Prediction of NO and NO2 Concentrations in Ozone Injected Diesel Exhaust after NTP Treatment Using Dimensional Analysis

Abstract

NTP based Ozone injection cascaded with catalysts/adsorbents for diesel exhaust treatment has been demonstrated by various researchers as a competent method for mitigation of nitrogen oxides. In this present study, one more NTP reactor is cascaded instead of catalysts/adsorbents to treat the ozone mixed diesel exhaust. While most of the laboratory studies were carried out using expensive dry air cylinders for ozone generation, in the present study, ozone has been generated from atmospheric air only. The nitrogen oxides removal/conversion efficiency of this process depends on various electrical and physical parameters. A dimensionless relation has been obtained between the ratio of summation of NO and NO2 concentrations after treatment to that before treatment and other parameters affecting nitrogen oxides removal using dimensional analysis. Prediction of sum of NO and NO2 concentrations with the variation in six dominant parameters have been done using nonlinear regression technique. Six parameters, i.e. ozone concentration, voltage, frequency, flow rate, temperature and discharge gap have been varied to collect the experimental data required to train and test this model. The predicted sum of NO and NO2 concentrations are found to be well matching with the experimental results. The RMS error is found to be 3.7 % and 5.9 % respectively for training and test data.