Convective Heat Transfer from a Circular Tube with Variable Dimple Dimension

This paper provides an experimental study of forced convection heat transfer from water flow in a pipe that has a hemispherical dimple where the dimple is towards the inside of the pipe. The heat provided by the heating wire wrapped around the pipe is conducted by a constant flux of electric current. The heat from the pipe wall is received by the water flow in the pipe. On the circumference of the pipe, three rows of dimples are made along the length of the pipe and the variations in diameter dimple dimension are d* = 0.21, 0,42 and 0,63. Variations in flow discharge expressed in the Reynolds number produce laminar and turbulent flow. The results show that there is an increase in temperature along the length of the pipe, the convection coefficient increases with increasing Reynolds number and heat transfer increases with increasing Reynolds number.