Fuzzy Logic Approach for Controlling Temperature in Electroosmotic Flow Fields

2009 ◽  
Author(s):  
Saeid Movahed ◽  
Mohammad Eghtesad ◽  
Reza Kamali
Keyword(s):  
Fuzzy Logic ◽  
Flow Field ◽  
Joule Heating ◽  
Electroosmotic Flow ◽  
Flow Fields ◽  
Heating Effect ◽  
Joule Heating Effect ◽  
Model Based ◽  
Fuzzy Logic Approach ◽  
Flow Field Characteristics

By entering technology to the area of micro and nano scales, the design and fabrication of miniaturized instruments such as microelectronic devices, MEMS, NEMS and ..., become very desirable. Many of these devices deal with flow field in micro- and nano-channels. By decreasing the dimensions of channels, the influence of surface effects becomes prominent and cannot be ignored. One of the most charismatic categories of these phenomena is elecrokinetic effect which can result in electroosmotic flow field (EOF) that has many advantages such as being vibration free, being much more compact, having flat-form velocity and etc. These beneficiaries lead to the increasing stimulus of using this type of flow field. Electroosmosis is defined as the motion of ionized liquid relative to the stationary charged surface by an applied electric field. One of the most important disadvantages of EOF is the Joule heating effect, the generation of heat due to the electroosmosis effect. Besides, micro- and nano-channels are usually used as heat sink in miniaturized devices. By considering these facts, it can be concluded that heat characteristics of EOF must be studied carefully in order to manage and control the Joule heating effect for utilizing the cooling characteristics of micro- and nano-channels. Flow field characteristics can be found by solving Navier-Stocks and Energy equations with proper slip boundary conditions. By considering the partial nature of these equations, many conventional model-based control techniques may not be useful. Therefore, one can suggest some non-model based strategies in order to control the properties of flow fields. In the present study, fuzzy logic controllers will be proposed in order to control the temperature and cooling characteristics of micro- and nano-channel heat sinks.

Analytical Approach for Finding Velocity and Temperature Distribution of Electroosmotic Flow in Micro- and Transitional Nano-Channels

2009 ◽  
Author(s):  
Saeid Movahed ◽  
Reza Kamali ◽  
Mohammad Eghtesad
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Flow Field ◽  
Channel Flow ◽  
Joule Heating ◽  
Electroosmotic Flow ◽  
Heat Transfer Analysis ◽  
Heating Effect ◽  
Joule Heating Effect ◽  
Miniaturized Devices

The past decade has seen tremendous growth in areas of micro- and nano-fluidics, and MEMs flow control. Nowadays, there is considerable interest in micro- and nano/technologies consisting of small structures in contact with liquid media. By increasing the motivations of using miniaturized devices such as MEMS and NEMS and inventing new methods of their manufacturing, the inspirations of their study and analysis have been increased more and more. One of the most important characteristics of these devices which have undeniable impacts on their performances is miniaturized-channel flow field. By decreasing the dimensions of channels, the influence of surface effects becomes prominent and cannot be ignored. One of the most charismatic categories of these phenomena is elecrokinetic effect which can results in electroosmotic flow field (EOF) that has many advantages such as being vibration free, being much more compact, having flat-form velocity and etc. These beneficiaries lead to the increasing stimulus of using this type of flow field. One of the most important disadvantages of EOF is the Joule heating effect, the generation of heat due to the electroosmosis effect. Besides, miniaturized-channels are usually used as heat sink in miniaturized devices. By considering these facts, it can be concluded that heat characteristics of EOF must be studied carefully in order to manage the Joule heating effect and to utilize the cooling characteristics of miniaturized-channels. By reviewing the studies that have been performed in this field of study, it can be concluded that there is not any analytical approaches in dealing with heat transfer of EOF in miniaturized-channels though analytical formulas are completely essential for investigating, monitoring and controlling of any systems. In this regards, having some analytical studies on heat transfer analysis of miniaturized-channel flow field is completely essential. In the present study, by using the Schwartz-Christoffel mapping, an analytical tactic will be proposed in order to find electroosmotic velocity and consequently temperature distribution of EOF in micro- and transitional nano-channels.

Numerical Simulation of Joule Heating Effect on Electroosmotic Flow and Electrokinetic Mass Transport in Microchannels

Volume 3 ◽  
2004 ◽  
Author(s):  
Gongyue Tang ◽  
Chun Yang ◽  
Cheekiong Chai ◽  
Haiqing Gong
Keyword(s):  
Numerical Simulation ◽  
Temperature Field ◽  
Mass Transport ◽  
Joule Heating ◽  
Electroosmotic Flow ◽  
Stokes Equations ◽  
Heating Effect ◽  
Species Transport ◽  
Joule Heating Effect ◽  
Numerical Predictions

This study presents a numerical simulation of Joule heating effect on electroosmotic flow and mass species transport in microchannels, which has direct applications in the capillary electrophoresis based Biochip technology. The proposed model includes the Poisson-Boltzmann equation, the modified Navier-Stokes equations, the conjugate energy equation, and the mass species transport equation. The numerical predictions show that the time development for both the electroosmotic flow field and the Joule heating induced temperature field are less than 1 second. The Joule heating induced temperature field is strongly dependent on channel size, electrolyte concentration, and applied electric field strength. The simulations reveal that the presence of Joule heating can result in significantly different characteristics of the electroosmotic flow and electrokinetic mass transport in microchannels.

Microfluidics Concentration of Sample Solutes Using Joule Heating Effects Under Combined AC and DC Electric Field

2010 ◽  
Author(s):  
Zhengwei Ge ◽  
Chun Yang
Keyword(s):  
Temperature Gradient ◽  
Electric Field ◽  
Joule Heating ◽  
Electroosmotic Flow ◽  
Heating Effect ◽  
Dc Voltage ◽  
Joule Heating Effect ◽  
Heating Effects ◽  
Concentration Enhancement ◽  
Dc Electric Field

Microfluidic concentration is achieved by utilizing Joule heating effect induced temperature gradient focusing (TGF) under a combined AC and DC electric field imposed in a straight microchannel with sudden expansion in cross-section. The introduction of AC electric field component services dual functions: one is to produce Joule heating effects for generating temperature gradient, and the other is to suppress electroosmotic flow with high frequencies. Therefore, the required DC voltage for achieving sample concentration with Joule heating induced TGF technique is remarkably reduced. The lower DC voltage can lead to smaller electroosmotic flow (EOF), thereby reducing the backpressure effect due to the finite reservoir size. It was demonstrated that using the proposed new TGF technique with Joule heating effect under a combined AC and DC field, more than 2500-fold concentration enhancement was obtained within 14 minutes in a PDMS/PDMS microdevice, which is an order of magnitude higher than the literature reported concentration enhancement achieved by microfluidic devices utilizing the Joule heating induced TGF technique.

Finite element analysis of vertical micro-probe considering Joule-heating effect

2017 ◽  
Vol 101 ◽  
pp. 96-105 ◽  
Author(s):  
Hyun-Woo Jung ◽  
Seung-Jae Kim ◽  
Yun-Jae Kim ◽  
Jung-Yup Kim ◽  
Joo-Yul Lee ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Joule Heating ◽  
Heating Effect ◽  
Element Analysis ◽  
Joule Heating Effect

scholarly journals Flow control in microfluidics devices: electro-osmotic Couette flow with joule heating effect

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
C. Ahamed Saleel ◽  
Saad Ayed Alshahrani ◽  
Asif Afzal ◽  
Maughal Ahmed Ali Baig ◽  
Sarfaraz Kamangar ◽  
...  
Keyword(s):  
Flow Control ◽  
Couette Flow ◽  
Joule Heating ◽  
Dynamic Viscosity ◽  
Microfluidic Devices ◽  
Heating Effect ◽  
Content Type ◽  
Osmotic Flow ◽  
Joule Heating Effect ◽  
Electro Osmotic Flow

PurposeJoule heating effect is a pervasive phenomenon in electro-osmotic flow because of the applied electric field and fluid electrical resistivity across the microchannels. Its effect in electro-osmotic flow field is an important mechanism to control the flow inside the microchannels and it includes numerous applications.Design/methodology/approachThis research article details the numerical investigation on alterations in the profile of stream wise velocity of simple Couette-electroosmotic flow and pressure driven electro-osmotic Couette flow by the dynamic viscosity variations happened due to the Joule heating effect throughout the dielectric fluid usually observed in various microfluidic devices.FindingsThe advantages of the Joule heating effect are not only to control the velocity in microchannels but also to act as an active method to enhance the mixing efficiency. The results of numerical investigations reveal that the thermal field due to Joule heating effect causes considerable variation of dynamic viscosity across the microchannel to initiate a shear flow when EDL (Electrical Double Layer) thickness is increased and is being varied across the channel.Originality/valueThis research work suggest how joule heating can be used as en effective mechanism for flow control in microfluidic devices.

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