Kyung-Beom Yoon

Estimation of the Properties for a Charring Material Using the RPSO Algorithm

Fire characteristics can be analyzed more realistically by using more accurate properties related to the fire dynamics and one way to acquire these fire properties is to use one of the inverse property estimation techniques. In this study two optimization algorithms which are frequently applied for the inverse heat transfer problems are selected to demonstrate the procedure of obtaining pyrolysis properties of charring material with relatively simple thermal decomposition. Thermal decomposition is occurred at the surface of the charring material heated by receiving the radiative energy from external heat sources and in this process the heat transfer through the charring material is simplified by an unsteady 1-dimensional problem. The basic genetic algorithm(GA) and repulsive particle swarm optimization(RPSO) algorithm are used to find the eight properties of a charring material; thermal conductivity(virgin, char), specific heat(virgin, char), char density, heat of pyrolysis, pre-exponential factor and activation energy by using the surface temperature and mass loss rate history data which are obtained from the calculated experiments. Results show that the RPSO algorithm has better performance in estimating the eight pyrolysis properties than the basic GA for problems considered in this study.

Study on inverse estimation of radiative reflection properties in mid-wavelength infrared region by using the repulsive particle swarm optimization algorithm.

In this study, we develop software that estimates radiative properties of painted surfaces in the mid-wavelength infrared (MWIR) region inversely from the measured temperature and radiance variations with time by applying the repulsive particle swarm optimization algorithm. In this study the radiance in the MWIR region and surface temperature are obtained from a commercial software considering winter weather, and these results are used to estimate radiative reflection properties. Surface radiative reflection properties for three different paints are estimated by using the predetermined radiance in the MWIR region and surface temperature. This finding suggests that the process for obtaining surface radiative properties proposed in this study could be a useful way to obtain infrared signatures from objects with various surface coatings of unknown radiative properties.