Jerome Anthoine

The French Aerospace Lab ONERA | ONERA · DMPE - Department of Multi-Physics for Energetics

The novel stepped helix design consists of a series of solid fuel grain segments aligned in a rotated manner to produce a stepped helical fuel port configuration. The design increases the regression rate by facilitating augmented mixing and convective heat transfer, leveraging centrifugal forces to mitigate the wall-blowing effect that hinders heat...

Hybrid rocket propulsion, first demonstrated by the Russian GIRD-09 rocket in 1933, combines liquid oxidizer and solid fuel for thrust generation. Despite numerous advantages, such as enhanced safety, controllability, and potential environmental benefits, hybrid propulsion has yet to achieve its full potential in space applications. In recent years...

Previous research using Forward Facing Steps (FFS) and Backward Facing Steps (BFS) in the solid fuel grain demonstrated increased regression rates compared to a cylindrical single port. Nonetheless, it is important to assess the combustion instabilities induced by stepped geometries to anticipate (and solve) potential negative side effects. This pa...

We propose a new engine concept which is an evolution of the stepped design approach previously developed and investigated by the authors. The novel helical design consists of a series of solid fuel grain segments (polyethylene) that are rotated against each other to form a stepped helical fuel port. The stepped helix design increases the regressio...

We investigate a new design approach to increase the performance and versatility of Hybrid Rocket Engines. The concept is to calculate optimized fuel grain profiles according to different criteria (lower oxidizer-to-fuel ratio (O/F) shift and O/F values closer to stoichiometry) using a genetic algorithm. These idealized profiles are then approximat...

In this study, we investigate the effect of single steps inside the fuel grains of typical hybrid rocket motors numerically. Steps can be a promising candidate to increase the regression rate of hybrid engines. We show that simulations on simplified geometries yield surprisingly close numerical regression rate profiles when compared to experimental...

In this work, we assess the impact of stepped hybrid rocket solid fuel grains on the performance of the engine. The influence of Forward Facing Steps (FFS) and Backward Facing Steps (BFS) on the regression rate is analysed on two different cylindrical motors and one slab burner with optical access. Accessible post-processing allows to quantify the...

A system design tool allowing to simulate the complete operation of a hybrid rocket engine is developed in this paper. The algorithm of the application is made in such a way that allows the simulation of an element, an ensemble of elements or all the elements constituting a hybrid space propulsion system. The objective is to simulate and predict th...

The LIF/Mie droplet sizing technique has been studied for many years, but its implementation remains challenging due to the fact that the usual assumptions behind it are not valid in practice. Not only the scattered light intensity is not proportional to the droplet surface area, but also single light scattering is not preserved in dense sprays. To...

In this work, the effect of Forward Facing Steps (FFS) and Backward Facing Steps (BFS) on the Hybrid Rocket Engine's regression rate is investigated through test firings on both a classic cylindrical motor and a two-dimensional slab burner with optical access. It serves as a first experimental investigation into the proposal to distribute a set of...

A sensitivity analysis of a 1.5-D combustion chamber model of a hybrid rocket engine is performed in this paper. The goal is to assess the impact that some of the most important engine parameters have over its performances. Studies are carried out by considering three categories of parameters: the aerodynamic characteristics at the inlet of the cha...

A pseudo 2-D model for the cylindrical combustion chamber of a hybrid rocket is developed in this article with the purpose of its integration in a system design tool used for engine predesign phases. A compromise of simplicity and accuracy is thus required. Integral transient boundary layer equations are included and coupled with the mass and energ...

The low regression rate of Hybrid Rocket Engines (HREs) is one prominent characteristic that is addressed in most abstracts concerning hybrid propulsion. Over the years, researchers developed and investigated numerous ways to tackle the low regression rate problem of HREs. This article is a collection and assessment of these diverse methods and des...

In this work, a novel approach to increase the performance of a Hybrid Rocket Engine (HRE) by approximating any idealized fuel port geometry by steps inside the fuel grain is proposed. This work serves as a first investigation into the effect of single steps inside the fuel grains of a typical HRE. In numerical simulations, it is shown that forward...

The growing demand for cheaper space access calls for a more economically and environmentally sustainable approach for launchers. Concurrently, the shift to smaller satellites and the rise of constellations necessitate launchers capable of precise multi-payload/multi-orbit injection. ASCenSIon (Advancing Space Access Capabilities-Reusability and Mu...

Hybrid Rocket Engines (HREs) generate thrust by combining a liquid and a solid propellant. Given the hybrid nature, HREs possess several advantages over Liquid Rocket Engines (LREs) and Solid Rocket Motors (SRMs). Hybrid engines are cheaper and less complex than LREs while being safer and more sustainable than SRMs. HREs are throttleable as well as...

View Video Presentation: https://doi.org/10.2514/6.2021-3562.vid This paper describes the evolution of surface tension of three green monopropellants according to temperature to facilitate the design of a green monopropellant thruster prototype. During the testing, reactions with some of the materials in contact with these monopropellants have been...

View Video Presentation: https://doi.org/10.2514/6.2021-3495.vid A 1.5-D model for the cylindrical combustion chamber of a hybrid rocket is developed in this article with the purpose of its integration in a design system tool allowing to estimate the rocket performances. A compromise of simplicity and accuracy is then required in the formulation of...

A post-processing tool for experimental data is developed to rebuild the instantaneous and local distributions of the fuel port diameter and the fuel regression rate throughout the port conduct during a firing test. The main objective is to use the developed methodology to be able, at a given instant during the firing test, to simulate a hybrid roc...

A new fuel regression model, based on the mass/energy balance at the fuel surface, is implemented in the computational fluid dynamics software CEDRE. The modeling aims at generalizing a practical use of the fuel regression model to improve, by means of numerical simulations, the knowledge about aerothermochemical phenomena in hybrid rocket engines....

Within the framework of the European H2020 HYPROGEO program, an innovative hybrid engine combustion chamber compatible with satellite requirements (constant thrust over very long burn-times) had to be developed. A first test rig was designed and tested in order to better understand the functioning of this innovative combustion chamber, and to help...

Firing tests of a H2O2/polyethylene hybrid rocket motor were performed and analyzed in terms of pressure oscillations under various configurations, using liquid oxidizer injection or gaseous injection through a catalyzer. Most of the firing tests presented pressure oscillations in the range of 200–2000 Hz, provoked by periodic vortex shedding occur...

In the framework of the European H2020 HYPROGEO program, an innovative hybrid engine combustion chamber compatible with satellite requirements (constant thrust over a very long burning duration) has to be developed. To design such an engine, a first test rig, similar to the considered innovative combustion chamber, was designed and tested. The test...

This paper presents the experimental results of a hybrid rocket engine fired both at ambient pressure and under low-pressure conditions. The hybrid engine includes a catalyst bed and a vortex injector, and it is fitted with ultrasound sensors to measure the instantaneous fuel regression rate. These tests have enabled demonstration of the experiment...

Numerical simulation is performed and compared with a firing test of an H2O2/polyethylene hybrid rocket engine equipped with a catalyzer. The simulation is performed assuming an axisymmetric flow, unsteady Reynolds-averaged Navier-Stokes equations are solved based on a single-phase flow. Stable pressure oscillations are observed during the firing t...

Hybrid propulsion generally combines a liquid oxidizer with a solid fuel. Compared to solid or bi-liquid engines, this type of propulsion offers advantages in terms of cost and flexibility. For several years, ONERA has been providing expertise in this area, both in experimental and numerical simulations. Various hybrid rocket motors have been desig...

Oxidizer injection plays a major role in the behaviour of hybrid rocket engines, especially regarding combustion efficiency and stability. This study aims to compare two firing tests with associated numerical simulations based on gaseous oxidizer axial or swirl injection through a catalyzer. The oxidizer and fuel couple used was H2O2(87.5 %)/HDPE....

Hybrid propulsion technology suffers from low propulsive performances generally due to low combustion efficiency in regards to the other chemical propulsion systems. When hydrogen peroxide is used as oxidizer, one of the most promising ways to increase this efficiency combines a catalyst and a swirl injector in order to have an oxidizing gaseous st...

This paper is devoted to a review of some recent studies conducted at ONERA within the framework of solid rocket propulsion for missiles, as well as space launchers. The viewpoint adopted is to present the physical phenomena studied using modeling, simulations and experimentations. Three major scientific topics will be investigated in this article:...

Numerical 2D URANS and 3D MILES single phase simulations are performed and compared to a firing test of a H2O2/PE hybrid rocket engine equipped with a catalyzer. Pressure instabilities were recorded during the firing test and could be explained by the simulations with the formation of large-scale vortices at the end of the fuel grain and in the pos...

Large solid rocket motors are subjected to pressure oscillations for which the origin lies in the coupling between hydrodynamic instabilities and the first longitudinal acoustic modes of the combustion chamber. Static firing tests using two propellant grains in the combustion chamber have been performed. The pressure oscillation amplitude can be st...

The objective of the present study is to generate a reliable experimental database on the fluid hammer phenomenon with real propellants (MMH and NTO) to validate the physical models implemented in the numerical codes. This database with real propellants extends the database obtained by the von Karman Institute on similitude fluids (water, ethanol a...

The wake flow field and radiated sound from a low speed axial fan is studied experimentally. The fan geometry uses controlled diffusion blades and is designed with a low aspect ratio (0.9). The fan is installed with a large tip gap, approximately 10% of the blade span. The radiated sound field is analyzed using a known trailing edge noise formulati...

Large solid rocket motors are subjected to pressure oscillations whose origin ties in the coupling between hydrodynamic instabilities and the first longitudinal acoustic modes of the combustion chamber. The pressure oscillations can be reduced by modifying the burn velocity ratio between the two solid fuel grains used in the motor tests. Static fir...

An anechoic wind tunnel dedicated to fan self-noise studies has been designed and constructed at the von Karman Institute The multi-chamber, mass flow driven design allows for all fan performance characteristics, aerodynamic quantities (e.g., wake turbulence measurements), and acoustic properties to be assessed in the same facility with the same co...

Imposing subsonic outlet boundary conditions for compressible flow simulations is still a challenging problem, since spurious reflections are occurring if unsteady disturbances leaving the domain. Most of the non-reflecting boundary conditions can be found in the literature performing very well if only acoustic perturbations are considered, but the...

This article deals with the discretization of linearized Euler equations by multidimensional upwind residual distribution methods. Linearized Euler equations are applied to model the propagation of sound in the domain where no source of sound is present and where the analogy methods such as Ffowcs-Williams can not be used because of gradients in th...

A method is proposed to calculate the trailing-edge broadband noise emitted from an airfoil, based on a steady Reynolds-averaged Navier–Stokes solution of the flowfield. For this purpose, the pressure spectrum on the airfoil surface near the trailing edge is calculated using a statistical model from the Reynolds-averaged Navier–Stokes mean velocity a...

Experimental measurements are taken on a (mechanically) simplified ducted rotor system with the aim of validating prediction methods. The acoustic measurements exhibit some typical behavior of stator-rotor interaction mechanism. PIV measurements are conducted to obtain some information on the flow behavior, particularly the strut wake evolution at...

The work deals with characteristic non-reflecting boundary conditions for subsonic outflow within the frame of aeroacoustic prediction. A multidimensional formulation of the characteristic theory is derived and associated different boundary conditions are applied for subsonic outlet in order to adjust it to the multidimensional upwind discretizatio...

This paper deals with Amiet's theory for incoming turbulence noise in three different aspects. In the first part, the effects of geometric and acoustic near-field terms are examined using numerical integration methods. A semi-analytical formulation, which takes an intermediate level of geometrical near-field correction into account, is proposed. Se...

The Taylor-Culick flow corresponds to the flow injection through the lateral wall of a semi-infinite channel. This flow is intrinsically unstable downstream of a critical axial position. The flow disturbances develop in vortices that could couple with the acoustics of the channel, generating pressure oscillations. This is what occurs in large solid...

Liquid and solid propulsion received strong investments to make them today nearly unavoidable for large space launchers and sounding rockets. However, each of them has significant drawbacks that may become more limiting when considering new transportation vehicles for space exploration missions or micro-gravity experiments for which simplified, low...

This paper explains how to correctly measure the drag coefficient of a circular cylinder in wind tunnels with large blockage ratios and for the sub-critical to the super-critical flow regimes. When dealing with large blockage ratios, the drag has to be corrected for wall constraints. Different formulations for correcting blockage effect are compare...

Incorporating a submerged nozzle for solid propellant rocket motors, the resulting cavity formed in the vicinity of the nozzle integration part enhances the entrapment of liquid residues of the combustion and leads to the accumulation of slag with a considerable mass. As a first step for the slag accumulation assessment, an experimental and numeric...

To be able to characterize the airflow in the presence of liquid droplets in a confined geometry, a new two-phase particle image velocimetry (PIV) method is developed. It is based on a two-colour YAG laser and two different fluorescent dyes dissolved in the gas-phase tracers and droplets. This approach permits to separate the images (and thus the i...

Whentraveling through a tunnel, a high-speed train generates pressure waves that propagate back and forth to the portals and affect passenger comfort. Part of the initial compression wave is also radiated at the tunnel's far end, as a micropressure wave, causing environmental nuisance. The strength of this micropressure wave is proportional to the...

In solid propellant rocket motors incorporating a submerged nozzle, liquid alumina residues of the combustion can be entrapped in the cavity formed by the casing and the nozzle integration part This continuous entrapment leads to an accumulation of slag, resulting in a considerable mass at the end of the booster operation. Various aspects of the sl...

This paper proposes to study the flow and corresponding noise around a segment of an automotive blade (CD-airfoil) at design conditions, namely a 8° angle of attack, and a higher angle of attack of 15° for which there is experimental evidence that the flow regime has significantly changed. This study encompasses two aspects, the flow resolution aro...

This article deals with the discretization of Linearized Euler Equations (LEEs) by multidimensional upwind Residual Distribution methods. Linearized Euler equations are applied in the domain where there is no source of sound and the analogy methods such as Ffowcs-Williams can not be used because of gradients in the mean ow. Residual distribution me...

Cold-gas experiments are used to study the pressure oscillations occurring in solid rocket motors and the performance of different ways of passive control of these oscillations. Previous studies stated that flow-acoustic coupling is mainly observed for nozzles including a cavity. The nozzle geometry has an effect on the pressure oscillations throug...

A study has demonstrated the possible application of the strip method to predict the noise radiated by airfoils in spanwise-varying upstream flow conditions. Researchers, on the basis of the Amiet's theory, have highlighted the limitations of the method of cutting the airfoil in strips each having its flow upstream flow conditions and to sum the re...

State of the practice of aeroacoustics relies on the use of analogies (decoupling the aerodynamic and acoustic fields), which are based on high quality time resolved aerodynamic solutions in order to ac-curately estimate the sources of sound [1]. Therefore, to develop a methodology for industrial appli-cations using off-the-shelf commercial softwar...

Pressure oscillations that occur in the boosters of Ariane 5 are explained through a coupling between acoustics and flow disturbances. One of these disturbances is called Surface Vortex Shedding (SVS), which comes from the natural instability of the Taylor flow induced by the propellant combustion. Depending mainly on the Reynolds number (based on...

Cold gas experiments are used to study the pressure oscillations occurring in solid rocket motors (SRM) and the performance of different ways of passive control of these oscillations. Previous studies stated that flow–acoustic coupling is mainly observed for nozzles including cavity. The nozzle geometry has an effect on the pressure oscillations th...

In solid propellant rocket motors (SRM) incorporating a submerged nozzle, the entrapment of liquid residues of the combustion in the cavity formed in the surrounding of the nozzle integration part can lead to the accumulation of slag with a considerable mass. In the framework of the slag accumulation investigation various aspects are considered usi...

In problem involving noise generated by fans or high-lift devices in uniform stationary flow, trailing edge noise has a primary interest. This paper proposes to study the trailing edge noise produced by a Controlled-Diffusion (CD) airfoil specially developed for automotive engine cooling by Valeo. A LES flow computation is realised through the Flue...

Noise prediction for turbulent interactions with fan-blades or high-lift devices has been continuously developed for the last thirty years. A benchmark solution to this problem is Amiet's theory for acoustic radiation from an airfoil in a turbulent stream. In most aerodynamic theories the incoming gust is assumed to be sinusoidal, which is also the...

This paper examines the effect of upstream excitation on the sound production and shear layer organization of a jet within a circular expansion chamber. The excitation fre- quencies are selected such that they correspond to the first longitudinal mode and first transverse mode of the jet. Additionally, from preliminary acoustic measurements, a low...

Hybrid methods based on acoustic analogies provide an efficient approach to compute flow generated sound in low Mach number engineering applications. In this paper, a comparative study of the numerical robustness of different formulations of Vortex Sound Theory and Curle's analogy is carried out. A particular focus is placed on the numerical effect...

To be able to characterize the airflow in the presence of liquid droplets in a solid rocket motor model, a new two-phase Particle Image Velocimetry (PIV) method is developed. It is based on a two-colour YAG laser and two different fluorescent dyes dissolved in the gas-phase tracers and droplets. This approach permits to separate the images (and thu...

The design of the lighting columns with octagonal cross-section, to be used along public roads, requires a precise knowledge of their aerodynamic force coefficients. The aerodynamic forces induced by the wind on octagonal cylindrical elements with different diameters, different edge curvature radii and different roughness's have been measured in a...

In solid propellant rocket motors incorporating a submerged nozzle, the entrapment of liquid residues of the combustion in the cavity formed in the surrounding of the nozzle integration part can lead to the accumulation of slag with a considerable mass. The goal of the present study is to characterize experimentally the driving parameters of the sl...

Cold gas experiments are used to study the pressure oscillations occurring in solid rocket motors (SRM). Previous studies stated that flow–acoustic coupling is mainly observed for nozzles including cavity. The nozzle geometry has an effect on the pressure oscillations through a coupling between the acoustic fluctuations induced by the cavity volume...

The present paper investigates the case of an airfoil placed in a turbulent jet. The Reynolds number based on the chord length is equal to 36,000 and the Mach number to 0.04. The unsteady, three-dimensional incompressible flow around the airfoil is first computed with the LES module of the commercial solver FLUENT. An innovative procedure is then p...

The emergence of commercial high-speed trains in the last 25 years has led to the development of an efficient short-range transport system competing with air transport. With the increase of speed, aerodynamic problems of such trains are coming out. Aerodynamic loads that occur when the train move in a tunnel and pass by each other are the typical o...

In solid propellant rocket motors incorporating a submerged nozzle, the entrapment of liquid residues of the combustion in the cavity formed in the surrounding of the nozzle integration part can lead to the accumulation of slag with a considerable mass. The long-term goal of the present study is to characterise experimentally the driving parameter...

In solid propellant rocket motors incorporating a submerged nozzle, the regression of the propellant during the combustion leads to the formation of a cavity around the submerged part, which can accumulate slag with a considerable mass, reducing the motor efficiency. This article continues the work presented at the AIAA conference of 2005 under th...

In solid propellant rocket motors incorporating a submerged nozzle, the entrapment of liquid residues of the combustion in the cavity formed in the surrounding of the nozzle integration part can lead to the accumulation of slag with a considerable mass. The long-term goal of the present study is to characterise experimentally the driving parameter...

Aeroacoustics is a growing field in aeronautical and automotive industry, mainly through the application of the aeroacoustical analogy. Curle's analogy is particularly popular in automotive industry. This paper presents some preliminary results of an aeroacoustical study of the sound produced by the leapfrogging of two rectilinear filament vortices...

The sound produced by vortex pairing in a Mach 0.1, acoustically excited air jet is considered. The sound produced by vortex pairing is predicted on the basis of an experimental description of the flow field and using an aeroacoustical analogy. The experimental data is provided by particle image velocimetry. The aeroacoustical analogy is a conserva...

The Ahmed body is used as a reference model for fundamental studies of car-type bluff body aerodynamics, in particular focused on the influence of the rear slant angle on the drag coefficient. The objectives of the present work are to obtain reliable drag coefficient comparable to the literature and to explain, based on the nature of the flow, its...

Flow instabilities in solid rocket boosters such as the Ariane 5 boosters could lead to pressure and thrust oscillations, which reduce the rocket motor performance and could damage the payload. Before any modification within the solid rocket boosters can be performed to eliminate the pressure oscillations, a good understanding of the fluid dynamic...

Aeroacoustic instabilities occur in many applications of technological interest and have undesirable effects on the steady operation of the system. Passive and active means are sought to reduce the level of oscillation and eliminate the instability. In the case of segmented solid rocket motors, observations indicate that low-frequency oscillations...