In order to demonstrate the enhancement effect of the metal foam cover on the nucleate pool boiling heat transfer, the test conditions also include a plain surface besides the three copper foam covers.
The nucleate pool boiling heat transfer coefficient h is calculated as
The uncertainty of nucleate pool boiling heat transfer coefficient [DELTA]h is calculated as
By substituting Equation 2 into Equation 3, the relative uncertainty of the nucleate pool boiling heat transfer coefficient is calculated as
The maximum relative uncertainty of nucleate pool boiling heat transfer coefficient is obtained at the condition of the smallest test surface temperature and the largest saturated liquid temperature, calculated to be 10.2%.
Onset of nucleate boiling process occurs as wall superheat reaches the value of 19 [degrees]C.
 Judd, R.L., Hwang, K.S., 1976, A Comprehensive Model for Nucleate Boiling Heat Transfer Including Microlayer Evaporation.
 Han, C.-Y., Griffith, P., 1965, The Mechanism of Heat Transfer in Nucleate Pool Boiling--Part 11 (The Heat Flux--Temperature Difference Relation).
 Benjamin, R.J., Balakrishnan, A.R., 1996, Nucleate pool boiling heat transfer of pure liquids at low to moderate heat fluxes.
Similar to the smooth tube, this is due to nucleate boiling being suppressed by the oil film.
This indicates that flow boiling heat transfer is dominated by nucleate boiling at the present experimental conditions.
This fact indicates that the flow boiling heat transfer changes from a nucleate boiling dominated regime to a convective evaporation dominated regime due to the existence of PAG oil.