Thermophysics and Aeromechanics最新文献

Features of nitrogen boiling dynamics on microstructured porous coatings 微结构多孔涂层上的氮沸腾动力学特征

IF 0.5 4区工程技术

Thermophysics and Aeromechanics Pub Date : 2024-12-13 DOI: 10.1134/S0869864324030107

D. V. Kuznetsov, A. N. Pavlenko

引用次数: 0

Experimental study of the influence of supersonic boundary-layer suction on its stability to controlled disturbances 超音速边界层吸力对受控扰动稳定性影响的实验研究

IF 0.5 4区工程技术

Thermophysics and Aeromechanics Pub Date : 2024-12-13 DOI: 10.1134/S0869864324030041

V. I. Lysenko, B. V. Smorodsky, Yu. G. Yermolaev, S. N. Tagaev, A. D. Kosinov

引用次数: 0

Numerical simulation of effective turbulent heat transfer at transverse streamlining of a rod bundle 杆束横向流线处有效湍流传热的数值模拟

IF 0.5 4区工程技术

Thermophysics and Aeromechanics Pub Date : 2024-12-13 DOI: 10.1134/S0869864324030065

M. V. Bayaskhalanov, I. G. Merinov, M. I. Pisarevskiy, V. S. Kharitonov, A. E. Aksenova, V. A. Pervichko, V. V. Chudanov

引用次数: 0

Experimental study of interfacial mass transfer for the transition from slug to bubbly flow in a rectangular microchannel 矩形微通道中从蛞蝓流向气泡流的界面传质实验研究

IF 0.5 4区工程技术

Thermophysics and Aeromechanics Pub Date : 2024-12-13 DOI: 10.1134/S0869864324030144

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

{"title":"Experimental study of interfacial mass transfer for the transition from slug to bubbly flow in a rectangular microchannel","authors":"G. V. Bartkus, N. A. Filatov, A. S. Bukatin, V. V. Kuznetsov","doi":"10.1134/S0869864324030144","DOIUrl":"10.1134/S0869864324030144","url":null,"abstract":"<div>The structure of a gas-liquid flow and interfacial mass transfer during the transition from the slug to the bubbly flow of ethanol-CO2 mixture in a horizontal straight microchannel were experimentally studied. The experiments were performed for a channel with a rectangular cross section of 141×385 µm in the range of superficial gas and liquid velocities JG = 0.16–0.8 m/s and JL = 0.22–0.5 m/s. To determine a change in the volume of the elongated bubble along the microchannel length due to CO2 absorption, the method of high-speed visualization with subsequent image processing was applied. The bubble frequency, velocity, size, and change in the volume of gas slugs and bubbles along the channel were measured, and volumetric coefficient of mass transfer from liquid kLa was calculated. The measured volumetric mass transfer coefficient was compared with the known correlations and a new correlation was proposed for the transition from the slug to the bubbly flow due to interfacial mass transfer.</div>","PeriodicalId":800,"journal":{"name":"Thermophysics and Aeromechanics","volume":"31 3","pages":"513 - 522"},"PeriodicalIF":0.5,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821423","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

Stability of a high-speed boundary layer over a plate with graphite coating sublimation 带有石墨涂层升华的板上高速边界层的稳定性

IF 0.5 4区工程技术

Thermophysics and Aeromechanics Pub Date : 2024-12-13 DOI: 10.1134/S0869864324030028

S. A. Gaponov, B. V. Smorodsky

{"title":"Stability of a high-speed boundary layer over a plate with graphite coating sublimation","authors":"S. A. Gaponov, B. V. Smorodsky","doi":"10.1134/S0869864324030028","DOIUrl":"10.1134/S0869864324030028","url":null,"abstract":"<div>The paper presents results of a theoretical study for parameters of a compressible boundary layer for the case of a re-entry space vehicle flying in atmosphere with the free flow at Mach 6 ≤ M ≤ 10 with sublimation of the carbon coating (graphite). Since a high flight velocity results in a higher wall temperature and a higher mass loss rate, the effect of wall material evaporation decreases the wall temperature as compared with the case of zero-sublimation flow. All that increases the gas mixture density in the sublimation vapor cloud nearby the wall; this is beneficial for stability of the high-speed boundary layer in the response to the first-mode disturbance. As for the second mode disturbances, the lower values of spatial amplification rate with increasing Mach number is observed due to the surface material sublimation. The position of laminar-turbulent transition was evaluated using the eN method. Our computations demonstrated that (for a flow with M = 6) the surface sublimation has no influence for laminar-turbulent transition; this transition is governed by the growth of three-dimensional (3D) first mode disturbances. At higher Mach numbers (for M = 8 and higher) we observe that the disturbance amplification rate in the downstream direction becomes smaller. The transition is driven by a 2D second mode. The graphite coating sublimation has destabilizing influence for the second mode; that accelerates the boundary layer transition to turbulence.</div>","PeriodicalId":800,"journal":{"name":"Thermophysics and Aeromechanics","volume":"31 3","pages":"411 - 429"},"PeriodicalIF":0.5,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821437","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

A method for determining the heat and mass transfer efficiency in a film cooling tower with intensified fill packs 确定带强化填料的薄膜冷却塔传热和传质效率的方法

IF 0.5 4区工程技术

Thermophysics and Aeromechanics Pub Date : 2024-12-13 DOI: 10.1134/S0869864324030090

A. G. Laptev, E. A. Lapteva

{"title":"A method for determining the heat and mass transfer efficiency in a film cooling tower with intensified fill packs","authors":"A. G. Laptev, E. A. Lapteva","doi":"10.1134/S0869864324030090","DOIUrl":"10.1134/S0869864324030090","url":null,"abstract":"<div>A modified method of transfer units is developed for a countercurrent film cooling tower with a structured tubular packing with surface intensifiers in order to determine the thermal efficiency of the gas and liquid phases and the temperature of the cooled water at the output. The approach of presenting the number of transfer units, taking into account additional terms with reverse mixing coefficients is applied to indirectly consider the hydrodynamic structure of flows and a decrease in the heat and mass transfer efficiency, compared with the ideal displacement model. An experimental installation with a layout (column) of a Plexiglass cooling tower with a diameter of 200 mm and a height of 2 m is described. Experimental data for water cooling in a structured packing block in the form of a vertical bundle of tightly packed polyethylene pipes with a diameter of 0.05 m with an annular discretely structured surface roughness are presented. Generalized calculated empirical expressions for the drag of dry and irrigated pipes, as well as the dependence of the volumetric mass transfer coefficient on air velocity at different irrigation densities, are obtained. The parameters of expression of the modified number of transfer units are identified based on experimental data on thermal efficiency in the gas phase. As a result, the dependence of the thermal efficiency in the gas phase on the pressure and design characteristics of the structured packing is obtained taking into account the reverse mixing of the flows. Reverse mixing is shown to reduce thermal efficiency by 8 – 15 %, which must be taken into account in the calculations of film cooling towers. The calculation results for the SK-400 industrial cooling tower using the presented expressions are provided and the agreement of the thermal efficiency of the cooling tower with the calculation according to the proposed method is shown.</div>","PeriodicalId":800,"journal":{"name":"Thermophysics and Aeromechanics","volume":"31 3","pages":"469 - 479"},"PeriodicalIF":0.5,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821431","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

Plasma technology for producing hydrogen and carbon black from hydrocarbon gases 利用烃类气体生产氢气和炭黑的等离子技术

IF 0.5 4区工程技术

Thermophysics and Aeromechanics Pub Date : 2024-12-13 DOI: 10.1134/S086986432403017X

V. E. Messerle, A. B. Ustimenko

引用次数: 0

Numerical investigation of entropy generation induced by assisted mixed convection in a vertical convergent channel: effects of geometric parameters 垂直辐合通道中辅助混合对流诱导熵产的数值研究：几何参数的影响

IF 0.5 4区工程技术

Thermophysics and Aeromechanics Pub Date : 2024-12-13 DOI: 10.1134/S0869864324030211

A. Abidi-saad, S. Hadjadj, S. Saouli, G. Polidori

{"title":"Numerical investigation of entropy generation induced by assisted mixed convection in a vertical convergent channel: effects of geometric parameters","authors":"A. Abidi-saad, S. Hadjadj, S. Saouli, G. Polidori","doi":"10.1134/S0869864324030211","DOIUrl":"10.1134/S0869864324030211","url":null,"abstract":"<div>In this paper, the analysis of the 2nd law of thermodynamics characteristics of assisted mixed convection heat transfer coupled with fluid flow within a vertical convergent isothermal channel is numerically carried out. The numerical model is undertaken for 2D, laminar and steady flow using finite volume approach and air as working fluid. The analysis focused on two pertinent geometric situations namely the variation of the minimal distance (Dmin) of the convergent channel while keeping the convergence angle fixed, and the change of the latter (2°, 10°, and 20°) while Dmin kept unchanged. Whereas, Dmax was used as the characteristic length. The measurements are performed for the following buoyancy-assisted cases: upward/downward flow within hot/cold walls. Several buoyancy parameters are considered ranging from 0.1 to 10 at Reynolds number equal to 100. The effect the aforementioned geometric parameters on entropy production and its distribution is investigated. The results revealed that the energy degradation is dominated by heat transfer irreversibility. Also, this latter is more influenced by Dmin variations.</div>","PeriodicalId":800,"journal":{"name":"Thermophysics and Aeromechanics","volume":"31 3","pages":"599 - 617"},"PeriodicalIF":0.5,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142821407","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

Investigating the contact thermal resistances of lead in a heat conducting sublayer 研究导热子层中铅的接触热阻

IF 0.5 4区工程技术

Thermophysics and Aeromechanics Pub Date : 2024-12-13 DOI: 10.1134/S0869864324030119

A. B. Kruglov, V. I. Rachkov, I. G. Merinov, V. S. Kharitonov, L. P. Paredes

引用次数: 0

Effect of reduced frequency on kinematics of self-excited oscillations for a conical-spherical body at Mach number M = 1.75 降低频率对马赫数 M = 1.75 时锥球体自激振荡运动学的影响

IF 0.5 4区工程技术

Thermophysics and Aeromechanics Pub Date : 2024-12-13 DOI: 10.1134/S0869864324030053

E. A. Chasovnikov

引用次数: 0