Fluids最新文献

{"title":"Grid-Characteristic Method for Calculation of Discontinuous Non-Steady Flows of a Multicomponent Reacting Gas in Channels","authors":"Vladimir Gidaspov, Natalia Severina","doi":"10.3390/fluids8100265","DOIUrl":"https://doi.org/10.3390/fluids8100265","url":null,"abstract":"This paper is devoted to the description of computational algorithms for modeling quasi-one-dimensional non-steady flows of a multicomponent reacting gas. The particularity of the developed modeling technique is that the paths of strong and weak discontinuities are mobile computational nodes, and the parameters for them are calculated using special algorithms. A set of programs has been developed, which can be used to solve the problems of the reacting gas dynamics that are of applied importance, as well as serve as an illustrator for physical gas dynamics training courses. The paper provides the results of the numerical modeling of the supersonic flow in a flat channel simulating the operation of experimental facilities of the Institute for Problems in Mechanics and the Institute of Physics and Technology. A satisfactory correlation between the calculated and experimental data has been obtained.","PeriodicalId":12397,"journal":{"name":"Fluids","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135536542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Recent Advances in Fluid Mechanics: Feature Papers, 2022","authors":"Mehrdad Massoudi","doi":"10.3390/fluids8100262","DOIUrl":"https://doi.org/10.3390/fluids8100262","url":null,"abstract":"This Special Issue is a collection of papers from some of the leading researchers discussing new findings or cutting-edge developments relating to all aspects of fluid mechanics [...]","PeriodicalId":12397,"journal":{"name":"Fluids","volume":"51 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134961104","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Study of Indoor Oil Mist Particle Concentration Distribution in an Industrial Factory Using the Eulerian–Eulerian and Eulerian–Lagrangian Methods","authors":"Yukun Wang, Jingnan Sun, Meng Zhao, Alicia Murga, Sung-Jun Yoo, Kazuhide Ito, Zhengwei Long","doi":"10.3390/fluids8100264","DOIUrl":"https://doi.org/10.3390/fluids8100264","url":null,"abstract":"The transport and prediction of the concentration of particles in confined spaces are crucial for human well-being; this has become particularly evident during the current worldwide pandemic. Computational fluid dynamics (CFD) has been widely used for such predictions, relying on Eulerian–Eulerian (EE) and Eulerian–Lagrangian (EL) models to study particle flow. However, there is a lack of research on industrial factories. In this study, a scaled laboratory in an industrial factory was established for oil mist particles in a machining factory, and oil mist dispersion experiments were conducted under roof exhaust and mixed ventilation conditions. After that, the oil mist concentration distribution in the factory under the same working conditions was calculated by Eulerian and Lagrangian methods, and the corresponding calculation errors and resource consumption were compared. It was found that the simulation results of both methods are acceptable for mixed ventilation and roof exhaust ventilation systems. When there are more vortices in the factory, the Lagrangian method increases the computation time by more than 53% to satisfy the computational accuracy, and the computational error between the Eulerian and Lagrangian methods becomes about 10% larger. For oil mist particles with an aerodynamic diameter of 0.5 μm, both Eulerian and Lagrangian methods have reliable accuracy. Based on the same flow field, the Lagrangian method consumes more than 400 times more computational resources than the Eulerian method. This study can provide a reference for the simulation of indoor particulate transport in industrial factories.","PeriodicalId":12397,"journal":{"name":"Fluids","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134886347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Effects of Mainstream Reynolds Number and Blowing Ratio on Film Cooling of Gas Turbine Vanes","authors":"Germán Sierra-Vargas, Diego Garzón-Alvarado, Carlos Duque-Daza","doi":"10.3390/fluids8100263","DOIUrl":"https://doi.org/10.3390/fluids8100263","url":null,"abstract":"Film cooling performance was evaluated numerically for three mainstream Reynolds numbers and four blowing ratios (BR). A computational model based on finite volume discretization was used to solve an incompressible and transient flow over a NACA 4412 cascade vane. Several passive scalars were included in the model to evaluate the condition of adiabatic temperature and constant temperature for the surface vane. For the adiabatic temperature condition, the film effectiveness mainly depends on the jet trajectory and recirculation zones. For the constant temperature condition, the net heat flux reduction (NHFR) varies according to the boundary layer separation and reattachment. Consequently, misleading conclusions could be drawn if only one of the two approaches is adopted. For instance, the mainstream Reynolds number Re∞ = 3615 reached a maximum average effectiveness lower than 0.3 with an average NHFR of 0.25. However, for Re∞ = 10,845 the maximum average effectiveness was close to 0.45, but with negative average NHFR values. This finding demonstrates the need to explore new indicators like jet trajectory, convective coefficient and skin friction coefficient, as presented in this paper.","PeriodicalId":12397,"journal":{"name":"Fluids","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134960624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhancement of an Air-Cooled Battery Thermal Management System Using Liquid Cooling with CuO and Al2O3 Nanofluids under Steady-State and Transient Conditions","authors":"Peyman Soleymani, Ehsan Saffarifard, Jalal Jahanpanah, Meisam Babaie, Amir Nourian, Rasul Mohebbi, Zineb Aakcha, Yuan Ma","doi":"10.3390/fluids8100261","DOIUrl":"https://doi.org/10.3390/fluids8100261","url":null,"abstract":"Lithium-ion batteries are a crucial part of transportation electrification. Various battery thermal management systems (BTMS) are employed in electric vehicles for safe and optimum battery operation. With the advancement in power demand and battery technology, there is an increasing interest in enhancing BTMS’ performance. Liquid cooling is gaining a lot of attention recently due to its higher heat capacity compared to air. In this study, an air-cooled BTMS is replaced by a liquid cooled with nanoparticles, and the impacts of different nanoparticles and flow chrematistics are modeled. Furthermore, a unique approach that involves transient analysis is employed. The effects of nanofluid in enhancing the thermal performance of lithium-ion batteries are assessed for two types of nanoparticles (CuO and Al2O3) at four different volume concentrations (0.5%, 2%, 3%, and 5%) and three fluid velocities (0.05, 0.075, and 0.1 m/s). To simulate fluid flow behavior and analyze the temperature distribution within the battery pack, a conventional k-ε turbulence model is used. The results indicate that the cooling efficiency of the system can be enhanced by introducing a 5% volume concentration of nanofluids at a lower fluid velocity as compared to pure liquid. Al2O3 and CuO reduce the temperature by 7.89% and 4.73% for the 5% volume concentration, respectively. From transient analysis, it is also found that for 600 s of operation at the highest power, the cell temperature is within the safe range for the selected vehicle with nanofluid cooling. The findings from this study are expected to contribute to improving BTMS by quantifying the benefits of using nanofluids for battery cooling under both steady-state and transient conditions.","PeriodicalId":12397,"journal":{"name":"Fluids","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135864027","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the Composite Velocity Profile in Zero Pressure Gradient Turbulent Boundary Layer: Comparison with DNS Datasets","authors":"Antonios Liakopoulos, Apostolos Palasis","doi":"10.3390/fluids8100260","DOIUrl":"https://doi.org/10.3390/fluids8100260","url":null,"abstract":"Data obtained by direct numerical simulations (DNS) of the Zero-Pressure-Gradient Turbulent Boundary Layer were analyzed and compared to a mathematical model of the mean velocity profile (MVP) in the range 1000 ≤ Reθ ≤ 6500. The mathematical model is based on the superposition of an accurate description of the inner law and Coles’ wake function with appropriately chosen parameters. It is found that there is excellent agreement between the mathematical model and the DNS data in the inner layer when the Reynolds number based on momentum thickness, Reθ, is greater than 1000. Furthermore, there is very good agreement over the entire boundary layer thickness, when Reθ is greater than 2000. The diagnostic functions Ξ and Γ based on DNS data are examined and their characteristics are discussed in relation to the existence of a logarithmic layer or a power law behavior of the MVP. The diagnostic functions predicted by the mathematical model are also presented.","PeriodicalId":12397,"journal":{"name":"Fluids","volume":"71 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135864297","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Yogurt Enriched with Mango Peel Extracts (Mangifera indica) in Chitosan–Xanthan Gum Dispersions: Physicochemical, Rheological, Stability, and Antioxidant Activity","authors":"Santander E. Lastra-Ripoll, Somaris E. Quintana, Luis A. García-Zapateiro","doi":"10.3390/fluids8100259","DOIUrl":"https://doi.org/10.3390/fluids8100259","url":null,"abstract":"Different strategies have been developed to incorporate bioactive compounds into food products to improve their biological activity against degradation effects. The aim of this study was to develop natural yogurt enriched with mango (Mangifera indica) peel extracts (MPEs) in chitosan–xanthan gum dispersions and to evaluate their physicochemical, rheological, and antioxidant activity. A hydroethanolic extract of mango peel was obtained, with a yield of 33.24 ± 1.27%, a total content of phenolic compounds of 305.04 ± 10.70 mg GAE/g, and an antioxidant activity of 1470.41 ± 59.75 μMol Trolox/g. The encapsulation of the extracts was achieved using a chitosan–xanthan gum dispersion, resulting in the rheological characteristic of a strong gel. The incorporation of dispersions into yogurt did not modify the physicochemical properties and increased their bioactive properties. The rheological properties show samples with double yield points and a decrease in viscoelastic parameters. These results show dispersions as a strategy to incorporate bioactive compounds into dairy products, preserve the physicochemical and rheological properties of yogurt, and improve their biological activities (such as antioxidant activity) and activities related to the compounds found in the MPE.","PeriodicalId":12397,"journal":{"name":"Fluids","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135924856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Relative Influences of Inertia and Polymeric Viscoelastic Effects on Nusselt Numbers within Rotating Couette Flows","authors":"Phil Ligrani, Valerie Hietsch, Mengying Su","doi":"10.3390/fluids8100258","DOIUrl":"https://doi.org/10.3390/fluids8100258","url":null,"abstract":"In past investigations of elastic instabilities and elastic turbulence, almost no attention has been devoted to the effects and influences of inertial phenomena. Within the present investigation, Nusselt number data are provided to illustrate the relative influences of inertia and polymeric viscoelastic phenomena within a rotating Couette flow (RCF) environment. Data are provided from experimental measurements of local surface heat transfer characteristics for different flow passage heights, one radial position, and different values of disk rotational speed for polyacrylamide polymer concentrations ρ of 0 ppm, 100 ppm, 150 ppm, and 300 ppm. With this approach, data for a wide range of shear rate γ˙ values, Weissenberg numbers, and first normal stress difference values are provided. Nusselt number data are provided as dependent upon a newly developed P′ parameter, equal to ReEI/Re0.22, which collapse into a single distribution over the range of P′ values considered which range from 0 to about 182. Such characteristics indicate that the P′ parameter provides an appropriate means to simultaneously account for the relative influences of inertia and polymeric viscoelastic effects. The use of such a power law dependence for Re additionally gives P′ values which are dominated by ReEI values when the Weissenberg number Wi is greater than the elastic instability transition onset value. The experimental conditions associated with this value correspond to the change from inertia domination (with buoyance influences) to polymeric viscoelastic domination which occurs for shear rates in the vicinity of 11 to 12 s−1. For Weissenberg numbers greater than the onset value, Nusselt numbers associated with H = 5 mm are generally the highest values measured, with magnitudes that steadily increase with γ˙. Associated Nusselt numbers become as high as about 3.0, whereas zero-shear rate values (obtained with zero rotation) are in the vicinity of 1.0. At lower Weissenberg number magnitudes (below the transition onset value), Nusselt numbers cover a wide range of values as experimental conditions and configuration are varied, as a consequence of the complicated and simultaneous influences of inertia, buoyancy, and dilute polymer presence.","PeriodicalId":12397,"journal":{"name":"Fluids","volume":"210 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136094256","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bioactive Fractions Isolated from By-Products of the Guava (Psidium guajava) and Mango (Mangifera indica L.) Agri-Food Industry","authors":"Leidy J. Cerón-Martínez, Andrés M. Hurtado-Benavides, Alfredo Ayala-Aponte, Liliana Serna-Cock, Diego F. Tirado","doi":"10.3390/fluids8090256","DOIUrl":"https://doi.org/10.3390/fluids8090256","url":null,"abstract":"Valorizing agri-food industrial waste is essential for a circular economy, yielding high-value products, waste reduction, technological solutions, employment opportunities, and enhanced food security. This work shows the valorization of seeds generated as residues from the agri-food industries of guava pera (Psidium guajava) and Tommy Atkins mango (Mangifera indica L.), through extraction with supercritical carbon dioxide (scCO2). After the optimization of the initial solid condition of the raw material (i.e., particle size and moisture content), scCO2 pressure and temperature were established through the response surface methodology (RSM) to obtain an oily extract with the highest content in bioactive compounds of commercial relevance, as well as with a high antioxidant capacity. The total amount of oily extract in guava and mango seeds was 14% and 9%, respectively, while the maximum recovery of supercritical extract was 95% from guava seeds at 38 MPa and 50 °C, and 88% from mango seeds at 37 MPa and 63 °C. Bioactive fractions rich in squalene, γ-tocopherol, α-tocopherol, campesterol, β-sitosterol, and stigmasterol were obtained. The best supercritical extraction conditions, in terms of the bioactive fractions richest in minor compounds, were at 17 MPa and 50 °C for guava seeds and at 23 MPa and 63 °C for mango seeds. At these conditions, the highest antioxidant capacities were also found for the extracts. Thus, these bioactive fractions could be used in a variety of products in the cosmetic, food, pharmaceutical, and medical activities due to the beneficial properties of the identified compounds in health as antioxidants, anti-inflammatories, and cholesterol reducers.","PeriodicalId":12397,"journal":{"name":"Fluids","volume":"41 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136237543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical Analysis of Multi-Particulate Flow Behaviour in CFB Riser Coupled with a Kinetic Theory","authors":"Fardausur Rahaman, Abd Alhamid Rafea Sarhan, Jamal Naser","doi":"10.3390/fluids8090257","DOIUrl":"https://doi.org/10.3390/fluids8090257","url":null,"abstract":"In this work, a three-dimensional CFD model for the gas–solid flow of two different particle sizes in a CFB riser coupled with a kinetic theory (KT) has been developed. The properties of the solid phases are calculated using the proposed multi-particle kinetic theory. The CFD model is implemented in the commercial CFD software CFX4.4. In the current model, one gas phase and two solid phases are used. However, the model is generalised for one carrier phase and N number of solid phases to enable a realistic particle size distribution in the system. The momentum, volume fraction and granular temperature equations are solved for each individual solid phase and implemented into the CFD model through user-defined functions (UDFs). The k-ε turbulence model is used in simulating the circulating fluidised bed model. For verification, simulation results obtained with the new KT model were compared with experimental data, and then the model was used for further analysis. It was found that the proposed multi-particle model can be used to calculate the properties of gas–solid systems with particles of different sizes and/or densities, removing the assumptions of previous models that required all the particles to be of an equal mass, size and density.","PeriodicalId":12397,"journal":{"name":"Fluids","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"136237542","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}