A simple and novel way of maintaining constant wall temperature in microdevices

Duryodhan, V. S.; Singh, Abhijeet; Singh, Shiv Govind; Agrawal, Amit

doi:10.1038/srep18230

Cited by 33 publications

(17 citation statements)

References 24 publications

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“…[1][2][3][4] Most of the earlier studies focused on microchannels with nonuniform cross-sections conducting liquid°ows. [5][6][7][8] To review works on gas°ows, one could note work of Varade et al 9 who performed an experimental and numerical study on gaseous°ow at slip regime through divergent microchannels. They showed that the pressure drop, centerline velocity, and wall shear decrease with an increase in divergence angle for their range of study.…”

Section: Introductionmentioning

confidence: 99%

On the thermally-driven gas flow through divergent micro/nanochannels

Mozaffari

Roohi

2017

Int. J. Mod. Phys. C

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A detailed study on thermally driven flows through divergent micro/nanochannels is presented. Rarefied gas flow behavior and thermal mass flow rate were investigated with different divergence angles ranging between 0[Formula: see text] and 7[Formula: see text] at two aspect ratios ([Formula: see text]) using particle-based direct simulation Monte-Carlo (DSMC) method. We compare our DSMC solutions for normalized thermal mass flow rate with the numerical solution of the Boltzmann–Krook–Walender (BKW) model and Bhatnagar–Gross–Krook (BGK) model and asymptotic theory over a wide range of Knudsen number in the transition regime. The flow field properties including Mach number, pressure, overall temperature and magnitude of shear stress are examined in detail. Based on our analysis, we observed an approximately constant velocity and pressure distribution at a microchannel with a small opening angle. Our results also demonstrate that the heat lines from weakly nonlinear form of Sone constitutive law and DSMC show good agreement at low Knudsen numbers. Moreover, we show that the effect of divergence angle is influential in increasing normalized thermal mass flow rate at early transition regime.

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Section: Introductionmentioning

confidence: 99%

On the thermally-driven gas flow through divergent micro/nanochannels

Mozaffari

Roohi

2017

Int. J. Mod. Phys. C

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“…Finally, the increase in supplied heat flux does not alter the heat distribution This is because, the value of M < 0.01, although the temperature gradients increase continuously. Detailed study of effect of wall conduction and area variation on temperature gradient in diverging microchannel is presented in Duryodhan et al (2016).…”

Section: Discussionmentioning

confidence: 99%

“…This indicates that the wall conduction is larger in diverging microchannel having smaller angle. This is because the surface temperature gradient is larger in smaller angle diverging microchannel compared to that in larger angle microchannel as studied separately in Duryodhan et al (2016).…”

Section: Effect Of Microchannel Anglementioning

confidence: 94%

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Three-Dimensional Numerical Study of Conjugate Heat Transfer in Diverging Microchannel

Duryodhan

Singh²,

Singh³

et al. 2016

Proceedings of the Indian National Science Academy

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Increase in applications of varying cross sectional area microchannels in microdevices has provided the need to understand fluid flow and heat transfer through such flow passages. This study focuses on conjugate heat transfer study through a diverging microchannel. Three-dimensional numerical simulations are performed using commercially available package. Diverging microchannels with different geometrical configurations (i.e. varying angle: 1-8°, depth: 86-200 µm, solid-tofluid thickness ratio: 1.5-4) are employed for this purpose. Simulations are carried out for varying mass flow rate (3.3 x 10 -5 -8.3 x 10 -5 kg/s) and heat flux (2.4-9.6 W/cm 2 ) conditions. Heat distribution along the flow direction is studied to understand the effect of wall conduction. Wall conduction number (M) varies from 0.006 to 0.024 for the range of parameters selected in the study. Wall conduction is observed to be a direct function of depth and solid-to-fluid thickness ratio, and varies inversely with angle of diverging microchannel. It is observed that the area variation and wall conduction contribute separately towards redistribution of the supplied heat flux. This leads to reduced temperature gradients in diverging microchannel. The results presented in this work will be useful for designing future microdevices involving heating or cooling.

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“…The small dimensions and the low flow velocity induce unsteady laminar regimes [3]. The oscillations induced by the flow patterns affects the force and thermal response of such devices that have to be taken into account in the design process [4,5]. Indeed the prediction of the performance of these devices is still the subject of study.…”

Section: Introductionmentioning

confidence: 99%

Buoyancy Effect on the Flow Pattern and the Thermal Performance of an Array of Circular Cylinders

Fornarelli

Lippolis

Oresta

2016

Journal of Heat Transfer

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In this paper we found, by means of numerical simulations, a transition in the oscillatory character of the flow field for a particular combination of buoyancy and spacing in an array of six circular cylinders at a Reynolds number of 100 and Prandtl number of 0.7. The cylinders are iso-thermal and they are aligned with the Earth acceleration (g). According to the array orientation, an aiding or an opposing buoyancy is considered. The effect of natural convection with respect to the forced convection is modulated with the Richardson number, Ri, ranging between −1 and 1. Two values of center to center spacing (s = 3.6d − 4d) are considered. The effects of buoyancy and spacing on the flow pattern in the near and far field are described. Several transitions in the flow patterns are found and a parametric analysis of the dependence of the force coefficients and Nusselt number with respect to the Richardson number is reported. For Ri = −1, the change of spacing ratio from 3.6 to 4 induces a transition in the standard deviation of the force coefficients and heat flux. In fact the transition occurs due to rearrangement of the near field flow in a more ordered wake pattern. Therefore, attention is focused on the influence of geometrical and buoyancy parameters on the heat and momentum exchange and their fluctuations. The available heat exchange models * for cylinders array provide a not accurate prediction of the Nusselt number in the cases here studied.

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A simple and novel way of maintaining constant wall temperature in microdevices

Cited by 33 publications

References 24 publications

On the thermally-driven gas flow through divergent micro/nanochannels

On the thermally-driven gas flow through divergent micro/nanochannels

Three-Dimensional Numerical Study of Conjugate Heat Transfer in Diverging Microchannel

Buoyancy Effect on the Flow Pattern and the Thermal Performance of an Array of Circular Cylinders

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