Determination of Pressure Profiles Behind Projectiles During Interior Ballistic Cycle

2013 ◽  
Vol 80 (3) ◽  
Author(s):  
Dejan Micković ◽  
Slobodan Jaramaz ◽  
Predrag Elek ◽  
Dragana Jaramaz ◽  
Dušan Micković
Keyword(s):  
Analytical Methods ◽  
Solid Propellant ◽  
Weapon System ◽  
Two Phase ◽  
Interior Ballistics ◽  
Pressure Profiles ◽  
Lumped Parameter ◽  
Lumped Parameter Models ◽  
Phase Mixture

The determination of pressure profiles behind a projectile has been a subject of investigations for more than 70 years. For lumped parameter models it was especially important to determine the pressure on the projectile base, pressure on the chamber base, and pressure for the propellant burning law. In the paper two analytical methods and one numerical method are considered. The analytical methods of proportionate expansion and two-phase mixture are studied. Pressure profiles are also computed numerically by TWO Phase Interior Ballistics (TWOPIB) code, which is based on the model of two-phase flow of solid propellant and its products of combustion, treated as separate phases with appropriate conservation laws and interactions between phases. Through comparison with experimental results on the real weapon system TWOPIB code showed great advantages over analytical methods.

Numerical Study on Properties of Interior Ballistics According to Solid Propellant Position in Chamber

2011 ◽  
Author(s):  
Jin-Sung Jang ◽  
Hyung-Gun Sung ◽  
Seung-Young Yoo ◽  
Tae-Seong Roh ◽  
Dong-Whan Choi
Keyword(s):  
Solid Propellant ◽  
Moving Boundary ◽  
Two Phase Flow ◽  
Numerical Study ◽  
Simple Algorithm ◽  
High Energy ◽  
Numerical Code ◽  
Phase Flow ◽  
Two Phase ◽  
Interior Ballistics

Analysis of the interior ballistics is essential for the development of gun or propellant configurations. The granular solid propellants with high energy and fast burning rate produce a large thrust in extremely short time intervals. For the study of these, therefore, it is necessary of a numerical code for the two-phase flow of the interior ballistics. Recently, an interior ballistics code (IBcode) for the two-phase flow using the Eulerian-Lagrangian approach has been developed. The SIMPLE algorithm and the SMART scheme have been used for the IBcode. The ghost-cell extrapolation method has been used for the moving boundary with the projectile movement. In this study, a performance of the interior ballistics according to the position of the solid propellant in the chamber has been investigated using the IBcode. In previous researches, propellants had been evenly distributed in the chamber. In this study, however, three cases of the existence of empty space in the chamber at which the propellants are not evenly distributed have been considered; Propellants are located in the region near the base, propellants in the region near the breech, and propellants in the center of the chamber, respectively. The 7-perforated configuration of the solid propellant has been used in this research. The results have shown the performance variations of the interior ballistics according to solid propellant position in the chamber. The cases of the propellants located in the region near the base and breech have shown that the value of the negative differential pressure and the difference between the breech pressure and the base pressure are much higher than those of the propellants located in the center of the chamber. The case of the propellants in the center of the chamber is, therefore, more profitable to improve the performance of the interior ballistics.

scholarly journals Precise Evaluation of Gas–Liquid Two-Phase Flow Pattern in a Narrow Rectangular Channel with Stereology Method

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3180
Author(s):  
Maciej Masiukiewicz ◽  
Stanisław Anweiler
Keyword(s):  
Flow Pattern ◽  
Transient Flow ◽  
Two Phase Flow ◽  
Volume Fraction ◽  
Rectangular Channel ◽  
Test Method ◽  
Phase Flow ◽  
Two Phase ◽  
Phase Mixture

The drive to increase the efficiency of processes based on two-phase flow demands the better precision and selection of boundary conditions in the process’ control. The two-phase flow pattern affects the phenomena of momentum, heat, and mass transfer. It becomes necessary to shift from its qualitative to quantitative evaluation. The description of the stationary structure has long been used in structural studies applied to metals and alloys. The description of a gas–liquid two-phase mixture is difficult because it changes in time and space. This paper presents a study of the precise determination of two-phase flow patterns based on stereological parameters analysis. The research area is shown against the flow map proposed by other researchers. The experiment was taken in the thin clear channel with dimensions of W = 50 × H = 1200 × T = 5 mm. The test method is based on the visualization of a two-phase air–water adiabatic flow pattern in the rectangular channel where superficial air velocities ranging from 0.006 to 0.044 m/s and the superficial water velocity ranged from 0.011 to 1.111 m/s. A high-speed camera was used for visualization. Images were analyzed with the use of stereological techniques. The study included the classification of structures according to generally accepted two-phase flow regime nomenclature for upwards co-current gas–liquid flow in a vertical rectangular channel. The result of the research was the determination of the stereological parameters’ changes with reference to the two-phase mixture flow hydrodynamics. The results were presented as waveform fluctuations in the values of stereological factors such as the volume fraction VV, interfacial surface SV, number of objects NV, mean chord l′m and the free distance λ. The description of how these parameters change with changes in phase fluxes is also presented. These waveforms help to distinguish the transient flow regimes, which allow for the automatic adjustment of the process stability. The authors found templates of the stereological parameters’ dependencies for flow pattern recognition. The research demonstrates wide possibilities of stereological methods’ application for the analysis of the two-phase gas–liquid process. The stereological model of two-phase pattern control enables the identification of process disorders.

Analytical Methods for Determination of Balofloxacin in Tablets

2012 ◽  
Vol 2 (8) ◽  
pp. 66-68
Author(s):  
Shreya Nayak ◽  
◽  
Sanjay Pai P.N. Sanjay Pai P.N.
Keyword(s):  
Analytical Methods
Sign in / Sign up

Export Citation Format

Share Document