Rheological Charactreistics Analysis And Mixing Study Of Classic Analog Explosives

Twin-screw extruder mixing explosives are a hot topic in today’s explosive mix directions, intermeshed co-rotating twin-screw extruder technology not only has high security, flexible continuous production, environmental protection, but also can provide high dispersion mixing capabilities. In this paper, four kinds of classic explosive analog materials as the research object, and mixed dispersion process in the twin-screw extruder have been examined, which provides a theoretical reference of Twin-screw extruder mixing explosives.This article analyses the internal structure and dispersive mechanism of agglomerates in melt polymer flow field, and introduces a mathematical model of powders dispersed agglomerates. In order to accurately simulate different kinds of explosive analog materials flow field distribution in the twin-screw extruder, the rheological properties of the four kind explosive analog materials have been analyzed in this article. To compare the dispersive mixing ability of discrete mixing elements,3D isothermal flow field of screw elements and disc elements is simulated. Built on the numerical simulation of instantaneous static flow fields, the shear rate field and pressure field are analyzed. With the numerical simulation of dynamic flow fields by particle tracking analysis method and statistical analyses, residence time distribution, weighted average shear stress and maximum tensile are analyzed.In order to obtain the mixing performance of the metering section in different screw combinations, we selected material2as the experimental object and compared with seven different combinations. The flow fields between screw and material are analyzed using the method of the finite element numerical simulation. According to the statistical analysis of mixing flow field, we evaluated the distributive and dispersive mixing capacities of seven combinations.Simulation results show that:The left handed screw element provides the strongest shearing, the large lead screw element provides large stretching effect, smaller lead screw element has powerful capabilities to build pressure, the wide kneading disk block elements provide strong shearing and large stretching, reverse kneading blocks have the worst stretching action.The results of the experiments are demonstrated that the comparison of eight mixing elements is consistent with the numerical analyses. This result means that the numerical analysis method in this study can be used to select the screw elements and combination to meet different dispersion demands based on the sensitivity of different explosives. This method could also be used to design the new mixing elements and analysis the dispersive mixing performance of these new elements.