scholarly journals Peristaltic motion of MHD nanofluid in an asymmetric micro-channel with Joule heating, wall flexibility and different zeta potential

2019 ◽  
Vol 2019 (1) ◽  
Author(s):  
S. Noreen ◽  
S. Waheed ◽  
A. Hussanan
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ramin Zakeri

AbstractOne of the unresolved issues in physiology is how exactly myosin moves in a filament as the smallest responsible organ for contracting of a natural muscle. In this research, inspired by nature, a model is presented consisting of DPD (dissipative particle dynamics) particles driven by electro-osmotic flow (EOF) in micro channel that a thin movable impermeable polymer membrane has been attached across channel width, thus momentum of fluid can directly transfer to myosin stem. At the first, by validation of electro-osmotic flow in micro channel in different conditions with accuracy of less than 10 percentage error compared to analytical results, the DPD results have been developed to displacement of an impermeable polymer membrane in EOF. It has been shown that by the presence of electric field of 250 V/m and Zeta potential − 25 mV and the dimensionless ratio of the channel width to the thickness of the electric double layer or kH = 8, about 15% displacement in 8 s time will be obtained compared to channel width. The influential parameters on the displacement of the polymer membrane from DPD particles in EOF such as changes in electric field, ion concentration, zeta potential effect, polymer material and the amount of membrane elasticity have been investigated which in each cases, the radius of gyration and auto correlation velocity of different polymer membrane cases have been compared together. This simulation method in addition of probably helping understand natural myosin displacement mechanism, can be extended to design the contraction of an artificial muscle tissue close to nature.


Author(s):  
Reza Monazami ◽  
Shahrzad Yazdi ◽  
Mahmoud A. Salehi

In this paper, a three-dimensional numerical model is developed to analyze the influence of the Joule heating on flow characteristics of an electroosmotic flow through square cross section micro-channels. The governing system of equations consists of three sets of equations: electric potential distribution, flow-field and energy equations. The solution procedure involves three steps. The net charge distribution on the cross section of the micro-channel is computed by solving two-dimensional Poisson-Boltzmann equation using the finite element method. Then, using the computed fluid’s charge distribution, the magnitude of the resulting body force due to interaction of an external electric field with the charged fluid elements is calculated along the micro-channel. Finally, three dimensional coupled Navier-Stokes and energy equations are solved by considering the presence of the electro-kinetic body forces and the volumetric heat generation due to Joule heating for three different external electric field strengths. The results reveal that flow patterns are significantly affected by temperature field distribution caused by Joule heating effect especially for high electric field strength cases.


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