Accession Number : AD0275418

Title :   STUDIES OF AIR FLOWS INTO UNCONTROLLED FIRES

Descriptive Note : Interim rept. no. 2, 1 Aug 61-30 Apr 62,

Corporate Author : BUREAU OF MINES PITTSBURGH PA

Personal Author(s) : GRUMER,J. ; STRASSER,A.

Report Date : 30 APR 1962

Pagination or Media Count : 22

Abstract : Flame piloting by convection currents of flame gases within the fuel bed accelerates the burning rate, while radiative heat transfer is less effective. This conclusion was based on observation of a maximum in the curve of maximum burning rate of 2 proximate fires versus spacing between them and on interpretation of wood crib fire data. Factors determining the velocity of naturally induced air currents feeding a fire are not well established. Fairly good correlation was obtained from observed air velocities induced by experimental fires matched with air velocities computed on the basis of theory involving the assumption that the pressure drop through the fuel bed for the induced air flow is equivalent to the pressure drop for the flow of fluid through a packed porous bed. This radial pressure drop was equated to the sum of the vertical buoyancy head and the vertical velocity head developed as the result of the combustion. Another factor which may influence the natural induction of air by a fire is the subatmospheric static pressures prevailing between certain proximate fires. The resulting pressure gradient may be the driving force for the induction of air through the burning fuel beds.

Descriptors :   *COMBUSTION, *FIRES, *FLAMES, AIR, AIRBURST, CONTROL, GAS FLOW, PRESSURE, TEST EQUIPMENT, TEST METHODS, THEORY, WIND

Distribution Statement : APPROVED FOR PUBLIC RELEASE