Rade Radojevic

Jednodimenzijska difuzijska jednadžba za raspodjelu veličine čestica granulacije perlita za pročišćavanje

Preliminary communication Many filtration systems employing perlite granulations have been designed so far. Size distribution of perlite particles directly influences the retention properties of filter media. The information on the size distribution of perlite particles, used in each specific dead-end filtration process (the flow of fluid being filtered is perpendicular to the surface of filter medium), is crucial for the adequate design of filter medium. In order to facilitate the design of filter systems possessing filter media of this kind, a new and particular mathematical model has been developed for this present study. It is based on an appropriate partial differential equation and additional mathematical conditions, whose solution is an exponential function describing the probability density distribution of perlite particle sizes. The formulated model was experimentally verified by measuring the particle sizes of a perlite granulation using the morphometric method, based on the application of a standard light microscope and digital image analysis software. The fitting procedure of experimental data gave acceptable values of accuracy parameters high R-square factor (R = 0,905) and small value of the root-mean square error (MSE = 0,490).

Water distribution uniformity of the traveling rain gun

An experimental method combined with a computer simulation technique, specified for optimizing the water distribution of a traveling rain gun system is presented in the paper. For given operational pressure and flat terrain, this method enables accurate evaluation of track overlapping and carriage velocity of the traveling rain gun that guarantee uniform water distribution at desired water deposit level. The evaluation criteria for water deposit quality have been formulated: minimum standard deviation, skewness factor as close to zero as possible and the highest possible flatness factor. It is verified that tested rain gun system achieves the uniform water distribution of 20.36 mm in lateral direction at track overlapping of 58%. The simple accurate formula specified for carriage velocity correction is also presented. Key words: Traveling rain gun, water deposition, track overlapping, carriage velocity, descriptive statistics.