A Self-Nucleating Evaporator: An Experimental Study of Low-Superheat Pool Boiling via Injection of Gaseous By-Products from the Thermal Decomposition of Azobis-Isobutyronitrile

For the purpose of exploring a novel heat transfer concept to radically enhance the evaporator performance of the microColumnated Loop Heat Pipe (μLHP) system, an experimental investigation into the feasibility of a lowsuperheat, passive, selfnucleating evaporator surface was performed. The evaporator test surfaces were treated with a coating of polymerencapsulated azobisisobutyronitrile (AIBN), a chemical compoundthat releases gaseous nitrogen upon thermal decomposition from 64100°C, while the control surfaces were coated with polymer alone. Cyclic pool boiling tests were performed at both saturated and subcooled conditions in two different dielectric refrigerants. In addition, a quasistatic, temperaturecontrolled boiling testwas performed to counteract experimental design flaws and thus provide evidence ofsuccessful selfnucleation, despite inconclusive temperaturebased numerical data.