Browsing by Author "Lapensée, Stéphane"
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Item Development and Characterization of Additive Manufacturing Flat Loop Heat Pipe Evaporator(2023 International Conference on Environmental Systems, 2023-07-16) Corrochano, Javier; Romera, Francisco; Galleguillos, Carlos; Periñán, Antonio; Lasagni, Fernando; Gottero, Marco; Lapensée, StéphaneThis work aims to show the results of the development of a novel ammonia flat Loop Heat Pipe (LHP) stainless steel evaporator manufactured by a combination of Additive Manufacturing (AM) technologies. Firstly, the materials and processes were validated by several tests performed at sample level. The results of this phase revealed that AM technology can manufacture porous stainless steel 316L primary wicks with porosity of 40% and pore diameter of 4.5 µm. Proof and burst tests showed that the flat stainless steel 316L compensation chamber manufactured by selective laser melting technology can withstand up to 200 bar without deformation. In addition, these AM stainless steel 316L materials showed good weldability and excellent chemical compatibility with ammonia. Finally, X-Ray Computed Tomography (CT) has been established as the preferable Non-Destructive Testing (NDT) method for analyzing the manufactured SLM components and flaw detection. For the second phase of the project, the AM flat evaporator was integrated in a technological loop and submitted to a thermal test campaign. The results revealed that the LHP works in a stable way up to 236 W without dry-out in a wide range of temperature sink conditions. The flat AM LHP evaporator combines the advantages of thermal control based on LHPs with the low cost and short production time of AM technologies. Thus, it can be considered as a promising alternative to conventional cylindrical evaporators for cooling applications.Item Development of a Passive Bypass Valve for one and two Phase Fluid Loops for Space Applications(48th International Conference on Environmental Systems, 2018-07-08) van Benthem, Roel; van Es, Johannes; Kay, Nigel; Rose-Innes, Douglas; Garcia, Vincent; Lapensée, Stéphane; van Gerner, Henk Jan; van Donk, Gerrit; van Vliet, AdryTo cope increasing cooling demands, single-phase and two-phase fluidic cooling loops are being developed by European Satellite primes. Innovative components are currently being developed such as the Passive Bypass Valve (PBV) which autonomously diverts flow from the radiator when thermal dissipation is low, maintaining the equipment within the operating temperature range. The objective of the ESA project was to develop an Engineering Model (EM) of the PBV for single-phase and two-phase Mechanically Pumped fluid Loops (MPL) and Loop Heat Pipes (LHP) up to TRL5. The development has been conducted by the Netherlands Aerospace Centre, Nammo and OHB. A trade-off study was done for conceptual designs of the bypass valve including: (1) Bi metallic actuated, (2) Differential temperature actuated, (3) Wax actuated (4) Thermostatic sensor actuated. Technical and non-technical requirements as well as system aspects were rated as well as breadboard testing was done for the most promising concepts. The valve type 4 was selected for the design and manufacturing of the Engineering Model (EM) Passive Bypass valve. The EM valve is hydraulically actuated via capillary tube by expansion of a liquid Galden HT80 inside a remotely located sensor. The EM valve showed an adjustable range (±9⁰C) and repeatable switching as function of temperature (±10⁰ C) in three orientations tested in the single phase MPL. A small hysteresis of ±1.5⁰C (up or down in temperature) has been observed which could be related to the thermal inertia of the hydraulic liquid. The two-phase LHP test showed that the valve stabilized the sensor (payload) temperature around 33⁰±5⁰C (upper limit of the valve) at a condenser temperature of -20⁰C under varying load cases ranging from 500W down to 20W.The conclusion was that EM valve has been successfully developed and tested to TRL 4-5. Activities are defined to improve its maturity further to TRL 5-6.Item Development of Passive Thermal Control for Mars Surface Missions(46th International Conference on Environmental Systems, 2016-07-10) Herndler, Stefan; Ranzenberger, Christian; Lapensée, StéphaneThe extreme thermal environment on Mars asks for an effective thermal insulation to keep equipment within allowable temperature limits and to limit power consumption. Furthermore the thermal insulation should be light weight, flexible, adaptable and consume minimum volume. As a consequence of the Mars atmosphere, conventional vacuum based multilayer insulation offers low efficiency. Therefore, a novel thermal insulation making use of the existing Mars atmosphere was developed. This paper describes in detail the entire process and its results. Potential materials were identified based on literature, samples and manufacturer data and underwent material testing for characterization. Concepts and designs of three-dimensional demonstrators incorporating attachment, grounding and venting provisions were developed. Thermal performance of the demonstrators was validated by measurements in representative environments.Item Thermal Control System for Low Noise Amplifiers based on Loop Heat Pipes(46th International Conference on Environmental Systems, 2016-07-10) Prado Montes, Paula; Mishkinis, Donatas; Corrochano, Javier; Torres, Alejandro; Lapensée, StéphaneThe thermal control of current telecommunications satellites is limited by the fact that the Low Noise Amplifiers (LNA) are installed close to the antenna feed sources and dedicated radiators are accommodated near the LNA. That implies reduced radiating areas and unfavorable radiating environments. The use of Loop Heat Pipes (LHPs) for the LNA thermal control allows delocalization of the radiator, while providing an efficient link with the dissipating unit and avoiding the use of expensive and heavy structures for radiators protection, which are used today. A thermal control system based on LHPs (LNA-LHP) has been developed. The LNA-LHP concept was defined based on an extensive and detailed trade-off with main drivers the operation at low temperatures, close to -40 ºC, and at wide heat transport capability ranges, from 6 W to 175 W. As a result, the LNA-LHP was designed including two condensers in parallel, each one connected to a dedicated radiator (i.e. North and South). The flow in the loop is directed to the radiator facing the coldest environment thanks to the operation of a capillary blocker. Also, the flow can be redirected by the activation of Pressure Regulating Valves (PRV). In symmetric conditions (i.e. equinox) the flow is shared between both radiators. PRV can be included for temperature regulation at evaporator level. Thanks to the LNA-LHP system flexibility, radiators can be located at any place of the spacecraft. To provide scalability, the heat spreading over the radiator is performed via Arterial Heat Pipes. The LNA-LHP concept has been validated through simulation in EcosimPro and testing, with the thermal characterization in vacuum of a representative Engineering Model. The successful results prove that the system is able to provide the thermal control for at least four applications in current telecommunications satellites, being extendable for Earth observation, scientific and other missions.