Development of Vapor Dispersion Models for Nonneutrally Buoyant Gas Mixtures--Analysis of USAF/N2O4 Test Data.
Abstract
The Air Force is taking steps to improve and update safety procedures available for use during operations involving hazardous chemicals and fuels. In support of this effort, the Lawrence Livermore National Lab. conducted two field scale releases(Eagle 3 and 6) of nitrogen tetroxide (N2O4) at the Nevada Test Site during 1983. An analysis of the chemical interaction of N2O4 with the ambient humidity and oxygen is made. The reported source mass evolution rate is adjusted to account for these reactions; the source rate for Eagle 3 is between 2.9 and 3.1 kg/s, while for Eagle 6, the source between 1.6 and 1.7 kg/s. Reported nitrogen dioxide (NO2) concentrations downwind of the source are adjusted for the source mass evolution rate, and these observed conditions are compared with predicted concentrations using the Ocean Breeze/Dry Gulch model, the Pasquill-Hanna Gaussian plume model, and DEGADIS. (Developed for the Coast Guard, DEGAIS describes the negative buoyancy-driven flows and reduced vertical mixing observed for releases of heavier-than-air gases in the atmosphere. Observed Gaussian equivalent concentration profiles (sigmay and sigmaz) are also compared to predicted values. For these tests, the DEGAIS predictions are consistent with the observed concentration and values sigma y and sigma z, while the Gaussian plume models are not consistent. Furthermore, the importance of negative buoyancy-driven flows and decreased vertical mixing rates for Eagle 3 and 6 is predicted by a characteristic release Richardson number.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1986
- Accession Number
- ADA172056
Entities
People
- Jerry A. Havens
- Thomas O. Spicer
Organizations
- University of Arkansas