Algorithm and Associated Computer Subroutine for Calculating Flow through a Horizontal Ceiling/Floor Vent in a Zone-Type Compartment Fire Model

摘要

An algorithm and associated computer subroutine is presented for calculating the effects on two-layer compartment fire environments of the quasi-steady flow through a horizontal vent connecting two spaces. The two spaces can be either two inside rooms of a multi-room facility or one inside room and the outside ambient environment local to the vent. The description of the flow through the vent is determined by combining considerations of (1) the unidirectional-type of flow driven by a cross-vent pressure difference and, when appropriate, (2) the exchange-type of flow induced when the fluid configuration across the vent is unstable, i.e., when a relatively cool, dense gas in the upper space overlays a less dense gas in the lower space. The algorithm/subroutine is called VENTCF. The computer subroutine is written in FORTRAN 77. The subroutine is completely modular, and it is suitable for general use in two-layer, multi-room, zone-type fire model computer codes. It has been tested over a wide range of input variables and these tests are described.