Artigos de revistas: "Thermo-hydraulic performance"

1

Hu, Bao, Hongjiao Liu e Mei Jin. "Numerical Simulation of Thermo-hydraulic Behaviour of Shell and Tube Heat Exchanger Equipped with Segmental Baffle and Helical Baffle". Journal of Physics: Conference Series 2584, n.º 1 (1 de setembro de 2023): 012050. http://dx.doi.org/10.1088/1742-6596/2584/1/012050.

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Abstract The baffle type and structure are critical to enhancing the comprehensive thermo-hydraulic behavior of shell-and-tube heat exchangers (STHX). In the study, Solidworks software was used to establish three-dimensional mesh models of STHX equipped with the segmental baffle and the continuous helical baffle, respectively. ANSYS software was adopted to study the effects of the baffle type and the baffle geometric parameters on the thermo-hydraulic characteristic of STHXs using the pressure drop of the shell side, the coefficient of heat transfer and isobaric JFP factor as the evaluation characteristics. For segmental baffles, better thermo-hydraulic performance could be obtained with a baffle spacing of 200 mm and a gap height of 0.4 D. For helical baffles, an optimized thermo-hydraulic performance could be obtained with a baffle pitch of 150 mm. By comparing the comprehensive thermo-hydraulic performances of STHXs equipped with two different baffles, it could be concluded that the isobaric JFP factor of STHX equipped with the helical baffle was 1.18 times that of STHX equipped with the segmental baffle under the different suitable flow rate.

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Zahid, Hamid, Abdullah Mubashar, Muhammad Waqas, Muhammad Siddiqi, Umair Munir e Syed Naqvi. "Experimental and CFD simulation study of shell and tube heat exchangers with different baffle segment configurations". Thermal Science, n.º 00 (2022): 75. http://dx.doi.org/10.2298/tsci220124075z.

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Shell and tube heat exchanger (STHX) is an implement that has tremendous applications in numerous industrial processes and research areas. In this study, the commercial software ANSYS is used for 3-D computational fluid dynamics (CFD) to compare the thermo-hydraulic performance of STHXs with recently developed tri-angular (TRI) baffles, and tri-flower (TF) baffles with conventional segmental (SG) baffles at different flow rates. Simulations have been performed to analyze the heat transfer coefficient, pressure drop, and overall thermo-hydraulic performance among the recently developed TRI-STHX, TF-STHX and conventional SG-STHX. The thermo-hydraulic performance of the numerical model of SG-STHX shows the promising results while validating it with the experimental results, Esso and Kern methods. Then the same study is carried out for comparing the two novel baffles with segmental baffle. The results depict that, novel baffles are much appreciable in increasing heat transfer coefficient. The TF-STHX offers a greater heat transfer coefficient than all others but also offers a higher pressure drop at the same flow rate. Computing the comprehensive performance (hs??p), the TRI-STHX offers a prominent increment in thermo-hydraulic performance compared to others. Moreover by inserting twisted tapes at the tube side, there is noticeable increase in heat transfer coefficient which tends to increase the thermo-hydraulic performance of STHX. By comparing the flow patterns of TRI-STHX and SG-STHX, the novel TRI-STHX shows the reduction in shell-side induced vibrations and hence helped to increase the overall efficiency of the STHX.

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Alam, Mir Waqas, e Basma Souayeh. "Parametric CFD Thermal Performance Analysis of Full, Medium, Half and Short Length Dimple Solar Air Tube". Sustainability 13, n.º 11 (7 de junho de 2021): 6462. http://dx.doi.org/10.3390/su13116462.

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In the present decade, research regarding solar thermal air heaters (SAHs) has noticed a continuous progression in thermo-hydraulic performance augmentation approaches. There now exists a wide variety of thermo-hydraulic performance augmentation approaches and researchers have designated various structures. Nevertheless, there seems to be no generalization to any of the approaches employed. The present numerical investigation reports on the thermo-hydraulic characteristics and thermal performance for flow through a varied length (full, medium, half, and short length) dimple solar air heater (SAH) tube. The study highlights recent developments on enhanced tubes to augment heat transfer in SAH. The influence of different length ratio, dimple height ratio (H), and pitch ratio (s) on thermo-hydraulic characteristics have been investigated in the Reynolds number (Re) range from 5000 to 25,000. Air is used as the working fluid. The commercial software ANSYS Fluent is used for simulation. The shear stress transport (SST) model is used as the turbulence model. Thermal energy transport coefficient is increased in the full-length dimple tube (FLDT), compared to the medium-length dimple tube (MLDT), half-length dimple tube (HLDT) and short-length dimple tube (SLDT). Similarly, the pitch ratio (s) has more influence on Nusselt number (Nu) compared to the dimple height ratio (H). The friction factor decreases with an increase in pitch ratio. Nu increases and f decreases with increasing Re for all combinations of H and s. Low s and higher H yields high enhancement of HT and PD. Integration of artificial roughness on the tube increases the values of Nu and f by 5.12 times and 77.23 times for H = 0.07, s = 1.0 at Re value of 5000 and 25,000, respectively, in regard to the plain tube. For all the tested cases, the thermo-hydraulic performances (η) are greater than unity.

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Akcayoglu, Azize, Halil Cebeci e Celal Nazli. "Thermo-Hydraulic Performance Evaluation of Inclined Vortex Generators". Advanced Materials Research 853 (dezembro de 2013): 317–22. http://dx.doi.org/10.4028/www.scientific.net/amr.853.317.

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In the present study, a commercial finite volume package ANSYS FLUENT 14.5 has been used to determine thermo-hydraulic performance of two different vortex generator (VG) configurations, namely, flow-up and flow-down, located in triangular ducts. A comprehensive literature survey on flow-up and flow-down configurations has shown that there are completely opposite results obtained in terms of performance of the two configurations. In some studies, flow-up configuration showed better performance characteristics over flow-down configuration while in other studies flow-down configuration was found better. This has been motivated the present authors to make a study covering the two VG configurations to find out which one has a better performance over the other one. Therefore flow and thermal fields together with the secondary flow induced by the two VG configurations have been analyzed extensively. The geometry comprised of double row of VGs located on the slant surfaces of equilateral triangular ducts. The angle of inclination of the VGs made with the flow direction is 30°. The results show that flow-down configuration has a 40.65% higher thermo-hydraulic performance over the flow-up configuration for Re=5000. It is also shown that the heat is transferred at a further downstream distance allowing in a reduction in the number of VGs to be used in of flow down case.

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Ahmed, Imtiyaz. "Thermo-Hydraulic Performance Investigation of Rib Enhanced Flow". International Journal for Research in Applied Science and Engineering Technology 7, n.º 7 (31 de julho de 2019): 1068–73. http://dx.doi.org/10.22214/ijraset.2019.7173.

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Chen, Li Xiang. "Laminar Heat Transfer Performances in a Tube with Center-Cleared Twisted Tape of Alternate Axes". Advanced Materials Research 1070-1072 (dezembro de 2014): 1803–7. http://dx.doi.org/10.4028/www.scientific.net/amr.1070-1072.1803.

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To improve the heat transfer performance of laminar tubular flow, a center-cleared twisted tape of alternate axes was developed as inserts. Numerical simulation was conducted to investigate the effect of dislocation angle of twisted tapes on the thermo-hydraulic performances. The numerical results show that, the largest Nusselt number occurs at a dislocation angle of 60°. The friction factorfis relatively larger than that when the dislocation angle is 0°, and it exhibits an obvious increment with the dislocation angle. From the value of performance evaluation criterion (PEC), the best thermo-hydraulic performance is achieved at a 60° dislocation angle. The underlying mechanisms are analyzed in terms of flow field and temperature field.

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Sabu Kurian, Tide P Sunny e Biju N. "The Effect of Baffle Configuration on Heat Transfer and Pressure Drop Characteristics of Jet Impingement System with Cross-Flow". Journal of Advanced Research in Fluid Mechanics and Thermal Sciences 86, n.º 2 (22 de agosto de 2021): 15–27. http://dx.doi.org/10.37934/arfmts.86.2.1527.

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Use of baffles in jet impingement systems in presence of initial cross-flow disturbs boundary layer that results in rise in heat transfer. Two configurations of baffle assisted impingement systems were considered and a comparative study on heat transfer and pressure drop is carried out based on operating parameters such as baffle clearance, blow ratio and h/D ratio using commercially available CFD package. Numerical predictions showed that both heat transfer and pressure drop in segmented configuration were higher than louvered configuration for all blow ratio employed in this study. Parametric studies showed that, thermo-hydraulic performance parameter is higher only for louvered configurations at low blow ratio. When cross-flow velocity is comparable with jet velocity, segmented baffles resulted in relatively higher thermo-hydraulic performance because of its higher heat transfer rate relative to the incurring pressure drop. An increase in clearance proportionally increases performance parameter. However, as jet to plate distance increases, thermo hydraulic performance declines significantly.

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Abdul Hasis, Fahd Bin, P. M. Mithun Krishna, G. P. Aravind, M. Deepu e S. R. Shine. "Thermo hydraulic performance analysis of twisted sinusoidal wavy microchannels". International Journal of Thermal Sciences 128 (junho de 2018): 124–36. http://dx.doi.org/10.1016/j.ijthermalsci.2018.02.018.

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Zhai, Xinfeng, Cong Qi, Yuqi Yang e Jiangyun Wang. "Thermo-hydraulic performance of nanofluids under adjustable magnetic field". Applied Thermal Engineering 186 (março de 2021): 116491. http://dx.doi.org/10.1016/j.applthermaleng.2020.116491.

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10

You, Yong Hua, Ai Wu Fan, Chen Chen, Shun Li Fang, Shi Ping Jin e Su Yi Huang. "Numerical Study of Shellside Performance of Heat Transfer and Flow Resistance for Heat Exchanger with Trefoil-Hole Baffles". Advanced Materials Research 557-559 (julho de 2012): 2141–46. http://dx.doi.org/10.4028/www.scientific.net/amr.557-559.2141.

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Trefoil-hole baffles have good thermo-hydraulic performances as the support of heat pipes, however the published research paper is relatively limited. The present paper investigates the shellside thermo-hydraulic characteristics of shell-and-tube heat exchanger with trefoil-hole baffles (THB-STHX) under turbulent flow region, and the variations of shellside Nusselt number, pressure loss and overall thermo-hydraulic performance (PEC) with Reynolds number are obtained for baffles of varied pitch with the numerical method. CFD results demonstrate that the trefoil-hole baffle could enhance the heat transfer rate of shell side effectively, and the maximal average Nusselt number is augmented by ～2.3 times that of no baffle, while average pressure loss increases by ～9.6 times. The PEC value of shell side lies in the range of 16.3 and 73.8 kPa-1, and drops with the increment of Reynolds number and the decrement of baffle pitch, which indicates that the heat exchanger with trefoil-hole baffles of larger pitch could generate better overall performance at low Reynolds number. Moreover, the contours of velocity, turbulent intensity and temperature are presented for discussions. It is found that shellside high-speed jet, intensive recirculation flow and high turbulence level could enhance the heat transfer rate effectively. Besides good performance, THB-STHXs are easily manufactured, thus promise widely applied in various industries.

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Barquín, Katherine, e Alvaro Valencia. "Comparison of Different Fin and Tube Compact Heat Exchanger with Longitudinal Vortex Generator in CFU-CFD Configurations". International Journal of Heat and Technology 39, n.º 5 (31 de outubro de 2021): 1523–31. http://dx.doi.org/10.18280/ijht.390514.

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Over the last decades several studies have searched for improved Fin and Tube Heat Exchanger (FTHE) designs capable of providing the best thermo-hydraulic performance. The present study aims at quantifying and comparing the thermo-hydraulic performance of different FTHE configurations. Six different designs were analyzed. The first FTHE consisted of an in-line circular tube arrangement and the last one was a FTHE with staggered oval tube with two pairs of Delta Winglet Vortex Generators (DWVG) in common flow up–common flow down (CFU-CFD) configuration. The best performance was obtained using DWVG in CFU-CFD orientation. This configuration enabled a 90% increase of the thermal performance factor when compared with the first case, using only two pairs of vortex generator´s per tube.

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Tang, Jinghua, Cong Qi, Zi Ding, Masoud Afrand e Yuying Yan. "Thermo-hydraulic performance of nanofluids in a bionic heat sink". International Communications in Heat and Mass Transfer 127 (outubro de 2021): 105492. http://dx.doi.org/10.1016/j.icheatmasstransfer.2021.105492.

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Bilen, Kadir, Nehir Tokgoz, İsmail Solmaz e Tuba Balta. "Thermo-hydraulic performance of tube with decaying swirl flow generators". Applied Thermal Engineering 200 (janeiro de 2022): 117643. http://dx.doi.org/10.1016/j.applthermaleng.2021.117643.

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Guo, Jiangfeng, Jian Song, Yao Zhao, Konstantin S. Pervunin e Christos N. Markides. "Thermo-hydraulic performance of heated vertical flows of supercritical CO2". International Journal of Heat and Mass Transfer 199 (dezembro de 2022): 123437. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2022.123437.

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Samal, Sangram Kumar, e Manoj Kumar Moharana. "Thermo-hydraulic performance evaluation of a novel design recharging microchannel". International Journal of Thermal Sciences 135 (janeiro de 2019): 459–70. http://dx.doi.org/10.1016/j.ijthermalsci.2018.09.006.

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Wang, Yuwei, Jie Yu, Cong Qi e Wenjie Zhang. "Review on Coupled Thermo-Hydraulic Performance of Nanofluids and Microchannels". Nanomaterials 12, n.º 22 (11 de novembro de 2022): 3979. http://dx.doi.org/10.3390/nano12223979.

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As electronic components continue to be miniaturized, the heat flux density continues to increase. Scholars have proposed the use of microchannel heat sinks (MCHS) to dissipate heat from devices with high heat flux density, and have pointed out that the heat dissipation capability of MCHS can be improved in two ways: using nanofluids with high thermal conductivity and optimizing the structure of MCHS. In this paper, the thermophysical parameters and thermo-hydraulic performance of nanofluids in microchannels are reviewed. Improving the heat dissipation of MCHS is analyzed and discussed in terms of both thermal properties and flow properties, respectively.

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Afsahnoudeh, Reza, Andreas Wortmeier, Maik Holzmüller, Yi Gong, Werner Homberg e Eugeny Y. Kenig. "Thermo-Hydraulic Performance of Pillow-Plate Heat Exchangers with Secondary Structuring: A Numerical Analysis". Energies 16, n.º 21 (26 de outubro de 2023): 7284. http://dx.doi.org/10.3390/en16217284.

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Pillow-plate heat exchangers (PPHEs) represent a suitable alternative to conventional shell-and-tube and plate heat exchangers. The inherent waviness of their channels promotes fluid mixing in the boundary layers and facilitates heat transfer. The overall thermo-hydraulic performance of PPHEs can further be enhanced by applying secondary surface structuring, thus increasing their competitiveness against conventional heat exchangers. In this work, various secondary structures applied on the PPHE surface were studied numerically to explore their potential to enhance near-wall mixing. Computational fluid dynamics (CFD) simulations of single-phase turbulent flow in the outer PPHE channel were performed and pressure drop, heat transfer coefficients, and overall thermo-hydraulic efficiency were determined. The simulation results clearly demonstrate a positive impact of secondary structuring on heat transfer in PPHEs.

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Kumar, Thakur Sanjay, N. S. Thakur, Anoop Kumar e Vijay Mittal. "Use of artificial roughness to enhance heat transfer in solar air heaters – a review". Journal of Energy in Southern Africa 21, n.º 1 (1 de fevereiro de 2010): 35–51. http://dx.doi.org/10.17159/2413-3051/2010/v21i1a3248.

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Improvement in the thermo hydraulic performance of a solar air heater can be done by enhancing the heat transfer. In general, heat transfer enhancement techniques are divided into two groups: active and passive techniques. Providing an artificial roughness on a heat transferring surface is an effective passive heat transfer technique to enhance the rate of heat transfer to fluid flow. In this paper, reviews of various artificial roughness elements used as passive heat transfer techniques, in order to improve thermo hydraulic performance of a solar air heater, is done. The objective of this paper is to review various studies, in which different artificial roughness elements are used to enhance the heat transfer rate with little penalty of friction. Correlations developed by various researchers with the help of experimental results for heat transfer and friction factor for solar air heater ducts by taking different roughened surfaces geometries are given in tabular form. These correlations are used to predict the thermo hydraulic performance of solar air heaters having roughened ducts. The objective is to provide a detailed review on heat transfer enhancement by using an artificial roughness technique. This paper will be very helpful for the researchers who are researching new artificial roughness for solar air heater ducts to enhance the heat transfer rate and comparing with artificial roughness already studied by various researchers.

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Khalatov, А. А., І. І. Borisov e S. B. Kulishov. "THERMO-HYDRAULIC CHARACTERISTICS OF ADDITIVELY MANUFACTURED MINI-CHANNELS". Thermophysics and Thermal Power Engineering 49, n.º 2 (11 de junho de 2023): 24–33. http://dx.doi.org/10.31472/ttpe.2.2023.3.

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The aim of this work is to analyze the heat transfer, hydraulic resistance and thermo-hydraulic performance of a new type of heat exchange channels made by additive technology. The main factors affecting the quality of products and determining the heat transfer and hydraulic resistance of the channels are noted. Well-known ratios for calculating hydraulic resistance and heat transfer are not suitable for such high roughness. Data on the AT resistance coefficient of the channels show that even at low Reynolds numbers there is a contribution of roughness. With increasing roughness, the intensification of resistance and heat exchange increases. The transition occurs at 700 < Re < 2000. Comparison of data on heat transfer augmentation and increase of hydraulic losses, as well as their thermo-hydraulic characteristics has been carried out. The hydraulic resistance coefficient of AT channels is significantly higher than the resistance coefficient of smooth channels. Heat transfer augmentation in wave-shaped channels is 2 times higher than augmentation in straight channels. Channels with pin fins allow to achieve a very high heat transfer augmentation (up to 8). Channels with internal grids provide high intensification, but have the highest hydraulic losses. The dependence of the Reynolds analogy factor on the resistance increase factor showed that the straight channels of all geometric forms fit on one dependence closed to the lower boundary line, and have a low hydraulic resistance. Data on channels with pin fins have a large spread. A number of points are above the upper boundary line, which refers to channels with low surface roughness.

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Singh, Niranjan Ramendra, Singh Onkar e Janakarajan Ramkumar. "Thermo-Hydraulic Performance of Square Micro Pin Fins under Forced Convection". International Journal of Heat and Technology 39, n.º 1 (28 de fevereiro de 2021): 170–78. http://dx.doi.org/10.18280/ijht.390118.

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Thermal management of the new generation’s high performance electronic and mechanical devices is becoming important due to their miniaturization. Conventionally, the plate fin arrangement is widely used for removal of dissipated heat but, their effectiveness is not up to mark. Among different options, the most attractive and efficient alternative for overcoming this problem is micro pin fin heat sink. This paper presents the experimental investigation of square micro-pin fins heat sink for identifying the most suitable pin fin geometry for heat removal applications under forced convection. Twenty five square micro pin fin heat sinks were tested for three different heat load and Reynolds number. The results show that for large fin height lower thermal resistance was observed at the cost of large pressure drop. The dimensionless heat transfer coefficient increases with fin height and Reynolds number while it decreases with increasing fin spacing. The improvement in micro pin fin efficiency were observed by about 2 to 9% owing to presence of fins on the impingement surface, flow mixing, disruption of the boundary layers, and augmentation of turbulent transport.

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Saghir, Mohamad Ziad, e Mohammad Mansur Rahman. "Thermo-Hydraulic Performance of Pin-Fins in Wavy and Straight Configurations". Micromachines 13, n.º 6 (16 de junho de 2022): 954. http://dx.doi.org/10.3390/mi13060954.

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Pin-fins configurations have been investigated recently for different engineering applications and, in particular, for a cooling turbine. In the present study, we investigated the performance of three different pin-fins configurations: pin-fins forming a wavy mini-channel, pin-fins forming a straight mini-channel, and a mini-channel without pin-fins considering water as the working fluid. The full Navier–Stokes equations and the energy equation are solved numerically using the finite element technique. Different flow rates are studied, represented by the Reynolds number in the laminar flow regime. The thermo-hydraulic performance of the three configurations is determined by examining the Nusselt number, the pressure drop, and the performance evaluation criterion. Results revealed that pin-fins forming a wavy mini-channel exhibited the highest Nusselt number, the lowest pressure drop, and the highest performance evaluation criterion. This finding is valid for any Reynolds number under investigation.

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Abdulrasool, Ali A., e Abdalrazzaq K. Abbas. "Computational analysis of novel channel design for improving thermo-hydraulic performance". International Communications in Heat and Mass Transfer 135 (junho de 2022): 106120. http://dx.doi.org/10.1016/j.icheatmasstransfer.2022.106120.

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Kathait, Pawan Singh, e Anil Kumar Patil. "Thermo-hydraulic performance of a heat exchanger tube with discrete corrugations". Applied Thermal Engineering 66, n.º 1-2 (maio de 2014): 162–70. http://dx.doi.org/10.1016/j.applthermaleng.2014.01.069.

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Kaood, Amr, e Muhammed A. Hassan. "Thermo-hydraulic performance of nanofluids flow in various internally corrugated tubes". Chemical Engineering and Processing - Process Intensification 154 (agosto de 2020): 108043. http://dx.doi.org/10.1016/j.cep.2020.108043.

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V. S. Hans, Sukhmeet Singh e R. S. Gill. "Thermal and Thermo-hydraulic Performance of Packed Bed Solar Air Heater". Journal of Agricultural Engineering (India) 51, n.º 1 (15 de fevereiro de 2024): 51–57. http://dx.doi.org/10.52151/jae2014511.1544.

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Modification of flow passage of air in a solar air heater using a packing material is one of available techniques to considerably improve thermal performance of solar air heaters. In an outdoor experimental study, thermal and thermohydraulic performance of a packed bed solar air heater were evaluated and compared with that of a conventional solar air heater. It was observed that due to presence of mild steel chips in the flow passage of air in packed bed solar air heater, its thermal efficiency improved considerably as compared to that of conventional solar air heater for the entire range of Reynolds number considered in the investigation. Thermo-hydraulic performance of packed bed solar air heater was found to be better than that of conventional solar air heater for most of the Reynolds number range considered. However, beyond Reynolds number of 15000, conventional solar air heater outperformed packed bed solar air heater in terms of effective efficiency.

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Altarazi, Faisal, Sunil Kumar, Gaurav Gupta, Muhammad Gulzar, Yaé Ulrich Gaba, Anil Kumar e Rajesh Maithani. "Analysis and Implementation of Thermal Heat Exchanger Tube Performance with Helically Pierced Twisted Tape Inserts Using ANFIS Model". Mathematical Problems in Engineering 2021 (20 de dezembro de 2021): 1–13. http://dx.doi.org/10.1155/2021/1734909.

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The present work used ANFIS, an adaptive neuro-fuzzy inference system modeling to analyze the effect of the variable parameters of helically pierced twisted tape inserts on the Nusselt number, friction factor, and thermo-hydraulic heat exchanger tube performance. The experimental data utilized for ANFIS modeling considered a diameter ratio ranging from 0.57 to 0.80, a relative pitch ratio ranging from 0.046 to 0.107, a perforation index ranging from 5% to 20% as variable twisted tape parameters and flow parameters. The Reynolds number varies from 4000 to 30000. The analysis showed that the maximum thermo-hydraulic performance was obtained at a diameter ratio of 0.65, a relative pitch ratio of 0.085, and a perforation index equal to 10%. The result predicts that the ANFIS model and experimental results are in good agreement as they have only ±0.53% deviations.

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Sanodiya, Gyaneshwar. "A Relative Study of Solar Air Heater Having Turbulators". Indian Journal of Energy and Energy Resources 1, n.º 4 (30 de agosto de 2022): 7–10. http://dx.doi.org/10.54105/ijeer.d1018.081422.

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Due to the depletion of fossil fuel reserves, it is now more important than ever to explore and use alternate forms of energy. “Solar energy is a promising long-term solution that can meet the world's energy needs. Due to the depletion of fossil fuel reserves, it is essential that we explore and use energy-related solutions as soon as possible. Solar energy is a promising long-term solution. Artificially roughened solar air heaters perform better than the smooth ones under the same operating conditions. However, artificial roughness leads to even more fluid pressure thereby increasing the pumping power. In this article a comparative study of thermo-hydraulic performance of two different types of artificial roughness geometries attached on the absorber plate of solar air heater” has been performed in terms of thermo-hydraulic performance parameter

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Wang, Wei, Liang Ding, Fangming Han, Yong Shuai, Bingxi Li e Bengt Sunden. "Parametric Study on Thermo-Hydraulic Performance of NACA Airfoil Fin PCHEs Channels". Energies 15, n.º 14 (12 de julho de 2022): 5095. http://dx.doi.org/10.3390/en15145095.

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In this work, a discontinuous airfoil fin printed circuit heat exchanger (PCHE) was used as a recuperator in a micro gas turbine system. The effects of the airfoil fin geometry parameters (arc height, maximum arc height position, and airfoil thickness) and the airfoil fin arrangements (horizontal and vertical spacings) on the PCHE channel’s thermo-hydraulic performance were extensively examined by a numerical parametric study. The flow features, local heat transfer coefficient, and wall shear stress were examined in detail to obtain an enhanced heat transfer mechanism for a better PCHE design. The results show that the heat transfer and flow resistance were mainly increased at the airfoil leading edge owing to a flow jet, whereas the airfoil trailing edge had little effect on the thermo-hydraulic performance. The airfoil thickness was the most significant while the arc height and the vertical spacing were moderately significant to the performance. Moreover, only the airfoil thickness had a significant effect on the PCHE compactness. Based on a comprehensive investigation, two solutions NACA-6230 and -3220 were selected owing to their better thermal performance and smaller pressure drop, respectively, with horizontal spacings of 2 mm and vertical spacings of 2 or 3 mm.

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Wang, Wei, Mengke Niu, Yufei Tan, Bingxi Li e Yong Shuai. "Investigation on Flow Maldistribution and Thermo-Hydraulic Performance of PCHEs with Spoiler Perforated Boards". Energies 15, n.º 18 (6 de setembro de 2022): 6518. http://dx.doi.org/10.3390/en15186518.

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In this study, the effects of the maldistribution coefficient on the thermo-hydraulic performance of discontinuous fin printed circuit heat exchanger (DF-PCHE) entrance head and channels are numerically investigated. To improve the flow uniformity at the entrance head, the flow in the exchanger with three types of spoiler perforated boards (SPBs) having 3 × 3, 4 × 4, and 5 × 5 holes and three kinds of hole diameters (Φd = 30, 25, and 20 mm), respectively, are compared to the flow in an exchanger with no SPB. The results show that a small maldistribution coefficient for the inlet velocity field is beneficial for the thermo-hydraulic performance of the DF-PCHE channels, and a maldistribution coefficient of 0.7 is an acceptable velocity distribution for the PCHE channel inlet. Using the 3 × 3 SPB with Φd = 30 mm, the maldistribution coefficient becomes 0.7, the fastest among all the SPB application cases at ΔL = 150 mm. Moreover, its heat transfer coefficient and pressure drop increase by 22.46% and decreases by 47.2% compared to those of the exchanger without SPB, respectively.

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Sepehrnia, Mojtaba, Hossein Khorasanizadeh e Mohammad Behshad Shafii. "Effect of transverse and parallel magnetic fields on thermal and thermo-hydraulic performances of ferro-nanofluid flow in trapezoidal microchannel heat sink". International Journal of Numerical Methods for Heat & Fluid Flow 31, n.º 7 (18 de maio de 2021): 2089–111. http://dx.doi.org/10.1108/hff-12-2019-0907.

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Purpose This paper aims to study the thermal and thermo-hydraulic performances of ferro-nanofluid flow in a three-dimensional trapezoidal microchannel heat sink (TMCHS) under uniform heat flux and magnetic fields. Design/methodology/approach To investigate the effect of direction of Lorentz force the magnetic field has been applied: transversely in the x direction (Case I);transversely in the y direction (Case II); and parallel in the z direction (Case III). The three-dimensional governing equations with the associated boundary conditions for ferro-nanofluid flow and heat transfer have been solved by using an element-based finite volume method. The coupled algorithm has been used to solve the velocity and pressure fields. The convergence is reached when the accuracy of solutions attains 10–6 for the continuity and momentum equations and 10–9 for the energy equation. Findings According to thermal indicators the Case III has the best performance, but according to performance evaluation criterion (PEC) the Case II is the best. The simulation results show by increasing the Hartmann number from 0 to 12, there is an increase for PEC between 845.01% and 2997.39%, for thermal resistance between 155.91% and 262.35% and ratio of the maximum electronic chip temperature difference to heat flux between 155.16% and 289.59%. Also, the best thermo-hydraulic performance occurs at Hartmann number of 12, pressure drop of 10 kPa and volume fraction of 2%. Research limitations/implications The embedded electronic chip on the base plate generates heat flux of 60 kW/m2. Simulations have been performed for ferro-nanofluid with volume fractions of 1%, 2% and 3%, pressure drops of 10, 20 and 30 kPa and Hartmann numbers of 0, 3, 6, 9 and 12. Practical implications The authors obtained interesting results, which can be used as a design tool for magnetohydrodynamics micro pumps, microelectronic devices, micro heat exchanger and micro scale cooling systems. Originality/value Review of the literature indicated that there has been no study on the effects of magnetic field on thermal and thermo-hydraulic performances of ferro-nanofluid flow in a TMCHS, so far. In this three dimensional study, flow of ferro-nanofluid through a trapezoidal heat sink with five trapezoidal microchannels has been considered. In all of previous studies, in which the effect of magnetic field has been investigated, the magnetic field has been applied only in one direction. So as another innovation of the present research, the effect of applying magnetic field direction (transverse and parallel) on thermo-hydraulic behavior of TMCHS is investigated.

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Singh, K. P. "On Some Performance Parameters for Closed Feedwater Heaters". Journal of Pressure Vessel Technology 109, n.º 2 (1 de maio de 1987): 200–204. http://dx.doi.org/10.1115/1.3264896.

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This paper gives a brief synopsis of the thermo-dynamic imperative of the feedwater heater in the power cycle, followed by the development of two performance parameters. These two parameters, the “Flash Protection Index” (FPI) and the “Heater Time Constant,” are closely linked to the heater thermal/hydraulic performance, and can be used to avert operational problems by identifying them at the design stage. Finally, a method to size the vapor suppression plate for feedwater heaters is also presented.

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Alihosseini, Yousef, Mohammad Zabetian Targhi e Mohammad Mahdi Heyhat. "Thermo-hydraulic performance of wavy microchannel heat sink with oblique grooved finned". Applied Thermal Engineering 189 (maio de 2021): 116719. http://dx.doi.org/10.1016/j.applthermaleng.2021.116719.

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Krishnan, Easwaran N., Hadi Ramin, A. Guruabalan e Carey J. Simonson. "Experimental investigation on thermo-hydraulic performance of triangular cross-corrugated flow passages". International Communications in Heat and Mass Transfer 122 (março de 2021): 105160. http://dx.doi.org/10.1016/j.icheatmasstransfer.2021.105160.

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Ma, Chunjing, Alice Di Donna, Daniel Dias e Tingting Zhang. "Thermo-hydraulic and sensitivity analyses on the thermal performance of energy tunnels". Energy and Buildings 249 (outubro de 2021): 111206. http://dx.doi.org/10.1016/j.enbuild.2021.111206.

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35

Hasan, Ibtisam, Wafa Maki e Yaser Enaya. "Thermo-hydraulic performance evaluation of heat exchanger tube with vortex generator inserts". Thermal Science 26, n.º 2 Part B (2022): 1545–55. http://dx.doi.org/10.2298/tsci210528289h.

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This work is undertaken as a scientific experiment to test a new design of a turbulent generator. The current research experiments the influence of novel vortex generator inserts on heat transfers within a tube under a uniform heat flux. A Cu tube with a 45 mm inner diameter and 1350 mm length is used along with a solid disc injector (swirl generator) that comprises ten crescent holes with equal circumferential distribution angles around the disk canter. Subsequently, a swirl flow is generated by deviating the stream flow 45? causing it to spin in the direction of the axial flow. Flow directors are on 45? angles toward the axial direction for each of the crescent holes. This study is an example of flow degradation. Reynolds numbers range from 6000 to 13500. Therefore, fluid-flow is treated as a turbulent system. All experiments done with air are regarded as a power fluid and Prandtl number is fixed at about 0.71. Thermo-hydraulic performance of heat exchanger is analyzed. The average heat transfer Nusselt number is calculated and discussed. The experiment found out that Nusselt number increases with an increase in Reynolds number as well as the number of swirl generators. At four vortex generators, the maximum augmentation in heat transfer is around 4.3 times greater than the plain tube and friction factor is about 1.28 with 5 vortex generators insets. The results indicate a promising heat exchanger enhancement in the local petroleum industries.

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36

Singh, Ajeet Pratap, e O. P. Singh. "Thermo-hydraulic performance enhancement of convex-concave natural convection solar air heaters". Solar Energy 183 (maio de 2019): 146–61. http://dx.doi.org/10.1016/j.solener.2019.03.006.

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Panday, Nitesh K., e Shailendra N. Singh. "Thermo-hydraulic performance analysis of multi-pass chevron type plate heat exchanger". Thermal Science and Engineering Progress 16 (maio de 2020): 100478. http://dx.doi.org/10.1016/j.tsep.2020.100478.

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Dilip, D., S. Vijay Kumar, M. S. Bobji e Raghuraman N. Govardhan. "Sustained drag reduction and thermo-hydraulic performance enhancement in textured hydrophobic microchannels". International Journal of Heat and Mass Transfer 119 (abril de 2018): 551–63. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2017.11.093.

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Pahlavanzadeh, H., M. R. Jafari Nasr e S. H. Mozaffari. "Experimental study of thermo-hydraulic and fouling performance of enhanced heat exchangers". International Communications in Heat and Mass Transfer 34, n.º 7 (agosto de 2007): 907–16. http://dx.doi.org/10.1016/j.icheatmasstransfer.2007.04.002.

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Kim, Duck-Hoi, Min-Su Ha, Do-Hyeong Kim, Young-Seok Lee, Byoung-Chul Kim, Hee-Jae Ahn, Joo-Shik Bak, Ki-Jung Jung e Fu Zhang. "Thermo-Hydraulic Performance Analysis for Conceptual Design of ITER Blanket Shield Block". Fusion Science and Technology 60, n.º 1 (julho de 2011): 118–22. http://dx.doi.org/10.13182/fst11-a12337.

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41

Allauddin, Usman, Muhammad U. Rafique, Osama Malik, Osama Rashid, Ashir Waseem, Peter King, Mounia Karim e Heather Almond. "Investigation of the Thermo-hydraulic performance of a roughened Parabolic trough collector". Applied Thermal Engineering 219 (janeiro de 2023): 119523. http://dx.doi.org/10.1016/j.applthermaleng.2022.119523.

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42

Morales-Fuentes, A., G. T. Polley, M. Picón-Núñez e S. Martínez-Martínez. "Modeling the thermo-hydraulic performance of direct fired heaters for crude processing". Applied Thermal Engineering 39 (junho de 2012): 157–62. http://dx.doi.org/10.1016/j.applthermaleng.2012.01.055.

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43

Nitesh, Devaneyan, Murat Aydin, Eda Aydin e Antonio F. Miguel. "Heat Dissipation by Streams of Bifurcated Tubes". Defect and Diffusion Forum 412 (12 de novembro de 2021): 39–47. http://dx.doi.org/10.4028/www.scientific.net/ddf.412.39.

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There is a need for solutions to provide sufficient cooling from power devices, which produce large amounts of heat. This paper focuses on the influence of design of bifurcated fluid streams to dissipate heat. In this study, a single Y-tubes, a double Y-tubes, and an X-tubes designs are studied numerically under space constraints. For a comprehensive and in-depth performance analysis, both heat dissipation and hydraulic performances are analyzed. The distributions of velocity and temperature in the fluid streams is simulated, also the flow resistances and dissipated heat are calculated. Based on the results obtained, a thermo-hydraulic performance factor is introduced for the designs under study. In addition, the accumulation of undesired substances on the wall surface (fouling) that may influence the heat exchanging capability is studied.

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44

Yadav, Anil Singh, Tabish Alam, Gaurav Gupta, Rajiv Saxena, Naveen Kumar Gupta, K. Viswanath Allamraju, Rahul Kumar et al. "A Numerical Investigation of an Artificially Roughened Solar Air Heater". Energies 15, n.º 21 (29 de outubro de 2022): 8045. http://dx.doi.org/10.3390/en15218045.

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Solar air heating devices have been employed in a wide range of industrial and home applications for solar energy conversion and recovery. It is a useful technique for increasing the rate of heat transfer by artificially creating repetitive roughness on the absorbing surface in the form of semicircular ribs. A thermo-hydraulic performance analysis for a fully developed turbulent flow through rib-roughened solar air heater (SAH) is presented in this article by employing computational fluid dynamics. Both 2-dimensional geometrical modeling and numerical solutions were performed in the finite volume package ANSYS FLUENT. The renormalization-group (RNG) k-ε turbulence model was used, as it is suitable for low Reynolds number (Re) turbulent flows. A thermo-hydraulic performance analysis of an SAH was carried out for a ranging Re, 3800–18,000 (6 sets); relative roughness pitch (RRP), 5–25 (12 sets); relative roughness height (RRH), 0.03–0.06 (3 sets); and heat flux, 1000 W/m2. The numerical analysis revealed that with an RRP of 5 and an RRH of 0.06, the roughened duct produces the highest augmentation in average Nur in the order of 2.76 times that of a plain duct at an Re of 18,000. With an RRP = 10 and RRH = 0.06, the roughened duct was found to provide the most optimum thermo-hydraulic performance parameter (THPP). The THPP was determined to have a maximum value of 1.98 when the Re is equal to 15,000. It was found that semi-circular ribs which have a rib pitch = 20 mm and a rib height = 2 mm can be applied in an SAH to enhance heat transfer.

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Cao, Hao Ran, Rong Hua Huang e Jun Heng Li. "Optimization Design and Analysis for the First Wall of CH HCSB TMB Based on Thermal Hydraulic". Advanced Materials Research 724-725 (agosto de 2013): 681–85. http://dx.doi.org/10.4028/www.scientific.net/amr.724-725.681.

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The thermo-hydraulic performance of the first wall for CH HCSB TMB was investigated, corresponding analysis have been carried out using CFX, a computational fluid dynamics (CFD) code. The simulation results show that the maximum temperature 565°C of the FW is slightly above the allowable temperature limit 550°C of material. Base on the results so far, a modified design of the FW was presented, in which the radial-toroidal direction of cooling channels was changed to radial-poloidal. The thermo-hydraulic computational results show the temperature of the FW with modified design decrease over all, and the maximum temperature 504°C was below the allowable temperature limit for structural material. It is found that the modified design for the FW is reasonable so that the FW is effectively cooled.

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46

Zhang, Jiamin, Daniel Dias, Qiujing Pan, Chunjing Ma e Cristina de Hollanda Cavalcanti Tsuha. "Long-Term Thermo-Hydraulic Numerical Assessment of Thermo-Active Piles—A Case of Tropical Soils". Applied Sciences 12, n.º 15 (29 de julho de 2022): 7653. http://dx.doi.org/10.3390/app12157653.

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Thermo-active piles are an upcoming technology for the utilization of subsurface geothermal energy in urban areas. This environmentally friendly technology has already been widespread for the heating and cooling of buildings in temperate regions, whereas in tropical regions it is still limited due to their unbalanced energy demands. This paper presents 3D thermo-hydraulic coupled numerical simulations to assess the long-term performance of thermo-active pile systems in tropical environments for different energy demands. The simulations are based on real data (in situ tests and field investigations) considering three typical thermal solicitations, thereby maintaining their practical relevance. Moreover, the energy exchange within soil control volumes is quantified based on an approach that allows calculating conductive and advective divergence. Parametric analyses regarding thermal solicitation, pile diameter, and groundwater flow are also performed. The results indicate that groundwater flow plays the most important role in improving the thermal balance of thermo-active piles.

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Zou, Zhongyu, Zhigang Zhu, Qiyong Zhang e Pengcheng Yang. "Optimization investigation for heat transfer enhancement of fins for plate-fin heat exchangers in cryogenic helium systems". IOP Conference Series: Materials Science and Engineering 1301, n.º 1 (1 de maio de 2024): 012035. http://dx.doi.org/10.1088/1757-899x/1301/1/012035.

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Abstract In order to further improve heat transfer performance and high compactness of plate-fin heat exchangers (PFHEs) in cryogenic helium systems, a new type of perforated-serrated fins is proposed by combining traditional serrated and perforated fins. In this paper, the flow and heat transfer characteristics of helium in perforated-serrated fins and serrated fins channels at low-temperature are investigated using numerical simulations. The numerical model invokes the properties of low-temperature helium by NIST-Real-Gas-Model. Meanwhile, Colburn factor j, friction factor f and JF factor are qualitatively evaluated for pressure drop, heat transfer performance and thermo-hydraulic performance, respectively. The results show that new perforated-serrated fins have better heat transfer performance. The j factor of the new fins increases by 32.58% to 15.63% compared with serrated fins. The flow performance of perforated-serrated fins is slightly worse than that of serrated fins, but the overall thermo-hydraulic performance is better, especially at low Reynolds number. Compared with serrated fins, the JF factor of perforated-serrated fins is significantly higher and increase by 25.95% to 10.86%. The optimizing method of fins structure can be used in the actual design of PFHEs in cryogenic helium systems.

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48

Liu, Kui, Renato Zagorščak, Richard J. Sandford, Oliver N. Cwikowski, Alexander Yanushkevich e Hywel R. Thomas. "Insights into the Thermal Performance of Underground High Voltage Electricity Transmission Lines through Thermo-Hydraulic Modelling". Energies 15, n.º 23 (24 de novembro de 2022): 8897. http://dx.doi.org/10.3390/en15238897.

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In this paper, a flexible numerical framework to provide thermal performance assessment for the underground buried cables, considering different geological and meteorological conditions, has been presented. Underground cables tend to retain the heat produced in the conductor, so complex coupled thermo-hydraulic response of the porous medium surrounding the cables needs to be assessed to prevent cable overheating and the associated reduction in cable capacity for carrying current. Applying a coupled thermo-hydraulic model within the developed numerical framework to conduct a health assessment on a subset of National Grid Electricity Transmission’s underground cables, this study provides novel insights into the thermal behaviour of buried circuits. The results indicate that backfill and surrounding native soil have the dominant effect on the thermal behaviour of cables, while the amount of precipitation and ambient temperature were found to have less impact on cable’s thermal behaviour. The findings strongly infer that the nature of the overloading which is undertaken in practice would have no ongoing negative impact, suggesting that more frequent or longer duration overloading regimes could be tolerated. Overall, this study demonstrates how the developed numerical framework could be harnessed to allow safe rating adjustments of buried transmission circuits.

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49

Nguyen Minh e Pham Ba Thao. "Thermohydraulic Performance of a Fin and Inclined Flat Tube Heat Exchanger: A Numerical Analysis". CFD Letters 13, n.º 7 (25 de julho de 2021): 1–12. http://dx.doi.org/10.37934/cfdl.13.7.112.

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Proper determination of inclination angle of a flat tube may increase the overall heat transfer performance without extending heat transfer surface. In this paper, the inclined flat tube heat exchanger with plain fins is numerically investigated. The influence of flat tube inclination angle and Reynolds number on the thermo-hydraulic performance index was evaluated. Tube pitch, fin spacing and flat tube size are fixed. Solving 3D computational domain with the symmetric boundary condition is used to reduce computation time. The results show that when increasing the inclination angle of the flat tube from 0 to 45°, both heat transfer and pressure loss increase because the free area of air flow decreases leading to an increase in air velocity and impingement heat transfer. The variation of inclination angle from 0 to 15°, the increase in heat transfer is stronger than the increase in the pressure loss penalty, so the performance index reaches a maximum of 0.405 at the angle of 15°. Contours of temperature, pressure and velocity at different inclination angles are presented to clarify the thermo-hydraulic characteristics of finned-tube heat exchangers using inclined flat tubes. The current work yields heat transfer enhancement ability by adjusting inclination angle of a heat transfer flat tube.

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50

Alam, Tabish, Chandan Swaroop Meena, Nagesh Babu Balam, Ashok Kumar e Raffaello Cozzolino. "Thermo-Hydraulic Performance Characteristics and Optimization of Protrusion Rib Roughness in Solar Air Heater". Energies 14, n.º 11 (28 de maio de 2021): 3159. http://dx.doi.org/10.3390/en14113159.

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To enhance the thermal performance of solar air heaters (SAHs), protrusion ribs on the absorber are considered to be an attractive solution due to their several advantages. These ribs do not cause a significant pressure drop in the SAH duct and help to enhance the heat transfer to flowing air. On the other hand, a degree of roughness of the protrusion rib on the absorber can be produced by pressing the indenting device without adding additional mass. In this paper, the thermo-hydraulic performances of different roughnesses of the conical protrusion rib on the absorber plate have been evaluated by the mutual consideration of thermal as well as hydraulic performance in term of net effective efficiency. Therefore, an analytical technique has been exploited to predict the characteristics of the net effective efficiency under various operating conditions, such as the flow Reynolds number, temperature increase parameter and insolation. The effects of the conical protrusion rib roughness—namely the relative rib pitch (p/e) and relative rib height e/D) in the ranges of 6–12 and 0.200–0.044, respectively—have been evaluated. The highest value of net effective efficiency of 70.92% was achieved at a p/e of 10 and e/D of 0.0289. The optimization of the rib parameters has been carried out in different ranges of temperature increase parameters for the highest values of net effective efficiency. A unique combination of rib parameters—a p/e of 10 and e/D of 0.044—are observed to lead to the best performance when operating a solar air heater with a temperature increase parameter of more than 0.00789 K·m2/W.

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