ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer最新文献_第5页

Experimental and Theoretical Study on the Effect of Pressure and Surface Roughness on Thermal Contact Resistance With LMA As TIM 压力和表面粗糙度对LMA热接触电阻影响的实验与理论研究

ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer Pub Date : 2019-12-02 DOI: 10.1115/mnhmt2019-4083

Yulong Ji, Jiantong Xu, W. Gao, Huilong Yan, F. Su, Hongbin Ma

{"title":"Experimental and Theoretical Study on the Effect of Pressure and Surface Roughness on Thermal Contact Resistance With LMA As TIM","authors":"Yulong Ji, Jiantong Xu, W. Gao, Huilong Yan, F. Su, Hongbin Ma","doi":"10.1115/mnhmt2019-4083","DOIUrl":"https://doi.org/10.1115/mnhmt2019-4083","url":null,"abstract":"\u0000 The recent research show that low melting temperature alloys (LMA) is a prospective thermal interface material (TIM). However, the effect of surface roughness and interface contact pressure on the thermal contact resistance with LMA as TIM is unclear. In the current research, copper plates with surface roughness of 0.28 μm, 0.54 μm, 0.96 μm and 2.59 μm were fabricated to make different test samples. Low melting temperature alloys Ga62.5In21.5Sn16 was used as TIM to make the Cu-LMA-Cu three-layer structure samples. The thermal contact resistance of these samples under different pressure of 0.05 MPa, 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.4 MPa and 0.6 MPa were measured based on the steady state method. The results show that when the pressure of 0.05 MPa, 0.1 MPa, 0.15 MPa, 0.2 MPa, 0.4 MPa, 0.6MPa is applied to the samples, the thermal contact resistance of sample with surface roughness of 0.28 μm decreased by 74.3%, 71.1%, 70.1%, 71.5%, 70.8%, 70.1% compared with that of the sample with surface roughness of 2.59 μm. In order to further study the influence of the factors on the thermal contact resistance, a theoretical model of solid-liquid-solid thermal contact resistance with contact pressure and surface roughness as factors was developed. Based on theoretical model, it is concluded that (1) the thermal contact resistance decreases as the pressure increases, and gradually stabilizes; (2) as the surface roughness increases, the thermal contact resistance increases; (3) As the surface roughness decreases, the influence of contact pressure on thermal contact resistance decreases. The above conclusions were verified by test results.","PeriodicalId":331854,"journal":{"name":"ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115320601","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}

引用次数: 1

Effect of Particle Sedimentation on Sessile Nanofluid Droplet 颗粒沉降对固定式纳米液滴的影响

ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer Pub Date : 2019-12-02 DOI: 10.1115/mnhmt2019-4053

M. Jin, Dinghua Hu

引用次数: 0

Effects of Operating Conditions on the Heat Management of a Microscale Fuel Cell 运行条件对微型燃料电池热管理的影响

ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer Pub Date : 2019-12-02 DOI: 10.1115/mnhmt2019-3903

Liyong Sun, Adam S. Hollinger, Jun Zhou

{"title":"Effects of Operating Conditions on the Heat Management of a Microscale Fuel Cell","authors":"Liyong Sun, Adam S. Hollinger, Jun Zhou","doi":"10.1115/mnhmt2019-3903","DOIUrl":"https://doi.org/10.1115/mnhmt2019-3903","url":null,"abstract":"\u0000 Higher energy densities and the potential for nearly instantaneous recharging make microscale fuel cells very attractive as power sources for portable technology in comparison with standard battery technology. Heat management is very important to the microscale fuel cells because of the generation of waste heat. Waste heat generated in polymer electrolyte membrane fuel cells includes oxygen reduction reaction in the cathode catalyst, hydrogen oxidation reaction in the anode catalyst, and Ohmic heating in the membrane. A novel microscale fuel cell design is presented here that utilizes a half-membrane electrode assembly. An ANSYS Fluent model is presented to investigate the effects of operating conditions on the heat management of this microscale fuel cell. Five inlet fuel temperatures are 22°C, 40°C, 50°C, 60°C, and 70°C. Two fuel flow rate are 0.3 mL/min and 2 mL/min. The fuel cell is simulated under natural convection and forced convection. The simulations predict thermal profiles throughout this microscale fuel cell design. The exit temperature of fuel stream, oxygen stream and nitrogen stream are obtained to determine the rate of heat removal. Simulation results show that the fuel stream dominates heat removal at room temperature. As inlet fuel temperature increases, the majority of heat removal occurs via convection with the ambient air by the exposed current collector surfaces. The top and bottom current collector removes almost the same amount of heat. The model also shows that the heat transfer through the oxygen channel and nitrogen channel is minimal over the range of inlet fuel temperatures. Increasing fuel flow rate and ambient air flow both increase the heat removal by the exposed current collector surfaces. Ultimately, these simulations can be used to determine design points for best performance and durability in a single-channel microscale fuel cell.","PeriodicalId":331854,"journal":{"name":"ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122589451","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}

引用次数: 0

First Principles Study of Interlayer Interaction Effect on Graphene Thermal Conductivity 层间相互作用对石墨烯导热性影响的第一性原理研究

ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer Pub Date : 2019-12-02 DOI: 10.1115/mnhmt2019-3905

Yuan Dong, Chi Zhang, Chenghao Diao, Jian Lin

{"title":"First Principles Study of Interlayer Interaction Effect on Graphene Thermal Conductivity","authors":"Yuan Dong, Chi Zhang, Chenghao Diao, Jian Lin","doi":"10.1115/mnhmt2019-3905","DOIUrl":"https://doi.org/10.1115/mnhmt2019-3905","url":null,"abstract":"\u0000 It is known that the interlayer van der Waals (vdW) interactions will decrease the thermal conductivity of graphene. Single layer graphene (SLG) has the highest thermal conductivities, double layer graphene (DLG) would decrease to about half of the thermal conductivity of SLG. The graphite was measured to have a thermal conductivity of about 2000 W/m-K. Some research shows that graphite differs from SLG within a factor of 2, and DLG has almost the same thermal conductivity with graphite. In theoretical aspect, how to simulate the vdW interaction between graphene layers is a long existing problem. It is only until recently that the vdW interaction is still an active topic in first principle calculations. The popular methods include the Grimme’s DFT-D, vdW-DF and vdW-DFT-R methods. The vdW-DFT-R method was further optimized to increase accuracy by Hamada and was found to predict the most accurate interlayer distance between AB-stacked graphene in our recent study. The motivation of this work is to investigate the effect of vdW interaction on the thermal conductivity of multiple layer graphene from principles. We will calculate firstly the phonon dispersion relations of multiple layer graphene with the vdW interaction included. The obtained phonon properties and force constants will be combined with the ShengBTE method to calculate the thermal conductivity. The results show how vdW interaction causes the dimensional crossover of graphene thermal conductivity.","PeriodicalId":331854,"journal":{"name":"ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126155629","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}

引用次数: 1

Effect of Surface Temperature on Rarefied Flow Past a Circular Micro-Cylinder 表面温度对微圆柱稀薄流动的影响

ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer Pub Date : 2019-12-02 DOI: 10.1115/mnhmt2019-4232

X. Gu, D. Emerson

引用次数: 0

A Method for Measuring Thermal Conductivity of Low-Dimensional Materials Based on DC Heating 基于直流加热的低维材料导热系数测量方法

ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer Pub Date : 2019-12-02 DOI: 10.1115/mnhmt2019-3911

Xiao Yang, Xinghua Zheng, Yang Zheng, Liang Wang, Chen Haisheng

引用次数: 1

Experimental Study on Oscillating Heat Pipe With Hydraulic Diameter Far Exceeding the Maximum Hydraulic Diameter 液压直径远超最大液压直径振荡热管的实验研究

ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer Pub Date : 2019-12-02 DOI: 10.1115/mnhmt2019-4092

L. Chu, Yulong Ji, Chunrong Yu, Yantao Li, Hongbin Ma, Yang Guo

{"title":"Experimental Study on Oscillating Heat Pipe With Hydraulic Diameter Far Exceeding the Maximum Hydraulic Diameter","authors":"L. Chu, Yulong Ji, Chunrong Yu, Yantao Li, Hongbin Ma, Yang Guo","doi":"10.1115/mnhmt2019-4092","DOIUrl":"https://doi.org/10.1115/mnhmt2019-4092","url":null,"abstract":"\u0000 In order to understand the heat transfer performance, startup and fluid flow condition of oscillating heat pipe (OHP) with hydraulic diameter far exceeding the maximum hydraulic diameter (MHD), an experimental investigation on heat transfer performance and visualization was conducted. From the experimental performance, it is found that the OHP can still work well with ethanol as the working fluid when the tube diameter has exceeded the MHD of 91.6%. In addition, the detailed flow patterns of the OHP were recorded by a highspeed camera for vertical and horizontal orientation to understand its physical mechanism. In the vertical orientation, initially working fluid generates small bubbles, and then the small bubbles coalesce and grow to vapor plugs, the vapor plugs finally pushes the liquid slugs to oscillate in the tube. In the horizontal orientation, the working fluid surface fluctuates due to the vapors flow from the evaporator to the condenser and bubbles burst in the evaporator. When the peak of liquid wave reaches the upper surface of tube, a liquid slug has been formed, and then the steam flow pushes the liquid slugs to oscillate in the tube.","PeriodicalId":331854,"journal":{"name":"ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer","volume":"66 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130175342","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}

引用次数: 0

Comparison of Heat Transfer Performance Between Smooth and Enhanced Heat Transfer Tubes 光滑传热管与强化传热管的传热性能比较

ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer Pub Date : 2019-12-02 DOI: 10.1115/mnhmt2019-4044

D. Kukulka, Wei Li, Rick Smith

{"title":"Comparison of Heat Transfer Performance Between Smooth and Enhanced Heat Transfer Tubes","authors":"D. Kukulka, Wei Li, Rick Smith","doi":"10.1115/mnhmt2019-4044","DOIUrl":"https://doi.org/10.1115/mnhmt2019-4044","url":null,"abstract":"\u0000 Heat transfer enhancement is an important factor in obtaining energy efficiency improvements in all heat transfer applications. A numeric study was performed that compares the performance of heat exchangers using the Vipertex enhanced heat transfer tubes (model 1EHT) to the performance of heat exchangers that use smooth surface tubes and other enhanced tubes. Surface enhancement of the 1EHT tube is accomplished through the use of the primary dimple enhancement and a secondary background pattern made up of petal arrays. Utilization of enhanced heat transfer tubes is an effective method that is utilized in the development of high performance thermal systems. Vipertex™ tubes, have been designed and produced through material surface modifications that produce flow optimized heat transfer tubes that increase heat transfer performance. Current energy demands and the desire to increase efficiencies of systems have prompted the development of optimized enhanced heat transfer surfaces. Enhanced heat transfer tubes are widely used in many areas (refrigeration, air-conditioning, process, petrochemical, chemical, etc.) in order to reduce cost, create a smaller application footprint or increase production. A new type of enhanced heat transfer tube has been created; therefore it is important to investigate relevant heat exchanger designs using the Vipertex enhanced surface tube in industrial applications and compare that performance to smooth tubes and other enhanced tubes. Results include design characteristics and performance predictions using the design simulations produced using HTRI Exchanger Suite (2016). Performance for all cases considered using the Vipertex tube predicted over design when compared to a smooth tube design. Vipertex 1EHT tubes produced enhanced heat transfer and cost efficient designs. In some of the case studies the 1EHT tubes produce an overdesign that is more than 35%, while smooth tubes produce an underdesign and other low fin tubes produce overdesign but not as large as the 1EHT tubes.","PeriodicalId":331854,"journal":{"name":"ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer","volume":"198 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134106600","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}

引用次数: 0

Fluid Flow and Thin Film Evolution Near the Triple Line of Evaporative Sessile Droplet During Mixing Process 蒸发无底液滴混合过程中三线附近流体流动与薄膜演化

ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer Pub Date : 2019-12-02 DOI: 10.1115/mnhmt2019-4085

Tengxiao Ma, Leping Zhou

{"title":"Fluid Flow and Thin Film Evolution Near the Triple Line of Evaporative Sessile Droplet During Mixing Process","authors":"Tengxiao Ma, Leping Zhou","doi":"10.1115/mnhmt2019-4085","DOIUrl":"https://doi.org/10.1115/mnhmt2019-4085","url":null,"abstract":"\u0000 Evaporation of a sessile droplet containing nanoparticles plays a crucial role in engineering. However, the internal flow of an evaporative droplet may be influenced by various factors. Therefore, it is necessary to explore the mechanisms of fluid flow, especially the evolution of thin liquid film near the triple line of an evaporating droplet. This paper describes an experimental study of fluid flow and thin film evolution near the triple line of a sessile droplet when it was mixed with another droplet of different size. The temporal and spatial evolution of thickness in the thin film near the triple line is obtained by using the sub-region method developed from the total internal reflection fluorescence microscopy. The experimental results show that the spatial variation of the local film thickness can be linear or oscillating depending on the mixing position of the droplets. When the mixing position is at the droplet apex, the film thickness near the triple line fluctuates drastically in an oscillating mode, indicating that the mixing of the small droplet causes a strong disturbance in the thin film region. By using the velocimetry technique, the distribution of near wall velocity in the sessile droplet during mixing process is obtained, which provides the basis for velocimetry near the triple line. This work helps to gain insight of the thin film evolution and the velocity field near the triple line on the mixing processes of droplets.","PeriodicalId":331854,"journal":{"name":"ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer","volume":"35 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131860102","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}

引用次数: 0

Heat Transfer Characteristics of Horizontal Nano-Structured Oscillating Heat Pipes 水平纳米结构振荡热管的传热特性

ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer Pub Date : 2019-12-02 DOI: 10.1115/mnhmt2019-4100

Tingting Hao, Huiwen Yu, Xuehu Ma, Z. Lan

{"title":"Heat Transfer Characteristics of Horizontal Nano-Structured Oscillating Heat Pipes","authors":"Tingting Hao, Huiwen Yu, Xuehu Ma, Z. Lan","doi":"10.1115/mnhmt2019-4100","DOIUrl":"https://doi.org/10.1115/mnhmt2019-4100","url":null,"abstract":"\u0000 Working fluid in the oscillating heat pipe (OHP) with low turn number (< 9) positioned in the horizontal heat mode could not easily backflow to the evaporator due to the absence of gravity. In this paper, copper OHP with superhydrophilic nano-structured inner surface by introducing additional capillary force was investigated through the visualization and thermal experiments. OHPs with 6 turns, charged with pure water as the working fluid, were fabricated with copper, and nano-structured inner surface and tested for comparison. Contact angles of water on the copper and superhydrophilic surface were 36.7 and 0 deg. The filling ratio of water was 50%, 65%, and 80%, respectively. Startup performance, thermal resistance, and liquid slug oscillation of OHPs were investigated experimentally at the heat input of 100–380 W. Experimental results showed that OHPs with the superhydrophilic nano-structured surface showed an enhanced heat transfer performance due to the nanostructure-induced capillary action for water in the horizontal direction. The optimum filling ratio was 65% in this work. Dryout was observed in the OHPs with the filling ratio of 50% at the heat input higher than 220 W. At the filling ratio of 80%, the working fluid was accumulated in the adiabatic and condensation section, and the driving force due to the water evaporation in evaporator was not high enough to activate the movements of liquid slugs. Heat transfer performance of OHP with nano-structured surface was higher than that of bare copper surface by introducing the additional capillary force.","PeriodicalId":331854,"journal":{"name":"ASME 2019 6th International Conference on Micro/Nanoscale Heat and Mass Transfer","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2019-12-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134579469","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}

引用次数: 0