Volume 8B: Heat Transfer and Thermal Engineering最新文献

{"title":"Evaluation of Heat Transfer Kinetics on Layers of Air-Rich Soft Materials in Their Natural State","authors":"Hiroki Kaneko, A. Sakuma","doi":"10.1115/IMECE2018-87268","DOIUrl":"https://doi.org/10.1115/IMECE2018-87268","url":null,"abstract":"Air-rich soft materials are widely used in textile products, such as clothes and towels, because they exhibit good heat-retaining properties. Quantification of the heat-retaining properties of materials is necessary for product design engineering. Here, the behavior of heat transfer in the layer structure of the material is evaluated to formulate its kinetics. Such evaluation can address the barriers to appropriate design. The heat transfer kinetics of the multilayered structure of the materials are evaluated by assessing the surface temperature of the outer layers. The evaluation equation for kinetics is formulated by applying the fundamental relationship of heat transfer, which is represented by thermal conductivity and the heat transfer coefficient. In the experimental evaluation, a simple wind tunnel was developed using a blower, hot plate, and digital radiation temperature sensor. The temperature of the hot plate was set at three levels. In the evaluation of surface temperature, the quantity of infrared ray was measured using the digital radiation temperature sensor, because it could be used without mechanically influencing the specimen. The surface temperature of the materials was measured by changing the number of layers from one to eight. In the evaluation of heat transfer kinetics, some properties of the conductivity and the transfer were identified by the formulated relationship for the kinetics of the layered structure and the numerical technique of inverse analysis. It was found that the heat conductivity of the material and heat conductivities between the layers can be identified by the examination of surface temperature variation caused by the change in the number of layers. Then, the crush effect of air-rich structures can be assessed by compressing the material and then analyzing the behavior change in heat transfer caused by the crush. The difference between the observed results and those obtained without the crush of air-rich structure was significant. Thus, we concluded that the physical properties of heat transfer in a multilayered structure of air-rich soft materials can be identified using the surface temperature change in the material resulting from the number of layers. Therefore, it is important to measure its behavior without the crush of the air-rich structure to evaluate the most natural state of the material appropriately.","PeriodicalId":307820,"journal":{"name":"Volume 8B: Heat Transfer and Thermal Engineering","volume":"55 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122578210","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":"Array Jet Impingement Onto High Porosity Thin Metal Foams at Zero Jet-to-Foam Spacing","authors":"Prashant Singh, Mingyang Zhang, J. Pandit, R. Mahajan","doi":"10.1115/IMECE2018-87915","DOIUrl":"https://doi.org/10.1115/IMECE2018-87915","url":null,"abstract":"Metal foams enhance heat transfer rates by providing significant increase in wetted surface area and by thermal dispersion caused by flow mixing induced by the tortuous flow paths. Further, jet impingement is also an effective method of enhancing local convective heat transfer rates. In the present study, we have carried out an experimental investigation to study the combined effect of the two thermal performance-enhancement mechanisms. To this end, we conducted a set of experiments to determine convective heat transfer rates by impinging an array of jets onto thin metal foams attached on a uniformly heated smooth aluminum plate simulating a high heat-dissipating chip. The metal foams used were high porosity aluminum foams (ε∼0.94–0.96) with pore densities of 5 ppi, 10 ppi and 20 ppi (ppi: pores per inch) with thicknesses of 19 mm, 12.7 mm and 6.35 mm, respectively. With the jet-to-foam distance (z/d) set to zero, we conducted experiments with values of jet-to-jet spacing (x/d = y/d) of 2, 3 and 5. The jet plate featured an array of 5 × 5 cylindrical jet-issuing nozzles. The normalized jet-to-jet distance was varied by changing the jet diameter and keeping the jet center-to-center distance constant. Steady state heat transfer and pressure drop experiments were carried out for Reynolds number (based on jet diameter) ranging from 2500 to 10000. We have found that array impingement on thin foams leads to a significant enhancement in heat transfer compared to normal impingement over smooth surfaces. The gain in heat transfer was greatest for the 20 ppi foam (∼2.3 to 2.8 times that for the plain surface smooth target). However, this enhancement came at a significant increase of about 2.85 times in the plenum static pressure. With the pressure drop penalty taken into consideration, the x/d = 3 jet plate for the 20 ppi foam and x/d = 2 jet plate for the 10 ppi foam were found to be the most efficient cooling designs amongst the 18 cooling designs investigated in the present study.","PeriodicalId":307820,"journal":{"name":"Volume 8B: Heat Transfer and Thermal Engineering","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116872408","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":"Performance Analysis of Multi-Pass Cross-Flow Heat Exchangers","authors":"K. Lankalapalli, Ahmed Elsawy, S. Idem","doi":"10.1115/IMECE2018-87049","DOIUrl":"https://doi.org/10.1115/IMECE2018-87049","url":null,"abstract":"A steady state sensible performance analysis of multi-pass cross-flow finned-tube heat exchangers is reported. The investigation considers various flow circuiting, such as counter cross-flow, parallel cross-flow, and cross-flow where the tube-side flow is in parallel. A previously developed matrix approach is used to evaluate the heat exchanger performance in each tube pass. The equations required to model the thermal performance of these configurations are presented, and the thermal performance is compared for each type of flow circuiting. Thereafter a parametric study on cross-flow heat exchanger performance is performed by varying physically significant parameters such as number of transfer units (NTU) and capacity rate ratios, and the graphical results for each type of flow circuiting are presented both for both two-pass and three-pass arrangements. A consistent criterion is proposed for each case, wherein increasing the NTU beyond a certain threshold value does not significantly improve heat exchanger thermal performance.","PeriodicalId":307820,"journal":{"name":"Volume 8B: Heat Transfer and Thermal Engineering","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128723705","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":"Phase Evolution and Corrosion Performance of Laser Processed Oxide Dispersion Strengthened Ferritic Alloys","authors":"A. H. Ettefagh, Hao Wen, Fengyuan Lu, Shengmin Guo","doi":"10.1115/IMECE2018-86736","DOIUrl":"https://doi.org/10.1115/IMECE2018-86736","url":null,"abstract":"The application of laser processing as a surface treatment method on oxide dispersion strengthened (ODS) Fe-14Cr ferritic alloys, Fe-14Cr-3W-0.3Ti-xY2O3 (x = 0.3, 0.6, 0.9) (wt%), was examined in this paper. The ODS ferritic alloys with different amount of Y2O3 particles were prepared by mechanical milling and subsequently consolidated by spark plasma sintering (SPS). The effect of surface laser processing on the corrosion behavior was investigated for these ODS alloys with different oxide contents. The corrosion behaviors of SPS consolidated ODS samples with subsequent laser melting/solidification were examined by the means of electrochemical tests and compared with the untreated ODS samples in salt water. Results indicated that for samples without laser treatment, powders are mainly in their elemental state. However, after laser processing, the formation of passive layer and the improvement in the corrosion resistance are noticeable. CALculation of PHAse Diagrams (CALPHAD) calculations were used to identify the equilibrium phases and compared well with the experimental results.","PeriodicalId":307820,"journal":{"name":"Volume 8B: Heat Transfer and Thermal Engineering","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114071271","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":"An Experimental and Numerical Study of Heat Transfer and Flow Characteristics of Laminar Flow in a Circular Tube With Wedge-Shaped Wavy-Tape Inserts","authors":"Yunmin Liang, Peng Liu, Nianben Zheng, F. Shan, Zhichun Liu, Wei Liu","doi":"10.1115/IMECE2018-88335","DOIUrl":"https://doi.org/10.1115/IMECE2018-88335","url":null,"abstract":"In this study, a new type of tube inserts, named wedge-shaped wavy-tape insert, which is designed from bionics based on the movement of cuttlefish, is reported. The numerical simulation was carried out to investigate the effects of wedge-shaped wavy-tape insert arrangements on the heat transfer and flow characteristics of laminar flow in a circular tube under constant heat flux conditions. Details of the flow structures in the circular tube with wedge-shaped wavy-tape inserts which are arranged in same phase (S-type wavy tape) and different phase (D-type wavy tape) were presented and analyzed respectively. Then stereoscopic particle image velocimetry (Stereo-PIV) measurements on the flow structures were conducted to verify the numerical results. The flow structures obtained through simulations and PIV measurements agree well. It was observed that the arrangements of wedge-shaped wavy-tape inserts have a significant influence on the thermo-hydraulic performance. The average friction factor enhancement ratio f/f0 of D-type wavy tape were about 14%–20% lower than S-type wavy tape, but average heat transfer enhancement ratio Nu/Nu0 of D-type wavy tape were about 7%–14% higher than S-type wavy tape. The best performance evaluation criterion of D-type wavy tape could be improved to 3.02. The result shown the wedge-shaped wavy-tape insert is a promising technique for laminar convective heat transfer enhancement.","PeriodicalId":307820,"journal":{"name":"Volume 8B: Heat Transfer and Thermal Engineering","volume":"135 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124233925","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":"Experimental Investigation of an R134a Loop Thermosiphon for Shaft Cooling","authors":"Li Fajing, Jianmin Gao, Guangwei Jiang, Liang Xu, F. Liang","doi":"10.1115/IMECE2018-88548","DOIUrl":"https://doi.org/10.1115/IMECE2018-88548","url":null,"abstract":"Shaft cooling based on a loop thermosiphon is an ideal method for cooling of motorized spindles since it transfers heat with high efficiency and does not require an external power supply. In this study, an experiment was conducted on an R134a single-loop thermosiphon when the evaporation and condensation sections were on the same pipe. Results indicated that the single-loop thermosiphon was still operational with a minimum average thermal resistance of 0.51 W/°C when the filling ratio (FR) was 40%. The temperature distribution of the test specimen was determined predominantly by the amount of heating power, and not the mode. The optimum liquid filling ratio was 40% – 60% under this special condition, and both the thermal resistance and the heat transfer limit increased with the increase of FR in this range. The maximum temperature of the 150SD motorized spindle decreased 29% with the use of the R134a shaft cooling structure.","PeriodicalId":307820,"journal":{"name":"Volume 8B: Heat Transfer and Thermal Engineering","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130062239","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":"Applying a Radiative Heat Transfer Finite-Volume Methodology to a Geometrically Complex Furnace","authors":"Georgios N. Lygidakis, Stavros N. Leloudas, I. Nikolos","doi":"10.1115/IMECE2018-86831","DOIUrl":"https://doi.org/10.1115/IMECE2018-86831","url":null,"abstract":"Considering that radiative heat transfer is encountered in many engineering and industrial applications, significant efforts have been applied during the last decades for the development of relevant numerical methodologies. In this study, such an inhouse academic radiative heat transfer method is presented in brief, whereas it is evaluated against a geometrically complex furnace. The proposed solver depends on the time-dependent RTE (Radiative Transfer Equation) aiming to predict radiative heat transfer in general enclosures through absorbing, emitting, and either isotropically or anisotropically scattering gray media. Spatial discretization is obtained with a node-centered finite-volume method on three-dimensional tetrahedral or hybrid unstructured grids. Increased accuracy is succeeded with a second-order scheme. The final steady-state solution is obtained with an iterative procedure, based on an explicit second-order accurate in time four-stage Runge-Kutta method and accelerated mainly via parallel processing and an agglomeration multigrid scheme. The proposed solver is assessed against an experimental three-dimensional furnace case, incorporating many of the geometric complexities encountered in industrial furnace systems. The predicted numerical results, regarding the incident wall fluxes, are compared with the available experimental data, revealing a satisfactory agreement and consequently demonstrating the proposed code’s potential to predict accurately radiative heat transfer in complex enclosures.","PeriodicalId":307820,"journal":{"name":"Volume 8B: Heat Transfer and Thermal Engineering","volume":"10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131025486","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":"3D-Printed PCM/HDPE Composites for Battery Thermal Management","authors":"Thomas B Freeman, Kaloki L. Nabutola, D. Spitzer, P. Currier, S. Boetcher","doi":"10.1115/IMECE2018-86081","DOIUrl":"https://doi.org/10.1115/IMECE2018-86081","url":null,"abstract":"Phase-change materials (PCMs) are a useful alternative to more traditional methods of thermal management of Li-ion batteries in electric or hybrid-electric vehicles. PCMs are materials which absorb large amounts of latent heat and undergo solid-to-liquid phase change at near-constant temperature. The goal of the research is to experimentally investigate the thermal properties of a novel shape-stabilized PCM/HDPE composite extruded filament. The extruded filament can then be used in a 3D printer for custom PCM/HDPE shapes. The PCM used in the study is PureTemp PCM 42, which is an organic-based material that melts around 42° C. Four PCM/HDPE mixtures were investigated (all percentages by mass): 20/80, 30/70, 40/60, and 50/50. Preliminary findings include differential scanning calorimeter (DSC) measurements of melting temperature and latent heat as well as scanning electron microscope (SEM) pictures of filament composition.","PeriodicalId":307820,"journal":{"name":"Volume 8B: Heat Transfer and Thermal Engineering","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117113265","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":"Pool Boiling Heat Transfer of N-Pentane and Acetone on Nanostructured Surfaces by Electrophoretic Deposition","authors":"Zan Wu, A. Pham, Z. Cao, Cathrine Albèr, P. Falkman, T. Ruzgas, B. Sundén","doi":"10.1115/IMECE2018-87752","DOIUrl":"https://doi.org/10.1115/IMECE2018-87752","url":null,"abstract":"This work aims to investigate pool boiling heat transfer enhancement by using nanostructured surfaces. Two types of nanostructured surfaces were employed, gold nanoparticle-coated surfaces and alumina nanoparticle-coated surfaces. The nanostructured surfaces were fabricated by an electrophoretic deposition technique, depositing nanoparticles in a nanofluid onto smooth copper surfaces under an electric field. N-pentane and acetone were tested as working fluids. Compared to the smooth surface, the pool boiling heat transfer coefficient has been increased by 80% for n-pentane and acetone. Possible mechanisms for the enhancement in heat transfer are qualitatively provided. The increase in active nucleation site density due to multiple micro/nanopores on nanoparticle-coated surfaces is likely the main contributor. The critical heat flux on nanostructured surfaces are approximately the same as that on the smooth surface because both smooth and modified surfaces show similar wickability for the two working fluids.","PeriodicalId":307820,"journal":{"name":"Volume 8B: Heat Transfer and Thermal Engineering","volume":"87 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122673700","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 Enhancement in Wavy Micro-Channels Through Multiharmonic Surfaces","authors":"J. Moon, J. R. Pacheco, A. Pacheco-Vega","doi":"10.1115/IMECE2018-86425","DOIUrl":"https://doi.org/10.1115/IMECE2018-86425","url":null,"abstract":"In this study, three-dimensional numerical simulations are performed to investigate heat transfer enhancement in multi-harmonic micro-scale wavy channels. The focus is on the influence of channel surface-topography, modeled as multi-harmonic sinusoidal waves of square cross-sectional area, on the enhancing mechanisms. A single-wave device of 0.5 mm × 0.5 mm × 20 mm length, is used as baseline, and new designs are built with harmonic-type surfaces. The channel is enclosed by a solid block, with the bottom surface within the sinusoidal region being exposed to a 47 W/cm2 heat flux. The numerical solutions of the governing equations for an incompressible laminar flow and conjugate heat transfer are obtained via finite elements. By using the ratio of the Nusselt number for wavy to straight channels, a parametric analysis — for a set of cold-water flowrates (Re = 50, 100, and 150) — shows that the addition of harmonic surfaces enhances the transfer of energy and that such ratio achieves the highest value with wave harmonic numbers of n = ±2. Use of a performance factor (PF), defined as the ratio of the Nusselt number to the pressure drop, shows that, surprisingly, the proposed wavy multi-harmonic channels are not as efficient as the single-wave geometries. This outcome is thought to be, primarily, due to the uncertainty associated with the definition of the Nusselt number used in this study, and establishes a direction to investigate the development of a more accurate definition.","PeriodicalId":307820,"journal":{"name":"Volume 8B: Heat Transfer and Thermal Engineering","volume":"360 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2018-11-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122771087","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}