Scanned-Wavelength-Modulation Spectroscopy in the Mid-Infrared for Measurements of Temperature and CO in Aluminized Composite-Propellant Flames

摘要

This work presents the application of a scanned-wavelength-modulation spectroscopy diagnostic for measuring the bulk gas temperature and CO concentration in flames of aluminized composite propellants of ammonium perchlorate (AP) and hydroxyl-terminated polybutadi-ene (HTPB). The temperature of two propellant flames (one with and one without aluminum) was measured at atmospheric pressure and various heights above the propellant surface. The maximum quasi-steady flame temperatures were 2544 and 2389 K for the propellants with and without aluminum, respectively. The temperature measured closest to the propellant surface (0.2 cm above the surface) was more than 150 K lower in the aluminized-propellant flame due to the delayed ignition of the aluminum particles. Measurements of path-integrated CO mole fraction indicate that air entrainment has a significant impact on the thermochemical structure of these flames. The results presented are the first to quantify how the bulk gas temperature of an aluminized composite-propellant flame varies with the distance above the burning surface.