The direction of flow of {HEAD ~ liquid} through {TAIL ~ the shell} 12, however, has no effect on efficiency and so does not matter 
The direction of flow of { HEAD ~ liquid } through { TAIL ~ the shell } 12 , however , has no effect on efficiency and so does not matter
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH