Combustion characteristics of JP-10 droplet loaded with Sub-micron boron particles

Abstract

The present study deals with the droplet combustion characteristics of JP-10 fuel droplets containing three commercially available boron particles at 10% loading (by weight). Characterization of feed boron particles regarding particle size, morphology, ignition temperature, and oxidation profile have been conducted using conventional material characterization techniques such as scanning electron microscope (SEM), X-ray diffraction (XRD), particle size analyzer and thermogravimetric analysis (TGA). Ignition and combustion characteristics of all the boron samples loaded in JP-10 at desired concentration have been analyzed to understand the burning behaviour of these boron samples in JP-10 fuel. The droplet diameter evolution profiles show distinctly different characteristics for Loba Chemie (BL), Sigma-Aldrich (BS) and Telmat Materials (BT) boron loaded droplets. For BL loaded JP-10 fuel sample, the droplet regresses smoothly till the mid-span of the burning process. Some strong fluctuations in droplet diameter were also observed during the process. Similarly, for BS laden JP-10 fuel droplet, the regression started smoothly with some catastrophic fragmentation which eventually prevailed and led to the disruption of the primary droplet. In contrast, the regression curve of BT laden JP-10 fuel droplet is fluctuating in nature which leads to the occurrence of multiple micro-explosion. SEM images of combustion residue show multiple blow holes on particle surface in case of BS laden JP-10 fuel droplet whereas there are no such blow holes present in the residue for BL loaded case. From the residue micrographs, the particles seem to be well separated for BS case while the particles are quite agglomerated in BL case. From the thermogravimetric analysis, the onset temperature of oxidation for BS particle is around 560 °C while it is approximately 760 °C for BL particles. It is also evident from the true colour flame images and emission spectra that the BS particles burn better than other two commercial boron particles.