This work presents a CFD analysis of heat transfer problem. The enhancement of heat transfer with mass in a tube has been investigated without and with insert. The combinations of without inserts, two inserts, four inserts, six inserts, eight inserts and ten inserts have been used. An 800 mm long pipe with 26 mm inner diameter and 30 mm outer diameter is considered for our simulation. 5. It is observed that outlet temperature increases to 313.15 K when two inserts are being fitted into the tube. We get the lowest outlet temperature for ten inserts. Therefore after 8 inserts outlet temperature decreases.