ANDRIANANTENAINA

This work deals with the modeling of the unsteady Newtonian fluid flow associated with an open cylindrical reservoir. This reservoir presents a hole on the right bottom wall. Fluid volume variation, heat and mass transfers are neglected. The unsteady governing equations are based on the conservation of mass and momentum. A finite volume technique is used to solve the non-dimensional equations and related boundary conditions. The algebraic system of equations resulting from the discretization process are solved by means of the THOMAS algorithm. For pressure-velocity coupling, the SIMPLE algorithm (Semi Implicit Method for Pressure Linked Equations) is used. Results for laminar flow (Re < 1000), including the pressure and velocities profiles as well as the streamlines in the reservoir are presented. Moreover, the effects of the D/d and H0/D ratios and Reynolds number Re on the fluid flow are discussed. It is shown that the velocities and pressure depend essentially on the reservoir size. To validate the model, the present results have been compared with Zhou et al.’s results, Poiseuille’s and Bernoulli’s exact solution.

Polynomial model adopted for the moisture content influence to the drying rate of non-hygroscopic products like the pozzolana presented some limits. This model was not universal and has diverged whether moisture content different to the appropriate experiment values has been used. Thus, a new exponential model based on the inverse of moisture content and respecting to the imposed boundary conditions has been proposed. Model parameters were determined using the least square approximation method of Newton-Marquart. The predicted temporal variations of moisture content were provided from the Runge-Kutta fourth order integration scheme computed on the new model of drying rate. Moreover, two-way ANOVA method was performed on data analysis, at the parameters statistical significance and in residual analysis for the model fit quality. Model validations were done by comparisons among theoretical and experimental values and between predicted and polynomial models. Comparisons showed a good agreement with highest R2 and lowest reduced chi-square, MBE, RMSE, and MAPE.

98 % of Malagasy population depend on household solid fuels as their primary cooking fuel. To improve the quality of life of such a large number of people, it is imperative that clean and renewable alternatives are provided for cooking. Low concentration ethanol fuel is considered cleaner because of its inherent characteristics of low pollutant formation and emissions during handling and use. The fuel is easy to distil and can be produced locally. Based on the Water Boiling Test protocol, this paper presents the performance, the safety analysis of the stove, the field tests and policy issues. Calculation method showed that the rate of principal pollutant gases such as carbon dioxide and carbon monoxide emission are very low. The greenhouse gas emission and stove capacity increase with increasing ethanol concentrations. The stove gives best results in terms of ease of use and performance with ethanol concentrations ranging from 50 to 75% (v/v).