Numerical Study on Delivery of Micro Particles Hydrodynamically Focused in Micro Channels

2019 ◽  
Author(s):  
Dingpeng Huang ◽  
Hangzhou Wang ◽  
Xiaoping Wang ◽  
Zexia Qiu ◽  
Ziqiang Ren
Keyword(s):  
Numerical Study ◽  
Micro Particles ◽  
Micro Channels

scholarly journals Numerical Study of Lorentz Force Interaction with Micro Structure in Channel Flow

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4286
Author(s):  
Shabbir Ahmad ◽  
Kashif Ali ◽  
Sohail Ahmad ◽  
Jianchao Cai
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Viscous Dissipation ◽  
Numerical Study ◽  
Nonlinear Differential Equations ◽  
Thermal Control ◽  
Shear Stresses ◽  
Fluid Temperature ◽  
X Rays ◽  
Micro Particles

The heat transfer Magnetohydrodynamics flows have been potentially used to enhance the thermal characteristics of several systems such as heat exchangers, electromagnetic casting, adjusting blood flow, X-rays, magnetic drug treatment, cooling of nuclear reactors, and magnetic devices for cell separation. Our concern in this article is to numerically investigate the flow of an incompressible Magnetohydrodynamics micropolar fluid with heat transportation through a channel having porous walls. By employing the suitable dimensionless coordinates, the flow model equations are converted into a nonlinear system of dimensionless ordinary differential equations, which are then numerically treated for different preeminent parameters with the help of quasi-linearization. The system of complex nonlinear differential equations can efficiently be solved using this technique. Impact of the problem parameters for microrotation, temperature, and velocity are interpreted and discussed through tables and graphs. The present numerical results are compared with those presented in previous literature and examined to be in good contact with them. It has been noted that the imposed magnetic field acts as a frictional force which not only increases the shear stresses and heat transfer rates at the channel walls, but also tends to rotate the micro particles in the fluid more rapidly. Furthermore, viscous dissipation may raise fluid temperature to such a level that the possibility of thermal reversal exists, at the geometric boundaries of the domain. It is therefore recommended that external magnetic fields and viscous dissipation effects may be considered with caution in applications where thermal control is required.

NUMERICAL STUDY OF THE EFFECT OF AREA OF MANIFOLD AND INLET/OUTLET FLOW ARRANGEMENT 0N FLOW DISTRIBUTION IN PARALLEL RECTANGULAR MICROCHANNEL COOLING SYSTEM

2017 ◽  
Vol 79 (7-3) ◽  
Author(s):  
Amirah M. Sahar ◽  
A. I. M. Shaiful
Keyword(s):  
Experimental Data ◽  
Pressure Drop ◽  
Cooling System ◽  
Numerical Study ◽  
Flow Distribution ◽  
Fluid Temperature ◽  
Rectangular Microchannel ◽  
Temperature Distributions ◽  
Micro Channels ◽  
Parallel Microchannels

Parallel microchannels have been widely used in cooling of compact electronic equipment due to large contact area with liquid and availability of large mass of fluid to carry away heat. However, understanding of flow distribution for microchannel parallel system is still unclear and there still lack of studies give a clear pictures to understand the complex flow features which cause the flow maldistribution. Generally, the geometrical structure of the manifold and micro channels play an important role in flow distribution between micro channels, which might affects the heat and mass transfer efficiency, even the performance of micro exchangers. A practical design of exchanger basically involves the selection of an optimized solution, keeping an optimal balance between gain in heat transfer and pressure drop penalty. A parallel microchannels configurations consisting inlet and outlet rectangular manifold were simulated to study flow distribution among the channels were investigated numerically by using Ansys Fluent 14.5. The numerical results was validated using existing experimental data and showed a similar trend with values 1% higher than experimental data. The influence of inlet/outlet manifold area and inlet/outlet arrangement on flow distribution in channels were carried out in this study. Based on the predicted flow non-uniformity value, 𝜙, Z- type flow arrangement exhibits higher value of 𝜙, which is 8%, followed by U-type, 2.6% and the I-type, 2.49%. Thus, a better uniformity of velocity and temperature distributions can be achieved in I-shape flow arrangement. The behavior of the flow distributions inside channels is due to the vortices that occurred at manifold. Besides comparing the pressure drop for case 1(D1) and case 2(D2), it is worth to mention that, as the area of inlet and outlet manifold decrease by 50%, the pressure drop is increasing about 5%. However, the inlet/outlet area of manifold on velocity and fluid temperature distributions was insignificant.

Light-Weight, Fast-Cycling, Shape-Memory Actuation Structures

2011 ◽  
Author(s):  
Aaron Stebner ◽  
Joseph Krueger ◽  
Anselm J. Neurohr ◽  
David C. Dunand ◽  
L. Catherine Brinson ◽  
...  
Keyword(s):  
Shape Memory ◽  
Surface Area ◽  
Numerical Study ◽  
Hot Isostatic Pressing ◽  
Milling Process ◽  
Constitutive Law ◽  
Micro Channel ◽  
Micro Channels ◽  
Increase Surface Area ◽  
Time Required

While bulk shape memory alloys (SMAs) have proven a successful means for creating adaptive aerospace structures in many demonstrations, including live flight tests, the time required to cool such actuators has been identified as a property that could inhibit their commercial implementation in some circumstances. To determine best practices for improving cooling times, several approaches to increase the surface area and reduce the mass of existing bulk actuator technologies have been examined. Specifically, geometries created using traditional milling and EDM techniques were compared with micro-channel geometries made possible by a new electrochemical milling process developed at Northwestern. The latter technique involves imbedding steel space-holders in a matrix of NiTi powders, hot isostatic pressing the preform into a dense composite, and then electro-chemically dissolving the steel. Thus, in a two-step process, it is possible to create an actuation structure with numerous micro-channels with excellent control of geometry, shape, size and placement, to reduce weight and increase surface area (and thus decrease response time) without compromising actuator performance. In this paper, the new, lighter-weight, faster cycling shape-memory alloy actuation structures resulting from each technique are reviewed. Their performances are compared and contrasted through the results of a numerical study conducted with a 3D SMA constitutive law developed specifically to handle the complex, non-proportional loadings that arise in porous structures. It is shown that using micro-channel technology, cooling times are significantly reduced relative to traditional machining techniques for the same amount of mass reduction.

scholarly journals Numerical Study of Joule Heating Effects on Microfluidics Device Reliability in Electrode Based Devices

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5819
Author(s):  
Caffiyar Mohammed Yousuff ◽  
Vineet Tirth ◽  
Mohamed Zackria Ansar Babu Irshad ◽  
Kashif Irshad ◽  
Ali Algahtani ◽  
...  
Keyword(s):  
Cross Sections ◽  
Joule Heating ◽  
Electrode Materials ◽  
Separation Efficiency ◽  
Numerical Study ◽  
Microfluidic Devices ◽  
Cell Loss ◽  
Heating Effects ◽  
Device Reliability ◽  
Micro Channels

In electrode-based microfluidic devices, micro channels having narrow cross sections generate undesirable temperature inside the microfluidic device causing strong thermal distribution (joule heating) that eventually leads to device damage or cell loss. In this work, we investigate the effects of joule heating due to different electrode configuration and found that, electrodes with triangular arrangements produce less heating effect even at applied potential of 30 V, without compromising the performance of the device and separation efficiency. However, certain electrode materials have low thermal gradients but erode the channel quickly thereby affecting the reliability of the device. Our simulation also predicts optimal medium conductivity (10 mS/m with 10 V) for cells to survive inside the channel until they are selectively isolated into the collection outlet. Our investigations will aid the researchers in the designing of efficient and reliable microfluidic devices to overcome joule heating inside the microchannels.

scholarly journals The Role Of Airborne Moments In The Spread Of The Coronavirus And The Course Of The Pandemic

2020 ◽  
Author(s):  
Kiran Bhaganagar ◽  
Sudheer BhimiReddy
Keyword(s):  
Large Scale ◽  
Numerical Study ◽  
Dispersion Model ◽  
Forecast Model ◽  
Initial Time ◽  
Small Scale ◽  
Turbulence Energy ◽  
Virus Concentration ◽  
Micro Particles

Abstract A numerical study using Weather Research Forecast model and Lagrangian HYSPLIT dispersion model was conducted to understand the meteorological factors influencing the transport and mixing of the blob of Corona virus-filled micro-particles (of radius 0.12mm) released into the atmosphere due to coughing, sneezing by infected patient. The study is offered as an important contribution demonstrating the role of local atmospheric dynamics in coronavirus spread during the period of March 9 – April 6, 2020 in New York City, the epicenter of the coronavirus in the USA. The results demonstrate that from the initial time of release, the virus can spread up to 30 minutes in air, covering a 200-m radius at a time, moving 1 – 2 km from the original source. Turbulence energy containing large-scale horizontal “rolls” and vertical thermal “updrafts” and “downdrafts” contribute to transport and advection processes, before small-scale turbulent eddies rapidly mix and dilute virus concentration.

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