Experimental determination of the rational geometrical parameters of the sprinkler frame arms and deflector on the expansion rate and stability of foam

The results of experimental studies on determination of the effect of the deflector-type sprinkler geometric parameters on the air-mechanical foam formation process are presented in the article. A collapsible sprinkler was developed for the experiment. The elements of the collapsible sprinkler which allow creating its various configurations in a fairly wide range of geometric parameters were made from polylactide (PLA-plastic) with the help of 3D printing. The dependencies of the air-mechanical foam expansion rate and stability on the sprinkler holder length, as well as the external diameter, the taper angle and the ledges height of the sprinkler sprayer were established. The ranges of optimal values along the holder length L = 45÷55 mm and the sprayer ledges height h = 1÷3 mm of the sprinkler for generation of foam with the greatest expansion rate and stability were determined, as well as the ranges of values of these parameters at which the change in the quality characteristics does not occur (L = 90÷150 mm, h = 5÷15 mm). A decrease in the foam quality characteristics with an increase in the sprayer taper angle of the sprinkler was established. Approximate dependencies of the foam expansion rate and stability on the sprayer taper angle of the sprinkler in the range α = 30÷135° were obtained. In addition, it is determined that an increase in the sprayer external diameter in the range from 20 mm to 100 mm results in a gradual deterioration in the foam qua lity. The results of the conducted researches will allow optimizing geometrical parameters of existing designs of deflector-type sprinklers with the aim to increase their fire extinguishing efficiency.

foam expansion rate, foam stability, additive technologies, deflector type sprinkler, holder, sprayer

1. John, R. Hall. U.S. Experience with sprinklers and other automatic fire extinguishing equipment. USA, JR. NFPA USA, 2017. Available at: https://www.nfpa.org/-/media/Files/News-and-Research/Fire-statistics-and-reports/Suppression/ossprinklers.pdf (accessed 2 July 2018).

2. Kiryukhina T. G., Smirnov N. V. Fire Extinguishing Systems. Basic Concepts, Design, Installation, Technical Operation. Moscow, NOU “TAKIR”, 2006. 302 p. (in Russian).

3. Kotov A. A., Petrov I. I., Reutt V. Ch. High-Expansion Foam Implementation for Fire Extinguishing. Moscow, Publishing House of literature on construction, 1972. 112 p. (in Russian).

4. Kamlyuk A. N., Likhomanov A. O. Experimental investigations of the influence of the structural elements of sprinklers on the expansion rate of air-mechanical foam. Vestnik Universiteta grazhdanskoy zaschityi MChS Belarusi = Vestnik of the University of Civil Protection of the MES of Belarus, 2017, no. 1, pp. 167–177 (in Russian).

5. Likhomanov A. O., Govor E. G., Kamlyuk A. N. The substantiation of the application of deflector sprinklers manufactured by additive technologies in experimental studies of qualitative characteristics of the low-expansion air-mechanical foam. Vestnik Universiteta grazhdanskoy zaschityi MChS Belarusi = Vestnik of the University of Civil Protection of the MES of Belarus, 2018, no. 1, pp. 25–39 (in Russian).

6. Kachanov I. V., Kulebyakin V. V., Pavlyukov S. Yu. On the effect of the preliminary gas saturation of the foaming solution on the characteristics of the foam generated in automatic firefighting installations. Vestnik Komandno-inzhenernogo instituta MChS Respubliki Belarus’ = Vestnik of the Institute for Command Engineers of the MES of the Republic of Belarus, 2015, no. 2, pp. 52–61 (in Russian).