Trapping and aerogelation of nanoparticles in negative gravity hydrocarbon flames

Rajan K Chakrabarty,Nicholas D Beres,Igor V Novosselov,Hans Moosmüller,Christopher B Stipe,Christopher M Sorensen

doi:10.1063/1.4884057

Abstract

We report the experimental realization of continuous carbon aerogel production using a flame aerosol reactor by operating it in negative gravity (−g; up-side-down configuration). Buoyancy opposes the fuel and air flow forces in −g, which eliminates convectional outflow of nanoparticles from the flame and traps them in a distinctive non-tipping, flicker-free, cylindrical flame body, where they grow to millimeter-size aerogel particles and gravitationally fall out. Computational fluid dynamics simulations show that a closed-loop recirculation zone is set up in −g flames, which reduces the time to gel for nanoparticles by ≈106 s, compared to positive gravity (upward rising) flames. Our results open up new possibilities of one-step gas-phase synthesis of a wide variety of aerogels on an industrial scale.

Highlights

Trapping and aerogelation of nanoparticles in negative gravity hydrocarbon flames Rajan K
We report the experimental realization of continuous carbon aerogel production using a flame aerosol reactor by operating it in negative gravity (Àg; up-side-down configuration)
Computational fluid dynamics simulations show that a closed-loop recirculation zone is set up in Àg flames, which reduces the time to gel for nanoparticles by %106 s, compared to positive gravity flames

Summary

Introduction

Trapping and aerogelation of nanoparticles in negative gravity hydrocarbon flames Rajan K. Buoyancy opposes the fuel and air flow forces in Àg, which eliminates convectional outflow of nanoparticles from the flame and traps them in a distinctive non-tipping, flicker-free, cylindrical flame body, where they grow to millimeter-size aerogel particles and gravitationally fall out.

Results

Conclusion