1. Αποθετήριο Παραδοτέων Υποτρόφων Δράσεων ΕΣΠΑ Τριτοβάθμιας Εκπαίδευσης 2017-2023
2. Όλο το Αποθετήριο
3. Μεταδιδακτορικοί ερευνητές

Τύπος:	Ανακοίνωση σε συνέδριο
Τίτλος:	Variable emissivity through multilayer patterned surfaces for passive thermal control: preliminary thermal design of a nano-satellite
Συγγραφέας:	[EL] Αθανασόπουλος, Νικόλαος[EN] Athanasopoulos, Nikolaos [EL] Σιακαβέλλας, Νικόλαος[EN] Siakavellas, Nicolaos
Ημερομηνία:	08/07/2018
Περίληψη:	We have developed patterned surfaces that control the thermal radiation without the use of controllers and power supplies. Ultralight patterned surfaces were designed to passively transform their geometry and change their effective emissivity as a function of temperature with the purpose of controlling the temperature of a satellite. These transformable patterned surfaces may consist of flat smaller arrays, passively reacting under temperature stimuli by reversibly transforming their geometry from 2D to 3D complex shapes. The transformation of the arrays conceals or reveals materials of different thermo-optical properties, while the view factor of the surface changes as well. Consequently, the entire emissivity function of a surface can be designed. The shape transformation is attributed to the anisotropic properties of a tri-layer material and to the coefficient of thermal expansion mismatch, which cause the patterns to transform at any temperature level. We developed a low-cost tri-layer material that has been optimized to achieve very large deformations within small temperature deviations. The emissivity of the patterned surface presents significant variation, namely Δε ≈ 0.7 within ΔΤ ≤ 40 °C. The weight of the smart surfaces is less than 330 gr/m2. The results are very promising because the degradation of the multilayer material of a unitary cell is negligible up to 78,000 thermal cycles. However, local degradation of the multilayer materials was observed near N ≈ 132,000 thermal cycles due to local imperfections. The predicted and measured emissivity functions that we obtained were used for the preliminary thermal design of a nano-satellite in order to re-calculate its temperature (worst hot- and cold-cases) while taking into consideration different scenarios. The temperature deviation of the nano-satellite, as well as the minimum temperature, had significantly improved. The proposed re-design will have an advantageous impact on the selection of the heaters and the energy demands of a nano-satellite.
Γλώσσα:	Αγγλικά
Τόπος δημοσίευσης:	Albuquerque, New Mexico, USA
Σελίδες:	14
Θεματική κατηγορία:	[EL] Αεροδιαστημική μηχανική[EN] Aerospace Engineering
Λέξεις-κλειδιά:	smart materials; thermal radiation; thermal control; nanosatellites
Κάτοχος πνευματικών δικαιωμάτων:	© 2018 Nikolaos Athanasopoulos
Διατίθεται ανοιχτά στην τοποθεσία:	https://ttu-ir.tdl.org/handle/2346/74239
Ηλεκτρονική διεύθυνση του τεκμηρίου στον εκδότη:	https://ttu-ir.tdl.org/handle/2346/74239
Όνομα εκδήλωσης:	48th International Conference on Environmental Systems
Τοποθεσία εκδήλωσης:	Albuquerque, New Mexico, USA
Ημ/νία έναρξης εκδήλωσης:	08/07/2018
Ημ/νία λήξης εκδήλωσης:	12/07/2018
Σημειώσεις:	Conference Paper identifier - CES-2018-296 This research is conducted through the IKY scholarships program, and is co-financed by the European Union (European Social Fund - ESF) and the Greek national funds through the action entitled “Reinforcement of Postdoctoral Researchers” of the National Strategic Reference Framework (NSRF), 2014–2020.
Εμφανίζεται στις συλλογές:	Μεταδιδακτορικοί ερευνητές