@InProceedings{SantosBBGCVBK:2014:PrAnRe,
               author = "Santos, Nadjara dos and Bertoldo Junior, Jorge and Brazolin, Herly 
                         and Gondo, Suely Mitsuko Hirakawa and C{\^a}ndido, Pedro Antonio 
                         and Vladimirovich, Valeri Vlassov and Batista Neto, Jos{\'e} 
                         Antonio and Kchoukina, Olga Viktorovna",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Instituto Nacional de Pesquisas Espaciais 
                         (INPE)} and {Instituto Nacional de Pesquisas Espaciais (INPE)} and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)}",
                title = "Preliminary analysis of results of comparative life test of 6063 
                         aluminum anodized and non-anodized thermosyphons charged with 
                         acetone as working fluid",
            booktitle = "Anais...",
                 year = "2014",
         organization = "Simp{\'o}sio Aeroespacial Brasileiro.",
             keywords = "thermosyphon, anodizing.",
             abstract = "This work purpose is to present a specific stage of development of 
                         HP (Heat Pipe) for space applications. The heat pipes are devices 
                         designed to transport or distribute heat very efficiently without 
                         generating significant temperature gradients. The HPs are widely 
                         used in satellites for thermal stabilization of structural panels 
                         and homogenization temperature in areas of higher heat dissipation 
                         due to the operation of electronics equipments. An important 
                         aspect to operation HPs is compatibility of the working fluid and 
                         the material used in the tube. Even when fluid is considered 
                         compatible very slow chemical reactions between the tube material 
                         and the fluid itself or impurities or usual rests may generate a 
                         small amount of non-condensable gas (NCG), which accumulates in 
                         the vapor channel and blocks part of the tube length affecting 
                         operating characteristics of the tube. The required qualification 
                         test is the Life Test (LT), which is usually conducted during at 
                         least two years in thermosyphon manufactured from the same 
                         material that the HPs and charged with the same working fluid In 
                         the proposed comparative LT the purpose was to evaluate if the 
                         internal anodizing contributes to improving the compatibility 
                         between the fluid and the material of the tube. Anodizing is an 
                         electrochemical process which consists in producing an oxide layer 
                         on the aluminium surface this layer of aluminum oxide (alumina) 
                         with hexagonal structure is compressed during sealing which is the 
                         last stage of the anodizing process. The sealing hydrates alumina 
                         pores, hampering the entrance of aggressive agent structure, 
                         making the tube more resistant to undesirable chemical reactions. 
                         In Life Test stands with 6 one-meter-long thermosyphon from 
                         Aluminum 6063, three of which are non- anodized and three - 
                         anodized. The thermosyphons were fixed in a vertical position, 
                         with the evaporator down (so-named reflux HP mode). The assembly 
                         was subjected to heating up to 100W with a maximum temperature of 
                         80 °C using natural convection to cooling the condensation zone. 
                         The LT was run for 6 months and Temperature profile along each 
                         tube was measured and recorded in data acquisition system. Based 
                         on these preliminary results it was possible to determine the 
                         effect of non-condensable gases (NCG) by changing the temperature 
                         profile over last 4 months of operation. The experimental results 
                         are then used in a mathematical model that will be able to predict 
                         the location of the barrier and lencth of NCG in the HP. The 
                         conclusions about the reasons for generation of NCG in the devices 
                         were derived and analyzed.",
  conference-location = "S{\~a}o Jos{\'e} dos Campos",
      conference-year = "2014",
                label = "lattes: 3449529561451602 6 SantosBBGCVBK:2014:ANPRRE",
             language = "en",
           targetfile = "santos_preliminary.pdf",
        urlaccessdate = "16 maio 2024"
}