1- A 6-inch diameter circular pan is placed on a scale and fuel is added to the pan. The scale reads 10.4kg. The fuel is ignited and allowed to burn unimpeded.After burning for 20 minutes, the scale now reads 10.02kg. What is the mass flux of this fuel during this time?

2- Using Table 7.6inFire Dynamics 2ndEdition, calculate the mass flux of a Xylene pool fire if the pool is circular with a diameterof 1.6 meters.

calculating a heat release rate is relatively simple. Pools may have physical restriction that establish boundaries (e.g., dikes or reservoirs), but pools also include situations when liquids are spilled without restriction. Once the fuel is ignited, it is assumed that the flam spread across the fuel's surface is almost instantaneous. For those fuels with higher flash points and viscosities, the entire surface area may not ignite simultaneously, and t flame spread may need to be calculated. For more information on calculating this type flame spread, refer to the work of Gottuk and White (2008). The heat release rate of a pool fire can be calculated by equation 7.1. The heat relea rate depends greatly on the extent of the burning fuel surface area. The heat release rates pool fires _ Fires pool fires are no different, except that the burning rate is not a set value with all surface ar involving horizontal fuel surfaces. diameters). Much experimental work has been performed on pool fires, and it has be shown that the burning rate increases with an increasing diameter (0.2 m in diameter greater) of the pool fire until the pool gets to a set diameter. At this point, a maximum aver burning rate is achieved, which is known as the asymptotic burning rate m' (see Table 7 TABLE 7.6 Large Pool Fire Burning Rate Data ASYMPTOTIC HEAT OF EMPIRICAL MASS LOSS RATE COMBUSTION DENSITY CONSTANT MATERI mo (kg/ m2 - sec) AHC,eff (kJ/kg) p (kg/ms) KB (m 1) Cryogenics Liquid H2 0.017 12,000 70 6.1 LNG (mostly CH4) 0.078 50,000 415 1.1 LPG (mostly C3H8) 0.099 46,000 585 1.4 Alcohols Methanol (CH3OH) 0.017 20,000 796 100 Ethanol (C2H5OH) 0.015 26,800 794 100 Simple Organic Fuels Butane (C4H10) 0.078 45,700 573 2.7 Benzene (C6H2) 0.085 40, 100 874 2.7 Hexane (C6H14) 0.074 44,700 650 1.9 Heptane (C7H16) 0. 101 44,600 675 1.1 Xylene (CH10) 0.090 40,800 870 1.4 Acetone (C3H80) 0.041 25,800 791 1.9 Dioxane (C4H802) 0.018 26,200 1,035 5.4 Diethyl ether (C4H100) 0.085 34,200 714 0.7 Petroleum Products Benzine 0.048 44,700 740 3.6 Gasoline 0.055 43,700 740 2.1 Kerosene 0.039 43,200 820 3.5 JP-4 0.051 43,500 760 3.6 JP-5 0.054 43,000 810 1.6 Transformer oil, hydrocarbon 0.039 46,400 760 0.7 Fuel oil, heavy 0.035 39,700 940-1,000 1.7 Crude oil 0.022-0.045 42,500-42,700 830-880 2.8 Solids Polymethylmethacrylate (C5 H8 02)n 0.020 24,900 1, 184 3.3 Polypropylene (C3H8)n 0.018 43,200 905 100 Polystyrene (CHg)n 0.034 39,700 100 1,050 Miscellaneous 561 Silicon transformer fluid 0.005 28, 100 100 960 "These values are to be used only for computation purposes; the true values are unknown. 138 Chapter 7 Heat Release Rate