Transpirational Performance of Oriented Porous SiC Transpiration Cooling Materials

This paper describes the fabrication of porous reaction-bonded SiC ceramics with radial directed pores and the application of these materials to transpiration cooling system of rocket engines. A special mold is designed for freeze-casting process to prepare SiC cylinders with radial directed pores. Green bodies with well-oriented pore structure are obtained from slurry with solid loading up to 47vol%. The pore size is in the level of several tens micron. Green bodies with various porosities are infiltrated with different amount of liquid Si. The intrinsic permeability of each sample is measured with air as flowing media. It is concluded that permeability has relationship with not only the porosity but also the pore structure of samples.

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Transpirational Performance of Oriented Porous SiC Transpiration Cooling Materials

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.368-372.837 ◽

2008 ◽

Vol 368-372 ◽

pp. 837-839

Author(s):

Jie Tang ◽

Yu Feng Chen ◽

Ji Guo Sun ◽

Hua Wang ◽

Hai Lin Liu

Keyword(s):

Casting Process ◽

Test Sample ◽

Electric Arc ◽

Thermal Testing ◽

Testing System ◽

Transpiration Cooling ◽

Cooling Efficiency ◽

Testing Device ◽

Testing Period ◽

Porous Sic

The application and the transpirational behavior of oriented porous SiC as transpiration cooling materials in a simulating test were studied. The test sample was shaped by freeze-casting process and reaction sintered. The testing device was composed by an electric arc combustor and a hydrogen coolant providing system. It was found that the permeability, the amount of coolant required and the uniformity of coolant infiltration were all effected by the microstructure of porous SiC, which furthermore influced the cooling efficiency of the testing system. In this test, the inner face temperature of the combustion chamber was maintained less than 400K throughout the thermal testing period contrasting with the fire temperature up to 3600K by the utilization of oriented porous SiC transpiration cooling materials.

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Determination of creep mechanisms in various silicon carbides via TEM

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100143973 ◽

1986 ◽

Vol 44 ◽

pp. 484-487

Author(s):

C. H. Carter ◽

J. E. Lane ◽

J. Bentley ◽

R. F. Davis

Keyword(s):

Heat Exchangers ◽

Sintered Material ◽

Polycrystalline Material ◽

Chemical Vapor ◽

Graphite Substrate ◽

Second Phase ◽

Reaction Bonding ◽

Creep Mechanisms ◽

Porous Sic

Silicon carbide (SiC) is the generic name for a material which is produced and fabricated by a number of processing routes. One of the three SiC materials investigated at NCSU is Norton Company's NC-430, which is produced by reaction-bonding of Si vapor with a porous SiC host which also contains free C. The Si combines with the free C to form additional SiC and a second phase of free Si. Chemical vapor deposition (CVD) of CH3SiCI3 onto a graphite substrate was employed to produce the second SiC investigated. This process yielded a theoretically dense polycrystalline material with highly oriented grains. The third SiC was a pressureless sintered material (SOHIO Hexoloy) which contains B and excess C as sintering additives. These materials are candidates for applications such as components for gas turbine, adiabatic diesel and sterling engines, recouperators and heat exchangers.

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