Floatwell panel assemblies and related systems

A combustion section of a gas turbine engine comprising:

• a floatwall panel assembly having a panel and a mount, the panel being formed of porous material, the porous material exhibiting a porosity gradient along at least one of a length, a width and a depth of the panel, the mount being configured to engage the panel and maintain the panel in a spaced relationship from a surface to which the panel is attached wherein porosity means the number of pores per given volume and/or the size of pores whereby transpirational cooling of said panel occurs as coolant passes through said pores;
• wherein the panel incorporates a first region, a second region, and a third region, the first, second, and third regions being arranged in series along a length of the panel, the length being parallel to a gas flow path, the first region being upstream of the second and third regions relative to the gas flow path;
• wherein the first region comprises an area of relatively uniform porosity across its length, width and depth, and wherein the second region exhibits a relatively uniform porosity across its length, width and depth, the porosity of the second region being greater than the porosity exhibited by the first region;
• and
• wherein the third region incorporates a first layer and a second layer, the second layer located closer to the expected gas flow path than the first layer, and wherein the first layer exhibits a higher porosity along its length, width and depth than the second layer.