Thermally Induced Stresses in Explosion-proof Electrical Enclosures With Windows. Part 2. Final Technical Report.
Stewart-SE; Lin-FD; Cox-PA
MISSING :119 pages
This report presents the solutions to linear transient thermal and stress analyses of explosion-proof enclosures used in underground mines. The results were used to assess the severity of certification tests for enclosure windows relative to possible loads occurring in the actual mine environment. Cast iron electric light enclosures with polycarbonate and glass windows were analyzed under steady-state thermal conditions (light burning) and for thermal shocks corresponding to an internal explosion (ignition of volatile mine gas) or external quenching (mine water spray system). Thermal shocks to the enclosure, caused by ignited gases or water spray, were applied via a series of load steps in the transient analysis. The temperature dependence of material properties and of the film heat transfer coefficients were included in the model. The work demonstrates that thermally induced stresses are strongly influenced by the way the window is mounted in the enclosure. It also shows that the MSHA thermal shock tests, if performed on an unsupported lens (or window), produces lower stresses than the lens (or window) may experience in the mine environment.
CP; Final Contract Report;
Southwest Research Instit.