Design and Experimental Investigation of a Gas-to-Gas Counter-Flow Micro Heat Exchanger

Yang, Yahui; Gerken, Iris; Brandner, Juergen J.; Morini, Gian Luca

doi:10.1080/08916152.2013.849179

Cited by 19 publications

(27 citation statements)

References 18 publications

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“…The literature references assume isothermal behavior due to strong longitudinal conduction along the solid walls (Bier et al, 1993;Kee et al, 2011;Koyama and Asako, 2010a, b;Meschke et al, 2005). The influence of longitudinal conduction has been previously investigated by Yang et al (Yang et al, 2012b). …”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…To illustrate the influence on the assessment of heat exchangers, results of pressure drop behavior and heat transfer performance presented by Yang et al (Yang et al, 2012b) are summarized in the following. The assessment has been performed in terms of the overall exergy loss with the above mentioned method (see equation 7).…”

Section: Theoretical Backgroundmentioning

confidence: 99%

“…An experimental device developed by Yang et al (Yang et al, 2012b) has been used to investigate the effects of different partition wall materials, partition wall thicknesses and flow arrangements leading to different gas-togas micro heat exchangers. To illustrate the influence on the assessment of heat exchangers, results of pressure drop behavior and heat transfer performance presented by Yang et al (Yang et al, 2012b) are summarized in the following.…”

Section: Theoretical Backgroundmentioning

confidence: 99%

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Heat transfer enhancement with gas-to-gas micro heat exchangers

Gerken

Brandner

Dittmeyer

2016

Applied Thermal Engineering

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A characterization of gas-to-gas micro heat exchangers has been performed in terms of pressure drop behavior and heat transfer performance. The gas-to-gas micro heat exchangers differ by partition wall material, partition wall thickness and flow arrangement. The pressure drop behavior has been analyzed due to the pressure losses in different sections of the gas-to-gas micro heat exchangers. Increased pressure losses in front of and behind the micro channels have been detected due to modified geometries in the inlet and outlet distribution chambers. The heat transfer performance has been determined in terms of thermal effectiveness. The comparison among different partition wall materials and partition wall thicknesses showed no significant criteria of the influence of thermal conductivity on the thermal effectiveness. An assessment due to an overall heat exchanger effectiveness has been performed to compare the gas-to-gas micro heat exchangers. For this purpose, the overall exergy loss has been calculated by combination of thermal effectiveness and pressure losses. A strong impact of the exergy loss due to pressure drop has been detected which influences the overall exergy loss of the gas-to-gas micro heat exchangers.

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Section: Theoretical Backgroundmentioning

confidence: 99%

Section: Theoretical Backgroundmentioning

confidence: 99%

Section: Theoretical Backgroundmentioning

confidence: 99%

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Heat transfer enhancement with gas-to-gas micro heat exchangers

Gerken

Brandner

Dittmeyer

2016

Applied Thermal Engineering

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“…For example, gas microflows are encountered in micro heat exchangers (Yang et al 2014) designed for cooling electronic components or for chemical applications, in fluidic micro-actuators for active flow control (Cattafesta and Sheplak 2011), in micronozzles used for the micropropulsion of nanosats or picosats (Louisos and Hitt 2005), in micro gas chromatographs (μGCs) (Lu et al 2005), in vacuum generators or Knudsen micropumps (Seungdo et al 2014) as well as in some microfluidic-based in vitro devices (μFIVDs) such as artificial lungs (Kovach et al 2015). Similar flows are also observed in porous media with applications relative to the extraction of shale gas (Niu et al 2014).…”

Section: Introductionmentioning

confidence: 99%

Role of diffusion on molecular tagging velocimetry technique for rarefied gas flow analysis

Frezzotti

Mohand

Barrot-Lattes

et al. 2015

Microfluid Nanofluid

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The molecular tagging velocimetry (MTV) is a well-suited technique for velocity field measurement in gas flows. Typically, a line is tagged by a laser beam within the gas flow seeded with light emitting acetone molecules. Positions of the luminescent molecules are then observed at successive times and the velocity field is deduced from the analysis of the tagged line displacement and deformation. However, the displacement evolution is expected to be affected by molecular diffusion, when the gas is rarefied. Therefore, there is no direct and simple relationship between the velocity field and the measured displacement of the initial tagged line. This paper addresses the study of tracer molecules diffusion through a background gas flowing in a channel delimited by planar walls. Tracer and background species are supposed to be governed by a system of coupled Boltzmann equations, numerically solved by the direct simulation Monte Carlo (DSMC) method. Simulations confirm that the diffusion of tracer species becomes significant as the degree of rarefaction of the gas flow increases. It is shown that a simple advection–diffusion equation provides an accurate description of tracer molecules behavior, in spite of the non-equilibrium state of the background gas. A simple reconstruction algorithm based on the advection–diffusion equation has been developed to obtain the velocity profile from the displacement field. This reconstruction algorithm has been numerically tested on DSMC generated data. Results help estimating an upper bound on the flow rarefaction degree, above which MTV measurements might become problematic

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“…Studies have showed that a high level of turbulence intensifies the self-cleaning inside complex microchannels [15]. On the contrary, increasing size to overcome pressure losses results in higher capital and reduces the performance advantages of miniaturization.Yang [16,17] compared the performance of heat exchange devices with different microstructures manufactured on thin foils to enhance heat transfer. He found that "partition foils having low thermal conductivity can enhance the heat transfer by decreasing the axial conduction" and that, at a microscale, cross-flow configuration tends to provide similar results to the counter-current arrangement at a large Reynolds number (>2400).…”

mentioning

confidence: 99%

Numerical and Experimental Study of Microchannel Performance on Flow Maldistribution

Joseph

Rehman

Delanaye³

et al. 2020

Micromachines

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Miniaturized heat exchangers are well known for their superior heat transfer capabilities in comparison to macro-scale devices. While in standard microchannel systems the improved performance is provided by miniaturized distances and very small hydraulic diameters, another approach can also be followed, namely, the generation of local turbulences. Localized turbulence enhances the heat exchanger performance in any channel or tube, but also includes an increased pressure loss. Shifting the critical Reynolds number to a lower value by introducing perturbators controls pressure losses and improves thermal efficiency to a considerable extent. The objective of this paper is to investigate in detail collector performance based on reduced-order modelling and validate the numerical model based on experimental observations of flow maldistribution and pressure losses. Two different types of perturbators, Wire-net and S-shape, were analyzed. For the former, a metallic wire mesh was inserted in the flow passages (hot and cold gas flow) to ensure stiffness and enhance microchannel efficiency. The wire-net perturbators were replaced using an S-shaped perturbator model for a comparative study in the second case mentioned above. An optimum mass flow rate could be found when the thermal efficiency reaches a maximum. Investigation of collectors with different microchannel configurations (s-shaped, wire-net and plane channels) showed that mass flow rate deviation decreases with an increase in microchannel resistance. The recirculation zones in the cylindrical collectors also changed the maldistribution pattern. From experiments, it could be observed that microchannels with S-shaped perturbators shifted the onset of turbulent transition to lower Reynolds number values. Experimental studies on pressure losses showed that the pressure losses obtained from numerical studies were in good agreement with the experiments (<4%).

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Design and Experimental Investigation of a Gas-to-Gas Counter-Flow Micro Heat Exchanger

Cited by 19 publications

References 18 publications

Heat transfer enhancement with gas-to-gas micro heat exchangers

Heat transfer enhancement with gas-to-gas micro heat exchangers

Role of diffusion on molecular tagging velocimetry technique for rarefied gas flow analysis

Numerical and Experimental Study of Microchannel Performance on Flow Maldistribution

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