{TAIL ~ The coolant} is introduced into the channels co currently with {HEAD ~ the direction} of flow of the reactants 
{ TAIL ~ The coolant } is introduced into the channels co currently with { HEAD ~ the direction } of flow of the reactants
TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH