https://cronfa.swan.ac.uk/Record/cronfa48864/Download/0048864-07032019141310.pdf

Reverse osmosis desalination: A state-of-the-art review

Numerical simulation of heat extraction performance in enhanced geothermal system with multilateral wells

Reactive transport processes in a porous medium will often both cause changes to the pore structure, via precipitation and dissolution of biomass or minerals, and be affected by these changes, via changes to the material’s porosity and permeability. An understanding of the pore structure morphology and the changes to flow parameters during these processes is critical when modeling reactive transport. Commonly applied porosity–permeability relations in simulation models on the REV scale use a power-law relation, often with slight modifications, to describe such features; they are often used for modeling the effects of mineral precipitation and/or dissolution on permeability. To predict the reduction in permeability due to biomass growth, many different and often rather complex relations have been developed and published by a variety of authors. Some authors use exponential or simplified Kozeny–Carman relations. However, many of these relations do not lead to fundamentally different predictions of permeability alteration when compared to a simple power-law relation with a suitable exponent. Exceptions to this general trend are only few of the porosity–permeability relations developed for biomass clogging; these consider a residual permeability even when the pore space is completely filled with biomass. Other exceptions are relations that consider a critical porosity at which the porous medium becomes impermeable; this is often used when modeling the effect of mineral precipitation. This review first defines the scale on which porosity–permeability relations are typically used and aims at explaining why these relations are not unique. It shows the variety of existing approaches and concludes with their essential features.

/pdf/porosity-permeability-relations-for-evolving-pore-space-a-4mdwj9d8yg.pdf

Porosity–Permeability Relations for Evolving Pore Space: A Review with a Focus on (Bio-)geochemically Altered Porous Media

THM (Thermo-hydro-mechanical) coupled mathematical model of fractured media and numerical simulation of a 3D enhanced geothermal system at 573 K and buried depth 6000–7000 M

https://backend.orbit.dtu.dk/ws/files/138397605/1_s2.0_S0375650517301013_main.pdf

A three-dimensional coupled thermo-hydro-mechanical model for deformable fractured geothermal systems

Gypsum scaling commonly occurs over cross-flow RO membrane during seawater desalination. It blocks the pores of the semi-permeable membrane and results in substantial permeate flux decline in a shorter time span. The aim of the present study is to understand the gypsum scaling pattern and permeate flux decline through numerical modelling of nucleation, growth of gypsum crystal, and membrane surface coverage using a moment-based population balance method and CFD (computational fluid dynamics). We have performed numerical simulations of gypsum scaling in a roto-dynamic RO filtration system for different combinations of CaSO4 concentrations and feed pressure while NaCl concentration remains the same to match seawater salinity. We have found that the scaling starts where shear rate over membrane is the least and the growth of membrane surface blockage by scaling is controlled by feed pressure and CaSO4 concentration. For higher feed pressure permeate discharge initially is more but stronger concentration polarization causes more scaling and faster permeate discharge decline. Hence, for higher CaSO4 concentrations moderate feed pressure may be suitable but for lower CaSO4 concentrations higher feed pressure may be advantageous. 

Numerical modelling and analysis of concentration polarization and scaling of gypsum over RO membrane during seawater desalination

The objective of this chapter is to develop a computationally efficient approach for system identification. An algorithm, the bootstrap filter in conjunction with polynomial chaos expansion, is proposed for identification of system parameters. The central idea of the proposed method is the introduction of response through polynomial chaos expansion in the filtering algorithm. Appreciable performance of the proposed algorithm is been provided by considering the problem of the identification of the properties of a single degree of freedom system.

Abhijit Chaudhuri

Papers

Numerical modelling and analysis of concentration polarization and scaling of gypsum over RO membrane during seawater desalination

Polynomial Chaos in Bootstrap Filtering for System Identification

Three-dimensional numerical simulations for mitigation of tsunami wave impact using intermittent sea dikes

Modelling of phase behaviours, viscous instabilities and oil recovery during different types of surfactant-polymer flooding in five-spot setup

Estimation of permeability field from sparse measurements of local permeability and water table fluctuations