L'AIRE - Laboratori Aeronàutic i Industrial de Recerca i Estudis
http://hdl.handle.net/2117/3480
2016-12-09T02:10:33ZSuccesses and challenges of a collaborative-PBL program in engineering degrees
http://hdl.handle.net/2117/97771
Successes and challenges of a collaborative-PBL program in engineering degrees
González Vila, Joaquin; Font Andreu, Jorge; Salán Ballesteros, Maria Núria; García-Almiñana, Daniel; Ortiz Marzo, José Antonio; Mudarra López, Miguel; Griful Ponsati, Eulàlia
This paper presents an extracurricular program called INSPIRE3 that has been implemented by the ETSEIAT (Escola Tècnica
Superior d’Enginyeries Industrial i Aeronàutica de Terrassa), a center belonging to the UPC-BarcelonaTech (Universitat
Politècnica de Catalunya). This program is mainly aimed at facilitating cross-curricular skills and developing abilities among
students through collaborative-project based learning. The projection of an attractive external image of engineering degrees
offered by ETSEIAT in order to increase the enrollment in such degrees is a secondary goal of this program. Under INSPIRE3,
several real, challenging and multidisciplinary engineering projects are currently under development. The main feature of this
program is that the subjects of the projects are proposed by the students themselves. In this paper, INSPIRE3 motivation,
program management and implementation process are described and a short description of projects under development is also
given.
Comunicació presentada a
2016-12-05T13:03:17ZGonzález Vila, JoaquinFont Andreu, JorgeSalán Ballesteros, Maria NúriaGarcía-Almiñana, DanielOrtiz Marzo, José AntonioMudarra López, MiguelGriful Ponsati, EulàliaThis paper presents an extracurricular program called INSPIRE3 that has been implemented by the ETSEIAT (Escola Tècnica
Superior d’Enginyeries Industrial i Aeronàutica de Terrassa), a center belonging to the UPC-BarcelonaTech (Universitat
Politècnica de Catalunya). This program is mainly aimed at facilitating cross-curricular skills and developing abilities among
students through collaborative-project based learning. The projection of an attractive external image of engineering degrees
offered by ETSEIAT in order to increase the enrollment in such degrees is a secondary goal of this program. Under INSPIRE3,
several real, challenging and multidisciplinary engineering projects are currently under development. The main feature of this
program is that the subjects of the projects are proposed by the students themselves. In this paper, INSPIRE3 motivation,
program management and implementation process are described and a short description of projects under development is also
given.Ram-air parachute simulation with panel methods and staggered coupling
http://hdl.handle.net/2117/91426
Ram-air parachute simulation with panel methods and staggered coupling
Ortega, Enrique; Flores Le Roux, Roberto Maurice; Pons Prats, Jordi
2016-11-03T13:43:42ZOrtega, EnriqueFlores Le Roux, Roberto MauricePons Prats, JordiReliability versus mass optimization of CO2 extraction technologies for long duration missions
http://hdl.handle.net/2117/89135
Reliability versus mass optimization of CO2 extraction technologies for long duration missions
Detrell Domingo, Gisela; Griful Ponsati, Eulàlia; Messerschmid, Ernst
The aim of this paper is to optimize reliability and mass of three CO2 extraction technologies/components: the 4-Bed Molecular Sieve, the Electrochemical Depolarized Concentrator and the Solid Amine Water Desorption. The first one is currently used in the International Space Station and the last two are being developed, and could be used for future long duration missions. This work is part of a complex study of the Environmental Control and Life Support System (ECLSS) reliability. The result of this paper is a methodology to analyze the reliability and mass at a component level, which is used in this paper for the CO2 extraction technologies, but that can be applied to the ECLSS technologies that perform other tasks, such as oxygen generation or water recycling, which will be a required input for the analysis of an entire ECLSS. The key parameter to evaluate any system to be used in space is mass, as it is directly related to the launch cost. Moreover, for long duration missions, reliability will play an even more important role, as no resupply or rescue mission is taken into consideration. Each technology is studied as a reparable system, where the number of spare parts to be taken for a specific mission will need to be selected, to maximize the reliability and minimize the mass of the system. The problem faced is a Multi-Objective Optimization Problem (MOOP), which does not have a single solution. Thus, optimum solutions of MOOP, the ones that cannot be improved in one of the two objectives, without degrading the other one, are found for each selected technology. The solutions of the MOOP for the three technologies are analyzed and compared, considering other parameters such as the type of mission, the maturity of the technology and potential interactions/synergies with other technologies of the ECLSS.
2016-07-25T10:43:03ZDetrell Domingo, GiselaGriful Ponsati, EulàliaMesserschmid, ErnstThe aim of this paper is to optimize reliability and mass of three CO2 extraction technologies/components: the 4-Bed Molecular Sieve, the Electrochemical Depolarized Concentrator and the Solid Amine Water Desorption. The first one is currently used in the International Space Station and the last two are being developed, and could be used for future long duration missions. This work is part of a complex study of the Environmental Control and Life Support System (ECLSS) reliability. The result of this paper is a methodology to analyze the reliability and mass at a component level, which is used in this paper for the CO2 extraction technologies, but that can be applied to the ECLSS technologies that perform other tasks, such as oxygen generation or water recycling, which will be a required input for the analysis of an entire ECLSS. The key parameter to evaluate any system to be used in space is mass, as it is directly related to the launch cost. Moreover, for long duration missions, reliability will play an even more important role, as no resupply or rescue mission is taken into consideration. Each technology is studied as a reparable system, where the number of spare parts to be taken for a specific mission will need to be selected, to maximize the reliability and minimize the mass of the system. The problem faced is a Multi-Objective Optimization Problem (MOOP), which does not have a single solution. Thus, optimum solutions of MOOP, the ones that cannot be improved in one of the two objectives, without degrading the other one, are found for each selected technology. The solutions of the MOOP for the three technologies are analyzed and compared, considering other parameters such as the type of mission, the maturity of the technology and potential interactions/synergies with other technologies of the ECLSS.Review of Lambert's problem
http://hdl.handle.net/2117/86429
Review of Lambert's problem
Torre Sangrà, David de la; Fantino, Elena
Lambert’s problem is the orbital boundary-value problem constrained by two points and elapsed time. It is one of the most extensively studied problems in celestial mechanics and astrodynamics, and, as such, it has always attracted the interest of mathematicians and engineers. Its solution lies at the base of algorithms for, e.g., orbit determination, orbit design (mission planning), space rendezvous and interception, space debris correlation, missile and spacecraft targeting. There is abundance of literature discussing various approaches developed over the years to solve Lambert’s problem. We have collected more than 70 papers and, of course, the issue is treated in most astrodynamics and celestial mechanics textbooks. From our analysis of the documents, we have been able to identify five or six main solution methods, each associated to a number of revisions and variations, and many, so to say, secondary research lines with little or no posterior development. We have ascertained plenty of literature with proposed solutions, in many cases supplemented by performance comparisons with other methods. We have reviewed and organized the existing bibliography on Lambert’s problem and we have performed a quantitative comparison among the existing methods for its solution. The analysis is based on the following issues: choice of the free parameter, number of iterations,generality of the mathematical formulation, limits of applicability (degeneracies, domain of the parameter, special cases and peculiarities), accuracy, and suitability to automatic execution. Eventually we have tested the performance of each code. The solvers that incorporate the best qualities are Bate’s algorithm via universal variables with Newton-Raphson and Izzo’s Householder algorithm. The former is the fastest, the latter exhibits the best ratio between speed, robustness and accuracy.
2016-04-29T13:51:49ZTorre Sangrà, David de laFantino, ElenaLambert’s problem is the orbital boundary-value problem constrained by two points and elapsed time. It is one of the most extensively studied problems in celestial mechanics and astrodynamics, and, as such, it has always attracted the interest of mathematicians and engineers. Its solution lies at the base of algorithms for, e.g., orbit determination, orbit design (mission planning), space rendezvous and interception, space debris correlation, missile and spacecraft targeting. There is abundance of literature discussing various approaches developed over the years to solve Lambert’s problem. We have collected more than 70 papers and, of course, the issue is treated in most astrodynamics and celestial mechanics textbooks. From our analysis of the documents, we have been able to identify five or six main solution methods, each associated to a number of revisions and variations, and many, so to say, secondary research lines with little or no posterior development. We have ascertained plenty of literature with proposed solutions, in many cases supplemented by performance comparisons with other methods. We have reviewed and organized the existing bibliography on Lambert’s problem and we have performed a quantitative comparison among the existing methods for its solution. The analysis is based on the following issues: choice of the free parameter, number of iterations,generality of the mathematical formulation, limits of applicability (degeneracies, domain of the parameter, special cases and peculiarities), accuracy, and suitability to automatic execution. Eventually we have tested the performance of each code. The solvers that incorporate the best qualities are Bate’s algorithm via universal variables with Newton-Raphson and Izzo’s Householder algorithm. The former is the fastest, the latter exhibits the best ratio between speed, robustness and accuracy.Analysis of perturbations and station-keeping requirements in highly-inclined geosynchronous orbits
http://hdl.handle.net/2117/86428
Analysis of perturbations and station-keeping requirements in highly-inclined geosynchronous orbits
Fantino, Elena; Flores Le Roux, Roberto Maurice; Di Salvo, Alessio; Di Carlo, Marilena
There is a demand for communications services at high latitudes that is not well served by conventional geostationary satellites. Alternatives using low-altitude orbits require too large constellations. Other options are the Molniya and Tundra families (critically-inclined, eccentric orbits with the apogee at high latitudes). In this work we have considered derivatives of the Tundra type with different inclinations and eccentricities. By means of a high-precision model of the terrestrial gravity field and the most relevant environmental perturbations, we have studied the evolution of these orbits during a period of two years. The effects of the different perturbations on the constellation ground track (which is more important for coverage than the orbital elements themselves) have been identified. We show that, in order to maintain the ground track unchanged, the most important parameters are the orbital period and the argument of the perigee. Very subtle changes in the orbital period (due mainly to lunar perturbations) cause a large east-west drift of the ground trace which dwarfs the displacement due to the regression of the ascending node. From these findings, a station-keeping strategy that minimizes propellant consumption has then been devised. Our results offer interesting guidelines for the design and operation of satellite constellations using these orbits.
2016-04-29T13:21:01ZFantino, ElenaFlores Le Roux, Roberto MauriceDi Salvo, AlessioDi Carlo, MarilenaThere is a demand for communications services at high latitudes that is not well served by conventional geostationary satellites. Alternatives using low-altitude orbits require too large constellations. Other options are the Molniya and Tundra families (critically-inclined, eccentric orbits with the apogee at high latitudes). In this work we have considered derivatives of the Tundra type with different inclinations and eccentricities. By means of a high-precision model of the terrestrial gravity field and the most relevant environmental perturbations, we have studied the evolution of these orbits during a period of two years. The effects of the different perturbations on the constellation ground track (which is more important for coverage than the orbital elements themselves) have been identified. We show that, in order to maintain the ground track unchanged, the most important parameters are the orbital period and the argument of the perigee. Very subtle changes in the orbital period (due mainly to lunar perturbations) cause a large east-west drift of the ground trace which dwarfs the displacement due to the regression of the ascending node. From these findings, a station-keeping strategy that minimizes propellant consumption has then been devised. Our results offer interesting guidelines for the design and operation of satellite constellations using these orbits.A meshless finite point method for three-dimensional analysis of compressible flow problems involving moving boundaries and adaptivity
http://hdl.handle.net/2117/86276
A meshless finite point method for three-dimensional analysis of compressible flow problems involving moving boundaries and adaptivity
Ortega, Enrique; Oñate Ibáñez de Navarra, Eugenio; Idelsohn Barg, Sergio Rodolfo; Flores Le Roux, Roberto Maurice
A finite point method for solving compressible flow problems involving moving boundaries and adaptivity is presented. The numerical methodology is based on an upwind-biased discretization of the Euler equations, written in arbitrary Lagrangian–Eulerian form and integrated in time by means of a dual-time steeping technique. In order to exploit the meshless potential of the method, a domain deformation approach based on the spring network analogy is implemented, and h-adaptivity is also employed in the computations. Typical movable boundary problems in transonic flow regime are solved to assess the performance of the proposed technique. In addition, an application to a fluid–structure interaction problem involving static aeroelasticity illustrates the capability of the method to deal with practical engineering analyses. The computational cost and multi-core performance of the proposed technique is also discussed through the examples provided.
This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.
2016-04-27T14:59:20ZOrtega, EnriqueOñate Ibáñez de Navarra, EugenioIdelsohn Barg, Sergio RodolfoFlores Le Roux, Roberto MauriceA finite point method for solving compressible flow problems involving moving boundaries and adaptivity is presented. The numerical methodology is based on an upwind-biased discretization of the Euler equations, written in arbitrary Lagrangian–Eulerian form and integrated in time by means of a dual-time steeping technique. In order to exploit the meshless potential of the method, a domain deformation approach based on the spring network analogy is implemented, and h-adaptivity is also employed in the computations. Typical movable boundary problems in transonic flow regime are solved to assess the performance of the proposed technique. In addition, an application to a fluid–structure interaction problem involving static aeroelasticity illustrates the capability of the method to deal with practical engineering analyses. The computational cost and multi-core performance of the proposed technique is also discussed through the examples provided.Three-dimensional numerical simulation of an external gear pump with decompression slot and meshing contact point
http://hdl.handle.net/2117/85440
Three-dimensional numerical simulation of an external gear pump with decompression slot and meshing contact point
Castilla López, Roberto; Gámez Montero, Pedro Javier; Campo Sud, David del; Raush Alviach, Gustavo Adolfo; García Vilchez, Mercedes; Codina Macià, Esteban
Recently several works have been published on numerical simulation of an external gear pump (EGP). Such kinds of pumps are simple and relatively inexpensive, and are frequently used in fluid power applications, such as fluid power in aeronautical, mechanical, and civil engineering. Nevertheless, considerable effort is being undertaken to improve efficiency and reduce noise and vibration produced by the flow and pressure pulsations. Numerical simulation of an EGP is not straightforward principally for two main reasons. First, the gearing mechanism between gears makes it difficult to handle a dynamic mesh without a considerable deterioration of mesh quality. Second, the dynamic metal-metal contact simulation is important when high pressure outflow has to be reproduced. The numerical studies published so far are based on a two-dimensional (2D) approximation. The aim of the present work is to contribute to the understanding of the fluid flow inside an EGP by means of a complete three-dimensional (3D) parallel simulation on a cluster. The 3D flow is simulated in a LINUX cluster with a solver developed with the OPENFOAM Toolbox. The hexahedral mesh quality is maintained by periodically replacing the mesh and interpolating the physical magnitudes fields. The meshing contact point is simulated with the viscous wall approach, using a viscosity model based on wall proximity. The results for the flow rate ripples show a similar behavior to that obtained with 2D simulations. However, the flow presents important differences inside the suction and the discharge chambers, principally in the regions of the pipes' connection. Moreover, the decompression slot below the gearing zone, which can not be simulated with a 2D approximation, enables a more realistic simulation of a contact ratio greater than 1. The results are compared with experimental measurements recently published.
2016-04-08T14:13:47ZCastilla López, RobertoGámez Montero, Pedro JavierCampo Sud, David delRaush Alviach, Gustavo AdolfoGarcía Vilchez, MercedesCodina Macià, EstebanRecently several works have been published on numerical simulation of an external gear pump (EGP). Such kinds of pumps are simple and relatively inexpensive, and are frequently used in fluid power applications, such as fluid power in aeronautical, mechanical, and civil engineering. Nevertheless, considerable effort is being undertaken to improve efficiency and reduce noise and vibration produced by the flow and pressure pulsations. Numerical simulation of an EGP is not straightforward principally for two main reasons. First, the gearing mechanism between gears makes it difficult to handle a dynamic mesh without a considerable deterioration of mesh quality. Second, the dynamic metal-metal contact simulation is important when high pressure outflow has to be reproduced. The numerical studies published so far are based on a two-dimensional (2D) approximation. The aim of the present work is to contribute to the understanding of the fluid flow inside an EGP by means of a complete three-dimensional (3D) parallel simulation on a cluster. The 3D flow is simulated in a LINUX cluster with a solver developed with the OPENFOAM Toolbox. The hexahedral mesh quality is maintained by periodically replacing the mesh and interpolating the physical magnitudes fields. The meshing contact point is simulated with the viscous wall approach, using a viscosity model based on wall proximity. The results for the flow rate ripples show a similar behavior to that obtained with 2D simulations. However, the flow presents important differences inside the suction and the discharge chambers, principally in the regions of the pipes' connection. Moreover, the decompression slot below the gearing zone, which can not be simulated with a 2D approximation, enables a more realistic simulation of a contact ratio greater than 1. The results are compared with experimental measurements recently published.Modelling harmonics drawn by nonlinear loads
http://hdl.handle.net/2117/76228
Modelling harmonics drawn by nonlinear loads
Lamich Arocas, Manuel; Balcells Sendra, Josep; Mon González, Juan; Corbalán Fuertes, Montserrat; Griful Ponsati, Eulàlia
This paper is devoted to obtain a model of
nonlinear loads (NLL) connected to LV electric networks, in
order to predict the consequences of including parallel active or
passive filters. The model is based on Neural Networks (NNs) and
its purpose is the prediction of harmonic currents generated by a
certain load when supplied by a network with significant series
impedance, disturbed by other random and unknown neighbour
loads. The NNs have been trained by using data obtained from
several circuit simulations of a network supplying several
unknown neighbour loads beside the load of interest, consisting
of a set of rectifiers. The model is validated using the same
network structure, with different neighbour loads and different
load conditions.
2015-07-20T11:37:01ZLamich Arocas, ManuelBalcells Sendra, JosepMon González, JuanCorbalán Fuertes, MontserratGriful Ponsati, EulàliaThis paper is devoted to obtain a model of
nonlinear loads (NLL) connected to LV electric networks, in
order to predict the consequences of including parallel active or
passive filters. The model is based on Neural Networks (NNs) and
its purpose is the prediction of harmonic currents generated by a
certain load when supplied by a network with significant series
impedance, disturbed by other random and unknown neighbour
loads. The NNs have been trained by using data obtained from
several circuit simulations of a network supplying several
unknown neighbour loads beside the load of interest, consisting
of a set of rectifiers. The model is validated using the same
network structure, with different neighbour loads and different
load conditions.A meshless finite point method for three dimensional analysis of compressible flow problems involving moving boundaries and adaptivity
http://hdl.handle.net/2117/28569
A meshless finite point method for three dimensional analysis of compressible flow problems involving moving boundaries and adaptivity
Ortega, Enrique; Oñate Ibáñez de Navarra, Eugenio; Idelsohn Barg, Sergio Rodolfo; Flores Le Roux, Roberto Maurice
A finite point method for solving compressible flow problems involving moving boundaries and adaptivity is presented. The numerical methodology is based on an upwind-biased discretization of the Euler equations, written in arbitrary Lagrangian–Eulerian form and integrated in time by means of a dual-time steeping technique. In order to exploit the meshless potential of the method, a domain deformation approach based on the spring network analogy is implemented, and h-adaptivity is also employed in the computations. Typical movable boundary problems in transonic flow regime are solved to assess the performance of the proposed technique. In addition, an application to a fluid–structure interaction problem involving static aeroelasticity illustrates the capability of the method to deal with practical engineering analyses. The computational cost and multi-core performance of the proposed technique is also discussed through the examples provided.
2015-07-13T10:44:47ZOrtega, EnriqueOñate Ibáñez de Navarra, EugenioIdelsohn Barg, Sergio RodolfoFlores Le Roux, Roberto MauriceA finite point method for solving compressible flow problems involving moving boundaries and adaptivity is presented. The numerical methodology is based on an upwind-biased discretization of the Euler equations, written in arbitrary Lagrangian–Eulerian form and integrated in time by means of a dual-time steeping technique. In order to exploit the meshless potential of the method, a domain deformation approach based on the spring network analogy is implemented, and h-adaptivity is also employed in the computations. Typical movable boundary problems in transonic flow regime are solved to assess the performance of the proposed technique. In addition, an application to a fluid–structure interaction problem involving static aeroelasticity illustrates the capability of the method to deal with practical engineering analyses. The computational cost and multi-core performance of the proposed technique is also discussed through the examples provided.Preliminary study on fluidic actuators. Design modifications
http://hdl.handle.net/2117/28310
Preliminary study on fluidic actuators. Design modifications
Campo Sud, David del; Bergadà Granyó, Josep Maria; Campo Gatell, Vanessa del
As fluidic actuators have the advantage of lacking moving parts, their use in real applications brings high reliability. This is why, once having overcome their drawbacks, which means being able to provide the appropriate momentum and frequency, they could extensively be used in a wide range of applications. The present paper will present a CFD evaluation of the flow inside a fluidic oscillator. Initially a standard fluidic actuator will be simulated and the results compared with existing experimental data. In a second step, several geometric parameters will be modified; the actuator performance under these new conditions is reported. The paper aims to be an aid for future innovative oscillator designs.
2015-06-15T15:31:45ZCampo Sud, David delBergadà Granyó, Josep MariaCampo Gatell, Vanessa delAs fluidic actuators have the advantage of lacking moving parts, their use in real applications brings high reliability. This is why, once having overcome their drawbacks, which means being able to provide the appropriate momentum and frequency, they could extensively be used in a wide range of applications. The present paper will present a CFD evaluation of the flow inside a fluidic oscillator. Initially a standard fluidic actuator will be simulated and the results compared with existing experimental data. In a second step, several geometric parameters will be modified; the actuator performance under these new conditions is reported. The paper aims to be an aid for future innovative oscillator designs.