The Piston motion in a Free-Piston driver for Shock Tubes & Tunnels
M Pramod,  M Bindu Bhargavi,  Dr. Maruthu Pandiyan
Hypersonic heating and Viscous heating are the major problems observed in the hypersonic vehicles such as re-entry vehicles or hypersonic missiles. This heating is due to the viscous effect of fluid that is the friction between the air and surface of the vehicle, the surface temperature of the vehicle may exceed 11000K and at those temperatures the survival of material and the avionics inside is not possible, the heat transfer rates or the heat flux is above 6MW/m2. So the thermal protection system is very mandatory for the re-entry vehicles and the hypersonic missiles in order to operate in safe conditions. These TPS system reduces the heat flux and results in lower temperature on the main frame of the vehicle. In order to design a TPS system, we should have the surrounding conditions, such as Density, Pressure, Viscosity etc., So to create those atmospheric conditions in the lab we use few devices such as Hypersonic wind tunnels and Shock Tubes etc., There are many types in HWT based upon speeds and enthalpy, few of them are Blow-down Hypersonic Wind Tunnel, Combustion Driven Shock Tube, Free-Piston Driven Shock Tunnel etc., These hypersonic devices can produce the exact atmospheric conditions can reach up to the speeds of 46 km/s and temperature can go beyond 25000K. The Free Piston shock tunnel is a hypersonic wind tunnel, in which a piston is used to accelerate the air in the driver section and then allowed to ruptures the diaphragm, the sudden expansion of air produces shockwave with a velocity higher than Mach 15 with high enthalpy. The current project deals with the mathematical simulation of the piston motion from its acceleration to brakes, the equations obtained are the coupled nonlinear differential equations. Computational solvers like MATLAB or Python is used to find the solutions of the equations and corresponding plots.
Keywords- Shock tube, heat flux, Thermal Protection System, Piston Motion.
Cite this Article
M Pramod,  M Bindu Bhargavi,  Dr. Maruthu Pandiyan,   "The Piston motion in a Free-Piston driver for Shock Tubes & Tunnels"
, International Journal of Engineering Development and Research (IJEDR), ISSN:2321-9939, Volume.9, Issue 2, pp.243-254, June 2021, Available at :http://www.ijedr.org/papers/IJEDR2102040.pdf