M. Tech. Chemical Engineering. / In this work the development of a mathematical model capable of determining suitable operating conditions and reactor configuration to produce nanoparticle products of specified average diameter as well as their deposition to the reactor are presented. The developed model consists of mass, momentum and energy conservation equations. The aim of this model was to predict the effect of inlet gas flow rate, temperature, reactant concentration on the average diameter, surface area, number and volume concentration of product TiO2 nanoparticles and most importantly particle deposition on the average diameter of TiO2 nanoparticle products. Possible formulations of such a model are discussed on the basis of efficiency, cost effectiveness, amount of data generated, inclusion into the computational fluid dynamics (CFD) technique and the best option chosen thereof. The performance of the present monodisperse model was validated by comparing its predicted results with previously published numerical data. Good correlations between the predicted and numerical results were achieved.