Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
ANALYSIS OF MULTILAYER INSULATION SYSTEM ON THE TEMPERATURE FIELD AND HEAT FLUX USING ALUMINUM/CARBON NANOTUBE COMPOSITE
Submission Author:
Guilherme Lacerda , RJ
Co-Authors:
Guilherme Lacerda, Marcos Curi
Presenter: Guilherme Lacerda
doi://10.26678/ABCM.COBEM2021.COB2021-1825
Abstract
Thermal insulation is a critical factor in real applications in engineering projects, especially aerospace engineering, where uses thermal control technologies to isolate satellites and spacecraft. Multilayer Insulation (MLI) is usually one method to guarantee safety and reliable developments in this area. Based on multiple layers built with different materials and parameters, it is mandatory to ensure a correct study of them, generating safe projects, avoiding any miss calculation that could result in complete damage and total failure of a system. Every mission, the requirements of an MLI are different, and then the design usually is not the same. Many materials are used to form an MLI blanket, each of them provides different performances. Studies in the literature are, predominantly, experimental tests about variations in its compositions. However, numerical analysis progressively becomes a growing field in the last years and minimizing the costs of an experiment. This paper focused on providing the temperature field and heat flux across the layers by numerical simulation for transient and stationary MLI performances using parameters of a recent and promising material, aluminum/carbon nanotube composite (CNT/Al), with properties close to a black body. The differential equations used to model the physical phenomenon is based on transient radiation-conduction theory, consisting of a fourth-order coupled non-linear ordinary differential equations system. The numerical simulation will be fed with experimental data of CNT/Al, providing results on a subject where few contributions in the numerical field, with this material, are available. The environment temperature was 4K for space temperature and 300K for the insulated surface. Also, the number of layers, outgassing rate, perforation coefficient, conductivity, and contact pressure were variable in the simulation. The best combination of these previous parameters, in a preliminary analysis, was the MLI with the lower values for each one, respecting the initial input. The results with CNT/Al composition show a good agreement with experimental results, although more experimental studies are under analysis in the literature, and different results are expected. Besides the severe space environment, the results obtained with CNT/Al reveals an excellent material to be used in that conditions, and tests concerning the material longevity and its performance in other different environments are necessary to guarantee an ideal MLI blanket composition. Further simulations will be evaluated with different conditions with CNT/Al composition and validate with experimental results using CNT/Al in a real MLI blanket.
Keywords
Thermal Insulation, numerical heat transfer, carbon nanotube, Multilayer Insulation
