Journal of Engineering Thermophysics最新文献_第6页

Mg–Li–Ca Eutectic Alloy. Phase Transitions and Thermophysical Properties 镁-锂-钙共晶合金。相变和热物理性质

IF 1.3 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2024-09-18 DOI: 10.1134/S1810232824030184

R. N. Abdullaev, A. Sh. Agazhanov, R. A. Khairulin, Yu. M. Kozlovskii, D. A. Samoshkin, S. V. Stankus

{"title":"Mg–Li–Ca Eutectic Alloy. Phase Transitions and Thermophysical Properties","authors":"R. N. Abdullaev, A. Sh. Agazhanov, R. A. Khairulin, Yu. M. Kozlovskii, D. A. Samoshkin, S. V. Stankus","doi":"10.1134/S1810232824030184","DOIUrl":"10.1134/S1810232824030184","url":null,"abstract":"A homogeneous eutectic alloy of the magnesium-lithium-calcium ternary system containing 72.5 at.% magnesium, 19.1 at.% lithium, and 8.4 at.% calcium was prepared. Experimental studies of the relative elongation, density, thermal expansion, heat capacity, thermal diffusivity and thermal conductivity of this ultralight alloy were performed in the temperature range of 120 K to 710 K. The behavior of density and thermal expansion in the melting-crystallization region and in the liquid state was also studied. A comparison with previously obtained results on the thermophysical properties of pure magnesium and magnesium-lithium, magnesium-calcium eutectic alloys was made. The temperature dependences were constructed and the table of the investigated properties recommended values were presented. It was found that in the Mg–Li–Ca alloy a phase transition occurs in the range of 225 K to 245 K, where the heat capacity and the linear thermal expansion coefficient change abruptly. This kind of transition was found earlier in the study of the Mg–Li eutectic alloy and is presumably related to the martensitic transformation of the lithium-rich bcc magnesium-lithium alloys to the hcp structure.","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"33 3","pages":"663 - 674"},"PeriodicalIF":1.3,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142250333","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}

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Hysteresis Phenomena at Boiling in Liquid Film Flowing down the Tubes with Microarc Oxidation Coating 带微弧氧化涂层的液膜流下管时的沸腾滞后现象

IF 1.3 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2024-09-18 DOI: 10.1134/S1810232824030019

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

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Mathematical Modeling of Reverse Processes with Consideration of the Water–Ice Phase Transition 考虑水冰相变的逆过程数学建模

IF 1.3 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2024-09-18 DOI: 10.1134/S1810232824030081

I. V. Mezentsev, N. V. Vernikovskaya, P. S. Melkov, S. I. Mezentsev, N. N. Mezentseva

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A Study of Low Global Warming Potential Refrigerants to Replace R123 for Chiller Application 冷风机应用中替代 R123 的低全球升温潜能值制冷剂研究

IF 1.3 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2024-09-18 DOI: 10.1134/S1810232824030147

L. Zhang, J. Zhao, L. Mu, H. Fang

{"title":"A Study of Low Global Warming Potential Refrigerants to Replace R123 for Chiller Application","authors":"L. Zhang, J. Zhao, L. Mu, H. Fang","doi":"10.1134/S1810232824030147","DOIUrl":"10.1134/S1810232824030147","url":null,"abstract":"The raising concern about climate change and global warming provides the searching for more environmental friendly refrigerants for chiller applications. In this study, an investigation for low GWP refrigerants to replace R123 has been conducted for evaluation for chiller systems. R1233zd(E), R1234ze(E), R1234yf, R290, and R600 have been compared with R123 under different effecting factors. R1233zd(E) and R600 display a close COP performance when compared with the baseline R123, while other R123 alternatives present a low COP level (more than 5% COP decrease from baseline R123). R290 displays the highest value of the compressor impeller speed while R123 the lowest. In general, R1233zd(E) is preferred for drop-in option to replace R123 due to close COP and unit capacity by volume. R1234ze(E), R1234yf, and R290 are preferred for chiller down-size options. Increasing evaporating temperature from 1°C to 5°C can display more than 15% COP enhancement and it does not have the significant change for the mass flow rate and the compressor impeller speed. The condensing temperature increase from 30°C to 40°C has significant influence on the system COP drop, with (sim30)% COP decrease there. Increasing the compressor isentropic efficiency from 0.6 to 0.8 can make the COP increased by more than 30%, and make the compressor power consumption to be reduced by more than 24%. From the single-stage cycle chiller system to the two-stage cycle chiller system, the COP can be improved by 3.0% for R123, 3.1% for R1233zd(E), 4.4% for R1234ze(E), 5.1% for R1234yf, 4.0% for R290, and 3.5% for R600, respectively. In general, R1234yf is more sensitive for the cycle improvement.","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"33 3","pages":"622 - 636"},"PeriodicalIF":1.3,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142250328","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}

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Experimental Study of Flow Crisis and Flow Structure in Ranque–Hilsch Vortex Tube 兰克-希尔施涡旋管中的流动危机和流动结构的实验研究

IF 1.3 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2024-07-17 DOI: 10.1134/S1810232824020073

M. H. Pravdina, I. K. Kabardin, S. V. Kakaulin, K. S. Zubanov, M. R. Gordienko, G. V. Bakakin, V. G. Meledin, V. I. Polyakova, N. I. Yavorskii

{"title":"Experimental Study of Flow Crisis and Flow Structure in Ranque–Hilsch Vortex Tube","authors":"M. H. Pravdina, I. K. Kabardin, S. V. Kakaulin, K. S. Zubanov, M. R. Gordienko, G. V. Bakakin, V. G. Meledin, V. I. Polyakova, N. I. Yavorskii","doi":"10.1134/S1810232824020073","DOIUrl":"10.1134/S1810232824020073","url":null,"abstract":"The work investigates the relationship between the energy separation in a Ranque–Hilsch tube and flow crisis manifestation in a translational swirling flow. The laser Doppler anemometry was used for the measurement of the transverse profiles of circumferential and longitudinal velocities in the mid-section along the entire length of the working channel in a vortex tube with a square cross-section. Analysis of the experimental data revealed signs of a series of hydraulic jumps that realize structural transitions from supercritical flow regimes of a near-wall swirl flow with longitudinal velocity exceeding the critical one to subcritical regimes, the longitudinal velocity in which is less than the critical one. The identified features suggest that there may be an increase in temperature in the near-wall flow due to the conversion of excess kinetic energy released during hydraulic jumps into heat, while conserving the momentum flow. A number of phenomena associated with the Ranque effect are discussed within the concept of crisis of a translational swirling flow and the more general concept of vortex breakdown.","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"33 2","pages":"316 - 328"},"PeriodicalIF":1.3,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141721586","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 of Interphase Mass Transfer for Gas-Liquid Flow in Microchannel with Successive Contractions and Expansions 微通道中连续收缩和膨胀的气-液流动的相间传质实验研究

IF 1.3 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2024-07-17 DOI: 10.1134/S1810232824020140

G. V. Bartkus, N. A. Filatov, A. S. Bukatin, V. V. Kuznetsov

{"title":"Experimental Study of Interphase Mass Transfer for Gas-Liquid Flow in Microchannel with Successive Contractions and Expansions","authors":"G. V. Bartkus, N. A. Filatov, A. S. Bukatin, V. V. Kuznetsov","doi":"10.1134/S1810232824020140","DOIUrl":"10.1134/S1810232824020140","url":null,"abstract":"The results of an experimental study on the gas-liquid flow structure and interphase mass transfer are presented for a periodic slug flow of ethanol-CO2 mixture in a straight microchannel and a microchannel with a sudden change in the cross-section. The experiments were carried out for a microchannel with successive contractions and expansions along its length and average cross-section of (132times 387) (mu)m2. For determination of the change in the volume of the gas slug along the microchannel length because of CO2 absorption, the method of high-speed flow visualization was used, followed by digital image processing. The frequency of generation, speed, size, and volume variation of the gas bubbles were measured along the length of the channel. From the data obtained, the volumetric mass transfer coefficient from the liquid side was determined. A comparison was made of the obtained volumetric mass transfer coefficient for the straight channel and for the channel with sudden enlargement of the cross-section: slight enhancement of the mass transfer in the channel with the sudden change in the cross-section, resulting from the pulsating shape of the bubbles, has been shown.","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"33 2","pages":"397 - 405"},"PeriodicalIF":1.3,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141721593","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

Heat Transfer during Boiling in Horizontal Layers of HFE-7100 on Smooth and Modified Surfaces HFE-7100 水平层在光滑表面和改性表面上沸腾时的热传递

IF 1.3 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2024-07-17 DOI: 10.1134/S1810232824020024

D. A. Shvetsov, A. N. Pavlenko, V. I. Zhukov

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Heat Transfer during Downflow Condensation of R21 in Plate-Fin Heat Exchanger with Inclined Texture 具有倾斜纹理的板翅式热交换器中 R21 的下流冷凝过程中的热传递

IF 1.3 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2024-07-17 DOI: 10.1134/S1810232824020048

V. V. Kuznetsov, A. S. Shamirzaev

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Evaporation of Water Droplets and Corrosion on Various Graphene Coatings 各种石墨烯涂层上的水滴蒸发和腐蚀情况

IF 1.3 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2024-07-17 DOI: 10.1134/S181023282402005X

S. Y. Misyura, V. S. Morozov, V. A. Andryushchenko, D. V. Smovzh, E. G. Orlova, D. V. Feoktistov, S. P. Bondarchuk, G. E. Kotelnikov, V. G. Makotchenko

{"title":"Evaporation of Water Droplets and Corrosion on Various Graphene Coatings","authors":"S. Y. Misyura, V. S. Morozov, V. A. Andryushchenko, D. V. Smovzh, E. G. Orlova, D. V. Feoktistov, S. P. Bondarchuk, G. E. Kotelnikov, V. G. Makotchenko","doi":"10.1134/S181023282402005X","DOIUrl":"10.1134/S181023282402005X","url":null,"abstract":"The wettability, evaporation droplets, and corrosion were experimentally studied for textured copper samples with graphene and smooth copper samples with fluorographene. With increase in the fluorination time, the wettability on fluorographene surfaces grew. Textured graphene surfaces have shown the maximum starting contact angle of 93°. Unlike smooth surfaces with graphene, the textures had a more stable contact line. With the fluorination time increase from 20 to 240 hours, inhomogeneous structures were formed on the surface of fluorographene, which led to roughness increase 2.6–2.7 times. With longer fluorination of graphene, the corrosion current became higher, which is associated with the defectiveness and high hydrophilicity of the surface. With longer fluorination time, the corrosion current became 1.6 times higher. As (EDS) analysis showed, corrosion led to about 10 to 15-fold decrease in the amount of fluorine on fluorographene. The highest anti-corrosion properties were demonstrated by a copper sample subjected to laser texturing, on which several layers of graphene were synthesized.","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"33 2","pages":"289 - 302"},"PeriodicalIF":1.3,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141721529","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}

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Heat Transfer in Liquid Film Falling Down Vertical Cylinder with Single-Layer and Gradient Two-Layer Mesh Coatings 带有单层和梯度双层网状涂层的垂直圆柱体液膜下坠时的热传递

IF 1.3 4区工程技术

Journal of Engineering Thermophysics Pub Date : 2024-07-17 DOI: 10.1134/S1810232824020036

O. A. Volodin, N. I. Pecherkin, S. V. Konev, M. K. Das, A. N. Pavlenko

{"title":"Heat Transfer in Liquid Film Falling Down Vertical Cylinder with Single-Layer and Gradient Two-Layer Mesh Coatings","authors":"O. A. Volodin, N. I. Pecherkin, S. V. Konev, M. K. Das, A. N. Pavlenko","doi":"10.1134/S1810232824020036","DOIUrl":"10.1134/S1810232824020036","url":null,"abstract":"The paper presents the results of a study of heat transfer in laminar-wave liquid films falling down the outer surface of a vertical cylinder. As intensifiers of heat transfer during boiling, single-layer micromesh coatings with different geometric characteristics and a two-layer gradient mesh coating were used. The working liquid was mixture of refrigerants R114-R21 with the initial concentration of the low-boiling component (R114) equal to 12%. The film Reynolds number at the entrance to the test section varied from 400 to 1300; the heat flux density varied in the range of 0–6 W/cm2. The results of measuring the heat transfer coefficients in the regimes of evaporation and nucleate boiling of the film are presented. A comparison is made of the results obtained on the single-layer and two-layer mesh coatings, as well as with previously obtained data for a combined coating (created by the method of deformational cutting in combination with a mesh coating). It has been shown that, in comparison with the smooth surface, the heat transfer coefficient during boiling of the falling film can be increased up to 2 times with the single-layer mesh coating and up to 1.7 times with the two-layer gradient mesh coating.","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"33 2","pages":"269 - 282"},"PeriodicalIF":1.3,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141721587","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