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Development and testing of a nitrous oxide/propane rocket engine
... Nitrous oxide is used in the space industry, particularly in hybrid rockets as an oxidiser [1][2][3], and is considered as a potential monopropellant for satellite thrusters [4,5]. Its main advantages are nontoxicity, low cost, market availability, and ease of storage at a wide range of temperatures. ...
... The first model is similar to the equilibrium model reported in [3] and will be referenced as the single node equilibrium (SNE) model. The fluid is assumed to be represented by a single node, being in the form of pure vapour or pure liquid or in a two phase state. ...
Nitrous oxide is often used in the space industry, as an oxidiser or monopropellant, mostly in self-pressurised configurations. It has potential for growth in use due to the recent rising interest in green propellants. At the same time, modelling the behaviour of a self-pressurising nitrous oxide tank is a challenging task, and few accurate numerical models are currently available. Two-phase flow, heat transfer and rapid changes of mass and temperature in the investigated system all increase the difficulty of accurately predicting this process. To get a get better understanding of the emptying of a self-pressurised nitrous oxide tank, two models were developed: a phase equilibrium model (single node equilibrium), treating the control volume as a single node in equilibrium state, and a phase interface model, featuring a moving interface between parts of the investigated medium. The single node equilibrium model is a variation of equilibrium model previously described in the literature, while the phase interface model involves a novel approach. The results show that the models are able to capture general trends in the main parameters, such as pressure or temperature. The phase interface model predicts nitrous oxide as a liquid, a two-phase mixture, and vapour in the lower part of the tank, which is reflected in the dynamics of changes in pressure and mass flow rate. The models developed for self-pressurisation, while created for predicting nitrous oxide behaviour, could be adapted for other media in conditions near vapour-liquid equilibrium by adding appropriate state equations.
... Mixtures of hydrocarbons and nitrous oxide get into the focus of science in the latest years. Besides the DLR, research programs in the US initiated by the Defense Advanced Research Projects Agency (DARPA) [7] are investigating such mixtures, especially C 2 H 2 /N 2 O [8] and C 3 H 8 /N 2 O [9]. In 2009, Mungas et al. [10,11] started testing mixtures in thrusters with ethane, ethene, or ethyne with nitrous oxides. ...
... Laminar burning velocities results for ethane/nitrous oxide and ethane/nitrous oxide are depicted in Figs. 8,9,10. Experimental (squares) and simulation results (lines) are shown as a function of equivalence ratio at an initial temperature of 473 K for different pressures (p = 1, 3, and 6 bar) and dilution with nitrogen d(N 2 ) = 50%; for reaction system C 2 H 6 /N 2 O also for different dilutions (d(N 2 ) = 40, 50, and 60%) at p = 1 bar. ...
Mixtures of hydrocarbons and nitrous oxide are known as green propellants and could replace the highly toxic hydrazine and hydrazine derivatives as rocket fuel, since they are non-toxic and easier to handle, but still have a high specific impulse. Possible hydrocarbon candidates are ethane or ethene. To check the applicability of the two reaction systems, C 2 H 6 /N 2 O and C 2 H 4 /N 2 O, experiments are a prerequisite for accurate predictions under various conditions that are of great importance for the design of safe and reliable thrusters. Therefore, experimental literature data obtained from ignition delay times and laminar burning velocities were used to validate and optimize a new reaction mechanism, which is designed for C 0 –C 3 and nitrogen oxides formation. To achieve a better predictive power of the detailed mechanism, the Arrhenius parameters of three reactions were adjusted: N 2 O + H ⇌ N 2 + OH, N 2 O (+ M) ⇌ N 2 + O (+ M), and NH + NO ⇌ N 2 O + H. A good agreement was achieved between simulation and experiment for ignition delay times at various pressures and equivalence ratios in a broad temperature range before and after the mechanism optimization. However, the laminar burning velocities in the whole measured range of the equivalence ratio for all pressures and dilutions showed a significant improvement after the optimization.
... Additional interest in nitrous oxide has arisen in the 21st century as it was being more widely considered as a safe, clean oxidizer for rocket propulsion systems, and that it is usable as both a monopropellant or as a bipropellant [7]. In 2001, Tiliakos et al. [8] tested nitrous oxide with propane in a bipropellant rocket engine. The nitrous oxide was catalytically decomposed and this exothermic process ignited the propane to produce sustained combustion. ...
... The premixed nature of the propellants offered the convenience of a monopropellant, but promised performance (I SP ) in the range of bipropellant engines. Their choice of ethylene as fuel was driven by the similar vapor pressures of ethylene and nitrous oxide, which was also suggested by Tiliakos et al. [8]. This similarity in vapor pressures assured good miscibility and simultaneous evaporation of the propellants in the tank. ...
Nitrous oxide (N2O) has gained popularity as a unique oxidizer for propulsion applications due to its ability to decompose exothermically, producing nitrogen and oxygen. In the current work, the flame acceleration, deflagration-to-detonation transition, and detonation properties of bipropellant mixtures with N2O as the oxidizer are studied for potential applications in pulsed blowdown and detonation-driven thrusters. These properties are compared with those in mixtures with oxygen (O2) or nitrogen tetroxide (N2O4) as the oxidizer. The performance of N2O versus O2/N2O4 for detonation engine applications is investigated using theoretical Chapman–Jouguet detonation calculations of bipropellant systems with ethylene (C2H4) and acetylene (C2H2) as fuels. A critical requirement for the application of bipropellant mixtures to pulsed propulsion systems is rapid flame acceleration to achieve significant chamber pressure rise in a short distance with the potential for a prompt transition to detonation. This deflagration-to-detonation transition behavior of mixtures using C2H4 and C2H2 with N2O and O2 is investigated for increasing initial pressures in the experimental portion of this work. While C2H2 is a highly energetic fuel with theoretically high performance, it presents serious practical storage concerns when considered for propulsion applications. These practical issues motivate investigation of C2H4 as a potential alternative fuel, which is relatively easy to manage. The precompression of the bipropellant mixtures during flame acceleration is also estimated and compared.
... At lower temperatures, N 2 O has high oxidative selectivity for methane, producing methanol and formaldehyde with molybdenum and vanadium catalysts [93]. In rocket engines, N 2 O is used as a propellant fuel oxidiser in monopropellant thrusters or in combination with other fuels including propane [94] increasing the fuel combustion rate. ...
... Nevertheless, green propellants for European space activities are an accepted challenge for research and for technology development. Similar to research programs in the United States initiated by DARPA (see Tiliakos et al., 2001or Keller, 2012, DLR investigates the combustion properties of propellants like ethene/nitrous oxide mixtures that have the potential to substitute hydrazine or hydranzine/dinitrogen tetroxide in chemical propulsion systems (Werling et al., 2015(Werling et al., , 2016(Werling et al., , 2017. Data from model combustors operated at DLR's rocket propulsion test site at Lampoldshausen (Germany) in combination with investigations of fundamental combustion properties provide valuable test cases to be analyzed by computational fluid dynamic (CFD) computations, thus gaining better insights to the specific design requirements of new rocket engines powered by green propellants. ...
... The pressure, temperature and high-speed video data of N 2 O/C 2 H 4 during the flame propagation process were collected by DLR (German Aerospace Center) [18]. N 2 O/C 3 H 8 (NOP) rocket engine was tested over a range of mixture ratios by Tiliakos et al. [19], experimental results match well with theoretical predictions, with proper modeling of heat losses. Movileanu et al. [20] measured maximum explosion pressures, explosion times and maximum rates of pressure rise for lean and stoichiometric ethylene-nitrous oxide mixtures diluted with 60% N 2 , at initial pressures within 50e150 kPa, in cylindrical vessels with different aspect ratio. ...
An experimental study was carried out to investigate the flame propagation and thermal hazard of the premixed N2O/fuel mixtures, including NH3, C3H8 and C2H4. The study provided the high speed video images and data about the flame locations, propagation patterns, overpressures and the quenching diameters during the course of combustion in different channels to elucidate the dynamics of various combustion processes. The onset decomposition temperature was determined using high-performance adiabatic calorimetry. It was shown that the order of the flame acceleration rate and thermal hazard was N2O/C2H4>N2O/C3H8>N2O/NH3.
... Nevertheless, green propellants for European space activities are an accepted challenge for research and for technology development. Similar to research programmes in the U.S. initiated by DARPA [1][2], DLR investigates the combustion properties of propellants like ethene/dinitrogen oxide mixtures that have the potential to substitute hydrazine/dinitrogen tetroxide in chemical propulsion systems [3][4]. Data from model combustors operated at DLR's rocket propulsion test site at Lampoldshausen (Germany) in combination with investigations of fundamental combustion properties provide valuable test cases to be analysed by CFD computations, thus gaining better insights to the specific design requirements of new rocket engines powered by green propellants. ...
... Small hybrid motors, however, are often electrically ignited by joule effect through a resistor, such as steel wool, located in the combustion port, or by use of a propane or hydrogen ignition system. A very interesting option use a catalyzer to decompose the oxidizer and to ignite the solid grain [41][37] [36]. Two different ignition system were compared: catalytic and sparks generator. ...
The Moon is the main objective for the next decade space missions. Exploitation, scientific research, robotic and manned exploration are planned by the most important space agencies. Just two transportation systems are currently used: liquid propellant and electric thrusters. The former has the advantage to be reliable and it has been tested in a wide range of missions, but it is heavy and complex, while the latter is usually lighter but it requires very long transfer time. This study proposes a hybrid propellant thruster as the best compromise for lunar missions in which an orbiter should leave the transfer orbit and inject in a lunar orbit. The safety of the system, the simplicity of the architecture, the weight comparable with the electric thruster propulsion make the hybrid motor the best and the more convenient solution to reach the Moon.
... The fact that no specific cause of the accident could have been found during the official investigation [7] leaves open the question of safety procedures with N 2 O handling. Since no hazard have been ever found to develop with N 2 O in liquid phase, a series of potential causes were considered as potential hazards for N 2 O handling, including contamination with organic soot, local overheating due to diverse causes, leading to a local vaporization and formation of bubbles, in fact a sort of static cavitation, the sudden opening of valves that produces a pressure transient with bubble formation, local catalytic effects due to the presence on unsuitable materials in the plumbing etc. [8,9] .One of the most subtle causes which are suspected for the apparently irregular detonation of this substance is the sudden dynamic cavitation that could develop into the transfer feed line during the liquid flow for tank feeling procedure [10]. ...
Nitrous oxide has recently entered violently the arena of space propulsion and gained interest, due to its high energy and gasification potential and despite its low oxygen content as an oxidizing chemical and its instability over some 600 C. However, its physical and chemical instability soon proved to be a potential hazard and led to a renewed interest in the study of its behavior as a fluid. In the present contribution computer simulation of the liquid phase flow of the nitrous oxide under high pressure is used to predict and avoid the cavitation into the feeding line tract of rocket engines, specifically of the compound rocket engines feeding line. The method involves a substantially simplified 1-D description of the fluid motion with sufficiently accurate determination of cavitation risk where the feeding duct suffers blunt variations of the cross area or steep turns and corners involving sensible static pressure variations of the fluid. A means of avoiding dangerous behaviors of the nitrous oxide is thus developed that could increase safety margins during the handling of this quite unpredictable oxidizer for the compound, combined or hybrid rocket engines.
This work proposes a design of a new propulsion module for a 3U CubeSat that will be used for collision avoidance and for deorbiting the spacecraft. We propose a bi-propellant, a mixture of Ethylene and Nitrous oxide which has no toxicity. The bi-propellant system used does not need an additional pressurizing system and will ignite automatically when the mixture will enter the combustion chamber. Due to these features, our propulsion module uses only 1U space of the CubeSat saving 2U for other systems. In this study, a program such as CEA and RPA were used for chemical equilibrium calculation developed in NASA and German Universities. It contains a thermodynamic data library, the PAC99 program which does regression and estimation of thermodynamics, numerical analysis data and chemical equilibrium analyzed by various stimulations. This propulsion evaluation aims at the calculation of efficiency, feasibility and specific impulse obtained was larger than 300 seconds.
Nitrous oxide fuel blends have been identified as a promising propellant to be used as a hydrazine replacement. In this study, the flame propagation and detonation characteristics of nitrous oxide, ammonia, and propane mixtures were investigated experimentally in a cylindrical channel (length, 2000 mm; inner diameter, 15 mm). Tests were performed for five propane mass fractions (0, 2.0, 3.8, 5.7, and 7.4 wt%) to investigate flame behavior and determine the suitable propellant formulation. The results demonstrated that the flame acceleration rate first increased and then decreased with additional increases of propane. The overpressures and shock velocities exhibited a similar trend and achieved the steady detonation stage except for the mixture with propane fraction of 7.4 wt%. Propane outperformed ammonia as an additive to nitrous oxide, and the addition of 2.0 wt% propane had a positive influence on the flame acceleration process, pressure, and shock buildup for premixed nitrous oxide and ammonia. However, for lower concentrations of nitrous oxide with the addition of excessive propane, a decrease in the aforementioned parameters was observed in the doped flames.
In this experiment, detonation cell sizes of propane/oxygen/nitrogen under different initial conditions was measured, including the ratio of nitrogen to oxidant, equivalence ratio and initial pressure. The influences of different conditions on the transition distance from deflagration to detonation and detonation velocity were analyzed. The results indicate that increasing the ratio of nitrogen to oxidant will increase the size of detonation cell and make its structure irregular. More nitrogen will reduce the detonation velocity. Besides, the relationship between the size of detonation cell and the equivalence ratio displays a U-shaped curve. When the equivalence ratio is 1.2, the size of detonation cell reaches the minimum value of 6.957 mm. In addition, the experimental data shows that increasing initial pressure will increase the concentrations of fuel and oxidant, accelerate the molecular movement inside the tube, and eventually accelerate the detonation velocity. The increase of initial pressure will increase the collision frequency between transverse waves and incident shock waves, and finally reduce the size of detonation cell.
A combustion-powered actuator has been proposed in our previous work (Wang et al., 2015), and it has shown great power hopping ability. To explore the hopping process and output performance of the actuator, the model of an actuator driving the hopping process is investigated through theoretical analysis and experimental validation. Firstly, the structure of the actuator and hopping process are described briefly, and the dynamic models of the process are constructed. Secondly, the thermodynamic model of the actuator is established by the Wiebe heat release function and the input energy density is computed by Chemkin for when propane and nitrous oxide with different equivalence ratios are injected into the chamber. Thus, the thermodynamic model is obtained by integrating dynamic and thermodynamic equations. After that, a few output performance parameters are identified to assess system performance. Lastly, the experimental rig of the combustion actuator is set up to test the displacement and pressure of the actuator driven hopping process. By solving the thermodynamic equations, the post-combustion pressure, the displacement and the velocity varying with time are computed, and are compared with the test results, indicating that the computational results match the experimental test well. At the end of the stroke, the velocities of the experiment and simulation are 6.5 m/s and 6.99 m/s, respectively. The hopping results are compared with the simulation when different pressures under equivalence ratio of 1 are injected, and the maximum and minimum deviations are 14.45% and 1.83%, respectively.
A methodological approach to defining propellant characterization is presented. The method is based on the well-established Technology Readiness Level nomenclature. This approach establishes the Propellant Readiness Level as a metric for ascertaining the readiness of a propellant or a propellant combination by evaluating the following set of propellant characteristics: thermodynamic data, toxicity, applications, combustion data, heat transfer data, material compatibility, analytical prediction modeling, injector/chamber geometry, pressurization, ignition, combustion stability, system storability, qualification testing, and flight capability. The methodology is meant to be applicable to all propellants or propellant combinations; liquid, solid, and gaseous propellants as well as monopropellants and propellant combinations are equally served. The functionality of the proposed approach is tested through the evaluation and comparison of an example set of hydrocarbon fuels.
Nitrous oxide is introduced as a multi-purpose propellant for spacecraft. Potential space applications of this propellant are given. Based on comparison to conventional systems, a multi-mode nitrous oxide propulsion concept is expected to deliver higher performance. Main features of a self-pressurising, nitrous oxide storage system are described. A nitrous oxide catalytic decomposition technique is suggested for restartable spacecraft propulsion. Up-to-date experimental results are presented. A conclusion describes the long-term feasibility of novel nitrous oxide propulsion option concepts.
Nitrous oxide is introduced as a rocket propellant for small satellites. The reasons for using this propellant on small spacecrafts are discussed. Potential space applications of nitrous oxide are listed. A nitrous oxide catalytic decomposition technique is suggested for restartable spacecraft propulsion. Theoretical performance of a nitrous oxide monopropellant thruster is shown. Basics of nitrous oxide catalytic decomposition are given. Operating principles of a nitrous oxide monopropellant thruster are described. The design of the test apparatus and the set-up for nitrous oxide decomposition are given. Up-to-date achievements of nitrous oxide decomposition research at Surrey are reported. Future design features of nitrous oxide monopropellant thrusters are discussed. A conclusion about future research on nitrous oxide catalytic decomposition is given.