The carbon nanotube yarns (CNTYs) are directly spun from an aerogel form in a chemical vapor deposition reactor. The as-spun CNTYs are subjected to different post-processes, such as nitric acid treatment, twisting, and doping with iodine. The defect concentrations are detected by Raman spectroscopy, and the effective thermal conductivity is measured by a T-type probe. The results show that, the lattice thermal conductance per unit length decreases smoothly with increasing defects induced by acid treatment and iodine-doping. The twisted yarn introduces moderate defect, but an abnormal decrease in the lattice thermal conductance per unit length is observed as the twist angle increases to ~70°, indicating the phonon-soften phenomenon when CNT is subjected to the torsion stress. The effective thermal conductivity is found to increase linearly as porosity decreases, however, it is still an open question if the linear relationship holds true for highly densified CNTYs.
{"title":"Characterization of Thermal Transport in Carbon Nanotube Yarns","authors":"Jianli Wang, Si-Ru He, Jia-Wei Bao, Xing Zhang, Juekuan Yang, Yunfei Chen","doi":"10.1260/1759-3093.5.2.59","DOIUrl":"https://doi.org/10.1260/1759-3093.5.2.59","url":null,"abstract":"The carbon nanotube yarns (CNTYs) are directly spun from an aerogel form in a chemical vapor deposition reactor. The as-spun CNTYs are subjected to different post-processes, such as nitric acid treatment, twisting, and doping with iodine. The defect concentrations are detected by Raman spectroscopy, and the effective thermal conductivity is measured by a T-type probe. The results show that, the lattice thermal conductance per unit length decreases smoothly with increasing defects induced by acid treatment and iodine-doping. The twisted yarn introduces moderate defect, but an abnormal decrease in the lattice thermal conductance per unit length is observed as the twist angle increases to ~70°, indicating the phonon-soften phenomenon when CNT is subjected to the torsion stress. The effective thermal conductivity is found to increase linearly as porosity decreases, however, it is still an open question if the linear relationship holds true for highly densified CNTYs.","PeriodicalId":89942,"journal":{"name":"International journal of micro-nano scale transport","volume":"5 1","pages":"59-68"},"PeriodicalIF":0.0,"publicationDate":"2014-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66151950","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}
Pub Date : 2014-12-04DOI: 10.1260/1759-3093.5.2.51
N. D. Patil, R. Bhardwaj
We investigated evaporation of sessile water microdroplets on heated hydrophobic glass substrate. An in-house, experimentally validated finite-element numerical model was employed to simulate internal fluid flow and heat transfer during the evaporation. We also validated the non-uniform evaporative flux for water droplets having different initial wetting angles with theoretical results from literature. During evaporation, the fluid flow is radially outward due to the largest evaporative flux near the wetting line. The isotherms are almost horizontal which indicates that the conduction between the droplet and substrate dominates over internal convection during the evaporation. The evolution of wetted radius and wetting angle indicates a two-stage evaporation process:during the first stage of the evaporation, wetted radius remains constant and wetting angle decreases with time; while in the second stage, wetting angle remains constant and wetted radius decreases with time. The droplet volume shows a linear ...
{"title":"Evaporation of a Sessile Microdroplet on a Heated Hydrophobic Substrate","authors":"N. D. Patil, R. Bhardwaj","doi":"10.1260/1759-3093.5.2.51","DOIUrl":"https://doi.org/10.1260/1759-3093.5.2.51","url":null,"abstract":"We investigated evaporation of sessile water microdroplets on heated hydrophobic glass substrate. An in-house, experimentally validated finite-element numerical model was employed to simulate internal fluid flow and heat transfer during the evaporation. We also validated the non-uniform evaporative flux for water droplets having different initial wetting angles with theoretical results from literature. During evaporation, the fluid flow is radially outward due to the largest evaporative flux near the wetting line. The isotherms are almost horizontal which indicates that the conduction between the droplet and substrate dominates over internal convection during the evaporation. The evolution of wetted radius and wetting angle indicates a two-stage evaporation process:during the first stage of the evaporation, wetted radius remains constant and wetting angle decreases with time; while in the second stage, wetting angle remains constant and wetted radius decreases with time. The droplet volume shows a linear ...","PeriodicalId":89942,"journal":{"name":"International journal of micro-nano scale transport","volume":"166 1","pages":"51-58"},"PeriodicalIF":0.0,"publicationDate":"2014-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66151710","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}
Pub Date : 2014-12-04DOI: 10.1260/1759-3093.5.2.69
Anup K. Paul, N. K. Bandaru, A. Narasimhan, Sarit K. Das
Targeting nanoparticles to the tumor site is a salient feature for the tumor ablation during plasmonic photo-thermal therapy. Many of the safety considerations in surgical intervention suggest the alternative route of laser irradiation for photo-thermal destruction of tissues in presence of gold nanorods. The degree of tissue damage depends on laser irradiation parameters such as power, and image size as well as absorption and scattering properties of tissues. This paper analyzes, using finite element modeling, photo-thermal heating of tumor in the presence of intravenous blood injection or intratumorally injected gold nanorods. The Pennes bio-heat transfer equation was solved to compute temperature evolution. A volumetric heat generation based on Beer-Lambert law was used to model the laser heating. The predicted temperatures at the tumor surface were compared with available experimental results and are found to be good. To determine the efficacy of intratumoral injection of nanoparticles, a comparative ...
{"title":"Subsurface Tumor Ablation with Near-infrared Radiation using Intratumoral and Intravenous Injection of Nanoparticles","authors":"Anup K. Paul, N. K. Bandaru, A. Narasimhan, Sarit K. Das","doi":"10.1260/1759-3093.5.2.69","DOIUrl":"https://doi.org/10.1260/1759-3093.5.2.69","url":null,"abstract":"Targeting nanoparticles to the tumor site is a salient feature for the tumor ablation during plasmonic photo-thermal therapy. Many of the safety considerations in surgical intervention suggest the alternative route of laser irradiation for photo-thermal destruction of tissues in presence of gold nanorods. The degree of tissue damage depends on laser irradiation parameters such as power, and image size as well as absorption and scattering properties of tissues. This paper analyzes, using finite element modeling, photo-thermal heating of tumor in the presence of intravenous blood injection or intratumorally injected gold nanorods. The Pennes bio-heat transfer equation was solved to compute temperature evolution. A volumetric heat generation based on Beer-Lambert law was used to model the laser heating. The predicted temperatures at the tumor surface were compared with available experimental results and are found to be good. To determine the efficacy of intratumoral injection of nanoparticles, a comparative ...","PeriodicalId":89942,"journal":{"name":"International journal of micro-nano scale transport","volume":"694 1","pages":"69-80"},"PeriodicalIF":0.0,"publicationDate":"2014-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1260/1759-3093.5.2.69","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66151961","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}
Pub Date : 2014-12-04DOI: 10.1260/1759-3093.5.2.81
R. Sayer, S. Hodson, T. Koehler, R. Cordova, Timothy C. Marinone, J. Serrano, T. Fisher
Removal of waste heat generated via Joule heating during the operation of electronic devices is critical to overall system performance and reliability. A significant fraction of the overall thermal budget is consumed by heat transfer across the interface of contacting materials. To enhance the flow of heat from source to sink, thermal interface materials (TIMs) are used to reduce thermal contact resistance (TCR) by increasing real contact area at the interface. In space systems, TIMs are exposed to high doses of gamma radiation not encountered in typical terrestrial applications. With typical design lifetimes of 5 years or more, total radiation exposure can be significant and can affect the structure and performance of the TIM. Here, we report measurements of the pressure-dependent TCR of metallic foils and carbon nanotube TIMs (CNT-TIMs) in both vacuum and ambient air environments. The TIMs were irradiated in a gamma cell at a rate of 200 rad/s to a total dose of 50 Mrad. TCR was measured before and afte...
{"title":"Characterization of Gamma-irradiated Carbon Nanotube and Metallic Foil Thermal Interface Materials for Space Systems","authors":"R. Sayer, S. Hodson, T. Koehler, R. Cordova, Timothy C. Marinone, J. Serrano, T. Fisher","doi":"10.1260/1759-3093.5.2.81","DOIUrl":"https://doi.org/10.1260/1759-3093.5.2.81","url":null,"abstract":"Removal of waste heat generated via Joule heating during the operation of electronic devices is critical to overall system performance and reliability. A significant fraction of the overall thermal budget is consumed by heat transfer across the interface of contacting materials. To enhance the flow of heat from source to sink, thermal interface materials (TIMs) are used to reduce thermal contact resistance (TCR) by increasing real contact area at the interface. In space systems, TIMs are exposed to high doses of gamma radiation not encountered in typical terrestrial applications. With typical design lifetimes of 5 years or more, total radiation exposure can be significant and can affect the structure and performance of the TIM. Here, we report measurements of the pressure-dependent TCR of metallic foils and carbon nanotube TIMs (CNT-TIMs) in both vacuum and ambient air environments. The TIMs were irradiated in a gamma cell at a rate of 200 rad/s to a total dose of 50 Mrad. TCR was measured before and afte...","PeriodicalId":89942,"journal":{"name":"International journal of micro-nano scale transport","volume":"5 1","pages":"81-94"},"PeriodicalIF":0.0,"publicationDate":"2014-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1260/1759-3093.5.2.81","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66151970","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}
Experimental and numerical analysis were performed to evaluate heat transfer characteristics of water through five sets of rectangular microchannels. Microchannels of hydraulic diameter of 222 μm, 267 μm, 323 μm, 330 μm and 343 μm respectively for Re number between 2.1 to 48 were analysed. Numerical analysis and experiments were conducted under a input heat of 10 W to 100 W, inlet fluid temperature 29°C and mass flow rates of 0.0167 kg/sec to 0.116 kg/sec. Nusselt number tends to be linear increasing as Reynolds number increases. Besides high temperature gradient exist in the region between inlet and exit of flow microchannel. For hydraulic diameter 222 μm, heat transfer coefficient seems to be higher as compare to other configurations of hydraulic diameters. Numerical results showed reasonably good agreement within 4-5% with experimental results.
{"title":"Experimental and Numerical Investigation of Forced Convection Heat Transfer in Rectangular Microchannels","authors":"D. Kamble, B. Gawali","doi":"10.1260/1759-3093.5.1.1","DOIUrl":"https://doi.org/10.1260/1759-3093.5.1.1","url":null,"abstract":"Experimental and numerical analysis were performed to evaluate heat transfer characteristics of water through five sets of rectangular microchannels. Microchannels of hydraulic diameter of 222 μm, 267 μm, 323 μm, 330 μm and 343 μm respectively for Re number between 2.1 to 48 were analysed. Numerical analysis and experiments were conducted under a input heat of 10 W to 100 W, inlet fluid temperature 29°C and mass flow rates of 0.0167 kg/sec to 0.116 kg/sec. Nusselt number tends to be linear increasing as Reynolds number increases. Besides high temperature gradient exist in the region between inlet and exit of flow microchannel. For hydraulic diameter 222 μm, heat transfer coefficient seems to be higher as compare to other configurations of hydraulic diameters. Numerical results showed reasonably good agreement within 4-5% with experimental results.","PeriodicalId":89942,"journal":{"name":"International journal of micro-nano scale transport","volume":"5 1","pages":"1-12"},"PeriodicalIF":0.0,"publicationDate":"2014-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1260/1759-3093.5.1.1","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66151623","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}
Pub Date : 2014-09-05DOI: 10.1260/1759-3093.5.1.13
A. Bandopadhyay, U. Ghosh, D. Pal, K. Chaudhury, S. Chakraborty
The pumping of an aqueous electrolyte by means of an asymmetrically placed thermal resistor and electrodes is investigated in this work. This device has no moving parts and provides a continuous and controllable pulsating flow, which make it a very attractive and viable option for use on lab-on-a-chip devices. The electric field induced modulation provides a higher degree of control on the mass flow rate, by means of which one can achieve on-the-fly mass flow rate control. The pumping action is achieved by means of a high-pressure bubble generated by actuating a thermal resistor which is located asymmetrically between two reservoirs. The ends of the channel are connected to fluidic columns. The combined action of an applied electric field and a faster refilling of the shorter arm after bubble collapse essentially drive a net amount of electrolyte through the system. We study the influence of the geometric parameters like the location of the heater, channel width and the channel length apart from the physiochemical parameters like the Debye length and the applied field strength on the mass flow rate achieved through this device.
{"title":"Electrokinetic Maneuvering of Bubble-Driven Inertial Micro-Pumping Systems","authors":"A. Bandopadhyay, U. Ghosh, D. Pal, K. Chaudhury, S. Chakraborty","doi":"10.1260/1759-3093.5.1.13","DOIUrl":"https://doi.org/10.1260/1759-3093.5.1.13","url":null,"abstract":"The pumping of an aqueous electrolyte by means of an asymmetrically placed thermal resistor and electrodes is investigated in this work. This device has no moving parts and provides a continuous and controllable pulsating flow, which make it a very attractive and viable option for use on lab-on-a-chip devices. The electric field induced modulation provides a higher degree of control on the mass flow rate, by means of which one can achieve on-the-fly mass flow rate control. The pumping action is achieved by means of a high-pressure bubble generated by actuating a thermal resistor which is located asymmetrically between two reservoirs. The ends of the channel are connected to fluidic columns. The combined action of an applied electric field and a faster refilling of the shorter arm after bubble collapse essentially drive a net amount of electrolyte through the system. We study the influence of the geometric parameters like the location of the heater, channel width and the channel length apart from the physiochemical parameters like the Debye length and the applied field strength on the mass flow rate achieved through this device.","PeriodicalId":89942,"journal":{"name":"International journal of micro-nano scale transport","volume":"5 1","pages":"13-22"},"PeriodicalIF":0.0,"publicationDate":"2014-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66151657","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}
Pub Date : 2014-09-05DOI: 10.1260/1759-3093.5.1.23
Prakash Goswami, S. Chakraborty
In the present study we obtain the mass flow rate characteristics in a cylindrical capillary due to a time-periodic electric field at high zeta potential, extending the conventional thin electrical double layer limit. The capillary cross section is divided into two regimes, the high potential regime (near surface region), and the low potential regime (capillary central line region). To obtain the potential distribution inside the capillary, the nonlinear part of the Poisson-Boltzmann equation is approximated by a linear function for the low potential regime and by an exponential function for high potential regime. Using the approximated potential distributions, the governing electro-hydrodynamic equation is then solved semi-analytically, where the imposed electric field and the velocity field is assumed to have the form which consist of a steady state term and a time-periodic term. A theoretical investigation on the mass flow rate, the phase difference is carried out on the basis of pulsation frequency, e...
{"title":"Mass Flow Rate Control in a Cylindrical Capillary by an AC Electric Field at High Zeta Potential","authors":"Prakash Goswami, S. Chakraborty","doi":"10.1260/1759-3093.5.1.23","DOIUrl":"https://doi.org/10.1260/1759-3093.5.1.23","url":null,"abstract":"In the present study we obtain the mass flow rate characteristics in a cylindrical capillary due to a time-periodic electric field at high zeta potential, extending the conventional thin electrical double layer limit. The capillary cross section is divided into two regimes, the high potential regime (near surface region), and the low potential regime (capillary central line region). To obtain the potential distribution inside the capillary, the nonlinear part of the Poisson-Boltzmann equation is approximated by a linear function for the low potential regime and by an exponential function for high potential regime. Using the approximated potential distributions, the governing electro-hydrodynamic equation is then solved semi-analytically, where the imposed electric field and the velocity field is assumed to have the form which consist of a steady state term and a time-periodic term. A theoretical investigation on the mass flow rate, the phase difference is carried out on the basis of pulsation frequency, e...","PeriodicalId":89942,"journal":{"name":"International journal of micro-nano scale transport","volume":"5 1","pages":"23-38"},"PeriodicalIF":0.0,"publicationDate":"2014-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66151665","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}
Pub Date : 2014-09-01DOI: 10.1260/1759-3093.5.3.131
Yahui Yang, C. Hong, G. Morini
This paper focuses on experimental and numerical analysis of convective heat transfer characteristics of pressure-driven gaseous flows through microtubes, which is frequently encountered in practical application of microfluidic devices accommodating gas flow, heat transfer and/or chemical reactions at microscale. The present work has been carried out with the objectives to: (i) verify the applicability of conventional theory for the prediction of internal forced convection heat transfer coefficient for tubes having an inner diameter lower than 1 mm and (ii) check the performance of some specific correlations proposed for the analysis of forced micro convection with gases in the last decades. Single commercial stainless steel microtubes are tested with inner diameters ranging from 1 mm down to 0.17 mm. The most common thermal boundary conditions, namely uniform heat flux (H boundary condition) and uniform wall temperature (T boundary condition), have been implemented by applying Joule heating on external s...
{"title":"Micro Convective Heat Transfer of Gas Flow Subject to H and T Boundary Conditions","authors":"Yahui Yang, C. Hong, G. Morini","doi":"10.1260/1759-3093.5.3.131","DOIUrl":"https://doi.org/10.1260/1759-3093.5.3.131","url":null,"abstract":"This paper focuses on experimental and numerical analysis of convective heat transfer characteristics of pressure-driven gaseous flows through microtubes, which is frequently encountered in practical application of microfluidic devices accommodating gas flow, heat transfer and/or chemical reactions at microscale. The present work has been carried out with the objectives to: (i) verify the applicability of conventional theory for the prediction of internal forced convection heat transfer coefficient for tubes having an inner diameter lower than 1 mm and (ii) check the performance of some specific correlations proposed for the analysis of forced micro convection with gases in the last decades. Single commercial stainless steel microtubes are tested with inner diameters ranging from 1 mm down to 0.17 mm. The most common thermal boundary conditions, namely uniform heat flux (H boundary condition) and uniform wall temperature (T boundary condition), have been implemented by applying Joule heating on external s...","PeriodicalId":89942,"journal":{"name":"International journal of micro-nano scale transport","volume":"5 1","pages":"131-146"},"PeriodicalIF":0.0,"publicationDate":"2014-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66152032","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}
Pub Date : 2014-09-01DOI: 10.1260/1759-3093.5.3.147
S. Roychowdhury, P. Vivekanand, Sarit K. Das, T. Sundararajan
The study of steam reforming of ethanol in micro-channels in a plate-type reformer has been carried out to understand the fluid mechanics, heat transfer and kinetics of ethanol conversion to hydrogen for fuel-cell applications. Heat exchange between alternate channels of combustion flue gas and steam-ethanol mixture has been considered, involving co-flow or counter-flow configurations. Combustion reactions are observed to be completed close to the entry. This results in higher rates of conversion for the co-flow configuration, owing to higher heat transfer rates at the entry. It is shown that end effects are felt only in the outer-most channels and hence a symmetric reformer channel analysis is adequate to predict the performance of a multi-channel reformer system. In the axial direction, the flow, temperature and concentration fields attain fully developed profile form at a short distance from the inlet. At larger axial distances, the velocity profile undergoes mild variations due to changes in the gas d...
{"title":"Optimization of Ethanol Reforming with micro-channels in Plate type reformer configuration","authors":"S. Roychowdhury, P. Vivekanand, Sarit K. Das, T. Sundararajan","doi":"10.1260/1759-3093.5.3.147","DOIUrl":"https://doi.org/10.1260/1759-3093.5.3.147","url":null,"abstract":"The study of steam reforming of ethanol in micro-channels in a plate-type reformer has been carried out to understand the fluid mechanics, heat transfer and kinetics of ethanol conversion to hydrogen for fuel-cell applications. Heat exchange between alternate channels of combustion flue gas and steam-ethanol mixture has been considered, involving co-flow or counter-flow configurations. Combustion reactions are observed to be completed close to the entry. This results in higher rates of conversion for the co-flow configuration, owing to higher heat transfer rates at the entry. It is shown that end effects are felt only in the outer-most channels and hence a symmetric reformer channel analysis is adequate to predict the performance of a multi-channel reformer system. In the axial direction, the flow, temperature and concentration fields attain fully developed profile form at a short distance from the inlet. At larger axial distances, the velocity profile undergoes mild variations due to changes in the gas d...","PeriodicalId":89942,"journal":{"name":"International journal of micro-nano scale transport","volume":"5 1","pages":"147-165"},"PeriodicalIF":0.0,"publicationDate":"2014-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66152039","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}
Pub Date : 2014-09-01DOI: 10.1260/1759-3093.5.3.95
S. N. Ritchey, J. Weibel, S. Garimella
Decreasing form factors and diminishing numbers of thermal interfaces and spreading layers in modern, compact electronic packages result in non-uniform heat generation profiles at the chip level being transmitted directly to the heat sinks. An improved understanding of the effects of non-uniform heating on the heat dissipation limits in microchannel heat sinks has become essential. An experimental investigation is conducted to measure the location and magnitude of critical heat flux (CHF) in a microchannel heat sink exposed to a range of non-uniform heating profiles. A 12.7 mm X 12.7 mm silicon microchannel heat sink with an embedded 5 X 5 array of individually controllable heaters is used in the experiments. The microchannels in the heat sink are 240 mm wide and 370 μm deep, and are separated by 110 mm wide fins. The dielectric fluid HFE-7100 is used as the coolant, with an average mass flux in the heat sink of approximately 800 kg/m2s. High-speed visualizations of the flow are recorded to capture the CH...
在现代紧凑的电子封装中，外形因素的减少、热界面和扩散层的减少导致芯片级的不均匀产热曲线直接传递到散热器。提高对非均匀加热对微通道散热器散热限制的影响的理解已经变得至关重要。实验研究了暴露在一系列非均匀加热剖面下的微通道散热器的临界热流密度(CHF)的位置和大小。实验中使用了一个12.7 mm X 12.7 mm的硅微通道散热器，其中嵌入了5 X 5独立可控加热器阵列。散热片中的微通道宽240mm，深370 μm，由110mm宽的鳍片隔开。采用介电流体HFE-7100作为冷却剂，散热器的平均质量通量约为800 kg/m2s。流的高速可视化被记录下来，以捕捉CH…
{"title":"Effects of Non-Uniform Heating on the Location and Magnitude of Critical Heat Flux in a Microchannel Heat Sink","authors":"S. N. Ritchey, J. Weibel, S. Garimella","doi":"10.1260/1759-3093.5.3.95","DOIUrl":"https://doi.org/10.1260/1759-3093.5.3.95","url":null,"abstract":"Decreasing form factors and diminishing numbers of thermal interfaces and spreading layers in modern, compact electronic packages result in non-uniform heat generation profiles at the chip level being transmitted directly to the heat sinks. An improved understanding of the effects of non-uniform heating on the heat dissipation limits in microchannel heat sinks has become essential. An experimental investigation is conducted to measure the location and magnitude of critical heat flux (CHF) in a microchannel heat sink exposed to a range of non-uniform heating profiles. A 12.7 mm X 12.7 mm silicon microchannel heat sink with an embedded 5 X 5 array of individually controllable heaters is used in the experiments. The microchannels in the heat sink are 240 mm wide and 370 μm deep, and are separated by 110 mm wide fins. The dielectric fluid HFE-7100 is used as the coolant, with an average mass flux in the heat sink of approximately 800 kg/m2s. High-speed visualizations of the flow are recorded to capture the CH...","PeriodicalId":89942,"journal":{"name":"International journal of micro-nano scale transport","volume":"5 1","pages":"95-108"},"PeriodicalIF":0.0,"publicationDate":"2014-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1260/1759-3093.5.3.95","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66152048","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}
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