DOI: 10.36347/sjet.2020.v08i06.001

Pages: 91-98

Bush fire modeling is a subset of the wild land fire operations. The need for its study remains imperative because of the positive and negative effects that encompass the act. This study is focused on the modeling and validation of combustion operation of a bush consisting majorly of cheat grass type. A finite bush model of length 70.8m having varying widths and heights according to the weights of the bush segments was set-up. The bush model was segmented at 60cm equal interval along the 70.8m length of the bush. The weight of each segment contained inside a vessel was determined with a spring balance after which the weight of the vessel was subtracted from the total measured weight. The set-up was set on fire. The time of fire-travel from one segment to another was noted with the aid of a stop watch. The values of the considered fire-travel time, distances, weights and fire propagation velocity were tabulated for 120 simulations/runs. Multiple regression analysis tool was employed in fitting a mathematical model for estimating any of the considered fire variables- velocity, distance, weight of fuel material and flow time. The developed model was validated using statistical tools such as: P-value, R-sq. value, mean bias error (MBE), root mean square error (RMSE), mean percentage error (MPE), the coefficient of correlation (r), Nash-Sutcliffe model (NSE), and t-statistic test. Sensitivity test was equally carried out using SIMLAB software version 2.2 to decipher the input variable with the most influence on the fire travel velocity using Extended Fourier Amplitude Sensitivity Test (FAST) approach. 10,000 sample elements of each independent variable- distance, flow time and weight of fuel material were randomly generated with their respective mean and standard deviation values normally distributed. The experimental results reveal a fluctuation in the rate of fire propagation along the segmented lengths of the bush and variations in the propagation time................