TEMPERATURES OF RESTRICTED TURBULENT FIRE PLUMES

A study has been made of the restricted plume flow above horizontal, f ine mesh screens which intercept a small-scale, turbulent fire plume. Measurements were made of centerline temperatures in both restricted a nd free plumes, together with screen friction forces associated with r estricted plumes. Counter to intuition, the restricted plume displayed higher time-averaged mean temperatures. A model based on the return o f the flow of the restricted plume to the pre-screen (universal) Froud e number has been developed to predict the increased time-averaged mea n temperatures above the screen, i.e. lifting of the virtual point sou rce, as a function of the plume/screen friction force. Assuming engine ering velocity distributions, the theoretical model was confirmed expe rimentally for screen friction forces up to at least half the total pl ume momentum at screen level. (C) 1998 Elsevier Science Ltd. All right s reserved.