Simulation of shape variation of projectile nose during high-speed penetration into concrete

A formula is developed to estimate the total mass loss of projectile, based on the assump- tions that the peeling of molten surface layer in projectile nose is the primary cause of mass loss, and the frictional heat is totally absorbed by the projectile. Extrapolating this formula to predict the mass loss of local area of projectile, the receding displacement on projectile surface is obtained, which is vertical to the symmetry axis of projectile. Thereby, a finite difference method model is constructed to simulate the variation of projectile shape. The shape of residual projectile, depth of penetration of projectile and its mass loss obtained by calculation are found in good consistency with respective experimental data.

Simulations of fast component and slow component of SMBI on HL-2A tokamak

It is very important to improve the penetration depth and fueling efficiency of supersonic molecular beam injection（SMBI） especially for the next generation fusion devices such as ITER. Two components, a fast component（FC） and a slow component（SC）, have been observed in the HL-2A SMBI experiments for several years, and the FC can penetrate much more deeply than the common SMBIs which draws a great deal of attention for a better fueling method. It is the first time to the FC and SC of SMBI have been simulated and interpreted in theory and simulation in this paper with the trans-neut module of the BOUT＋＋ code. The simulation results of the FC and SC are clear and distinguishable in the same way as the observation in experiment. For the major mechanism of the FC and SC, it is found that although the difference in the injection velocity has some effect on the penetration depth difference between the FC and SC, it is mainly caused by the self-blocking effect of the first ionized SMB. We also discuss the influence of the initial plasma density on the FC and SC,and the variation of the SC penetration depth with its injection velocity.

Spray Characteristics of Biodiesel Fuel in Constant Volume Chamber using Multi-response Optimization Technique

This study discusses about the optimization of spray characteristics of biodiesel fuel in a spray chamber.Three factors namely,fuel injection pressure,fuel temperature and fuel blends were chosen as the influencing factor for the set objective.Four levels were chosen in each factor and spray tip penetration,spray cone angle and Sauter mean diameter(SMD) were taken as the response variables.Experiments were designed by employing design of experiments method and Taguchi full factorial array was used to conduct the tests with different levels of the chosen factors.Multi Response Signal to Noise ratio(MRSN) was calculated for the response variables and the optimum combination level of factors was obtained simultaneously using Taguchi's parametric design.Confirmation experiments were conducted for the obtained optimum combination level of factors and the results were compared with the normal operating conditions and significant improvement were observed in the response variables.