Surface Deposition Characteristics on Long Thermal Duration Within Treated and Untreated Stain Steel Tubes of Supercritical Kerosene RP-3 Fuel

Aimed to the development of aero-engine cooled cooling air (CCA) technology, the thermal deposition characteristics of kerosene fuel RP-3 have been experimentally studied for long thermal duration at supercritical pressure. The fuel has been heated for 5 h in the three different stainless steel and passivated tube respectively at the pressure of 5 MPa. During the test, the fuel inlet and outlet temperature were fixed at 400 and 723 K with 3 g/s flow mass rate. In this work, it was found that the electrolytic passivation treatments could reduce the total deposition amount about 71.8%, while the pre-oxidized treatment gives nearly the same deposition amount compared with the as-received SS321 tube. In contrast to our previous short thermal duration experiments (1 h), the 5 h thermal duration deposition mechanisms have been discussed on the treated tubes surface based on the integrated analysis of local inner wall temperature, surface deposition distribution, SEM morphology and chemical composition.