Week 7: Shock tube simulation project
SHOCK TUBE SIMULATION
Introduction: It consist of tube which is divided by high pressure and low pressure region and both regions are connected by diaphram.When this diaphram is ruptured, a pattern of shock wave is produced which occurs due to pressure difference.This shock wave expand in low pressure region and then it gets reflected by the wall.This effect is studied in chemical kinetics in order to calculate the ignition delay.
Case setup
Two regions high pressure and low pressure region is intialized with pressure in region 0(high pressure) is 4 bar and pressure in region(1) is 1 bar.Nitogen species with mass fraction 1is used in region 0 while oxygen species with mass fraction 1 is used in region 1.Two boundary contions with wall type slip conditions is used.
Sequential type events are created to close and open the diaphram.
The Plots and Mesh generation are shown below
The cell count is zero when the diaphram is closed but when it is open it increases with time.The fluctuation in cell count with respect to time is due to Adaptive mesh refinement of N2 species which increases the total cell count.
The pressure in region 0(high pressure) decreases due to expansion of Nitrogen species and this pressure increases due to reflection.This sudden increase and decrease in pressure causes shock wave
Similarly temperature also increases due to compression of the species and decreases due to expansion.