Thiswork aims to study the effect ofchanging diameter intern and extern onthe lengthand
temperatureof the establishment of a turbulent flowin acoaxialheat exchangerwith a counter current
flow.The studyis based onanumerical simulation using fluentsoftware. For better illustration, this
study presents a mathematical model governing a flowin the presence of aheat transfer(continuity
equation, Navier-Stokesequationandenergy equation)
