International Journal of Heat and Fluid Flow最新文献

{"title":"Visual experimental study on flat-plate pulsating heat pipe with double condensers","authors":"Xiaohan Sun,&nbsp;Li Jia","doi":"10.1016/j.ijheatfluidflow.2025.109831","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109831","url":null,"abstract":"<div><div>In the present study, a visual experiment is performed to investigate the thermo-hydrodynamic characteristics of the flat-plate pulsating heat pipes (FPPHP) with double condensers. The operating performance of a FPPHP with double condensers is compared to that of a typical FPPHP with a single condenser. The results indicate that the FPPHP with double condensers exhibits higher imbalance pressure difference between its condensers and evaporator, leading to an enhanced oscillation frequency of the internal gas–liquid plug, which expands the working range of this FPPHP and at the same time significantly reduces thermal resistance. With power inputs ranging from 60 W to 720 W, its thermal resistance ranges from 0.12 K/W to 0.04 K/W, a decrease of 12 % to 46.9 % compared to that with a single condenser. The mechanism of the influences of temperature of the condensing side and length ratio of the two condensers on the operating performance of the FPPHP with double condensers is studied. The experimental results show that the FPPHP with symmetrical double condensers (i.e., in equal cooling areas) has better temperature uniformity and wider operating range than that with asymmetric double condensers in the same cooling areas. Hence, this research has important implications for the design of high-power electronics cooling and thermal management in confined spaces.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109831"},"PeriodicalIF":2.6,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Vapor quality distribution in a microchannel heat exchanger Header: Impact of downward and horizontal distributor spraying","authors":"Chao Yuan ,&nbsp;Hequn Liu ,&nbsp;Wenzhe Li ,&nbsp;Jiajia Song ,&nbsp;Zhongbing Liu ,&nbsp;Houpei Li","doi":"10.1016/j.ijheatfluidflow.2025.109828","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109828","url":null,"abstract":"<div><div>The vapor quality distribution in the header of a microchannel heat exchanger significantly affects the refrigerant charge, distribution, pressure drop, and heat transfer efficiency. However, the distribution differs markedly with and without a distributor. This study examines the use of a 2 mm nozzle in a 5 mm inner diameter circular tube as a distributor in an inlet header, spraying R134a into the header. Capacitance measurements are analyzed to characterize the distribution under two orientations: downward and horizontal, and compare with a no-distributor configuration. The test conditions cover inlet vapor qualities from 0.1 to 0.6 and mass flow rates of 5, 7, and 10 g-s⁻¹. The local vapor qualities are calculated based on the capacitance. For the downward configuration, distribution is relatively uniform at lower vapor qualities as the flow rate increases. The local vapor quality on the left side of the nozzle typically exceeds that on the right. For the horizontal configuration, a bimodal distribution is observed, except at high flow rates and vapor qualities (<span><math><mrow><msub><mover><mi>m</mi><mo>̇</mo></mover><mrow><mi>in</mi></mrow></msub></mrow></math></span> = 10 g-s⁻¹ and<span><math><mrow><msub><mi>x</mi><mrow><mi>in</mi></mrow></msub></mrow></math></span> &gt; 0.4). For both configurations, vapor phase superficial velocity is the key parameter influencing distribution. A comparison shows that the downward configuration improves uniformity at the inlet vapor qualities below 0.4.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109828"},"PeriodicalIF":2.6,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of non-equilibrium turbulence dissipation downstream of regular and fractal grids in an open channel flow","authors":"Amir Sagharichi,&nbsp;Mark Francis Tachie","doi":"10.1016/j.ijheatfluidflow.2025.109822","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109822","url":null,"abstract":"<div><div>This study investigates the relationship between the turbulence energy dissipation rate coefficient (<span><math><msub><mtext>C</mtext><mi>ε</mi></msub></math></span>) and turbulence Reynolds number (<span><math><msub><mtext>Re</mtext><mi>λ</mi></msub></math></span>) in the streamwise and cross-stream directions downstream of four passive grids using a high-resolution particle image velocimetry (PIV) in an open channel. The grids include two regular square grids with 35 % and 48 % blockage ratios and two fractal square grids with 32 % and 41 % blockage ratios. PIV measurements were performed in the production, peak, and decay regions, and the data were analyzed in terms of mean velocity, turbulence intensities, small- and large-scale isotropy, velocity gradient tensor invariants, turbulence length scales, and the energy dissipation rate coefficient. The results in the production region and peak location in the cross-stream direction conform to a non-equilibrium scaling for turbulence energy dissipation rate. It is also shown that the turbulence dissipation rate coefficient (<span><math><msub><mtext>C</mtext><msup><mrow><mi>ε</mi></mrow><mo>′</mo></msup></msub></math></span>) in the production region and peak location of both regular and fractal grids can be related to a newly proposed local Reynolds number (<span><math><msub><mtext>Re</mtext><mrow><mi>λ</mi><mo>′</mo></mrow></msub></math></span>) and global Reynolds number (<span><math><msub><mtext>Re</mtext><mtext>L</mtext></msub></math></span>) by the relations <span><math><mrow><msub><mtext>C</mtext><msup><mrow><mi>ε</mi></mrow><mo>′</mo></msup></msub><mspace></mspace><mo>∝</mo><msubsup><mtext>Re</mtext><mrow><mtext>L</mtext></mrow><mrow><mtext>- 0.4</mtext></mrow></msubsup><mo>/</mo><msub><mtext>Re</mtext><mrow><mi>λ</mi><mo>′</mo></mrow></msub></mrow></math></span> and <span><math><mrow><mspace></mspace><msub><mtext>C</mtext><msup><mrow><mi>ε</mi></mrow><mo>′</mo></msup></msub><mspace></mspace><mo>∝</mo><msubsup><mtext>Re</mtext><mrow><mtext>L</mtext></mrow><mrow><mtext>- 0.2</mtext></mrow></msubsup><mo>/</mo><msub><mtext>Re</mtext><mrow><mi>λ</mi><mo>′</mo></mrow></msub></mrow></math></span>, respectively. This scaling differs from the traditional non-equilibrium equation that relates the local and global Reynolds numbers and energy dissipation rate coefficient (<span><math><mrow><msub><mtext>C</mtext><mi>ε</mi></msub><mo>∝</mo><msubsup><mtext>Re</mtext><mrow><mtext>0</mtext></mrow><mtext>1/2</mtext></msubsup><mo>/</mo><msub><mrow><mi>R</mi><mi>e</mi></mrow><mi>λ</mi></msub></mrow></math></span>) along the grids<span><math><mo>′</mo></math></span> centerline.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109822"},"PeriodicalIF":2.6,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747491","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical study on flow and heat transfer characteristics in manifold microchannel heat sinks with rectangular restrictors","authors":"Hao Wu ,&nbsp;Keyong Cheng ,&nbsp;Xunfeng Li ,&nbsp;Jingzhi Zhou ,&nbsp;Xiulan Huai","doi":"10.1016/j.ijheatfluidflow.2025.109823","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109823","url":null,"abstract":"<div><div>The Z-type manifold microchannel (MMC) heat sink could efficiently dissipate the heat for electronic devices. However, this structure has a drawback of non-uniform flow distribution. To enhance the flow uniformity, three optimization schemes are proposed in this study. The first one is to add a rectangular restrictor in each microchannel and the rectangular restrictor width is set to an uneven size. The second one is to add a rectangular restrictor on the top of each fin and the gap of adjacent rectangular restrictors is set into uneven dimensions. The third one is to set the width of each microchannel into uneven dimensions. The influences of the rectangular restrictor height and the microchannel widths on the flow and heat transfer characteristics have been numerically investigated. The results show that the MMC with uneven microchannel width exhibits the best flow uniformity and minimum thermal resistance. The flow uniformity factors of the three optimization schemes are all below 13.35% and the MMC with uneven microchannel widths has the lowest flow uniformity factor of 7.87%. The flow uniformity of the MMC with uneven microchannel widths is improved by 84.88%, and the thermal resistance of the case is reduced by an average of 21.67%. On the other hand, the flow uniformity of the MMCs with restrictors in each microchannel and on the top of each fin is improved by 74.34% and 80.53%, respectively. The thermal resistance of the two cases is reduced by 9.74% and 11.22%, respectively. Moreover, the pressure drops of the three optimized MMCs are relatively similar in magnitude.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109823"},"PeriodicalIF":2.6,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143747493","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Large eddy simulation of CO2 direct air capture units in different atmospheric boundary layer wind profiles","authors":"Esmaeel Eftekharian ,&nbsp;Ali Kiani ,&nbsp;Vassili Kitsios ,&nbsp;Ashok K. Luhar ,&nbsp;Paul Feron ,&nbsp;Aaron W. Thornton ,&nbsp;Kathryn M. Emmerson","doi":"10.1016/j.ijheatfluidflow.2025.109824","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109824","url":null,"abstract":"<div><div>Direct air capture of CO₂ (DAC) is one of the promising technologies for removing CO₂ from the atmosphere and combating global warming. This study explores the effect of wind velocity on the atmospheric dispersion of CO₂-depleted air released from the outlet of DAC units. This is an important consideration in determining the optimum design and location of DAC units in a large-scale CO₂ capture plant and ultimately the overall land footprint requirement. We considered a crosswind cooling tower as a single DAC absorption unit. Following its validation with field-scale and lab-scale experimental data as well as direct numerical simulation (DNS) data, the large eddy simulation (LES) technique was used to simulate the interaction between the longitudinal atmospheric boundary layer wind and the vertical plume of CO₂-depleted air exiting the DAC unit. The behaviour of the DAC-wind flow regime depends on the velocity ratio of the DAC vertical flow and the longitudinal wind velocity (<em>R_U</em>) which can be divided into three DAC-wind flow regimes: <span><math><mrow><msub><mi>R</mi><mi>U</mi></msub><mo>≫</mo><mn>1</mn></mrow></math></span>, <span><math><mrow><msub><mi>R</mi><mi>U</mi></msub><mo>≈</mo><mn>1</mn></mrow></math></span>, and <span><math><mrow><msub><mi>R</mi><mi>U</mi></msub><mo>≪</mo><mn>1</mn></mrow></math></span>. As the wind velocity increases, the CO₂-depleted air is mixed faster with the free-stream atmospheric flow. Some CO₂-depleted air re-enters the unit through the leeward inlet at moderate and high wind velocities. Using the LES results, practical statistical relationships were developed for CO₂-depleted plume concentration as a function of distance downwind of a DAC unit for different DAC-wind flow regimes. The findings of this study provide insights into the impact of wind on DAC unit performance and the optimal distance required between the units in a large-scale DAC plant.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109824"},"PeriodicalIF":2.6,"publicationDate":"2025-03-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143715032","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation of turbulent/non-turbulent interfaces in high Reynolds number adverse pressure gradient boundary layers","authors":"Luka Lindić,&nbsp;Wagih Abu Rowin,&nbsp;Rahul Deshpande,&nbsp;Ivan Marusic","doi":"10.1016/j.ijheatfluidflow.2025.109815","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109815","url":null,"abstract":"<div><div>This study utilises high-magnification two-dimensional Particle Image Velocimetry (2D-PIV) to investigate adverse pressure gradient (APG) turbulent boundary layers at high friction Reynolds numbers, which evolve from a canonical zero pressure gradient (ZPG) upstream condition. The primary focus is on comparing the turbulent/non-turbulent interface (TNTI) for ZPG and APG at high Reynolds number. Local kinetic energy (LKE) and spanwise vorticity methods are considered for TNTI detection, with Joint Probability Density Functions (JPDFs) for LKE/vorticity and wall-normal distance used to determine the respective thresholds and estimate corresponding TNTI heights. A sensitivity analysis of the mean TNTI height with respect to the selected threshold for distinguishing turbulent and non-turbulent regions is conducted for both methods, with the LKE method demonstrating a lower sensitivity to the threshold compared to vorticity. The results confirm the inadequacy of using in-plane vorticity for the current experimental data while also highlighting the limitations of the LKE method. Overall, the present findings based on relatively small thresholds support a decrease in normalised TNTI height with increasing adverse pressure gradients at high Reynolds number, demonstrating consistency with previous low Reynolds number results. Conditional averaging analysis is conducted for the instantaneous streamwise and wall-normal velocities based on TNTI height, confirming that the APG outer wake region is distinctly different to the ZPG case. For the APG flow, the spread in the conditional averaged velocity curves is larger than in the ZPG case, with the start of the deviation from the mean velocity profile occurring closer to the normalised position from the wall.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109815"},"PeriodicalIF":2.6,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143705598","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigation on gas–liquid two-phase flow in the mixer of a liquid metal magneto-hydro-dynamic system and wavelet-based analysis","authors":"Qingsong Wei ,&nbsp;Peng Lu ,&nbsp;Xiaolong Zhao ,&nbsp;Jinwang Li ,&nbsp;Hulin Huang","doi":"10.1016/j.ijheatfluidflow.2025.109819","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109819","url":null,"abstract":"<div><div>In this paper, turbulent elements are introduced into the mixer of a two-phase magneto-hydro-dynamic power generation system, effectively addressing the challenges of transporting high-density and high-viscosity liquid metals and inhomogeneous gas–liquid mixing. The effects of different types and numbers of turbulent elements on the gas–liquid two-phase flow pattern and phase change heat transfer are investigated using numerical simulation and wavelet multiscale analysis methods. A comprehensive evaluation index for the mixer is established, considering performance indicators such as gas–liquid mixing uniformity, friction coefficient, volumetric heat transfer coefficient, and velocity. The results indicate that the turbulent elements significantly enhance heat transfer performance, liquid metal transport velocity, and mixing uniformity. However, an increase in the number of turbulent elements also leads to an increase in the friction coefficient, particularly in the SX type mixer, where it is approximately 20% higher than that in the SK type mixer. A comprehensive analysis reveals that the overall performance of the SX mixer surpasses that of the SK mixer, with the optimal number of turbulent elements being 3 for the SX mixer and 1 for the SK mixer. Additionally, there is a clear gravity-induced stratified flow in the empty pipe mixer. The flow pattern in the SK type mixer is primarily influenced by the ratio of gravity to centrifugal force, while that in the SX type mixer is predominantly determined by gravity and the number of turbulent elements. Wavelet multiscale analysis demonstrates that the pressure fluctuations in the mixer are primarily influenced by gas–liquid interface deformation and bubble collision frequency.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109819"},"PeriodicalIF":2.6,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143697968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Thermo-Fluidic characterization of different protuberance shapes upstream of transverse trench on the film cooling performance","authors":"Muhammad Nauman ,&nbsp;Muhammad Kashif ,&nbsp;Qianlong Wang","doi":"10.1016/j.ijheatfluidflow.2025.109816","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109816","url":null,"abstract":"<div><div>The efficiency of turbomachines is limited by the maximum temperature that can be supported by the blades without failure and strategy. The combined impact of transverse trenches and divided step for improving the efficiency of film cooling has been numerically investigated. The synergistic effect on working fluid and coolant flows changing position and shape of divided steps upstream of transverse trenches has been studied that can help in better coolant dispersion in the boundary-layer flow. The impact of six different configurations was analyzed with four different spacing arrangements for divided steps i.e., 2.5 mm, 5 mm, 10 mm, and 15 mm gap in the middle, one arrangement with 2.5 mm gap on both sides of the step and one full step. The effectiveness of film cooling was evaluated for blowing ratio, M = 1.0, 1.5, and 2.0 while keeping a constant density ratio of 0.97. The complex flow dynamics are simulated using the classic k-ε model in combination with 3-dimensional average Navier-Stokes equations. The results highlight the significant impact on the film cooling performance downstream of the film holes due to combined impact of trench and divided step at different blowing ratios. A 2.5 mm center dividing gap upstream of the coolant hole, in particular, show encouraging outcomes at M = 2.0. These arrangements show promise for greatly increasing the efficiency of lateral adiabatic cooling while reducing the corresponding penalty for total pressure loss. The analysis of the results shows that Case 4 with a gap size of 10 mm and at <em>M</em> = 2.0, exhibited the highest overall effectiveness rendering this arrangement the best for film cooling design in the gas turbines. These revelations provide significant contributions to the engineering field, where film cooling optimization, with minimum impact on mainstream flow, is crucial for overall performance, increased efficiency, and reliability.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109816"},"PeriodicalIF":2.6,"publicationDate":"2025-03-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143680023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Outer scaling of rough and smooth wall boundary layers under adverse pressure gradient conditions","authors":"Ralph J. Volino ,&nbsp;Michael P. Schultz","doi":"10.1016/j.ijheatfluidflow.2025.109821","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109821","url":null,"abstract":"<div><div>Experiments were conducted in adverse pressure gradient (APG) boundary layers over rough and smooth walls. Cases were considered with various pressure gradient strengths and upstream conditions. Profiles of mean velocity and turbulence quantities were measured at multiple streamwise stations to document the response of the flow to the APG. The data suggest that an APG causes attached turbulent eddies to become detached, and motivates the proposal of a new scaling to collapse the data in the outer part of the boundary layer. The distance from the wall is normalized as <em>y*=(y − δ*)/(</em>δ<em>-</em>δ<em>*</em>), where <em>δ</em> and <em>δ</em>* are the boundary layer thickness and displacement thickness, respectively. Velocity is scaled using the friction velocity at the start of the APG region. Data from all cases in which an APG is imposed on a canonical zero pressure gradient (ZPG) boundary layer show good collapse of the mean velocity and Reynolds stress profiles with the new scaling. For cases in which an APG followed directly after a favorable pressure gradient (FPG), the initial development of the boundary layer was changed, but after some distance the new scaling again collapsed the profiles.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109821"},"PeriodicalIF":2.6,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143680022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of the Weber number and structural parameters on combustion characteristics of LOX/methane liquid–liquid swirl coaxial injectors","authors":"Ping Jin ,&nbsp;Danqi Yang ,&nbsp;Bingyang Liu ,&nbsp;Yushan Gao ,&nbsp;Guobiao Cai","doi":"10.1016/j.ijheatfluidflow.2025.109817","DOIUrl":"10.1016/j.ijheatfluidflow.2025.109817","url":null,"abstract":"<div><div>LOX/methane engines have the advantages of a<!--> <!-->rich source, good cooling performance, low combustion temperature, difficult coking, etc., and a broad application prospect in reusable liquid rocket engines. Reasonable injector design is the key to organizing efficient and stable combustion of the engine. Among various types of injectors, the liquid–liquid swirl coaxial injector is widely used in a variety of two-component liquid rocket engines for its good atomization and high mixing efficiency. In order to comprehensively study the influence of multiple factors on combustion characteristics of LOX/methane liquid–liquid swirl coaxial injection, a 3-D combustion simulation model based on the improved 6-step mechanism is established. The simulation results of the Weber number show that when the ɷ (the Weber number ratio of methane to LOX) is in the range of 0.71 ∼ 2.64, the longest combustion length is found for ɷ of 1.36. Decreasing or increasing either propellant Weber number will shorten the combustion length. Further, combustion efficiency increases with increment of mixing ratio as well as decreasing ɷ. The simulation results of the structural parameters show that the combustion efficiency increases as the geometric characteristic coefficient (in the range of 0.5 ∼ 2.5) of the inner injector and the recess length (in the range of 0.42 ∼ 2.1) grow. The same rotation of the inner and outer injectors can effectively shorten the combustion length, but the reverse rotation has a higher combustion efficiency. The work can provide a theoretical basis for the optimal design of LOX/methane liquid–liquid swirl coaxial injectors and support the development of high-performance reusable LOX/methane engines.</div></div>","PeriodicalId":335,"journal":{"name":"International Journal of Heat and Fluid Flow","volume":"114 ","pages":"Article 109817"},"PeriodicalIF":2.6,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143680021","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}