Numerical Investigation of Thermal Stability of Catalyst Granules with Internal Heat Generation in a Random Temperature Field

Method for numerical simulation of temperature of granules with internal heat release in a medium with random temperature fluctuations it is proposed. The method utilized solution of a system of ordinary stochastic differential equations describing temperature fluctuations of surrounding and granules. Autocorrelation function of temperature fluctuations has a finite decay time. The suggested method is verified by the comparison with exact analytical results. Random temperature behavior of a granule with internal heat release qualitatively differs from the results obtained in the deterministic approach. Mean first passage time of granules temperature intersects critical temperature is estimated at different regime parameters.

Heat Conduction in Solids With Random Initial Conditions

The problem of heat conduction in solids with random initial condition is studied. A general theory is first discussed and several examples are considered. It is observed that the homogeneity of the random initial condition is sufficient for the homogeneity of the temperature field in an unbounded domain. But in bounded domains the random temperature field becomes nonhomogeneous even though the initial condition is homogeneous.

Snap-Through Buckling of a Viscoelastic von Mises Truss in a Random Temperature Field

The reduction of the expected lifetime of a temperature-sensitive viscoelastic von Mises truss caused by small random temperature fluctuations is calculated, assuming the probability density of the temperature process to be a known (symmetric) function. Results are derived for a normal and a rectangular probability distribution of the temperature fluctuations.

Comparison of the Frequency Responses and Time Constants of Mineral Insulated Thermocouples in Sodium and Water

Frequency responses of mineral insulated thermocouples are investigated in sodium by a new method which uses a random temperature field generated by the action of turbulence. This forms the basis for a comparison with the frequency response measured in room temperature, water, and the deduction of time constants for the thermocouples in sodium.