Bulletin of Japan Association for Fire Science and Engineering Vol. 62. No. 1 (2012) Development of Two-Dimensional Simple Simulation Model and Evaluation of Discharge Ability for Water Discharge of Firefighting Tatsuya MIYASHITA* 1, Osami SUGAWA* 2, Yoshitaka WADA* 2, Ryo ISHIKAWA* 3 and Yasuo KAWAGUCHI* 4 * 1 Graduate School of Science and Technology, Department of Mechanical Engineering, Tokyo University of Science, 2641 Yamazaki, Noda, 278-8510, Japan * 2 Faculty of System Engineering, Department of Mechanics Design, Tokyo University of Science, Suwa, 5000-1 Toyohira, Chino, 391-0292, Japan * 3 Graduate School of Engineering and Management, Department of Engineering and Management, Tokyo University of Science, Suwa, 5000-1 Toyohira, Chino, 391-0292, Japan * 4 Faculty of Science and Technology, Department of Mechanical Engineering, Tokyo University of Science, 2641 Yamazaki, Noda, 278-8510, Japan Abstract It is necessary to estimate the efficient water discharge performance to a burning area of fire with considering the water delivering characteristics. The objective of this study is to develop the two-dimensional simple numerical simulation model and to evaluate discharge ability of water that is discharged like a rod by a fire fighter hose nozzle. The simulation model based on MPS method have been constructed with considering the breakup model for the discharged water applying the Rosin-Rammler distribution to estimate the diameter distribution of water droplets. The quantitative evaluation method for the discharge ability has been established by analyzing the distribution of the water volume dropped on the surface as footprint (or landing zone). We conducted the small scale water discharge experiments (3.7 L/min by 0.05 MPa) in order to evaluate quantitatively the simulation model. The maximum range and maximum height of the discharged water are simulated well with less than 4 % difference in comparison with measured data. Key Words : Water discharge, MPS method, Rosin-Rammler distribution, Footprint, Landing zone
1,000 L/min 50 m 100 500 L/min 20,000 L/min 3.7 L/min Fig. 2 65 65 mm 60 60 mm 100 mm 520 3640 mm Footprint Landing Zone Unit:mm 20 L 450 mm Fig. 1 6.1 mm φ 4.9 mm 10.4 mm 2 3.7 L/min 0.05 MPa 25 35 45 55 65 Fig. 1 Cross section of a nozzle for the small scale water discharge experiment. MPS Moving Particle Semi-implicit Method MPS Lagrange Navier-Stokes Fig. 2 Methodology that measured the distribution of the water volume dropped on the ground.
Footprint ab Rosin Rammler Rosin-Rammler 0.8 mm 300 20,000 MPS MPS 0.87.7 m/sec 450 mm 1.0 10 4 3.00 GHz CPU Fig. 3 35 60 % Footprint Fig. 3 Fig. 3 Contour of water volume that received measuring boxes in the water discharge experiment at the angle of 35. Fig. 4 35 Fig. 4 Distribution of water volume that received meas uring boxes in the water discharge.
Footprint 60 % 10 % Footprint Footprint 1 Fig. 5 35 Fig. 5 Comparison of the distribution of water volume ratio between measured data and the Gaussian distribution estimated. Table 1 3.7 L/min 35 45 4% Table 1 Comparison of trajectory between measured data and simulated data at the flow of 3.7 L/min. Angle [ ] 25 35 45 55 65 Max. range [m] Max. height [m] M 4.89 0.97 0.20 S 4.90 1.00 M 5.32 1.50 0.38 S 5.30 1.50 M 5.30 1.98 1.89 S 5.40 2.00 M 4.76 2.50 2.94 S 4.90 2.40 M 4.09 2.83 0.24 S 4.10 2.80 3.09 0.00 1.01 4.00 1.06 M : Measured data, S : Simulated data Fig. 6 35 Fig. 6(b) Fig. 6(a) 6.0 7.0 mm 0.4 1.0 mm 35 45 Fig. 7 25 35 45 20 %
１７ (a) (b) Fig. 6 Side view of the small scale water-discharge. Discharge flow : 3.7 L/min, Angle : 35 (a) Experiment, (b) 2D Simulation. Fig. 7 Comparison of the water volume distribution between measured data and simulated data in the each discharge angle. １７
55 65 45 55 65 65 45 10 % 55 65 55 65 Table 2 Footprint Footprint 10 % 45 55 9 10 % 5% Table 2 Comparison of footprint range between measured data and simulated data at the flow of 3.7 L/min. Angle [ ] 25 35 45 55 65 Short range [m] Range of footprint from a nozzle Long range [m] M 3.87 4.79 2.22 S 3.78 4.68 M 4.00 4.99 0.95 S 3.96 5.22 M 3.87 4.92 2.43 S 3.96 5.40 M 3.47 4.46 3.75 S 3.60 4.86 M 3.07 4.13 6.31 S 2.88 3.96 2.30 4.65 9.71 8.97 4.12 M : Measured data, S : Simulated dataa Footprint MPS 3.7 L/ min Rosin-Rammler MPS 4% Footprint Footprint Footprint [m 2 ] [ ] [ ] [mm] [mm]
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