Analysis Of Jet Formation Mechanism Of Two Hypercumulative Structures

The concept of hypercumulative jet was firstly proposed by Minin et al,preliminary numerical studies showed that the hypercumulative charge structure can improve the mass as well as the velocity of the jet.Their research shed light into a new field.Based on the investigation of the mechanism of the formation of the hypercumulative jet,the truncatedauxiliary and the ejective structure are studied.With the numerical simulation as the main method,the difference between the truncated liner with additional plat top,the conical liner and the liner with plat top was studied.The jet formation theory was used as an auxiliary method to explain the formation process of the formation of hypercumulative jet by classical jet formation theory.This essay is to find the limitation of the existing theory and the essential characteristics of the auxiliary liner.At last,the mechanism of the ejective structure is studied and improved too.During the study of the theory of jet formation,theories of quasi-stationary theory and unsteady theory were reviewed and summarized,and a computer program was written to compare with the results of simulations to analysis advantages and disadvantages of those theories.It has showed that the way which calculate the axial velocity and the radial velocity respectively did not work well,and the effective adiabatic compression method did not fix well either.Applying the cylindrical control body and static surface method to calculate the maximum crushing speed is a feasible method.It fixed well with simulation results.The PER theory did not consider the process of crushing speed changes.A numerical method was proposed to make up for this deficiency,made the theory program stronger.Comparison of cone-shaped liner,flat top liner and the truncated-additional liner,results show that a truncated-additional liner could form jets with higher head speed and longer body.Based on the theoretical program,the jet formation mechanism of the truncated-additional liner is analyzed.The preliminary results show that this new structure did not perform better in quantity,but it could produce a jet with higher head speed and longer body.Further study found that in the case of a specific case,15.5% of the liner mass was affected.Taylor angle,the collapse angle,and the collision speed all increased.The mass increased,but the velocity dropped.For the mass which was involved is little,the final jet did not change much.An ejective structure was studied,The basic mechanism is that the main liner be squeezed on the inclined wall surface of the auxiliary liner to cause the main liner to flow along the inner wall to form an annular aggregation.In order to solve problems appeared in simulation,the optimal design of main liner and auxiliary structure were made respectively,and worked well.