Optimization of Pressure and Temperature Characteristics of a High Pressure Shock Tube

Shock tubes develop high pressures and temperatures over short times in a reaction region which can then be used to carry out chemical kinetic studies of the combustion of hydrocarbon fuels. The accuracy of these studies depends on the pressure and temperature characteristics of the reaction region. Constant pressures and temperatures during the chemical reaction time are desired to reduce uncertainty in results. Several methods such as tailoring of the driver gas and using a varying area driver insert can obtain close to constant pressure and temperature conditions. Back filling of the shock tube driver section with a gas having low speed of sound can produce long reaction times which are needed to study fuels at low temperatures. Both low and high temperatures obtained in the shock tube are often determined through calibration using chemical thermometers. The calibrated temperatures obtained by using the optimized shock profile resulting from the techniques of gas tailoring, placement of a driver insert and driver gas back filling as applied to the University of Illinois at Chicago high pressure single pulse shock tube and as discussed in this thesis closely agree with the temperatures obtained using the incident shock Mach number and the ideal shock tube equations. The agreement lends further support for the use of chemical thermometers in shock tubes and in particular to their use in the UIC shock tube.