Question

1. Define heat release rate (HRR) and explain its importance, in your own words. Specifically, what clements affect the HRR of a single fuel package? What is the mathematical formula for determining the HRR, and what does each element of the equation represent? Write your answers in your own words. Provide all references. Determine the peak HRR of the following items in Review Questions 2-5 (provide refer- ences for your answers): 2. Bunk bed 3. Sofa 4. Mattress 5. Kiosk 6. Given the following graphs and information, dis- cuss the hazard associated with this fuel. What is the peak HRR? Identify the x- and y-axes on each graph. Discuss what mass loss rate and the upper layer temperature represent. Specifically, look at the HRR graph and identify the different growth stages of this fuel at the different points denoted on the graph (i.e., what stage is this fire in at each particular point)? 7. What is the heat release rate for a 30-m diameter gasoline pool fire? 8. Estimate the flame height from the following burning objects. Show all three calculations by hand for each question. a. 2 m transformer oil fire b. 2 m² wood pallets, pallet stack height is 1.5 m 9. Why are there so many different flame height cor. relations? What is a correlation and why are they used for fire problems? 10. A truck carrying kerosene fuel flipped over while driving down the road. a. What is the heat release rate for a 5.5-m diameter kerosene pool fire? Assume a combustion efficiency of 70 percent and 10 gallons of fuel spilled. b. What is the flame height? c. What would be the burning duration of this pool fire if 10 gallons were spilled? d. What would the HRR be if there were 100 gallons spilled? e. What would be the flame height? f. What would the burning duration be for 100 gallons? g. Is there a difference in HRR or flame height with the addition of volume? If not, why not? If so, why so? 11. The kerosene fire (see Figure 7.27) has a diameter of 26 in. What is an estimation of the fire's steady state heat release rate? 12. Using the image of the 26-in kerosene fire shown below: a. Compare the flame height calculated using the equation presented in this chapter with the measurement of the average flame height of the picture using a linear scaling technique. b. Do the two answers match? c. What are some reasons for any difference in the two answers? 13. What is the difference in mass flux rates for a 0.2 m diameter kerosene fire and a 5 m diameter kerosene fire?

Answer 1

1) Heat release rate :- it is the release of heat through combustion medium like fire by burning of wood, coal etc.

It depends on the fuel type. And structure of of the object. Structure consist of shape, size and thickness of object.

heat release rate = efficiency x mass x heat combustion.

= X x m x Delta H_c