An experimental investigation of the effect of the addition of nano Aluminum oxide on pool boiling of refrigerant 134A

The pool boiling of R-134a has been experimentally investigated with an addition of nano particles of Aluminum oxide. The experiments were carried out using a cylindrical stainless-steel heater. The roughness of the heater surface was changed. Different concentrations of nano Aluminum oxide particles to the base R-134a were tested. Different heat fluxes as well as different boiling pressures were considered during the experimental tests. The results show that the suspension of Al 2 O 3 nano particles enhances heat transfer coefficient in the nucleate pool boiling zone for concentrations ranging from 0.01 to 0.25% by volume. Higher heat flux and pressure result in enhancements of 37.6, 55.4, 90.2 and 167.7% corresponding to 0.042, 0.84, 1.54 and 2.35 μm surface roughness respectively. The more concentration of Al 2 O 3 nano particles deteriorates the heat transfer coefficient. An empirical correlation was deduced to formulate the relation among heat transfer coefficient, heat flux, pressure, concentration, and surface roughness within a maximum deviation of about ±9%.