No abstract

The desalination process using reverse osmosis membrane is used around the globe to produce fresh water. In the present paper, simulations are conducted to examine steady and transient nature of the flow inside a three dimensional desalination module containing cylindrical spacers. Navier-Stokes and mass transport equations are solved to determine the flow and concentration field in the feed channel for Reynolds number of 800. The spiral wound membrane is treated as a functional surface where the solution-diffusion model is applied. The flow and the concentration field are strongly three dimensional and transient in nature. The present authors demonstrated that the momentum mixing induced by the presence of spacers enhances the flux performance of the membrane. It is also shown that transient effects and the secondary flows induced by three dimensional flow transitions are mitigating the concentration polarization and fouling/scaling that occurs along the surface of the membrane.

This article discusses the flow of a non-Newtonian Carreau nanoliquid across a stretching radiative nonlinear sheet that is exposed to a variable heat flux. Analysis is done with changing thermal conductivity since it affects how heat and mass transfer occur. Nanoparticles are modelled using the Brownian motion and the thermophoresis phenomenon. The introduction of a similar solution to our challenge, as obtained by our paper, received significant attention. To create a dimensionless system, the governing partial differential equations are subjected to the mathematical model’s convenient similarity transformations after it has been developed. The numerical solution of the coupled highly nonlinear ordinary differential equations characterizing velocity, temperature and nanoparticles concentration is shown using an effective shooting approach. Additionally, all factors affecting the situation that could increase the effectiveness of cooling operations will be looked into. Results for velocity, the thermal field, the concentration of nanoparticles, the skin-friction coefficient, and the local Nusselt and Sherwood numbers are provided and explored. Tables and graphics will be used to illustrate the paper’s conclusions. Results are also given in comparison to existing literature. Excellent agreement has been reached. Furthermore, it is clear that the local Sherwood number, the local Nusselt number, and the skin friction coefficient are all observed to increase as the power law index does.

Hollow fiber membrane (HFM) modules are among the most common separation devices employed in membrane separation applications. Three-dimensional steady-state computational fluid dynamics (CFD) simulations are carried out to study flow past hollow fiber membrane banks (HFMB). The current study investigates the effects of flow behavior on membrane performance during binary mixture separations. Carbon dioxide (CO2) removal from methane (CH4) is examined for various arrangements of HFMs in staggered and inline configurations. The common HFM module arrangement is the axial flow configuration. However, this work focuses on the radial cross-flow configuration. The HFM surface is a functional boundary where the suction rate and concentration of each species are coupled and are functions of the local partial pressures, the permeability, and the selectivity of the HFM. CFD simulations employed the turbulent k–ω shear stress transport (SST) model to study HFM performance for Reynolds numbers, 200 ≤ Re ≤ 1000. The efficiency of the inline and staggered arrangements in the separation module is evaluated by the coefficient of performance and the rate of mass flow per unit area of CO2 passing across the membrane surface. This work demonstrates that the module with staggered arrangement outperforms the module with the inline arrangement.