Simulation of Printer Nozzle for 3D Printing TNT/HMX Based Melt-Cast Explosive

Abstract

Fused deposition modelling (FDM) has been one of the most widely used rapid prototyping (RP) technologies, which has been attracted increasing attentions in the world. However, existing literatures about energetic material flow inside the 3D printer nozzle are sparse. For plunger 3D printer, we summarized the experimental and related literatures, finding that viscosity, temperature, outlet velocity, pressure, and nozzle diameter are the main factors to affect the flow state in the nozzle. Based on the actual printer nozzle structure, in this paper, a finite element model was established by SOLIDWORKS software firstly, meanwhile, the flow channel model of the nozzle was extracted and simplified. Secondly, the factors influencing the printing results were researched and analysed. In the end, numerical simulation on velocity field and temperature field was carried out by FLUENT software. Moreover, the printing test of HMX/TNT was also carried out by using EAM-D-1 3D printer. The printed sample shows that 3D printing is more satisfactory than conventional melt-casting ways to prepare high viscocity and unconventional structure explosives

Mathematical modeling of high-energy materials rheological behavior in 3D printing technology

“…The obtained dependences correspond to those obtained in [ 5 ] by simulating the flows in the nozzle used in the FFF technology.…”

“…The implementation of FFF technology to the production of high-energy materials (HEM) is even more challenging. These materials are characterized by high combustion heat (∼1–10 MJ/kg), for example solid rocket fuel and thermite [ 4 , 5 , 6 ].…”

“…Such material can ignite already when heated to ∼200–250 °C, which is comparable with the temperatures in a typical 3D printer nozzle. This limits the range of HEM that can be practically used by FFF to those with melting points well below the decomposition temperature [ 4 , 5 ]. Another approach, which, however, does not completely exclude ignition during printing, is filling the thermoplastic polymer filament with solid HEM particles [ 6 ].…”

“…Authors consider competing process parameters such as layer thickness, assembly orientation, fill density and number of contours. Recent work [ 5 ] investigates the effect of density and size of solid High Melting Explosive (HMX) particles on the viscosity of melted explosives materials (TNT/HMX). Computational fluid dynamics (CFD) and the discrete element method (DEM) are used to simulate the impact of viscosity, pressure, temperature, nozzle diameter and particle diameter on the fluid flow inside the 3D printer nozzle.…”

Review of the Problems of Additive Manufacturing of Nanostructured High-Energy Materials

“…The reason for this is obvious: FDM involves a rather high degree of material heating to increase its fluidity. This limits the range of materials that can be printed with FDM to those with a melting point significantly lower than the reaction temperature [ 30 , 31 ].…”