Fluid Gravity Engineering Ltd

Saint Andrews, United Kingdom

Fluid Gravity Engineering Ltd

Saint Andrews, United Kingdom
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News Article | July 19, 2017
Site: phys.org

Planetary landers or reentering spacecraft need to lose their speed rapidly to achieve safe landings, which is where parachutes come in. They have played a crucial role in the success of ESA missions such as ESA's Atmospheric Entry Demonstrator, the Huygens lander on Saturn's moon Titan and the Intermediate Experimental Vehicle spaceplane. This 1.25-m diameter 'Supersonic Parachute Experiment Ride on Maxus', or Supermax, flew piggyback on ESA's Maxus-9 sounding rocket on 7 April, detaching from the launcher after its solid-propellant motor burnt out. After reaching its maximum 679 km altitude, the capsule began falling back under the pull of gravity. It fell at 12 times the speed of sound, undergoing intense aerodynamic heating, before air drag decelerated it to Mach 2 at an altitude of 19 km. At this point the capsule's parachute was deployed to stabilise it for a soft landing, and allowing its onboard instrumentation and camera footage to be recovered intact. The experiment was undertaken by UK companies Vorticity Ltd and Fluid Gravity Engineering Ltd under ESA contract. The data gathered by this test are being added to existing wind tunnel test campaigns of supersonic parachutes to validate newly developed software called the Parachute Engineering Tool (also developed by Vorticity), allowing mission designers to accurately assess the use of parachutes. Explore further: Image: Taking it to the Supermax


White C.,University of Glasgow | Scanlon T.J.,University of Strathclyde | Merrifield J.A.,Fluid Gravity Engineering Ltd | Kontis K.,University of Glasgow | And 2 more authors.
AIP Conference Proceedings | Year: 2016

Soft landings on extra-terrestrial airless bodies will be required for future sample return missions, such as the Phobos Sample Return (PhSR). PhSR is a candidate mission of ESA's Mars Robotic Exploration Preparation (MREP-2) Programme. Its main objective is to acquire and return a sample from the Martian moon Phobos, after a scientific characterisation phase of the moon and of the landing site. If a rocket is used to slow down the spacecraft to a vertical descent velocity that it will be able to free-fall from, care has to be taken to ensure that the rocket exhaust does not contaminate the surface regolith that is to be collected and that the rocket does not cause unacceptable levels of erosion to the surface, which could jeopardise the mission. In addition to the work being done in the scope of PhSR, the European Space Agency is funding an experimental facility for investigating these nozzle expansion problems; the current progress of this is described. To support this work, an uncoupled hybrid computational fluid dynamics-direct simulation Monte Carlo method is developed and used to simulate the exhaust of a mono-propellant rocket above the surface of an airless body. The pressure, shear stress, and heat flux at the surface are compared to an analytical free-molecular solution to determine the altitude above which the free-molecular solution is sufficient for predicting these properties. The pressures match well as low as 15 m above the surface, but the heat flux and shear stress are not in agreement until an altitude of 40 m. A new adsorption/desorption boundary condition for the direct simulation Monte Carlo code has also been developed for future use in in-depth contamination studies.


Frost D.L.,McGill University | Loiseau J.,McGill University | Goroshin S.,McGill University | Zhang F.,Defence R and D Canada Suffield | And 2 more authors.
AIP Conference Proceedings | Year: 2017

The explosive compaction, fracture and dispersal of aluminum particles contained within a cylinder were investigated experimentally and computationally. The aluminum particles surrounded a central, cylindrical high explosive burster charge and were weakly confined in a cardboard tube. The compaction and fracture of the particles were visualized with flash radiography and the subsequent fragment dispersal was recorded with high-speed photography. The aluminum fragments produced were much larger than the original aluminum particles and similar in shape to those generated from the explosive fracture of a solid ductile metal cylinder, suggesting that the shock transmitted into the aluminum compacted the powder to near solid density. The presence of a casing on the burster explosive had little influence on the fragmentation behavior. The effect of an air gap between the burster and the aluminum particles was also investigated. The expansion and fracture of the aluminum were compared with the predictions of a multi-material hydrocode which indicated that the first appearance of cracks through the compacted aluminum layer occurred approximately when the release wave reached the inner surface of the compacted powder.


Grant
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: SPA.2012.2.2-02 | Award Amount: 2.74M | Year: 2013

As mentioned in the FP7 space call for Europe to be active in space in the long term, be it in earth-orbit or across the solar system, it is essential that space technologies with key capabilities are at its disposal. This goal requires developments by radical innovation which may then lead to disruptive technologies. In this frame new thermal shielding and low risk return strategies are defined as European key activities in the future. In Europe the design of spacecraft for high-energetic interplanetary or sample return flights is still performed with big safety margins, which means high mass. This again leads to higher costs and a reduction in scientific payloads or instrumentation. Ablative thermal protection materials are a key technology for current and future space exploration missions. However, the mission feasibility is determined by the materials available, and the development of new materials is performed, essentially, by an iterative trial-and-error process. This is due to the absence of validated predictive models for ablative material behaviour models are tuned to bulk material properties from tests. For each new material, this tuning has to be redone because the models are not of sufficiently high fidelity to be able to make even small extrapolations. This means that materials cannot be designed to a specification to fulfil the needs of a particular mission. The aim of this project is to make a substantial step towards a predictive model of an ablative thermal protection system by incorporating aspects of high fidelity mesoscale ablator physics within a modular framework. In order to successfully develop such physics modules, the understanding of the fundamental processes occurring within the ablative materials must be improved. To this end, existing ablative materials will be tested in the most powerful European long duration high enthalpy facilities using both standard instrumentation and advanced measurement techniques. From the data obtained, and the state-of-the-art knowledge of ablator physical processes, modules for the specific processes of internal gas flow, internal radiation and gas-surface interaction will be developed to fit inside an overall multi-scale ablator modelling scheme. The improvements made in the representation of an ablative material will be validated against the ground testing, and this advanced ablator model will be applied to realistic flight configurations to demonstrate the impact of the enhanced physics on the understanding of real ablator performance. The existence of this capability will allow improvements in the efficiency and cost of developing advanced new ablative materials which are tailored to meet the specifications of Europes future mission needs. In order to reach this objective, the ABLAMOD project brings substantial expertise from across Europe in ablator materials, thermochemistry, microfluidics, entry systems and instrumentation.


Neeb D.,German Aerospace Center | Gulhan A.,German Aerospace Center | Merrifield J.A.,Fluid Gravity Engineering Ltd.
Journal of Spacecraft and Rockets | Year: 2016

Surface roughness, especially if enhanced due to ablative form change, increases skin friction drag and convective heat transfer over reentry vehicles. Although the corresponding heat flux augmentation is usually lower compared to increased friction, careful consideration in the prediction of the resulting heat load levels is required. Within the European Mars mission ExoMars, the potential roughness impact on the thermal protection system of the descent module has been analyzed based on analytical predictions, numerical calculations, and dedicated experimental campaigns. This paper describes the experimental efforts in the compressible flow regime to study the impact of roughness at representative conditions. The data are discussed based on comparisons with prediction methods and results of other investigators. Based on these data, the numerical predictive capabilities within the ExoMars program are characterized and validated. Copyright © 2015 by German Aerospace Center (DLR).


Neeb D.,German Aerospace Center | Gulhan A.,German Aerospace Center | Merrifield J.A.,Fluid Gravity Engineering Ltd
AIAA AVIATION 2014 -11th AIAA/ASME Joint Thermophysics and Heat Transfer Conference | Year: 2014

Surface roughness, especially if enhanced due to ablative form change, increases skin friction drag and convective heat transfer over re-entry vehicles. Although the corresponding heat flux augmentation is usually lower compared to increased friction, careful consideration in the prediction of the resulting heat load levels is required. Within the European Mars mission ExoMars, the potential roughness impact on the thermal protection system of the descent module has been analyzed based on analytical predictions, numerical calculations and dedicated experimental campaigns. This paper describes the experimental efforts in the compressible flow regime to study the impact of roughness at representative conditions. The data is discussed based on comparisons with prediction methods and results of other investigators. Based on this data the numerical predictive capabilities within the ExoMars program is characterized and validated.


Grant
Agency: European Commission | Branch: FP7 | Program: CP-FP | Phase: SPA.2012.2.2-02 | Award Amount: 2.72M | Year: 2013

There are key space technologies existing at European level and during the last space calls many European projects are framed on space re-entry, but none of them dealing with radically new technologies, able to compete with technologies from other leading countries or allowing collaboration with them. The THOR project will provide knowledge in key space technologies for accessing space, through the design and development of disruptive technologies based on novel thermal management concepts which are specifically targeted to atmospheric entries of future space vehicles and hypersonic transport vehicles. This project, including the participation of several SMEs and relevant end-users, aims at the collaboration among them to strengthen the European space sector and enable international cooperation. The technical approach is focused non-local concepts for thermal management including active cooling as well as passive cooling technologies, in order to extent the capabilities of re-usable Thermal Protection Systems (TPS) towards the requirement of future space flight including hypersonic transport. To achieve this technical target radically new thermal management solutions will be implemented in a new concept of TPS together with innovative materials and unique ceramic structures, reaching a TRL 2-3 at the end of the project. The passive systems will be based on thermal equilibration establishing an efficient heat transfer from highly loaded areas to regions with less loading. New ceramic matrix composites incorporating a new generation of highly thermal conductive fibres will be applied. In addition, active cooling will be implemented by passing a fluid through a ceramic porous structure. The project includes a strong effort on design, modelling and simulation in order to fulfil the technical requirements before integrating the complete TPS. Finally the concepts will be verified by ground tests under realistic entry conditions in high enthalpy facilities.


Joiner N.,University of Saskatchewan | Joiner N.,Fluid Gravity Engineering Ltd. | Hirose A.,University of Saskatchewan | Dorland W.,University of Maryland University College
Physics of Plasmas | Year: 2010

At low Β it is common to neglect parallel magnetic field perturbations on the basis that they are of order Β2. This is only true if effects of order Β are canceled by a term in the ∇B drift also of order Β [H. L. Berk and R. R. Dominguez, J. Plasma Phys. 18, 31 (1977)]. To our knowledge this has not been rigorously tested with modern gyrokinetic codes. In this work we use the gyrokinetic code GS2 [Kotschenreuther, Comput. Phys. Commun. 88, 128 (1995)] to investigate whether the compressional magnetic field perturbation B is required for accurate gyrokinetic simulations at low Β for microinstabilities commonly found in tokamaks. The kinetic ballooning mode (KBM) demonstrates the principle described by Berk and Dominguez strongly, as does the trapped electron mode, in a less dramatic way. The ion and electron temperature gradient (ETG) driven modes do not typically exhibit this behavior; the effects of B are found to depend on the pressure gradients. The terms which are seen to cancel at long wavelength in KBM calculations can be cumulative in the ion temperature gradient case and increase with e. The effect of B on the ETG instability is shown to depend on the normalized pressure gradient Β′ at constant Β. © 2010 American Institute of Physics.


Reynier P.,Ingenierie et Systmes Avances | Bugel M.,Ingenierie et Systmes Avances | Smith A.,Fluid Gravity Engineering Ltd.
International Journal of Aerospace Engineering | Year: 2011

In the frame of future sample return missions to Mars, asteroids, and comets, investigated by the European Space Agency, a review of the actual aerodynamics and aerothermodynamics capabilities in Europe for Mars entry of large vehicles and high-speed Earth reentry of sample return capsule has been undertaken. Additionally, capabilities in Canada and Australia for the assessment of dynamic stability, as well as major facilities for hypersonic flows available in ISC, have been included. This paper provides an overview of European current capabilities for aerothermodynamics and testing of thermal protection systems. This assessment has allowed the identification of the needs in new facilities or upgrade of existing ground tests for covering experimentally Mars entries and Earth high-speed reentries as far as aerodynamics, aerothermodynamics, and thermal protection system testing are concerned. © 2011 Mathilde Bugel et al.


Dunnett J.,Fluid Gravity Engineering Ltd.
Proceedings - 29th International Symposium on Ballistics, BALLISTICS 2016 | Year: 2016

The Holmquist-Johnson-Cook (HJC) concrete model has been implemented in the EDEN hydrocode and applied in studies investigating the normal impacts of simple projectiles against finite thickness concrete barriers. The results of these calculations have been used to investigate how the loading on the projectile and the residual velocity varies as a function of the projectile speed and barrier thickness. Results from the simulations are compared against predictions from cavity-expansion theory based engineering models for projectile penetration, such as those due to Li and Chen, and Forrestal. Special attention is paid to the roles that release waves from the barrier's back surface play in the process and further comparisons are made to investigate how well the extended model of Sjol and Teland is able to account for these effects. An empirically-derived release model is derived and applied to predict penetration data.

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