Riccardo Gelain

Royal Military Academy · Department of Chemistry

Delft Aerospace Rocket Engineering (DARE) has developed a 1 kN hybrid rocket motor, using nitrous oxide as oxidizer and a mixture of sorbitol and paraffin as fuel. During the test campaign different motor configurations were tested, changing both the injector plate design and the mass fraction of the fuel grain constituents. The paper starts with a l...

Hybrid rocket propulsion systems have proved to be a suitable option for some specific applications in the space transportation domain such as in launch vehicle upper stages, orbit transfer spacecrafts, decelerator engines for re-entry capsules, and small satellites launchers. Part of the renewed interest in hybrid rocket propulsion is due mainly t...

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...

As an emerging trend, Green Propulsion has been exponentially growing over the last decades in the space sector. This paper assesses different technologies in a trade-off study weighting their applicability to a specific class of upper stage systems currently developed by many companies and often referred to as kick-stages or orbital stages. In a g...

High-speed video recordings of slab burner experiments were analyzed using a machine learning approach with convolutional neural networks in order to compute the regression rate of hybrid rocket fuels over time. Combustion tests of paraffin-based fuel grains performed in two different hybrid rocket slab burners were recorded with high-speed video c...

This paper elaborates on the initial design and development process of the MOUETTE (Moteur Optique pour ÉTudier et Tester Ergols hybrides) optical access slab burner for investigation of the combustion behaviour of hybrid rocket fuels. The motor has been developed at Université Libre de Bruxelles to enhance the research capabilities of the rocket p...

The combustion behaviour of hybrid rocket propellants can be investigated using hybrid rocket slab burners. Combining high-speed camera visualisation and experimental data allows to estimate the combustion internal ballistics features. However, difficulties are still encountered in transposing viable results evaluated on slab burners to large-scale...

Semantic image segmentation using a convolutional neural network was applied to image data of hybrid rocket combustion tests to accurately compute the fuel regression rate over time. Combustion tests with different paraffin-based fuels have been performed at the German Aerospace Center (DLR) and have been captured with a high-speed video camera lea...

Hybrid rocket slab burners can be used to study the combustion behaviour of different hybrid rocket fuels at different operating conditions thanks to optical accesses and high-speed video techniques. This paper focuses on the combustion visualization of a paraffin-based fuel grain burning with oxygen at different pressure and oxidizer mass flux. Af...

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...

The combustion process of solid propellants in hybrid rocket engines can be visualized using hybrid rocket slab burners. By employing high-speed cameras, a vast amount of data can be gathered from the combustion chamber, enabling the estimation of the combustion's internal ballistics features both qualitatively and quantitatively. In this paper, th...

Preliminary investigations carried out at the Aero-Thermo-Mechanics Department (ATM) of Université Libre de Bruxelles (ULB) with paraffin doped with magnesium diboride (MgB2) showed that this additive has the potential to improve some characteristics of the pure paraffin grains, such as the average regression rate and the average specific mass, but...

The contemporary space transportation industry is based on complex and expensive rocket engines derived from the last century successful space programs of the United States, Russia, and the European Union. The development and operational costs of such technologies have been supported mostly by government agencies, to acquire and ensure the strategi...

The exploitation of Hybrid Rocket Engines (HREs) for future space transportation systems is currently being investigated in the framework of the ASCenSIon project, where Université Libre de Bruxelles (ULB) provides expertise in the field of design and experimental investigation of HREs. In particular, the Aero-Thermo-Mechanics (ATM) department of U...

Previous studies carried out by the Aero-Thermo-Mechanics Department at Université Libre de Bruxelles and the Belgium Royal Military academy indicate that Magnesium diboride, MgB2, is a candidate for paraffin-based fuels performance enhancement agent. The main advantage of using Magnesium diboride lies in the fact that this additive is more stable...

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...

This paper illustrates the design and development process of the MOUETTE (Moteur OptiqUe pour ÉTudier et Tester Ergols hybrides) optical access slab burner for investigation of the combustion behaviour of hybrid rocket fuels. The system has been conceived to use gaseous oxygen as oxidizer with a mass flow rate of up to 100 g/s and a maximum combust...

As an emerging trend, Green Propulsion has been exponentially growing over the last decades in the space sector. This paper assesses different technologies in a trade-off study weighting their applicability to a specific class of upper stage systems, currently developed by many companies and often referred to as kick-stages or orbital stages. In a...

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 motors (HRMs) present numerous advantages when compared to other chemical rocket propulsion systems, mainly safety, reliability, and cost. Conventional solid fuels suffer from a low regression rate and poor combustion efficiency, drawbacks that restrained further developments and exploitation of the technology. Two methods are being u...

In the frame of the LYRA Program, funded by the Italian Space Agency, the LM-10-MIRA engine has been successfully tested. The engine has a vacuum thrust of 10-tons and has been developed by a joint Avio-KBKhA propulsion team in the frame of a dedicated ASI-Roscosmos inter-agencies agreement. After the experimental test campaign, further improvement...

The pintle injector is distinguished by its unique geometry and injection characteristics, compared to the impinging or coaxial distributed-element injectors typically used on liquid bipropellant rocket engines. The pintle injector design can deliver high combustion efficiency (typically 96-99%) and enables some unique operating features, such as d...

Delft Aerospace Rocket Engineering has developed a 1 kN hybrid rocket motor, using Nitrous Oxide as oxidizer and a mixture of Sorbitol and Paraffin as fuel. During the campaign, different motor configurations were tested. The thesis starts with the numerical simulation of the rocket motor firing in the different tests, modelling the discharge of se...