A fuel burner comprising: an outer tube extending along a central axis from a first end to a second end , the outer tube including an outer surface and an inner surface defining a passage , the outer tube including fluid directing structure having a plurality of openings and a guide associated with each opening; an inner tube extending from a first end to a second end and being positioned within the passage of the outer tube , the inner tube including an outer surface and an inner surface defining a central passage , wherein a fluid passage is defined between the outer surface of the inner tube and the inner surface of the outer tube, the central passage being supplied with a mixture of air and combustible fuel pre-mixed upstream of the inner tube , the inner tube having fluid directing structure for directing the pre-mixed mixture radially outward from the central passage to the fluid passage such that the pre-mixed mixture rotates radially about the central axis between the inner tube and the outer tube , the fluid directing structure on the outer tube being supplied with the pre-mixed mixture and directing the pre-mixed mixture radially inward to the fluid passage to mix with the pre-mixed mixture from the fluid directing structure on the inner tube ; a first end wall closing the second end of the inner tube in a fluid-tight manner; and a second end wall securing the first end of the inner tube to the outer tube in a fluid-tight manner such that the fluid directing structure on the inner tube provides the only fluid path from the central passage to the fluid passage, characterized in that the first end wall intersects the central axis . an outer tube extending along a central axis from a first end to a second end , the outer tube including an outer surface and an inner surface defining a passage , the outer tube including fluid directing structure having a plurality of openings and a guide associated with each opening; an inner tube extending from a first end to a second end and being positioned within the passage of the outer tube , the inner tube including an outer surface and an inner surface defining a central passage , wherein a fluid passage is defined between the outer surface of the inner tube and the inner surface of the outer tube, the central passage being supplied with a mixture of air and combustible fuel pre-mixed upstream of the inner tube , the inner tube having fluid directing structure for directing the pre-mixed mixture radially outward from the central passage to the fluid passage such that the pre-mixed mixture rotates radially about the central axis between the inner tube and the outer tube , the fluid directing structure on the outer tube being supplied with the pre-mixed mixture and directing the pre-mixed mixture radially inward to the fluid passage to mix with the pre-mixed mixture from the fluid directing structure on the inner tube ; a first end wall closing the second end of the inner tube in a fluid-tight manner; and a second end wall securing the first end of the inner tube to the outer tube in a fluid-tight manner such that the fluid directing structure on the inner tube provides the only fluid path from the central passage to the fluid passage, <EOS>