ASME 2018 16th International Conference on Nanochannels, Microchannels, and Minichannels最新文献

{"title":"Milliliter Scale Acoustophoresis Based Bioparticle Processing Platform","authors":"M. A. Faridi, Adnan Faqui Shahzad, A. Russom, M. Wiklund","doi":"10.1115/ICNMM2018-7634","DOIUrl":"https://doi.org/10.1115/ICNMM2018-7634","url":null,"abstract":"Bioparticles such as mammalian cells and bacteria can be manipulated directly or indirectly for multiple applications such as sample preparation for diagnostic applications mainly up-concentration, enrichment & separation as well as immunoassay development. There are various active and passive microfluidic particle manipulation techniques where Acoustophoresis is a powerful technique showing high cell viability. The use of disposable glass capillaries for acoustophoresis, instead of cleanroom fabricated glass-silicon chip can potentially bring down the cost factor substantially, aiding the realization of this technique for real-world diagnostic devices. Unlike available chips and capillary-based microfluidic devices, we report milliliter-scale platform able to accommodate 1ml of a sample for acoustophoresis based processing on a market available glass capillary. Although it is presented as a generic platform but as a demonstration we have shown that polystyrene suspending medium sample can be processed with trapping efficiency of 87% and the up-concentration factor of 10 times in a flow through manner i.e., at 35μl/min. For stationary volume accommodation, this platform practically offers 50 times more sample handling capacity than most of the microfluidic setups. Furthermore, we have also shown that with diluted blood (0.6%) in a flow-through manner, 82% of the white blood cells (WBCs) per ml could be kept trapped. This milliliter platform could potentially be utilized for assisting in sample preparation, plasma separation as well as a flow-through immunoassay assay development for clinical diagnostic applications.","PeriodicalId":137208,"journal":{"name":"ASME 2018 16th International Conference on Nanochannels, Microchannels, and Minichannels","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129797207","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Investigation of Heat Transfer in the Wake of a Single Highly Confined Bubble in a Horizontal Minichannel","authors":"John R. Willard, D. K. Hollingsworth","doi":"10.1115/ICNMM2018-7693","DOIUrl":"https://doi.org/10.1115/ICNMM2018-7693","url":null,"abstract":"Confined bubbly flows in millimeter-scale channels produce significant heat transfer enhancement when compared to single-phase flows. Experimental studies support the hypothesis that the enhancement is driven by a convective phenomenon in the liquid phase as opposed to sourcing from microlayer evaporation or active nucleation. A numerical investigation of flow structure and heat transfer produced by a single bubble moving through a millimeter-scale channel was performed in order to document the details of this convective mechanism. The simulation includes thermal boundary conditions emulating those of the experiments, and phase change was omitted in order to focus only on the convective mechanism. The channel is horizontal with a uniform-heat-generation upper wall and an adiabatic lower surface. A Lagrangian framework was adopted such that the computational domain surrounds the bubble and moves at the nominal bubble speed. The liquid around the bubble moves as a low-Reynolds-number unsteady laminar flow. The volume-of-fluid method was used to track the liquid/gas interface.\u0000 This paper reviews the central results of this simulation regarding wake heat transfer. It then compares the findings regarding Nusselt number enhancement to a reduced-order model on a two-dimensional domain in the wake of the bubble. The model solves the advective-diffusion equation assuming a velocity field consistent with fully developed channel flow in the absence of the bubble. The response of the uniform-heat-generation upper wall is included. The model assumes a temperature profile directly behind the bubble which represents a well-mixed region produced by the passage of the bubble.\u0000 The significant wake heat transfer enhancement and its decay with distance from the bubble documented by the simulation were captured by the reduced-order model. However, the channel surface temperature recovered in a much shorter distance in the simulation compared to the reduced-order model. This difference is attributed to the omission of transverse conduction within the heated surface in the two-dimensional model. Beyond approximately one bubble diameter into the bubble wake, the complex flow structures are replaced by the momentum field of the precursor channel flow. However, the properties and thickness of the heated upper channel wall govern the heat transfer for many bubble diameters behind the bubble.","PeriodicalId":137208,"journal":{"name":"ASME 2018 16th International Conference on Nanochannels, Microchannels, and Minichannels","volume":"52 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130554569","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Heat Transfer Model for Liquid-Liquid Taylor Flow in Mini-Scale Coiled Tubing","authors":"W. Adrugi, Y. Muzychka, K. Pope","doi":"10.1115/ICNMM2018-7743","DOIUrl":"https://doi.org/10.1115/ICNMM2018-7743","url":null,"abstract":"In this paper, an experimental study on heat transfer enhancement using non-boiling liquid-liquid Taylor flow in mini scale coiled tubing for constant wall temperature conditions is conducted. Coiled copper tubing with different radii of curvature and lengths were used as test sections. Segmented slug flow with water and three low viscosity silicone oils (1 cSt, 3 cSt, 5 cSt) were used to examine the effect of Prandtl number on heat transfer rates in coiled tubing. Additionally, benchmark tests were conducted of single-phase flow in a straight tube. The experimental results are compared with models for liquid-liquid Taylor flow in straight and coiled tubing. This research provides new insights on the enhanced heat transfer rates attainable with using liquid-liquid Taylor flow in mini scale coiled tubing. This enhancement occurs due to internal circulation and secondary flow in the fluid segments.","PeriodicalId":137208,"journal":{"name":"ASME 2018 16th International Conference on Nanochannels, Microchannels, and Minichannels","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121197897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Investigation of Transition of Flow Condensation in Microchannel","authors":"I. Park, J. Son","doi":"10.1115/ICNMM2018-7644","DOIUrl":"https://doi.org/10.1115/ICNMM2018-7644","url":null,"abstract":"Due to the miniaturization of electronic devices and advanced machines, the micro-channel phase change heat transfer is used for heat removal on limited surfaces. However, since the complexity of the phase change phenomenon, it is difficult to numerically analyze the phase change phenomenon inside the microchannel. In this study, the flow condensation problem of FC-72 fluid in a microchannel is numerically analyzed with the phase change model. SST k-omega turbulence model is used and Volume of Fluid method is used for tracking the gas-liquid interface inside micro-channels. The condensation phenomenon is analyzed by applying the phase change model based on the difference of the phase interface and saturated temperature. The transition of two-phase flow pattern, cross-sectional velocity profiles in a micro-channel are studied according to the inlet mass flux and the heat flux at the channel wall surface. The heat transfer coefficient was compared with the experimental results and it is confirmed that the heat transfer coefficient at the wall increase when the inlet mass flux increase. Also, the channel wall side surface temperature profiles, changes of isotherms, and velocity vector field inside channel due to liquid-phase creation are presented.","PeriodicalId":137208,"journal":{"name":"ASME 2018 16th International Conference on Nanochannels, Microchannels, and Minichannels","volume":"1 ","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114094164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Measurements for Condensation of Steam-Ethanol Mixtures in Microchannels","authors":"Lei Chai, N. Hua, R. Xu, J. Liu, G. Yu, J. Rose, Hua Sheng Wang","doi":"10.1115/ICNMM2018-7724","DOIUrl":"https://doi.org/10.1115/ICNMM2018-7724","url":null,"abstract":"The paper reports heat-transfer measurements for condensation of pure steam and steam-ethanol mixtures in parallel horizontal microchannels in an aluminum test section cooled from above and below by water in counter-current flow. The local heat flux and channel surface temperature were determined from temperatures measured by 100 thermocouples accurately located in small holes above and below the microchannels and spaced at 10 locations in the flow direction. Tests were conducted for a range of vapor mass fluxes and cooling intensities. The streamwise distributions of channel heat flux, channel surface temperature and vapor quality were obtained by curve-fitting the test block temperatures. Heat-transfer coefficients were obtained for the cases where complete condensation did not occur in the channels by assuming linear pressure distribution between accurately measured pressures at inlet and exit and assuming saturation conditions in the two-phase flow region of the channels.","PeriodicalId":137208,"journal":{"name":"ASME 2018 16th International Conference on Nanochannels, Microchannels, and Minichannels","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114845742","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Periodic Flow Structure on Heat Transfer in Milliscale Confined Impinging Newtonian and Non-Newtonian Flow","authors":"A. Chatterjee, D. Fabris","doi":"10.1115/ICNMM2018-7636","DOIUrl":"https://doi.org/10.1115/ICNMM2018-7636","url":null,"abstract":"Impinging flows are widely used to enhance convective heat transfer by promoting separation, recirculation and higher rates of local convection. We consider unsteady flow and heat transfer effects in a prototypical T-shaped geometry as an impinging jet. Depending on the relative length scales, the steady laminar flow in this geometry may lose stability and transition to time periodic flow even at a low Reynolds number. A key feature of the periodic structure is the presence of ‘twin’ circulation regions adjacent to the jet column, and separation vortices anchored at the impinging surface in place of the wall jet in steady flow. The separation vortices are located above shear layers lying along the confining plane of the geometry which is flush with the jet exit. Consequently, convective heat transfer is enhanced across this plane. We present calculations to show the effect of the structure of the periodic flow on heat transfer rates across the two parallel surfaces. For a shear thinning fluid the local Nusselt number at the confining surface averaged over a long length scale (∼ 50 times the nozzle width) is more than twice as large compared to that in steady flow, while for the Newtonian fluid the mean Nusselt number increases about 60%. A mild increase in the transport rate across the impinging surface is also observed. Thus flow periodicity due to instability of the steady flow field provides a mechanism to increase the total heat transfer rate across the two surfaces.","PeriodicalId":137208,"journal":{"name":"ASME 2018 16th International Conference on Nanochannels, Microchannels, and Minichannels","volume":"14 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126341164","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Reduction of Hydraulic Friction in Confined Flows by Laser Texturing: Experiments and Theoretical Validation","authors":"Avinash Kumar, S. Datta, D. Kalyanasundaram","doi":"10.1115/ICNMM2018-7740","DOIUrl":"https://doi.org/10.1115/ICNMM2018-7740","url":null,"abstract":"Hydraulic friction reduction in a microchannel due to superhydrophobic texturing of its walls was studied theoretically and experimentally. A modified Poiseuille equation formulated from an earlier-established semi-analytical approach to model texturing of slip lengths and the “gas cushion model” was used to predict the hydraulic conductance of a microchannel. An experimental setup with a microfluidic flow cell consisting of syringe pump, pressure manometer and tubing measured the pressure drop at different flow rates through a microchannel. The top and bottom walls of the microchannel was textured with micro-pits using nanosecond pulsed laser on the titanium alloy Ti6Al4V. A very high contact angle was observed on the textured surfaces suggesting entrapped gas bubbles. Liquid slippage leading to reduced hydraulic friction is attributable to the bubbles. The pressure-flow rate characteristics of the microchannels confirm friction reduction and also demonstrate a reasonable agreement with the theoretical predictions from the developed fluid dynamic model.","PeriodicalId":137208,"journal":{"name":"ASME 2018 16th International Conference on Nanochannels, Microchannels, and Minichannels","volume":"44 7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132372199","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of the Effect of Non-Uniform Membrane Properties on Performance of Mini/Microchannel Energy Recovery Ventilator Devices","authors":"Paul D. Armatis, B. Fronk","doi":"10.1115/ICNMM2018-7615","DOIUrl":"https://doi.org/10.1115/ICNMM2018-7615","url":null,"abstract":"Membrane based energy recovery ventilators (ERV) can be used to recover sensible and latent energy from exhaust-to-supply air in building applications. These typically consist of parallel layers of membrane separating the air streams, across which heat and moisture are exchanged. Reducing equipment cost and size remain a key challenge for continued commercialization and adoption of these devices. As membrane effectiveness improves, the air-side heat resistance can begin to dominate transport. To mitigate this, minichannel flow passages (DH < 2 mm) can be used to reduce convective heat and mass transfer. Channels can be formed through direct manipulation of membrane (e.g., pleating, corrugating, etc.), or through the use of spacer or other insert. The use of multiple parallel channels can result in large spatial variations in driving temperature and humidity ratio differences in a single layer membrane, impacting overall transport. Furthermore, the local membrane mass transfer resistance is typically a function of the surface temperature and relative humidity and not a constant value throughout the device. Accurate design models are required to appropriately size ERV equipment and maximize performance for a given equipment volume. Thus, the goal of this study is to use simulation tools to understand how the use of parallel mini- and microchannels and non-uniform membrane properties effect the performance of a membrane ERV in a building application. A two dimensional coupled heat and mass transfer resistance network model is developed. The model is compared against existing data from more detailed CFD analysis, and used to parametrically investigate effects different inlet conditions on device performance.","PeriodicalId":137208,"journal":{"name":"ASME 2018 16th International Conference on Nanochannels, Microchannels, and Minichannels","volume":"39 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132416332","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Loop Thermosyphon With Hydrophobic Spots Evaporator Surface","authors":"Hongbin He, B. Shen, S. Hidaka, Koji Takahashi, Y. Takata","doi":"10.1115/ICNMM2018-7623","DOIUrl":"https://doi.org/10.1115/ICNMM2018-7623","url":null,"abstract":"Heat transfer characteristic of a closed two-phase thermosyphon with enhanced boiling surface is studied and compared with that of a copper mirror surface. Two-phase cooling improves heat transfer coefficient (HTC) a lot compared to single-phase liquid cooling. The evaporator surfaces, coated with a pattern of hydrophobic circle spots (non-electroplating Ni-PTFE, 0.5∼2 mm in diameter and 1.5–3 mm in pitch) on Cu substrates, achieve very high heat transfer coefficient and lower the incipience temperature overshoot using water as the working fluid. Sub-atmospheric boiling on the hydrophobic spot-coated surface shows a much better heat transfer performance. Tests with heat loads (30 W to 260 W) reveals the coated surfaces enhance nucleate boiling performance by increasing the bubbles nucleation sites density. Hydrophobic circle spots coated surface with diameter 1 mm, pitch 1.5 mm achieves the maximal heat transfer enhancement with the minimum boiling thermal resistance as low as 0.03 K/W. The comparison of three evaporator surfaces with same spot parameters but different coating materials is carried out experimentally. Ni-PTFE coated surface with immersion method performs the optimal performance of the thermosyphon.","PeriodicalId":137208,"journal":{"name":"ASME 2018 16th International Conference on Nanochannels, Microchannels, and Minichannels","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133306698","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Flow Regime Detection of Boiling Flow in Microchannels Using Electrical Sensing Elements Validated by Videography","authors":"M. Talebi, K. Cobry, S. Sadir, R. Dittmeyer, P. Woias","doi":"10.1115/ICNMM2018-7729","DOIUrl":"https://doi.org/10.1115/ICNMM2018-7729","url":null,"abstract":"In this work we present a method that provides the possibility to analyze directly the electrical properties of two-phase flow in microchannel boiling systems. It is shown that the use of impedimetric sensing techniques can be used to track two-phase boiling flow. In order to perform such measurements, the electrical impedance of the composite medium in the channel is measured using planar capacitive elements that are implemented over the channel on a glass lid. Working electrodes are fabricated using indium tin oxide on glass and are compressed against a precision machined metal microchannel. Therefore, it is possible to visually analyze two-phase flow inside the microchannel while simultaneously performing electrical impedance measurements. In order to prevent electrochemical reactions between the fluid inside the microchannel and electrodes on the glass lid, a thin layer of SU8 photoresist was deposited as a protective layer. The electrical impedance measurements were characterized over two-phase flow regimes including bubbly flow, slug flow and annular flow via comparison with simultaneous video recordings.","PeriodicalId":137208,"journal":{"name":"ASME 2018 16th International Conference on Nanochannels, Microchannels, and Minichannels","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115195312","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}