Monika Gwadera

Kinetic curves for multiple reactions have been determined by the means of the Monte Carlo method. Both reversible and nonreversible parallel, series, series-parallel and autocatalytic reactions have been taken under consideration. The complete consistency between results of stochastic calculations and results obtained with the use of deterministic models has been shown.

The paper refers to the kinetics of batch adsorption in a perfect mixing reservoir. Systems
with a linear adsorption equilibrium, spherical adsorbent pellets and mass transfer resistance
in both phases are considered. An approximate kinetic model, based on approximation with
the use of continued fractions, was used in calculations. It was found that the model gives
results consistent with the exact solution.

Computational models for adsorption in a tank are presented. The approximate model provides the same results as the exact model. The diffusion coefficient of a dye in an adsorbent pellet and the mass transfer coefficient in a fluid phase were determined on the basis of the measurements of dye adsorption on the activated carbon. It was determined how the fraction of the resistance to mass transfer in the fluid to the overall mass transfer resistance changes during adsorption. It was found that, for the examined system, the main resistance to mass transfer is located in the liquid phase.

The results of the numerical simulation of heat conduction in ground with a horizontal, tubular (parallel pipes) heat exchanger installed are presented in this paper. On the basis of analysis of courses of temperature isolines in the ground, a simplified mathematical heat transfer model in a horizontal ground exchanger was developed. The ground thermal diffusivity was assumed to be a variable of location. On the basis of the model, the temperature profiles in the ground with a heat exchanger installed were determined.

The aim of this work is to present the results of studies on heat and mass transfer in an adsorber, which is the main part of an adsorption chiller. The paper refers to adsorption of water vapor on silica gel grains. Adsorbent grains were coated on the outer surface of a copper pipe. The influence of grains diameter and flow rate of the gas phase on process intensity was considered.

Temperatura gruntu zmienia się z głębokością oraz w czasie. Zmienność czasowa ma charakter harmoniczny. Równanie opisujące zmiany temperatury gruntu zawiera cztery parametry: średnioroczną temperaturę powierzchni gruntu, roczną amplitudę temperatury powierzchni gruntu, kąt fazowy oraz dyfuzyjność cieplną gruntu. Na podstawie wyników pomiarów przedstawionych w literaturze wyznaczono parametry równania kombinowaną metodą opierającą się na regresji liniowej, opisaną w literaturze. Metoda ta prowadzi jednak do otrzymania niejednoznacznej wartości współczynnika dyfuzyjności cieplnej. Stwierdzono, że znacznie lepsze wyniki daje metoda regresji nieliniowej, prowadząc do otrzymania dokładnych i jednoznacznych wartości wszystkich parametrów równania. 

The ground temperature changes with depth and time. Time variability is considered as a harmonic function. The equation describing changes of the ground temperature contains four parameters: the average annual  temperature of the surface of the ground, the annual amplitude of the temperature of the ground surface as well as the phase angle of the temperature and thermal diffusivity of the ground. Based on the results of the measurements presented in the literature, the parameters of the equation using the combined method on the basis of linear regression, described in the literature, were determined. This method, however, leads to an ambiguous value of the thermal diffusivity. It was found that the nonlinear regression method gives much better results, leading to obtaining precise and unambiguous values of all parameters of the equation.