Post-test calculation of measurement of heat transfer in hot, dry Al2O3 particle beds

This report describes a numerical simulation of a dry particle bed heat transfer experiments performed in MOSES project. The goal of the simulation was to validate the model of effective heat transfer coefficient developed and applied in PASULA code. The test facility was set up to measure temperatures in a vertically aligned, cylindrical Al2O3-particle bed, which was heated electrically from the top. Both axial and radial temperature profiles were measured in the particle bed at four different temperature ranges produced by varying heating power. Temperature profiles were also measured from the surrounding insulator material, to facilitate the overall energy balance estimation. Calculation model in the PASULA code is based on control volume method of solving heat transfer equations in defined geometry. Material properties of Al2O3 particles, insulator materials surrounding the test cylinder and used in the resistance heater module, in the ceramic cylinder housing the particles and t he steel shell surrounding the whole apparatus were given as polynomial fittings. All measured data points were used to quantify the parameters in the fitting polynomials. The solution of the coefficients was searched by minimising the error between measured and calculated values over the whole data set. An excellent agreement was achieved with a well defined parameter set. When comparing the obtained calculated material properties and heat transfer coefficients with the sparse data points obtained from the manufacturer or from the literature, the agreement was reasonably good. Thus it can be concluded that the numerical model developed for particle bed effective heat transfer coefficient in PASULA code is capable of predicting heat transfer phenomena in a dry rubble bed with good accuracy, once the solid particle material and cover gas properties are known.