separated by a thin membrane that will be severed during its operation. As a part of the qualification program, a set of pyro valves were tested at the operating temperature of 20 K. During post-test examination of the hardware, membrane separation was not observed in one of the pyro valves tested. The failed and successfully tested valves were analysed to understand the reason for the non-separation of the pyro valve membrane. The present work brings out the details of metallurgical and mechanical aspects of the failed as well as successfully tested isolation pyro valves.

Dynamic Model-Based Identification of Cavitation Compliance and Mass Flow Gain Factor in Rocket Engine Turbopump Inducers

Abstract Cavitation dynamics continue to pose a significant risk in the development and operation of launch vehicle (LV) propulsion systems. In addition to generating unsteady loads that can directly damage turbopump hardware, cavitation dynamics often couple with LV fluid feed systems, producing system wide POGO instability that can cause catastrophic failures. Despite its importance, the current understanding of cavitation dynamics, and especially pump transfer matrices, is limited. Given the relatively sparse amount of inducer transfer matrix data available, there is a critical need for more in-depth characterization of the cavitation dynamics in turbopump inducers to avoid POGO instability. This paper defines and validates a new reduced-order approach to infer key parameters such as cavitation compliance, K, and mass flow gain factor, M, from simple, single sensor unsteady pressure measurements during inducer inlet pressure ramps. The utility of this approach is demonstrated for a range of inducer geometries reported in the literature. The results are in agreement with experimental data and the paper provides a new capability supporting the assessment of LV POGO instability.

Mathematical modelling of start-up transients at clustered propulsion system with POGO-suppressors for CYCLON-4M launch vehicle

Liquid-propellant rocket propulsion systems of the first stages of launch vehicles of medium, heavy, and super-heavy class usually include POGO-suppressors, which are one of the most widely used methods to eliminate launch vehicle longitudinal structural vibrations (POGO phenomena). However, until now, the theoretical studies and analysis of the effect of the POGO-suppressors’ installation in the feedlines of main liquid rocket engines on transient processes in systems during rocket engine starting have not been carried out due to the complexity of such analysis and the lack, first of all, reliable nonlinear models of cavitation phenomena in rocket engine pumps. A mathematical model for the start-up of a clustered rocket propulsion of the Cyclone-4M launch vehicle has been developed that takes into account the low-frequency dynamics of the POGO-suppressors and the asynchronous start-up timeline sequences of the rocket engines. The first stage of the launch vehicle propulsion system includes four RD-870 rocket engines. A nonlinear mathematical model of low-frequency dynamic processes of the POGO-suppressor with bellows separation of liquid and gaseous media is presented. A significant effect of cavitation in the pumps of engines and the POGO-suppressor installation to the LOX feedline on the propulsion system dynamic gains is shown. Based on the developed mathematical model of the clustered rocket propulsion start-up, the studies of the Cyclone-4M main engines’ start-up transients were carried out. The asynchronous start-up timeline sequences of the rocket engine and the places of installation of the POGO-suppressors in the LOX feedline branches to the RD-870 rocket engine – near the general feedline collector as standard placement or directly at the entrance to the engines – were investigated. The analysis of start-up transients in the oxidizer feed system of the considered propulsion (the time dependences of the flowrate and pressure at the engine inlet) showed the following. Firstly, while the synchronous start-up of the engines, the installation of the POGO-suppressors near the feedline collector makes it possible to eliminate all engine inlet overpressures that exist in the rocket propulsion system in case of the absence of the POGO-suppressors. Secondly, the RD-870 engine asynchronous start-up operation affects negatively the time dependences of the propellant flowrate and pressure at the engine inlet if the POGO-suppressors are located near the feedline collector. So, in the propulsion system’s start-up timeline interval 0.95 s - 1.35 s, for some computational variants of the initial moments of the engine operation start, an abnormally large drop in the LOX flow rate and the overpressures at the engine inlet is observed. The asynchronous start-up of the RD-870 engines with the installation of the POGO-suppressors at the engine inlet does not significantly change the start-up transients compared to the synchronous starting of the engines. Thirdly, thus, it is shown that the installation of the POGO-suppressors both at the engine inlet and at the RD-870 branches near the collector has a significant positive effect on the quality of start-up transient processes for the main engines of the 1st stage of the Cyclone-4M launch vehicle. Placing the POGO-suppressors at the engine inlets is not standard and is considered without reference to the propulsion system layout. Nevertheless, the POGO-suppressors installed at the inlet to the engines are an effective means of preventing overshoots and dips in the parameters of the liquid-propellant rocket engine, including the conditions of asynchronous starting of the liquid rocket engines in the clustered propulsion system. The results obtained can be used in mathematical modeling of the start-up of the first stage propulsion system either for multistage sustainer rockets used in parallel with booster rockets or for the clustered multi-engine rocket propulsion system containing POGO-suppressors.

A Modular Fault Diagnosis and Prognosis Method for Hydro-Control Valve System Based on Redundancy in Multisensor Data Information

Fault diagnosis and prognosis (FDP) are important capabilities that can enable autonomous detection and prediction of failures’ progress in complex engineering systems. This paper introduces an innovative modular FDP method for a hydro-control valve system. The hydro-control valve is a critical part of the space launch vehicle propulsion system, and health monitoring of this hydro-valve is essential to ensure safety and reliability of the spacecraft. In this study, three main failures, i.e., piston leakage, drain blockage, and filter malfunction, in the hydro-control valve system are considered for monitoring and prognosis. The proposed FDP system has three main components including fault detection and diagnosis (FDD) unit, failure parameter estimation unit, and remaining useful life (RUL) estimation unit. A feature selection strategy and a support vector machine technique are together utilized to capture redundancy in multisensor data information and to isolate failures in the FDD unit. Then, a decentralized network of three adaptive neuro–fuzzy inference systems (ANFIS) is developed to estimate the failure parameters. Afterward, the RUL unit is constructed using an adaptive Bayesian algorithm. Finally, a performance measure, called the relative accuracy index, is introduced and applied to evaluate the performance of the proposed health monitoring system. Simulation studies confirm the effective performance of the proposed design methodology.

Прогноз времени выгорания твердого топлива в двигательной установке ракеты-носителя в полете

Прогноз времени выгорания твердого топлива в двигательной установке ракеты-носителя в полете