A long pipe that is 2.5 cm in diameter carries engine oil with a mean velocity of 0.3 m/s. The pipe is exposed to sunlight. The heating effect of sunlight can be idealized as a uniform heat flux of...

A long pipe that is 2.5 cm in diameter carries engine oil with a mean velocity of 0.3 m/s. The pipe is exposed to sunlight. The heating effect of sunlight can be idealized as a uniform heat flux of 500 W/m²
·K.

a. Calculate the hydrodynamic and thermal entrance lengths.

 b. Find the local mean temperature, the heat transfer coefficient, and the wall surface temperature at 12 m downstream from the entrance of the tube.

For engine oil, you can use the following properties: