On the Formation and Accumulation of Solid Carbon Particles in High-Enthalpy Flows Mimicking Re-Entry in the Titan Atmosphere

Fluids

Gennaro Zuppardi¹  Antonio Esposito¹  Marcello Lappa²  Christophe Allouis³  Mario Commodo³  Barbara Apicella³  Carmela Russo³  Patrizia Minutolo³ 

[1] Department of Industrial Engineering, Aerospace Branch, University of Naples “Federico II” Via Claudio 21, 80125 Naples, Italy;Department of Mechanical and Aerospace Engineering, University of Strathclyde, James Weir Building, 75 Montrose Street, Glasgow G1 1XJ, UK;Istituto di Ricerche sulla Combustione, CNR, Piazzale Tecchio 80, 80125 Naples, Italy;

关键词: hypersonic flow;    methane;    chemical reactions;    solid particles;    arc-heated facility;    Direct Simulation;   

DOI  :  10.3390/fluids5020093

来源: DOAJ

【 摘 要 】

The problem relating to the formation of solid particles enabled by hypersonic re-entry in methane-containing atmospheres (such as that of Titan) has been tackled in the framework of a combined experimental–numerical approach implemented via a three-level analysis hierarchy. First experimental tests have been conducted using a wind tunnel driven by an industrial arc-heated facility operating with nitrogen as working gas (the SPES, i.e., the Small Planetary Entry Simulator). The formation of solid phases as a result of the complex chemical reactions established in such conditions has been detected and quantitatively measured with high accuracy. In a second stage of the study, insights into the related formation process have been obtained by using multispecies models relying on the NASA CEA code and the Direct Simulation Monte Carlo (DSMC) method. Through this approach the range of flow enthalpies in which carbonaceous deposits can be formed has been identified, obtaining good agreement with the experimental findings. Finally, the deposited substance has been analyzed by means of a set of complementary diagnostic techniques, i.e., SEM, spectroscopy (Raman, FTIR, UV–visible absorption and fluorescence), GC–MS and TGA. It has been found that carbon produced by the interaction of the simulated Titan atmosphere with a solid probe at very high temperatures can be separated into two chemically different fractions, which also include “tholins”.

【 授权许可】

Unknown