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Abstract
The NASA MIRO Center for Space Exploration and Technology Research (cSETR) located at the University of Texas at El Paso has designed an experimental high heat flux test facility to investigate the steady- state heat transfer performance of cryogenic propellants. This facility is critical for the investigation of the performance of regenerative cooled engine channel design. For it captures one dimensional and asymmetric heat flow performance as experienced in the regenerative cooled rocket engine channels. Due to the increased interest of deep space exploration, rocket engine fuel alternatives have been discussed in order to design a high-performance engine suited for deep spaceflight missions. Due to its low toxic emissions, and ease of storage, liquid methane (LCH4) is currently being considered as an alternative option of fuel in regenerative cooled engines. Therefore, the working fluid of this investigation was dictated to be LCH4. The focus of this specific study is on the investigation of the heat transfer performance of LCH4 through different four Inconel 625 channels varying in surface roughness and manufacture methods. This experiment will aid in the investigation of the heat transfer performance through different temperatures and pressures. The cross section for the cooling channels investigated in this project was a 3.2 x 3.2 square channel with varying surface roughness. Surface roughness values were as follows: 0.8, 3.2, 6.3 and 12.5 µm. Results show that these channels (3.2 x 3.2) at their designated test pressure, the Reynolds numbers vary from 30,000 at the lowest flow rate and 110,000 at the highest flow rate. Where Nusselt numbers reached in this experiment vary from 225 to 31. There was a 150 % increase of the heat transfer coefficient with the increase of surface roughness
