Usually, in concentration polarization models, the mass transfer coefficient is an unknown parameter. Also, its variation with changing experimental circumstances is in question. In the literature, many relationships can be found to describe the mass transfer coefficient under various conditions, as well as various corrections for deviating behaviour during ultrafiltration. To obtain reliable m...

An analytical study was performed to study effects of thermo-diffusion and chemical reactions on a three-dimensional MHD mixed convective flow of dissipative fluid along an infinite vertical porous plate with transverse sinusoidal suction velocity. The parabolic partial differential equations governing the fluid flow, heat transfer, and mass transfer were solved using perturbation technique and...

An experimental investigation was conducted to study the average and the fully-developed heat (mass) transfer coefficients in a rectangular smooth duct and a duct with repeated-baffle blockages. The focus of attention in this work is the conventional correlation Nu / Nufd 1 + C / ( X / D ) for the average heat transfer coefficient. It was shown that for relatively short ducts, the coefficient C...

in this paper, we have considered the problem of rotating, magnetohydrodynamic heat and mass transfer by free convective flow past an exponentially accelerated isothermal vertical plate in the presence of variable mass diffusion. while the temperature of the plate is constant, the concentration at the plate is considered to be a linear function with respect to time t. the plate is assumed to be...

the present paper describes the designing of a thermally and economically optimum mechanical draft counter-flow wet cooling tower. the design model allows the use of a variety of packing materials in the cooling tower toward optimizing heat transfer. once the optimum packing type is chosen, a compact cooling tower with low fan power consumption is modelled within the known design variables. mor...

a one–dimensional, transient and thermal degradation model for predicting responses of composite materials when are exposed to the fire is presented. the presented model simulates ablation of composites with different layers of materials and considers material properties as functions of temperature. the reactions are modeled by using arrhenius-type parameters and density-temperature diagrams wh...

recently, the production of biosurfactants in bioreactors and their use in various pharmaceutical,chemical and food industries have been developed. optimum production is directly related to the physicochemicalcondition of culture medium (such as ph and temperature) and engineering parameters of bioreactors (such asaeration rate, volume of operation and the amount of energy input). understanding...

this study aimed to find an appropriate way to minimize water utility in the petrochemical and petroleum industries. for this purpose, tehran oil refinery was chosen to analyze feasibilities of regeneration, reuse and recycling in the water network. in this research, two key contaminants including cod and hardness were analyzed. amount of freshwater was reduced about 180 m3/h (53%) and 216.88 m...

a numerical model is developed to simulate the transport phenomena in the flow channel between parallel plates with porous and non-porous (or impermeable) walls. the continuity and momentum equations were solved first, assuming the wall reynolds number in the range of with the suction or injection of air at a speed equal to the uniform inlet velocity. the results show that at constant inlet and...