1.Estimate a value for the constant maximum energy release rates from burning pools of
(a) 2 m2 transformer oil fire
(b) 2 m2 wood pallets, pallet stack height is 1.5 m
(c) mail bags, full, stored 1.5m high, floor area of fuel is 2 m2
(d) the Christmas tree fire in Figure 3.12 (test 17), diameter 1 m
(e) sofa in figure 3.8, projected floor area of fuel is 2 m2
2. Continued from problem 1, estimate the flame height from the following burning objects.
(a) 2 m2 transformer oil fire
(b) 2 m2 wood pallets, pallet stack height is 1.5 m
(c) mail bags, full, stored 1.5m high, floor area of fuel is 2 m2
(d) the Christmas tree fire in Figure 3.12 (test 17), diameter 1m
(e) sofa in figure 3.8, projected floor area of fuel is 2 m2
3. (a) Estimate the potential energy release rate from a circular heptane pool with diameter of 1.2 m (as a free burning pool fire)
(b) If the heptane pool is burning in a room 3 m by 4 m and 2.4 m high. The room has an opening that is 1 m wide and 2 m high. The mass flow rate of air through the opening can be approximated by ma = 0.5 A0 H00.5 kg/s, where A0 is the area of the opening and H0 is its height. If all oxygen flows through the opening is used for combustion, calculate the maximum energy release rate of the heptane pool fire.
4. A pump in a large industrial hall containing 30 liters gasoline breaks down, causing the gasoline to spill into a 3 m2 sump surrounding the pump. The liquid pool is ignited by sparks. Assume the combustion to be 70% effective and the heat loss due to radiation from the flame to be 30%. The ambient temperature in the hall is 27 °C. A pipeline of diameter d = 1.5 m runs horizontally at a 6 m height above the pump. To calculate the heat transfer to the cylindrical pipe one needs to know the convective heat transfer coefficient at the cable surface.
(a) Calculate the plume centerline temperature at 6 m height.
(b) Calculate the plume centerline velocity at this height.
(c) Calculate the convective heat transfer coefficient hc = Nu k/d, where
Nu = 0.024 Re0.805 and Re = u0??d/n. The value of k and n for air are evaluated at an average film temperature Tf = 450 K giving k = 0.037 W/(m K) and n = 31.7 10-6 m2/s.
(d) Estimate the duration of the fire.