A study on nucleate boiling heat transfer characteristics of pentane and CuO-pentane nanofluid on smooth and milled surfaces

• Nucleate boiling experiment of pool boiling on smooth brass surface is conducted.
• Effect of surface enhancement is studied.
• Effect of surface material is studied.
• Effect of nanoparticle on boiling characteristic are studied.

Nucleate boiling heat transfer characteristic of pentane and CuO-pentane nanofluid is studied on smooth and enhanced circular brass surfaces of 20 mm diameter. The study is carried out at a pressure of 1 bar for the heat flux ranging between 1 and 10 W cm−2. The measured experimental heat transfer coefficient of pure pentane on the smooth brass surface is validated against established correlation within acceptable limits of ±5%. Further, two enhanced surfaces are prepared from plain surfaces by grooving in two perpendicular directions with pitches of 1 and 1.5 mm surfaces, which are named as fine and coarse surfaces respectively. Also, the effect of surface material on boiling is studied on similar enhanced surfaces made of steel, where the brass surfaces showed a 20–30% higher heat transfer coefficient for the tested condition. Further, the presence of nano-particle in the base fluid influence the heat transfer coefficient and the enhancement due to its presence is seen to be higher for lower volume fraction nanofluid.