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.

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.

Behavior of a smart one-way micro-valve considering fluid–structure interaction

2018 ◽  
Vol 29 (20) ◽  
pp. 3960-3971 ◽  
Author(s):  
H Mazaheri ◽  
AH Namdar ◽  
A Amiri
Keyword(s):  
Interaction Effect ◽  
Fluid Structure Interaction ◽  
Pressure Head ◽  
Soft Materials ◽  
Crosslinking Density ◽  
Operational Parameters ◽  
Sensors And Actuators ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Different Temperatures

Smart hydrogels are soft materials which can be applied in sensors and actuators especially in microfluidics in which the fluid–structure interaction is important. In this work, first, the behavior of a one-way hydrogel micro-valve is investigated by considering the fluid–structure interaction effect for a specified geometry of the micro-valve. Second, both the fluid–structure interaction and non-fluid–structure interaction simulations are conducted to study the fluid flow effect on the operational parameters of the micro-valve. The obtained results show that the fluid–structure interaction effects are important and have a considerable influence on the micro-valve parameters especially on its closing temperature. Thereafter, a precise study on the micro-valve is executed by considering the micro-valve operational parameters such as inlet pressure, head size, crosslinking density, and breaking pressure at different temperatures. The results show the importance of considering the fluid–structure interaction effect in the design of these devices.

Dynamics of a Free Heaving and Prescribed Pitching Hydrofoil in a Turbulent Flow, With a Fluid-Structure Interaction Approach

2018 ◽  
Author(s):  
P. Brousseau ◽  
M. Benaouicha ◽  
S. Guillou
Keyword(s):  
Fluid Structure Interaction ◽  
Vertical Displacement ◽  
Rotational Displacement ◽  
Fluid Structure ◽  
Strongly Coupled ◽  
Structure Interaction ◽  
Maximum Angle ◽  
High Maximum ◽  
Oscillating Foil ◽  
Interaction Approach

This paper deals with the dynamics of an oscillating foil, describing a free heaving (vertical displacement) and prescribed pitching (rotational displacement) movement which is computed from its position in two different ways. A fluid-structure interaction approach is chosen, as the physics of the flow and the structure are strongly coupled. The flow is unsteady, turbulent and incompressible. The pressure/velocity problem is solved using SIMPLEC scheme. First, the pitching movement is considered as a given continuous function of the hydrofoil heaving position. Second, the pitching motion is performed alternately at the end of each heave cycle. For each case, two maximum angles of attack and one heaving amplitudes are studied. Preliminary results showed that a high maximum angle of attack generates more lift hydrodynamics force, but also requires more energy to perform the rotation of pitch.

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