Apparatus for combusting a fuel at high pressure and high temperature, and associated system

An apparatus, comprising:

• a mixing arrangement configured to mix a carbonaceous fuel with enriched oxygen and a working fluid to form a fuel mixture;
• and
• a combustor arrangement defining a combustion chamber having an inlet portion longitudinally spaced apart from an opposing outlet portion, the inlet portion being configured to receive the fuel mixture for combustion within the combustion chamber at a combustion temperature to form a combustion product, the combustion chamber being further configured to direct the combustion product longitudinally toward the outlet portion, the combustor arrangement comprising:
• a pressure containment member;
• and
• a porous perimetric transpiration member at least partially defining the combustion chamber, and being at least partially surrounded by the pressure containment member, the porous transpiration member being configured to substantially uniformly direct a transpiration substance therethrough toward the combustion chamber, such that the transpiration substance is directed to flow helically about the perimeter thereof and longitudinally between the inlet portion and the outlet portion, to buffer interaction between the combustion product and the porous transpiration member.