Erik Ninnemann

Shock Tube/Laser Absorption and Kinetic Modeling Study of Triethyl Phosphate Combustion

Pyrolysis and oxidation of triethyl phosphate (TEP) were performed in the reflected shock region at temperatures of 1462-1673 K and 1213-1508 K, respectively, and at pressures near 1.3 atm. CO concentration time histories during the experiments were measured using laser absorption spectroscopy at 4580.4 nm. Experimental CO yields were compared with model predictions using the detailed organophosphorus compounds (OPC) incineration mechanism from the Lawrence Livermore National Lab (LLNL). The mechanism significantly underpredicts CO yield in TEP pyrolysis. During TEP oxidation, predicted rate of CO formation was significantly slower than the experimental results. Therefore, a new improved kinetic model for TEP combustion was developed, which was built upon the AramcoMech2.0 mechanism for C0-C2 chemistry and the existing LLNL submechanism for phosphorus chemistry. Thermochemical data of 40 phosphorus (P)-containing species were reevaluated, either using recently published group values for P-containing species or by quantum chemical calculations (CBS-QB3). The new improved model is in better agreement with the experimental CO time histories within the temperature and pressure conditions tested in this study. Sensitivity analysis was used to identify important reactions affecting CO formation, and future experimental/theoretical studies on kinetic parameters of these reactions were suggested to further improve the model. To the best of our knowledge, this is the first study of TEP kinetics in a shock tube under these conditions and the first time-resolved laser-based species time history data during its pyrolysis and oxidation.

High-Altitude Balloon Flight Demonstration of LED-Based NDIR Multi-Gas Sensor for Space Applications

A sensor which measures the concentrations of CO and CO2 aboard spacecraft could be used as an early fire detection system and a vital component of primary life support systems. Herein, such a sensor is presented which utilizes non dispersive infrared spectroscopy to detect gases. Design and results from testing on a high altitude baloon flight are presented. The goal of this work is to develop the hardware so that it is a rugged and viable technology for a variety of sensor applications in a variety of environments. It is, therefore, crucial that the hardware can reject heat at low pressures, survive the low-temperature operation, have low drift (stable output), remain low power, and be insensitive to humidity.