Journal of Engineering Thermophysics最新文献_第7页

Structure of Liquid Jets and Wetting Front in the Refrigerant Mixture Falling Films at Various Contact Angles 不同接触角下制冷剂混合物落膜中的液体射流和润湿前沿的结构

IF 1.3 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2023-12-14 DOI: 10.1134/S1810232823040021

A. Yu. Sakhnov, A. N. Pavlenko, N. I. Pecherkin, O. A. Volodin

{"title":"Structure of Liquid Jets and Wetting Front in the Refrigerant Mixture Falling Films at Various Contact Angles","authors":"A. Yu. Sakhnov, A. N. Pavlenko, N. I. Pecherkin, O. A. Volodin","doi":"10.1134/S1810232823040021","DOIUrl":"10.1134/S1810232823040021","url":null,"abstract":"The paper presents 3D numerical modeling of spreading dynamics of R21 (mol. fraction: 0.9) and R114 refrigerant mixture film. We considered an outer flow along a round vertical cylinder at Reynolds number 104 and contact angles of 10°, 30°, 50°, 70°, and 90°. The simulation was performed in OpenFOAM software on the basis of the volume of fluid (VOF) method. Simulated results show an occurrence of the liquid jets flowing from the upper continuous falling film in the range of contact angles 30°–90°, while the liquid flow at contact angle of 10° keeps the only continuous film till the bottom boundary of the cylinder. We defined two scenarios for wetting of the cylinder sidewall at different contact angles: liquid near the contact line moves down and towards to the cylinder surface at (theta = 10^circ), 30°, and 50°, while only vertical velocity differs from zero at (theta = 70^circ) and 90°, excluding jets at (theta = 70^circ). The increase of the contact angle leads to complication of the structure of the refrigerant mixture falling films, arising of jets and redistribution of flow rate between them.","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"32 4","pages":"672 - 691"},"PeriodicalIF":1.3,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138630641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Experimental Study and Analysis of Turbulent Natural Convection at Isothermal Vertical Plate 等温垂直板湍流自然对流的实验研究与分析

IF 1.3 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2023-12-14 DOI: 10.1134/S1810232823040082

A. G. Kirdyashkin, A. A. Kirdyashkin

引用次数: 0

Evaporation and Boiling Heat Transfer at Film Irrigation of Horizontal Roughened Tubes 水平粗化管薄膜灌溉时的蒸发和沸腾传热

IF 1.3 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2023-12-14 DOI: 10.1134/S181023282304001X

A. N. Pavlenko, A. I. Kataev, I. B. Mironova

引用次数: 0

Saturated Pool Boiling Heat Transfer of R-141b on Al2O3 Nano-Structured Surfaces Fabricated by Dip-Coating Method 浸涂法制造的 Al2O3 纳米结构表面上 R-141b 的饱和池沸腾传热

IF 1.3 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2023-12-14 DOI: 10.1134/S1810232823040100

A. S. Katarkar, A. D. Pingale, S. Satpathy, V. Goyal, B. Majumder, A. Saha, S. Bhaumik

{"title":"Saturated Pool Boiling Heat Transfer of R-141b on Al2O3 Nano-Structured Surfaces Fabricated by Dip-Coating Method","authors":"A. S. Katarkar, A. D. Pingale, S. Satpathy, V. Goyal, B. Majumder, A. Saha, S. Bhaumik","doi":"10.1134/S1810232823040100","DOIUrl":"10.1134/S1810232823040100","url":null,"abstract":"In pool boiling applications, appropriate surface properties of the heating surface are crucial for improving the heat transfer. In this study, two different Al2O3 nano-structured surfaces were fabricated using dip-coating method by controlling coating thickness, and adopted to conduct pool boiling experiments with R-141b. Prepared Al2O3 nano-structured surfaces were characterized by scanning electron microscopy (SEM), elemental dispersive spectroscopy (EDS), ellipsometer, contact angle meter, and 2D profilometer to investigate the surface morphology, elemental composition, thickness, angle of contact, and surface roughness, respectively. Based on the surface characterization and boiling curves, the effects of coating thickness (300 nm and 400 nm) on the pool boiling heat transfer were examined. The heat transfer coefficient (HTC) of Al2O3 nano-structured surface (S2) was the highest, followed by those of Al2O3nano-structured surface (S1), and plain copper surface. The outstanding heat transfer performance of Al2O3 nano-structured surfaces is mainly associated with enhanced surface wettability and increased active nucleation site density.","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"32 4","pages":"776 - 787"},"PeriodicalIF":1.3,"publicationDate":"2023-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138629689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Influence of Nonuniform Irrigation of Structured Packing on Heat and Mass Transfer in Distillation Column 规整填料非均匀灌溉对精馏塔传热传质的影响

IF 2.4 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2023-11-08 DOI: 10.1134/S1810232823030013

I. I. Gogonin

引用次数: 0

Theoretical Study of Formation of Hydrates from High-Concentration Metastable Solution of Carbon Dioxide in Water at Various Gas Concentrations 不同气体浓度下二氧化碳在水中的高浓度亚稳态溶液形成水合物的理论研究

IF 2.4 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2023-11-08 DOI: 10.1134/S1810232823030074

K. V. Gets, R. K. Zhdanov, Y. Y. Bozhko, O. S. Subbotin, V. R. Belosludov

引用次数: 0

Calculation of Heat Loads in Analysis of Superorbital Entry of Spacecraft into Atmosphere of the Earth 航天器超轨道进入地球大气层分析中的热负荷计算

IF 2.4 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2023-11-08 DOI: 10.1134/S1810232823030050

D. L. Reviznikov, A. V. Nenarokomov, M. S. Konstantinov, I. A. Nikolichev, A. V. Morzhukhina, L. M. Chernova

引用次数: 0

Thermal Conductivity and Thermal Diffusivity of Mg–Ca Eutectic Alloys in Solid State 固态Mg–Ca共晶合金的热导率和热扩散率

IF 2.4 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2023-11-08 DOI: 10.1134/S1810232823030049

A. Sh. Agazhanov, R. N. Abdullaev, D. A. Samoshkin, S. V. Stankus

引用次数: 0

Enhancement of Heat Transfer Rate with a Low-Pressure Drop in Shell and Tube Heat Exchanger through Optimal Spacing of Helical Baffle 优化螺旋折流板间距提高管壳式换热器低压降传热率

IF 2.4 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2023-11-08 DOI: 10.1134/S1810232823030104

S. K. Prasad, M. K. Sinha

{"title":"Enhancement of Heat Transfer Rate with a Low-Pressure Drop in Shell and Tube Heat Exchanger through Optimal Spacing of Helical Baffle","authors":"S. K. Prasad, M. K. Sinha","doi":"10.1134/S1810232823030104","DOIUrl":"10.1134/S1810232823030104","url":null,"abstract":"Shell and tube heat exchangers are used in factories for heat exchangers. Major issues of these heat exchangers are low heat, low frequency and high-pressure drop. Numerical study of the difference between gap and angle of barrier in volume firth and outlet move medium is determined for variation or movement of pipes to accept flow medium. Each baffle system is considered under the variation of flow medium controlled in the path and heat exchanger. It defines the variation of surface and heat exchanger with the flow of hot and cold fluid in surface and heat exchanger and the number of baffle structures. The number of turn units (NTU), overall heat exchanger coefficient (U) and efficiency ((varepsilon)) are evaluated based on different Reynolds numbers (Rec) on the shell side (17693–30331). On the surface edge of the proposed method, the pressure drop is evaluated as the loss of strength from the system. In addition, the impact of inlet cooling fluid temperature, baffle spacing and baffle cutting ratio (BCR) is analyzed and discussed. As the results in all cases, the proposed configuration significantly increases the efficiency of heat exchangers compared to the other two configurations. The proposed method, reducing the pressure drop by 12.40%–11.22%, increases U, (varepsilon) and NTU by 4.51%, 2.87%–4.51% and 5.78%–8.17% respectively.","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"32 3","pages":"532 - 559"},"PeriodicalIF":2.4,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71909642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Entropy and Exergy Analysis in an Experimental Thermal System Used GO–DW Nanofluid Having Straight Copper Pipes with Different Diameters 不同直径直管GO–DW纳米流体实验热系统的熵和火用分析

IF 2.4 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2023-11-08 DOI: 10.1134/S1810232823030177

N. Ocak, K. Karabulut

{"title":"Entropy and Exergy Analysis in an Experimental Thermal System Used GO–DW Nanofluid Having Straight Copper Pipes with Different Diameters","authors":"N. Ocak, K. Karabulut","doi":"10.1134/S1810232823030177","DOIUrl":"10.1134/S1810232823030177","url":null,"abstract":"Entropy and exergy analysis of a thermal system are the most powerful tools that can be employed to specify the optimum operating conditions of that system and utilization rate from the system. In the experimental thermal system in this work, entropy generation and exergy analyzes of GO–DW nanofluids have been carried out in straight copper pipes with constant heat load and 8 mm and 16 mm inner diameters. While the heat loads applied to the pipes are 250 W and 350 W, the range of fluid flow rate values in the pipes is 0.9 l/min–1.8 l/min. GO–DW nanofluids with 0.01% and 0.02% volumetric concentrations and DW have been used as working fluids in the pipes. The outcomes acquired from this work have been matched with the studies using different nanofluids in the literature and it has been noticed that the outcomes are reasonable and consistent. The results of the study have been presented at different GO–DW nanofluid concentrations in pipes with 8 mm and 16 mm inner diameters as thermal, friction and total entropy production, output exergy ratio and 2nd law efficiency. The obtained outcomes have exhibited that the lowest total entropy generation has been obtained for the 8 mm diameter pipe and the nanofluid with 0.02% GO–DW concentration. Besides, 2nd law efficiency is 12% higher for the 8 mm diameter pipe than 16 mm at flow rate of 1.2 l/min and 0.02% GO–DW nanofluid, and 350 W heat load.","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"32 3","pages":"637 - 655"},"PeriodicalIF":2.4,"publicationDate":"2023-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"71909577","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0