The cavity may include a plurality of pedestals and protrusions configured to create one or more spirals flow paths of {HEAD ~ a gas} traveling through {TAIL ~ the cavity} 
The cavity may include a plurality of pedestals and protrusions configured to create one or more spirals flow paths of { HEAD ~ a gas } traveling through { TAIL ~ the cavity }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL