PH-sensitive hydrogel-based valves: A transient fully-coupled fluid-solid interaction study

2021 ◽  
pp. 1045389X2110116
Author(s):  
Soha Niroumandi ◽  
Mohammad Shojaeifard ◽  
Mostafa Baghani
Keyword(s):  
Fluid Structure Interaction ◽  
Planck Equation ◽  
Transient Behavior ◽  
Ph Sensitive ◽  
External Loading ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Gent Model ◽  
Fully Coupled ◽  
Ph Sensitive Hydrogel

pH-sensitive hydrogels are promising materials to be employed in microfluidic devices, especially microvalves. In this paper, a theory of transient swelling of pH-sensitive micro-valve is presented. A transient constitutive model that captures electrical, chemical, and mechanical fields is considered to model the swelling phenomenon. The diffusion of ions into the hydrogel, the electromigration, and convection are described by implementing the Nernst-Planck equation. Assuming Gent model, hydrogel is considered as a compressible hyperelastic material and osmotic pressure is assumed as an external loading. Due to benefits of in-plane valves, a design of the micro-valve is studied. Design simplicity and great sealing are vital factors which can be considered as an advantage of this valve for fabrication. This design and modeling approach has not been used for pH-sensitive hydrogels in earlier works. Thus, we have studied the transient swelling of pH-sensitive hydrogel microvalve, when effects of fluid-structure-interaction are examined on valve performance. It is noted that in most previous studies, equilibrium conditions have been assumed. While considering transient fully-coupled fluid-structure-interaction is necessary to capture a more realistic modeling. The results illustrate that the microvalve blocks the channel much earlier than reaching the equilibrium-state, which implies importance of the transient behavior of hydrogels.

Study on pH-sensitive hydrogel micro-valves: A fluid–structure interaction approach

2016 ◽  
Vol 28 (12) ◽  
pp. 1589-1602 ◽  
Author(s):  
Nasser Arbabi ◽  
Mostafa Baghani ◽  
Jalal Abdolahi ◽  
Hashem Mazaheri ◽  
Mahmoud Mosavi-Mashhadi
Keyword(s):  
Fluid Structure Interaction ◽  
Soft Materials ◽  
Element Model ◽  
Ph Sensitive ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Ph Values ◽  
External Forces ◽  
Interaction Approach ◽  
Ph Sensitive Hydrogel

Hydrogels are categorized as soft materials that undergo large deformation when they are subjected to even minor external forces. In this work, the performance of a variety of micro-valves, based on pH-sensitive hydrogel jackets coated on rigid pillars, is studied considering the gel deformation under fluid flow, employing fluid–structure interaction simulations. In this regard, an analytical solution to plane-strain inhomogeneous swelling of a cylindrical jacket is proposed. This is used as a tool to validate the finite element model. Then, a micro-valve consisting of one hydrogel jacket is studied in various inlet pressure and pH values performing fluid–structure interaction simulations. Thereafter, a variety of jacket patterns are investigated in order to identify the effects of the pattern on the micro-valve performance for various fluid stream pressures and pH values. The leakage pressure of the valves is also computed for each of the patterns. Fluid–structure interaction simulation is found to be essential to accurate design of the hydrogel-based microfluidic devices.

scholarly journals A fully coupled fluid-structure interaction model of the secondary lymphatic valve

2018 ◽  
Vol 21 (16) ◽  
pp. 813-823 ◽  
Author(s):  
John T. Wilson ◽  
Lowell T. Edgar ◽  
Saurabh Prabhakar ◽  
Marc Horner ◽  
Raoul van Loon ◽  
...  
Keyword(s):  
Fluid Structure Interaction ◽  
Interaction Model ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Lymphatic Valve ◽  
Fully Coupled

Scalability study of an implicit solver for coupled fluid-structure interaction problems on unstructured meshes in 3D

2016 ◽  
Vol 32 (2) ◽  
pp. 207-219 ◽  
Author(s):  
Fande Kong ◽  
Xiao-Chuan Cai
Keyword(s):  
Stokes Equations ◽  
Fluid Structure Interaction ◽  
Three Dimensional ◽  
Coupled System ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Krylov Method ◽  
Fine Mesh ◽  
Processor Cores ◽  
Fully Coupled

Fluid-structure interaction (FSI) problems are computationally very challenging. In this paper we consider the monolithic approach for solving the fully coupled FSI problem. Most existing techniques, such as multigrid methods, do not work well for the coupled system since the system consists of elliptic, parabolic and hyperbolic components all together. Other approaches based on direct solvers do not scale to large numbers of processors. In this paper, we introduce a multilevel unstructured mesh Schwarz preconditioned Newton–Krylov method for the implicitly discretized, fully coupled system of partial differential equations consisting of incompressible Navier–Stokes equations for the fluid flows and the linear elasticity equation for the structure. Several meshes are required to make the solution algorithm scalable. This includes a fine mesh to guarantee the solution accuracy, and a few isogeometric coarse meshes to speed up the convergence. Special attention is paid when constructing and partitioning the preconditioning meshes so that the communication cost is minimized when the number of processor cores is large. We show numerically that the proposed algorithm is highly scalable in terms of the number of iterations and the total compute time on a supercomputer with more than 10,000 processor cores for monolithically coupled three-dimensional FSI problems with hundreds of millions of unknowns.

An Overview of IAEA Technical Guidelines on Fluid-Structure Interaction

2014 ◽  
Author(s):  
M. Kim ◽  
P. Hughes ◽  
R. A. Ainsworth
Keyword(s):  
Fluid Structure Interaction ◽  
Cross Flow ◽  
External Loading ◽  
Flow Induced Vibration ◽  
Energy Agency ◽  
Fluid Structure ◽  
Safety Standards ◽  
Structure Interaction ◽  
Fluid Sloshing ◽  
Reactor Types

This paper provides an overview of International Atomic Energy Agency (IAEA) draft technical guidelines on Fluid-Structure Interaction (FSI), which is supporting document for IAEA Safety Standards aimed at providing method and practices. The technical guidelines are based on sections in codes and standards, more general documents on FSI and documents describing particular plant issues or problems. The technical guidelines recognise that FSI has led to a range of problems in a range of reactor types including: flow-induced vibration in light water reactor (LWR) steam generators under external loading including seismic loading; fretting of LWR heat exchangers with the fretting loading dependent on cross-flow velocity; seismic effects and fluid sloshing in liquid metal cooled faster breeder reactor (LMFBR); and water hammer. In addition to providing an overview description of the technical guidelines, the paper also describes the process followed to produce and obtain peer review of the document.

Parametric Analysis of Eustachian Tube Function Using Fully Coupled Fluid-Structure Interaction Models

2010 ◽  
Author(s):  
Francis J. Sheer ◽  
Samir N. Ghadiali
Keyword(s):  
Eustachian Tube ◽  
Healthy Adult ◽  
Fluid Structure Interaction ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Related Cost ◽  
Tube Function ◽  
Histological Images ◽  
Fully Coupled ◽  
Onset Rate

Otitis Media (OM) is the most commonly diagnosed childhood illness and has health care related cost of four billion dollars annually. [1] The onset of OM has been directly related to Eustachian Tube (ET) dysfunction. The ET has three main physiological functions, and when these functions are compromised, middle ear (ME) disorders arise. It is also known that specific populations of patients, such as those with cranio-facial abnormalities, such as a cleft palate, have a 100% onset rate of OM. Even though ET dysfunction has been related to OM, the underlying reasons for ET dysfunction in certain populations remains unknown. To gain an understanding of this system, we use fully coupled fluid-structure interaction (FSI) models of the ET based on geometries reconstructed from histological images. Using these models in systematic parameter variation studies allows us to identify which parameters of the ET can cause dysfunction. Using healthy adult subjects as a model for a well-functioning ET, we determined ET function to be sensitive to changes in TVP muscle force.

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