The design, construction, demonstraion and operation of a bench-scale device capable of screening the fire suppression efficiency of liquid agents are described in detail in this report. The apparatus is based on a well-characterized flame, a means to facilitate the introduction of liquid agens, and a way t generate liquid droplets. A Tsuji-type burner, a porous cylinder used in a counterflow diffusion configuation is used. Both wake and enveloped flames can be maintained over a wide range of fuel and oxidizer flows. The flame is easily observed and critical stges such as the blow-off limit can be ascertained with ease and high reproductivity. A Small-scale vertical wind tunnel, which allows for the delivery of a uniform flow of oxidier to the burner at a low turbulence intensity and also assists in the delivery of liquid agent droplets to the flame, is used for the flor facility. Two techniques of generating droplets have been examined: (1) a piezoelectric droplet generator and (2) a small glass nebulizer. The piezoelectric droplet generator was found incapable of handling fluids with high loading of dissolved solid due to frequent clogging of the orifice opening. The nebulizer is used in the curren liquid screen apparatus.
Citation: NIST Interagency/Internal Report (NISTIR) - 6319Report Number:
NIST Pub Series: NIST Interagency/Internal Report (NISTIR)
Pub Type: NIST Pubs