Journal of Engineering Thermophysics最新文献

{"title":"Dynamics of Condensation and Evaporation of Liquid Nitrogen in a Closed Vessel Pressurized with Helium, Nitrogen, and Their Mixture","authors":"V. I. Trushlyakov,&nbsp;A. N. Pavlenko,&nbsp;V. E. Zhukov,&nbsp;V. A. Urbansky,&nbsp;N. N. Mezentseva","doi":"10.1134/S1810232824020012","DOIUrl":"10.1134/S1810232824020012","url":null,"abstract":"<p>Pressurization systems for propellant tanks of launch vehicles (LVs) with a liquid rocket engine are complex LV systems to provide cavitation-free operation of pumps and constant pressure in the gas cushion of the fuel tanks at constant consumption of liquid components of rocket propellant. There were already studies on the influence of the pressurant type on the heat and mass transfer in the LV propellant tank. The simulation was performed for a ground experiment with liquid nitrogen with helium gas and nitrogen gas used as the pressurant. In this work, experimental studies were performed on the dynamics of evaporation and condensation, changes in the pressure in the gas cushion, as well as changes in the mass of liquid nitrogen with the vessel pressurized with helium, nitrogen, and their mixtures with molar content of nitrogen of 23.2 mol. % and 52.2 mol. % and filled with liquid nitrogen to 30–70%. The experiments were conducted in a cylindrical vessel with height of 650 mm and internal diameter of 213 mm, pressurized to pressure of 0.3 MPa. The experiments resulted in dependences of variation of the pressure in the vessel and the mass of liquid nitrogen in the vessel at the stage of pressurization with a nitrogen-helium mixture of various concentrations at different levels of initial filling of the vessel with liquid nitrogen. The dependences of temperature changes in the liquid and vapor phases at eight different levels in the vessel height (50–600 mm) were obtained. During condensation, at the pressurization stage, and immediately after the end of pressurization, the surface layer of the liquid (about 10 mm) was observed to warm to a temperature close to the saturation point corresponding to the pressure in the vessel. The formation of this layer leads to cessation of condensation, cessation of pressure drop in the vessel, and beginning of evaporation due to external heat inflows. When the vessel is half filled with the liquid, loss of stability of the heated near-surface layer of liquid is observed because of the formation of large-scale convective flows. The destruction of the heated surface layer and its cooling to the temperature of the core of liquid, which is significantly subcooled, results in abrupt intensification of the condensation of the nitrogen vapor and significant decrease in the pressure in the vessel to a pressure equilibrium with the temperature of the liquid core.</p>","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"33 2","pages":"231 - 249"},"PeriodicalIF":1.3,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141721526","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}

{"title":"Experimental Investigation of the Heat Transfer under Air or Helium-Xenon Mixture Flow into the Heated 7-Rod Bundle with Spaced Grids","authors":"O. V. Vitovsky,&nbsp;M. S. Makarov","doi":"10.1134/S1810232824020061","DOIUrl":"10.1134/S1810232824020061","url":null,"abstract":"<p>The experimental results on heat transfer and pressure drop during the gas coolant flow into a space formed by a dense packing of 7 heated tubes are presented. To fix the tubes rigidly, 8 spacer grids, evenly distributed along the tube lengths, are used together with longitudinal displacers, which ensure a uniform gas flow field in the internal and external channels of the tube bundle. As a working fluid, gas mixtures with a large difference in the Prandtl number were used: air (Pr = 0.7) and helium-xenon mixture (Pr = 0.23). The experiments were carried out in the range of Reynolds numbers of 1926–11200. The wall temperature distributions of the central and peripheral tubes along the length are measured in detail. Particular attention is paid to the areas of gas flow restructuring near the spacer grid. The heat transfer coefficients and friction factors are determined, and the obtained correlations are compared with the known correlations for round channels. The effect of spacer grids, fixing the heated tubes, on local and average heat transfer and friction factors has been analyzed.</p>","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"33 2","pages":"303 - 315"},"PeriodicalIF":1.3,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141721585","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}

{"title":"Dynamics of Gas Motion in Pipe with Permeable Wall","authors":"E. M. Abbasov,&nbsp;N. R. Abdullaeva,&nbsp;N. A. Agaeva","doi":"10.1134/S1810232824020152","DOIUrl":"10.1134/S1810232824020152","url":null,"abstract":"<p>A model has been built for unsteady motion of gas in a pipe with a permeable wall clogged by sand. Solutions to the resulting system of equations are given. Analytical formulas have been obtained for determination of the pressure field in the pipe and the fluid flow rate in any cross section of the pipe. Numerical calculations have been carried out for real-life values of the system parameters.</p>","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"33 2","pages":"406 - 425"},"PeriodicalIF":1.3,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141721595","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}

{"title":"Exact Transient Heat Conduction of Functionally Graded Thick Structures","authors":"M. Eker,&nbsp;E. Temo,&nbsp;D. Yarımpabuç","doi":"10.1134/S1810232824020103","DOIUrl":"10.1134/S1810232824020103","url":null,"abstract":"<p>Closed form solution of the transient thermal analysis in functionally graded cylindrical and spherical bodies under different thermal loads are presented. It is assumed that the material properties change according to the different inhomogeneity parameters according to the power-law in the radial direction. In the partial differential equation obtained under these conditions, the time dependence is eluted with the Laplace transform and transformed into Bessel differential equation in Laplacian space. This equation, which is solved with Bessel functions in Laplacian space, is transformed into physical space with the modified inverse Durbin method. Behaviors of cylindrical and spherical bodies under constant, convective and time-dependent boundary conditions are investigated. Besides, it is aimed to obtain benchmark solutions for these structures to the literature.</p>","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"33 2","pages":"354 - 364"},"PeriodicalIF":1.3,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141721590","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}

{"title":"Up-to-Third-Order Determination of Time Constants of Models of Avionics Thermocouples in Gas Temperature Control Loop of Automatic Control System of Gas Turbine Engine","authors":"A. F. Sabitov,&nbsp;I. A. Safina","doi":"10.1134/S1810232824020127","DOIUrl":"10.1134/S1810232824020127","url":null,"abstract":"<p>Ensuring the necessary accuracy of measurement of unsteady temperature of gas in an aircraft gas turbine engine (GTE) is a topical problem. The use of thermocouples in the gas temperature control loop of the automatic control system (ACS) of a GTE is complicated by the need of reducing the thermocouple inertia, which varies significantly in dependence on the GTE operation regimes. The existing methods and means for compensating the inertia of aircraft thermocouples in the gas temperature control loop of the GTE ACS are based solely on the use of a mathematical model of thermocouple in the form of a first-order inertia element. This mathematical description of avionics thermocouples with wire sensors is very approximate. An avionics thermocouple is described more accurately with a second-order mathematical model and in some cases with a third-order one in accordance with OST 1 00334-79 “Temperature Sensors. Dynamic characteristics.” The difficulty with the use of second- and third-order thermocouple models is associated with the need to establish the dependence of all time constants of a selected model on the changing operating regimes of GTE. No such dependencies have been determined yet for practical use. The purpose of this work is to find out the functional dependence of all time constants occurring in mathematical models up to the third-order inclusive on actual operating parameters of GTE. The time constants calculated from the established dependencies can be used for continuous correction of the gas temperature control loop of the GTE ACS to ensure optimal correction of the dynamic characteristics of thermocouples.</p>","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"33 2","pages":"376 - 383"},"PeriodicalIF":1.3,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141721591","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}

{"title":"Soret and Radiation Effect on MHD Flow over Magnetized Vertical Surface with Hall Current and Induced Magnetic Field","authors":"A. Agrawal,&nbsp;J. P. Panda","doi":"10.1134/S1810232824020164","DOIUrl":"10.1134/S1810232824020164","url":null,"abstract":"<p>We investigate, the impact of Soret and radiation parameters on MHD mixed convection flow of a viscoelastic fluid over a vertical surface. We also study the Hall and induced magnetic field effects. The governing equations are solved by perturbation method. The nature of flow is depicted in graphs. We observe that both the Soret and radiation parameters enhance the velocity of fluid.</p>","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"33 2","pages":"426 - 443"},"PeriodicalIF":1.3,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141721594","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}

{"title":"Exploring the Influence of Surfactants on Methane Hydrate Formation Kinetics Beyond Its Thermodynamic Stability Region from a Supersaturated Solution ’Water + Sodium Lauryl Sulfate + Methane’","authors":"K. V. Gets,&nbsp;R. K. Zhdanov,&nbsp;Y. Y. Bozhko,&nbsp;O. S. Subbotin,&nbsp;V. R. Belosludov","doi":"10.1134/S1810232824020115","DOIUrl":"10.1134/S1810232824020115","url":null,"abstract":"<p>In this paper, the effect of sodium lauryl sulfate (SDS) molecules in a homogeneous and already supersaturated aqueous methane solution on the structure of the hydrogen bond network and the kinetics of methane hydrate growth at moderate temperature and pressure is studied by the molecular dynamics method. From calculation of the number of hydrogen bonds and parameters of the tetragonal and torsion orders in comparison with a water + SDS solution and a pure water + methane solution, it is shown that the hydrate growth rate and its crystallinity grow as the methane concentration in the supersaturated solution decreases. In this case, increase in the SDS concentration in a solution with a higher gas concentration leads to phase separation.</p>","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"33 2","pages":"365 - 375"},"PeriodicalIF":1.3,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141721447","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}

{"title":"Identifying Transport Properties of Gas from Measurements of Heat Flux at Stagnation Point of Blunt Body. Technique and Experimental Results","authors":"A. V. Nenarokomov,&nbsp;D. L. Reviznikov,&nbsp;S. A. Budnik,&nbsp;D. M. Titov,&nbsp;A. V. Morzhukhina,&nbsp;A. V. Netelev,&nbsp;I. A. Borisenko","doi":"10.1134/S1810232824020139","DOIUrl":"10.1134/S1810232824020139","url":null,"abstract":"<p>In their previous work [1], the authors presented a method of identifying the characteristics of a gaseous medium from measurements of the heat flux absorbed by the surface of a blunt body in a gas flow. The identification problem was stated in an extreme formulation: the sought-for transport properties of a gaseous medium were determined via minimization of the objective function of the estimated and measured heat fluxes absorbed by the surface of a solid body. For minimization of the objective function, the Nelder–Mead method was used in combination with random restarts; the results of testing the algorithm in a model experiment are given. This paper presents the technique of conduction of experiment to verify the method for identification of the gas flow parameters. Experimental results are given for two different gas flow sources.</p>","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"33 2","pages":"384 - 396"},"PeriodicalIF":1.3,"publicationDate":"2024-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141721592","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}

{"title":"Horse Herd Optimization and LSTM Configuration for Minimizing Pressure Drop and Predicting Thermal Performance in Shell and U-Tube Heat Exchanger","authors":"Sh. K. Prasad,&nbsp;M. K. Sinha","doi":"10.1134/S1810232824010107","DOIUrl":"10.1134/S1810232824010107","url":null,"abstract":"<p>The industrial component that transfers heat from one fluid to another most frequently uses Shell and Tube Heat Exchangers (STHE). Enhancing the heat transfer efficiency of heat exchangers has garnered more attention as a result of scarce energy resources and high energy expenditures. In STHE, the pressure drop is considered an important issue that causes cracks and economic losses. An essential factor in improving the performance of a heat exchanger with low pressure drop was the angle and distance of the baffles. Several methods were developed to reduce pressure drop and speed up heat transfer. But those methods were not provide a satisfactory pressure drop reduction, so the optimal baffle configuration was still a task in the heat exchanger. In the proposed model, Horse-herd Optimization Algorithm (HOA) based baffle design and neural network based thermal performance prediction arrangement was developed to reduce the pressure drop and predict the rate of transferring heat. Shells and tubes were developed at the corresponding material, inside the shell, a baffle was designed to barrier the flow of cold water. The optimal solution of baffle configuration was solved through HOA, which finds the appropriate baffle’s distance and angle by reducing the pressure drop. After the water flow modelling, the seven key parameters values were observed, and create a dataset. Using this data, a thermal performance prediction system was developed to analyze each period input value to predict the net energy, heat transfer rate, and Nussle number. The proposed model provides 52 Pa pressure drop, 0.59 effectiveness, 0.59 NTU, 417 U, and 92% accuracy. The output of the suggested approach is contrasted with that of other current methods for validation. The proposed model offers a high heat transferring capacity and reduces pressure effects risk.</p>","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"33 1","pages":"110 - 142"},"PeriodicalIF":1.3,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140569466","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}

{"title":"Experimental Study of Heat Transfer of Different-Thickness Plate Modules of Heat and Mass Transfer Device","authors":"A. V. Stepykin,&nbsp;A. A. Sidyagin,&nbsp;D. M. Bukharov,&nbsp;E. M. Tutanina,&nbsp;D. E. Sukhanov","doi":"10.1134/S1810232824010090","DOIUrl":"10.1134/S1810232824010090","url":null,"abstract":"","PeriodicalId":627,"journal":{"name":"Journal of Engineering Thermophysics","volume":"33 1","pages":"102 - 109"},"PeriodicalIF":1.3,"publicationDate":"2024-04-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140569323","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}