The simultaneous estimation of multi-mode heat transfer properties, conductive and
radiative, is investigated for materials that include significant heat transfer by radiation. The
focus is on insulative type materials with a relatively large optical thickness. Two basic
models were developed for the combined conduction and radiation heat transfer: a diffusion
solution and a more exact absorbing and isotropically scattering solution. Both solutions
were written for one-dimensional heat transfer in gray, isotropically scattering materials.
Different experimental setups were compared through a sensitivity analysis of the parameters
to determine the best experiment for estimating the properties.
An experiment was performed to collect real data to verify estimation procedures. The
material used for the experiment was Styrofoam and the experiment consisted of a heat flux
supplied by a thin film heater on one boundary and a constant temperature on the other
boundary. The thermal capacitance of the heater proved to have an effect on the temperature
measurements at the heated surface and had to be incorporated into the model.
The estimation procedure involved the use of two methods, the modified Box
Kanemasu algorithm and a genetic algorithm. Difficulties were encountered in simultaneously
estimating all the properties due to correlation between the thermal conductivity and the
radiation parameters, as well as some correlation between the heat capacity of the Styrofoam
and the heat capacity of the heater. However, the genetic algorithm did provide fairly narrow
and well-defined property ranges and confrrmed that radiation transfer was significant in the
Styrofoam.
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