Highly stable macroinitiator/platinum/hydrocarbon nanofluids for efficient thermal management in hypersonic aircraft from synergistic catalysis

摘要

For efficient thermal management in hypersonic aircraft, a series of highly stable macroinitiator/platinum/hydrocarbon nanofluids with great energy absorption capacity were designed in this work. Pt nanoparticles capped by hydrophobic hyperbranched polyglycerol (HMS) with average sizes of 1.2 nm and high dispersibility in hydrocarbons were synthesized through a facile phase transfer method and named as Pt@HMS. Nanofluids consisting of methylcyclohexane and Pt nanoparticles (MCH + Pt@HMS) presented admirable stability in the 180-day storage. On a simulated cooling channel of aircraft, the cracking performance and the energy absorption capacity of MCH + Pt@HMS were promoted significantly. At 650 degrees C, the heat sink of MCH + Pt@HMS reached 2.39 MJ/kg with an increase of 20.7% compared to thermal cracking. Larger macroinitiators HMS were beneficial. To acquire the same heat sink of 2.20 MJ/kg, the temperature can be lowered from 675 degrees C to 664 degrees C, 653 degrees C and 638 degrees C for the MCH + Pt@HMS with macroinitiator molecular weights of 3 k, 5 k and 13 k, respectively. The enhancements were ascribed to the synergistic catalysis of Pt@HMS. Endothermic reactions generating hydrogen and unsaturated hydrocarbons with higher enthalpies of formation were preferred for the cracking of MCH + Pt@HMS. Highly stable macroinitiator/platinum/hydrocarbon nanofluids are potential alternatives with great cracking performance and energy absorption capacity for efficient thermal management in hypersonic aircraft.