Parametric Analysis of Heat Transfer in Gypsum Wallboard Partitions

Abstract

One-dimensional heat transfer in gypsum wallboard partitions is studied using sensitivity analysis and calibration by error minimization. Analysis of an existing heat and mass transfer model indicates that mass transfer and condensation of water vapor are not of primary importance in predicting board temperatures. A computationally efficient and robust heat transfer model is developed for predicting temperatures in gypsum wallboard partitions. Kinetic parameters are calibrated by error minimization with respect to literature thermogravimetric analysis (TGA) data. Additional thermophysical parameters are calibrated by error minimization with respect to literature ASTM E119 furnace test data. It is found that the calibrated heat transfer model is capable of predicting board temperatures given large thermal conductivities and specific heats at high temperatures. It is hypothesized that these observations imply the need to account for porous media radiation, temperature varying specific heats, and calcium carbonate decomposition in future models. Local sensitivity analysis reveals that board temperatures are most sensitive to initial density, thermal conductivity at moderately high temperatures ( 800 C), and the activation energy of the dehydration reactions. Conversely, model predictions are relatively insensitive to dehydration reaction pre-exponentials and low-temperature heat capacities.