Application of Inverse Analysis to Determine the Parameters of the Weighted Multi Point Source Model for the Prediction of Heat Flux From Flames

Thermal radiation is responsible for a substantial portion of the heat transfer from a flame. Radiative characteristics of jet fires are usually expressed through the use of the fraction of heat radiated. Detailed flame simulations provide useful information but may be prohibitive for practical applications due to the significant computational resources that are required. The weighted-multi-point-source model uses point sources with different weights to simulate the contribution of each portion of the flame. This method can give good predictions of the radiant heat flux both in the near and far fields. While previous studies used the trial-and-error approach to determine the weights of the sources, this paper proposes a method to obtain the weight of each source by inverse analysis. In the analysis, the experimental measured radiation heat flux distribution is the input data, while the weights of the sources and the fraction of heat radiated are the sought parameters. The inverse problem is formulated as an optimization problem, which is solved by the generalized extremal optimization. As will be shown in the paper, the inverse method is capable of recovering the weights of the sources that lead to results with more accuracy than the single source model or the multiple sources model with the commonly employed linear variation in the weights.