Regeneration of diesel particulate filter using sliding discharge
Diesel particulate filter (DPF) is widely used to trap fine soot particles emitted from diesel engines. It can collect particles as small as submicron but it is necessary to oxidize accumulated particles by heating the filter. Temperatures of 600 degree C or higher is required to oxidize the soot but it is difficult to maintain stable reaction because this is exoergic reaction. The filter is sometimes damaged due to thermal runaway of the reaction. To address this trade-off problem, we have studied low temperature regeneration of DPF using sliding discharge, which can be generated on the surface of DPF and produces oxidative species at room temperature. Diesel soot collected by DPF was used. Simulated air consisting of N2 and O2 and not including CO2 or CO was used and CO and CO2 concentration was monitored by real time FTIR to estimate the soot oxidation. All the experiment was carried out at temperatures between 100 and 190 degree C to simulate exhaust temperature under low load. Experimental results show that soot was oxidized by generating sliding discharge on the DPF. No thermal damage of the DPF was found. Energy efficiency, denoted by the amount of oxidized soot per electric energy dissipated in the sliding discharge, increased with increasing the temperature as well as oxygen concentration in the test gas. Small amount of Ag2O supported by the DPF significantly increase the energy efficiency of soot oxidation. On the contrary, excessive amount of Ag2O resulted in energy efficiency lower than that of DPF without Ag2O probably because the sliding discharge was not generated favorably due to high conductivity resulted from metal Ag. These results suggest that sliding discharge can induce soot oxidation and that Ag2O possibly catalyzes soot oxidation.
Sliding Discharge Inside Glass Capillaries
The generation of stable and homogenous plasma inside an automobile honeycomb catalyst is very difficult. This paper presents a technique to create plasma inside the thin channels of the honeycomb monolith by using a sliding discharge. The electrical and optical properties of the discharge are described.
Far-field dispersal modeling for fuel-air-explosive devices
A computer model for simulating the explosive dispersal of a fuel agent in the far-field regime is described and is applied to a wide variety of initial conditions to judge their effect upon the resulting fuel/air cloud. This work was directed toward modeling the dispersal process associated with Fuel-Air-Explosives devices. The far-field dispersal regime is taken to be that time after the initial burster charge detonation in which the shock forces no longer dominate the flow field and initial canister and fuel mass breakup has occurred. The model was applied to a low vapor pressure fuel, a high vapor pressure fuel and a solid fuel. A strong dependence of the final cloud characteristics upon the initial droplet size distribution was demonstrated. The predicted fuel-air clouds were highly non-uniform in concentration. 18 refs., 86 figs., 4 tabs.