INVESTIGATION OF THE EXTINGUISHING FEATURES FOR LIQUID FUELS AND ORGANIC FLAMMABLE LIQUIDS ATOMIZED BY A WATER FLOW

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1 EPJ Web of Conferences 110, (2016) DOI: / epjconf/ C Owned by the uthors, published by EDP Sciences, 2016 INVESTIGATION OF THE EXTINGUISHING FEATURES FOR LIQUID FUELS AND ORGANIC FLAMMABLE LIQUIDS ATOMIZED BY A WATER FLOW Ivn V. Voytkov 1, Mksim V. Zbelin 1, Olg V. Vysokomorny 1, 1 Ntionl Reserch Tomsk Polytechnic University, Tomsk, Russi Abstrct. The processes of het nd mss trnsfer were investigted experimentlly while moving nd evporting the tomized wter flow in high-temperture combustion products of typicl liquid fuels nd orgnic flmmble liquids: gsoline, kerosene, cetone, crude oil, industril lcohol. We determined typicl periods of liquid extinguishing by n tomized wter flow of vrious dispersbility. Dt of the dischrge of extinguishing medium corresponding to vrious prmeters of tomiztion nd durtion of using the tomiztion devices ws presented. It is shown tht U m 3.5 m/s is miniml outflow velocity of droplets during moving while pssing the distnce of 1m in the hightemperture gs medium to stop the combustion of orgnic liquids. 1. Introduction Technologicl fcilities nd industril esttes of oil nd gs extrction nd petrochemicl industries re chrcterized by n incresed risk of unregulted fires. Usully, fires t such esttes fll into incresed complexity due to the dissemintion of n ignition source over lrge res, low flmmble level nd extreme explosion risk of orgnic liquids nd fuels, significnt energy relese from the combustion of oil nd products of its processing [1, 2]. When extinguishing fires of oil nd petroleum products by tomized liquid flows (wter, solutions, emulsions nd suspensions bsed on it), the rte of evportion of extinguishing composition in the high-temperture combustion products is determintive one. The wter vpors resulting from phse trnsformtion, on the one hnd, reduce the temperture of ignition source due to the expenditure of energy for evportion, nd, on the other hnd, displce the oxidnt from the fire zone. The results of experiments [3] suggest the possibility of using the liquid extinguishing compositions bsed on wter to suppress the combustion of liquid fuels nd orgnic combustible liquids, considering restrictions for certin prmeters of tomizing the extinguishing medium (stepwise tomiztion of droplets of vrying dispersion) in order to void overspending of wter to extinguish by lrge droplets nd entrinment of extinguishing medium prticles with typicl size less thn 10 μm by opposite high-temperture gs flow of quenching medium prticles with typicl size less thn 10 microns [3]. It is of interest to estimte the consumption, s well s typicl times of tomizing the extinguishing liquid to the moment of liquidtion of fire in the forming flow of different dispersion. Corresponding uthor: vysokomornj@tpu.ru 4 Article vilble t or

2 EPJ Web of Conferences The purpose of the work is to investigte experimentlly estblishing the extinguishing periods of fires of typicl flmmble liquids by the polydisperse droplet flow of wter with controlled prmeters of tomiztion (sizes of droplets in flow (R d ), velocity of droplet flow (U m ), component composition of extinguishing liquid). 2. Experimentl setup nd procedure In conducting the experimentl investigtions, we used the setup which is similr to tht presented in the works [4, 5]. The min equipment being prt of the experimentl setup includes genertor of lser emission, two-pulse Nd:YAG lser (wvelength m, miniml energy in pulse J, mximl durtion of pulse s, repetition frequency 15 Hz), sync processor, cross-correltion (picture formt 2048x2048 pixels, frme frequency 1.5 Hz, miniml dely between frmes s) nd high-speed video cmers (shooting speed is not less thn 10 5 frmes per second (when the definition is pixels)). In experimenttions we pplied severl opticl methods of droplet flow dignostic (PIV, PTP, Stereo PIV, SP) together with corresponding hrdwre nd softwre for processing the results of experiments. The tomizer, tht turns ccording to necessry tomiztion prmeters (in the experiments we used specil metl pulverizers), ws connected through the chnnel with the outlet of vessel contining wter with known prmeters nd chrcteristics. Depending on the type of experiment, we chose the height for instlltion of cross-correltion video cmers nd lser (in the cse of mesuring by PIV nd PTV the instlltion height of video cmer nd lser were chosen so tht the opticl xis of the cmer nd the plne of the light sheet of lser intersect t n ngle of 90 degrees in the registrtion re; in the cse of mesuring by Stereo PIV method the ngle between the opticl xes of the cmers nd the plne of the light sheet of lser is degrees; in the cse of using SP method in front the cmer we set the strobe light specil diffuse screen, connected by fiber with lser, mounting height of lser in this cse is not importnt). The bse of hollow cylinder ws filled with typicl liquid petroleum product (bout 250 ml), which ws initited by the ignition before the experimenttion. When the temperture of the combustion products T g reches the vlue of bout 1100 K, the tomizer fixed t distnce of 0.5 m from the upper fce of the cylinder ws switched. The specilized softwre (relizing the opticl methods s PIV [6], PTV [7], Stereo PIV [8] or SP [9]) strted on the PC, nd the motion of the tomized flow of suspension ws recorded by video (it ws t the inlet nd outlet from cylindricl chnnel). Chrcteristic extinguishing time of typicl flmmble substnces t e ws the min prmeter determined in experimenttions. Extinguishing ws considered s chieved while reducing the temperture of the gseous medium, mesured by thermocouples instlled in the region bove the surfce of liquid fuel, by 50% or more within two minutes. Gsoline ON-92, vition kerosene TS-1, cetone (dimethyl ketone), crude oil (from the Chyndinskoye field with density of ρ 667 kg/m 3, industril lcohol (methnol) were used s typicl liquid fuels. 3. Results nd Discussion For tomiztion pulverizers pplied in experiments, we defined the chrcteristics of tomiztion: size of the generted droplets R m nd dischrge intensity of liquid μ w by pulverizer per unit time. Fig. 1 illustrtes the dependence of liquid volume expended by pulverizer of ech type on the length of tomiztion time nd initil sizes of droplets p.2

3 Thermophysicl Bsis of Energy Technologies 2015 b Figure 1. Approximtion dependences of liquid volume V e expended by pulverizers on the chrcteristic times of tomiztion t e for different vlues of R m () nd initil sizes of droplets R m for vrious lengths of tomiztion times (b) t U m 2m/s. The chrcteristic curves presented in Fig. 1 set up correspondence between volume flow of extinguishing composition, chrcteristic size of droplets of tomized liquid nd using length of tomizer. Experimentl investigtions of het nd mss trnsfer while moving the tomized wter flow in high-temperture combustion products of flmmble liquids llowed defining the typicl extinguishing times t e for typicl combustible substnces (gsoline, kerosene, cetone, oil, industril lcohol) corresponding to vrious vlues of the speed of droplet flow U m nd speed of the opposite flow of high-temperture combustion products U g. Fig. 2 shows the obtined dependencies of chrcteristic times t e on speeds U g of counter combustion products of studied oil products (for two groups of droplets vrious in sizes n two vlues of U m ) p.3

4 EPJ Web of Conferences b Figure 2. Approximtion dependences of chrcteristic extinguishing times t e of flmmble liquids on the speeds of combustion products U g for vrious initil motion speeds of droplets U m : R m = mm; b R m = mm (deficiency or interruption of the curve in the figure corresponds to the conditions under which extinguishing is not reched). The curves presented in Fig. 2 llow drwing the conclusion of filure in reching the conditions of the extinguishing of combustible liquids used in experiments by flow of tomized wter if the speed of extinguishing composition droplets is lower thn U m =3 m/s. The resulting effect is due, possibly, to the phenomen of brking, turning nd entrinment of droplets of tomized extinguishing liquid by the high-temperture combustion products moving opposite (fetures of the tomized liquid droplets moving in the hot gses were studied in the references [3, 10]). Perhps, the reltively low initil speed of extinguishing composition droplets does not llow them to rech the re of the flme. The stock of the kinetic energy of droplets t n initil rte U m =3 m/s mkes it possible for the tomized flow to rech the re of the combustion source, reduce the temperture in this re nd expel the oxidizer from the flme zone formed s result of the phse trnsition of vpor cloud. Also, ccording to the results of the reserches for the two groups of chrcteristic droplet size, we obtined the dependences of the composition of the extinguishing composition on the speed of hightemperture gs flow U g for different vlues of the initil velocity of wter droplets U m (Fig. 3). The nlysis of dependences presented in Fig. 3 llows concluding tht the most fvorble prognosis in extinguishing by tomized wter flow mong tht flmmble liquids used in the experiments include is typicl of oil. When extinguishing the fires by droplet flows of both dispersion groups, it ws possible to stifle fire with less consumption of extinguishing medium (Fig. 3). Probbly, the result is connected to high temperture of evportion of oil. As is well known [11], the oxidtion (burning) of liquids occurs in the gs phse. The oil evportes intensively t considerbly higher tempertures (bout 500 K) thn the corresponding tempertures of other flmmble liquids. As result of the thermo-physicl properties, to mintin the concentrtion of oil vpors in the level required for stble combustion, the tempertures in the source must comply with the temperture of intensive evportion. When extinguishing this fire by flow of tomized wter, the injection of extinguishing composition in the flme zone reduces quickly the temperture of the source up to vlues which re lower thn the temperture of intensive evportion of oil p.4

5 Thermophysicl Bsis of Energy Technologies 2015 b Figure 3. Approximtion dependences of chrcteristic consumptions V e for extinguishing the flmmble liquids on the speeds of combustion products U g for vrious initil speeds of droplet movement U m : R m = mm; b R m = mm (deficiency or interruption of the curve in the figure corresponds to the conditions under which extinguishing is not reched). 4. Conclusions The conducted experimenttion investigtions llowed defining the typicl times for extinguishing different flmmble liquids by flow of tomized wter of vrious dispersbility. Also, we determined the extreme vlues of initil efflux speed for droplets of tomized extinguishing composition t which the conditions of flme suppression of combustible liquids re provided. The results of conducted reserches llow us to conclude bout possibility in fire suppression of liquid fuels nd orgnic flmmble liquids by flows of tomized wter, nd to formulte the recommendtions on the selection of dispersion of droplets, the durtion of exposure to the het source, nd estimte the costs of extinguishing medium. The obtined dt for fetures of extinguishing the fires of oil nd oil products by tomized wter flow cn be used for development nd improvement of the polydisperse fire extinguishing systems p.5

6 EPJ Web of Conferences Acknowledgments This work ws supported by the Russin Foundtion for Bsic Reserch (project ). References 1. S.V. Sobur, Pozhrny bezopsnost neftegzokhimicheskikh predpriytiy: Sprvochnik [Fire sfety in petrochemicl enterprises: Guide]. Moskow, PozhKnig Publ., 2004 (in Russin). 2. V.I. Gorshkov, Tusheniye plmeni goryuchikh zhidkostey [Extinguishing the flme of combustible liquids]. Moskow, Pozhnuk Publ., 2007 (in Russin). 3. R.S. Volkov, G.V. Kuznetsov, P.A. Strizhk, Int. J. Het nd Mss Trns. 79 (2014). 4. D.O. Glushkov, G.S. Nyshin, P.A. Strizhk, R.S. Volkov, IOP Conf. Series: Erth nd Environmentl Science. 27 (2015). 5. G.V. Kuznetsov, M.V. Piskunov, P.A. Strizhk, Int. J. Het nd Mss Trns. 92 (2016). 6. R.D. Kene, R.J. Adrin, Appl. Sci. Res. 49 (1992). 7. D. Dmini, E. Meillot, D. Trlet, J. Therm. Spry Technol. 23, 3 (2014). 8. M. Legrnd, J. Nogueir, A. Lecuon, S. Nuri, P.A. Rodríguez, Exp. Fluids 48, 5 (2010). 9. R.S. Volkov, G.V. Kuznetsov, P.A. Strizhk, Int. J. Het Mss Trnsfer 85 (2015). 10. O.V. Vysokomorny, G.V. Kuznetsov, P.A. Strizhk, Fire Sf. Journ. 70 (2014). 11. V.N. Vilyunov, V.E. Zrko, Ignition of Solids, Elsevier, Amsterdm, p.6