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