Assessment of the Thermal Radiation Spread in Special Conditions

Abstract

Increase of the requirements for the safety of hazardous production facilities stimulates the development and improvement of the methodological approaches to accidents consequences assessment on the main gas and other pipelines. Existing models for determining heat fluxes from radiating flame surfaces are focused on assessing damage under standard conditions when the epicenter of the accident is at the same altitude level with potential recipients and there are no barriers between them. In practice, special conditions are often implemented, in particular: fires on the pipelines located in the mountainous areas, safe passage of aircraft near the burning site, protection of objects from thermal radiation by installing impenetrable screens. Approaches are proposed related to assessing heat fluxes at the receiving sites located at different altitude levels with the fire source, as well as during accidents with ignition on the gas pipelines in the presence of screens protecting against thermal radiation. A parameter is introduced that describes the effect of the multilevel location of the source and the recipient on radiation — the coefficient of change in the thermal radiation flux from the side surface of a column-type fire in the absence of a wind, depending on the location height and distance in relation to the ground source of combustion of the site receiving the radiation. An expression is given for determining safe height of the flight of aircraft over a column-type fire in the range of flame heights from 50 to 850 m. Isolines of the fields of heat fluxes from the flame of a high-speed flat jet are calculated when the radiation is screened by a wall located at a normalized distance. The results obtained make it possible to predict the consequences of accidents on the main gas pipelines with gas ignition considering the relief, to assess the boundaries of safe corridors for flights of the aircraft near gas pipelines, and to efficiently develop means of protecting objects surrounding the main pipelines from thermal radiation from a flat torch.