This rare kanji has no clear standalone meaning. Treat its meaning as uncertain.
The exact historical development of 灮 is uncertain. It visually contains 火 (fire) and 儿 (legs), but the original meaning and component relationship are unclear.
The top is 火 (fire) and the bottom is 儿 (legs). Picture a person running with fire on their legs, but the meaning is uncertain.
For コウ, imagine a person with fire on their legs making a loud 'koh!' sound as they run: koh -> コウ.