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Rueda A.,Empresarios Agrupados | Avezuela R.,Empresarios Agrupados | Cobas P.,Empresarios Agrupados | Perez-Vara R.,Iberespacio
40th International Conference on Environmental Systems, ICES 2010

EcosimPro is used by the European Space Agency (ESA) as the standard tool to support Environmental Control and Life Support Systems (ECLSS) analysis. EcosimPro is a generic, flexible and modular tool based on the concept of object-oriented programming. It is capable of solving a large set of Differential-Algebraic equations (DAEs). These features make EcosimPro a multidisciplinary tool and as such it can be used to model different application domains, including electrical circuits, hydraulic networks and thermal and chemical systems, to name just a few. The new enhanced EcosimPro, version 4.6, released in November 2009, features numerous improvements. Among these are an upgraded wizard for creating mathematical models, customer deck generation for end users, a new attribute editor to configure component data more easily, improved treatment of post-processing results, and new wizards for performing parametric studies and optimization analyses. This paper shows how EcosimPro and its new capabilities make it easier for the user to model complex systems such as ECLS systems or two-phase heat transport devices. © 2010 by 2020. Published by the American Institute of Aeronautics and Astronautics, Inc. Source

Iwata N.,Japan Aerospace Exploration Agency | Ogawa H.,Japan Aerospace Exploration Agency | Molleda J.M.,Iberespacio | Takashima T.,Japan Aerospace Exploration Agency | Takahashi T.,Japan Aerospace Exploration Agency
42nd International Conference on Environmental Systems 2012, ICES 2012

A thermal control system (TCS) of a microsatellite is proposed with loop heat pipes (LHPs) including bypass valves. "Free from restrictions in thermal design," all instruments can be mounted anywhere on the internal side of the six structure panels making up the satellite without concern for the thermal design of the entire satellite and other instruments. The temperatures of all instruments are maintained under any attitude (i.e., external thermal environment) by concentrating dissipated heat in a "center heat source" (CHS) using six LHPs mounted between the CHS and structure panels and other heat transport devices. An experimental study and numerical simulation are conducted to validate the microsatellite TCS. In the experimental study, two LHPs are connected to a heat source and a heat load is input to a condenser to simulate the heat input to a radiator in orbit. The heat from the heat source is successfully transported via one LHP if heat is input to the radiator connected to the second LHP. Orbital thermal analyses of the microsatellite are also conducted. Typical low-Earth, geostationary, and polar orbits are investigated for spinning and three-axis stabilized satellites. Heat from the CHS is transported via the LHPs, and the CHS temperature is maintained within the required temperature range in all analysis cases as a result of bypass valve operation. © 2012 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. Source

Torres A.,Iberespacio | Mishkinis D.,Iberespacio | Kaya T.,Carleton University
Applied Thermal Engineering

A novel satellite thermal architecture connecting the east and west radiators of a geostationary telecommunication satellite via loop heat pipes (LHPs) is flight tested on board the satellite Hispasat 1E. The LHP operating temperature is regulated by using pressure regulating valves (PRVs). The flight data demonstrated the successful operation of the proposed concept. A transient numerical model specifically developed for the design of this system satisfactorily simulated the flight data. The validated mathematical model can be used to design and analyze the thermal behavior of more complex architectures. © 2014 Elsevier Ltd. All rights reserved. Source

Torres A.,Iberespacio | Mishkinis D.,Iberespacio | Kaya T.,Carleton University
Applied Thermal Engineering

An entirely novel satellite thermal architecture, connecting the east and west radiators of a geostationary telecommunications satellite via loop heat pipes (LHPs), is proposed. The LHP operating temperature is regulated by using pressure regulating valves (PRVs). A transient numerical model is developed to simulate the thermal dynamic behavior of the proposed system. The details of the proposed architecture and mathematical model are presented. The model is used to analyze a set of critical design cases to identify potential failure modes prior to the qualification and in-orbit tests. The mathematical model results for critical cases are presented and discussed. The model results demonstrated the robustness and versatility of the proposed architecture under the predicted worst-case conditions. © 2013 Elsevier Ltd. All rights reserved. Source

Terrado E.,CSIC - Institute of Carbochemistry | Molina R.,Institute of Chemical and Environmental Chemistry of Barcelona | Natividad E.,University of Zaragoza | Castro M.,University of Zaragoza | And 4 more authors.
Journal of Physical Chemistry C

Porous material is a critical component in the loop heat pipe (LHP) device, the efficiency of which depends on the thermal conductivity of the wick and its capillary capacity. A new bilayer wick based on ceramic material and carbon nanotubes in the outer surface has been designed. The thermal conductivity and capillary pressure of the surface of a ceramic LHP wick prototype have been modified by growing multiwalled carbon nanotubes (MWCNTs). The presence of a thin layer of MWCNTs increased the thermal conductivity of wick specimens between 18.87 and 26.42% for temperatures ranging from -50 to 50 °C. The thermal conductivity of the grown MWCNTs calculated considering a mean layer thickness of 5 μm was 59 W/mK. The effective pore diameter of zircon ceramic wicks decreased from 0.54 to 0.31 μm leading to an important increase in capillary pressure. The maximum heat transfer capacity and thermal resistance of the designed by-layer wick have been determined. The presence of carbon nanotubes decreases the thermal resistance and enabled the enhancement of the thermal and porous characteristics of the wicks in a promising way so as to optimize their performance as LHPs wicks. © 2011 American Chemical Society. Source

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