Microgravity Science and Technology最新文献

{"title":"Average Deformation of Sessile Drop Under High Frequency Vibrations","authors":"Andrey Ivantsov,&nbsp;Tatyana Lyubimova","doi":"10.1007/s12217-024-10146-4","DOIUrl":"10.1007/s12217-024-10146-4","url":null,"abstract":"<div><p>The behavior of a liquid drop placed on an oscillating solid substrate is studied. The vibrations are normal to the plane of the substrate. The amplitude of the vibrations is assumed to be small compared to the radius of the drop, and the vibration frequency is suppose to be much larger than the frequencies of the natural oscillations of the drop shape. The effect of vibrations on the drop shape is studied for a small values of the vibration parameter equal to the ratio of the vibration pressure to the capillary pressure. It is assumed that the drop surface in the absence of vibrations is hemispherical. Under the influence of vibrations, the drop height decreases and the base area increases. In this case, the surface deformation changes proportionally to the vibration parameter. At finite values of the vibration parameter, the quasi-equilibrium shape can differ significantly from spherical. In this case, the problem for pulsations is solved numerically using the boundary element method. To determine the average shape of a drop at finite values of the vibration parameter, the variational principle is used. The obtained results are in good agreement with the solution in the limit of small values of the vibration parameter. With an increase in the vibration parameter, the average contact angle decreases, the area of the base area increases, and the height decreases.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"36 6","pages":""},"PeriodicalIF":1.3,"publicationDate":"2024-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142565735","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":"Stability Analysis of Mixed Convection of Nanofluid Flow Through a Horizontal Porous Channel Using LTNE Model","authors":"Harsha S V,&nbsp;Chandra Shekara G,&nbsp;Hemanth Kumar C,&nbsp;Mayur D H","doi":"10.1007/s12217-024-10140-w","DOIUrl":"10.1007/s12217-024-10140-w","url":null,"abstract":"<div><p>The present article investigates the stability of the mixed convective flow of nanofluids through a horizontal porous channel under the influence of a constant pressure gradient, utilizing the local thermal nonequilibrium (LTNE) model. The governing equations are derived by integrating the Oberbeck-Boussinesq theory with the Darcy model for low-permeability porous media. Using linear stability theory, we formulate a generalized eigenvalue problem (GEP) in terms of non-dimensional parameters. The weighted residual Galerkin method (WRGM) is then employed to solve the GEP, and the results are compared analytically. The findings of this study reveal that a horizontal pressure gradient initiates convection in an oscillatory mode rather than a stationary one. We identify that the interphase scaled heat transfer coefficient, thermal diffusivity ratio, nanoparticle volume fraction, and horizontal pressure gradient collectively influence the onset of oscillatory convection. Notably, our investigation into Titanium Oxide (TiO₂), Copper Oxide (CuO), and Aluminum Oxide (Al₂O₃) nanoparticles reveals that TiO₂ particles enhance the onset of convection compared to Al₂O₃ and CuO, while CuO nanoparticles exhibit greater thermal stability. Further, the nonlinear stability analysis is performed using the method of lines in conjunction with regularization and finite difference schemes for spatial derivatives. The time evolution of all field variables is simulated through the visualization of streamlines and isotherms, providing a detailed representation of the system's dynamics. Additionally, the critical values of the Darcy-Rayleigh number are computed and compared for both linear and nonlinear stability analyses. The results demonstrate the equivalence of linear instability and nonlinear stability boundaries in the absence of a constant pressure gradient, whereas subcritical instability becomes apparent in its presence. These insights advance our understanding of mixed convective flows in porous media, with potential implications for various engineering and environmental applications.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"36 6","pages":""},"PeriodicalIF":1.3,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540726","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":"A Ternary Phase-Field Model for Separation of Water from a Water/Oil Mixed Drop Using Lamb Waves","authors":"Zhijie Zhang,&nbsp;Zichen Wang,&nbsp;Zhaodong Yang,&nbsp;Yang Wang,&nbsp;Wei Liang","doi":"10.1007/s12217-024-10144-6","DOIUrl":"10.1007/s12217-024-10144-6","url":null,"abstract":"<div><p>In this work, we propose a ternary phase-field model for separation of water from a water/oil mixed drop using Lamb waves. In this model, we describe a Cahn–Hilliard/Navier–Stokes model for the simulation of incompressible flows composed of three immiscible components, where surface tension, gravity, and the acoustic streaming force of Lamb waves act on a water/oil mixed drop are taken into account through volumic forces. To test the present model, we further conduct separation experiments of oil–water mixtures driven by surface acoustic waves on a non-piezoelectric substrate. The numerical results are in good agreement with the experimental solutions illustrate that present model has the good capability in the study of the separation of water from a water/oil mixed drop using Lamb waves.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"36 6","pages":""},"PeriodicalIF":1.3,"publicationDate":"2024-10-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142540727","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":"Relative Trajectories of Contaminated, Spherical Drops in a Temperature Gradient and Gravity at Finite Stokes Numbers","authors":"Michael Rother","doi":"10.1007/s12217-024-10141-9","DOIUrl":"10.1007/s12217-024-10141-9","url":null,"abstract":"<div><p>This work is a theoretical investigation into the effect of finite droplet inertia on combined gravitational and thermocapillary interactions of spherical drops covered with an incompressible surfactant film. The significance of droplet inertia is indicated by the magnitude of the Stokes number <b><i>St</i></b>. Initial calculations are a continuation of previous results from <b><i>St</i></b> = 0 to finite Stokes numbers at <span>(varvec{O(1)})</span> drop-to-medium viscosity and thermal conductivity ratios. Interesting outcomes, such as stable tandem motion and complex relative trajectories, are observed. At more realistic <span>(varvec{O(10)})</span> ratios, the results tend to be dampened from those at lower values, although unusual behavior still occurs. Finally, interactions are determined for two physical systems, water drops in air and mercury drops in <b><i>n</i></b>-pentane. At normal gravity, two limits are usually possible. In order for the thermocapillary and gravitational contributions to be equal, the drops and their corresponding Stokes numbers must be small, while for larger drops at higher <b><i>St</i></b>, gravity is the dominant driving force. For water droplets in air with radii less than 10 <span>(varvec{mu })</span>m, van der Waals forces control the interactions. However, drop inertia is the most important factor for droplets with radii greater than 25 <span>(varvec{mu })</span>m. Even a small thermocapillary effect can have noticeable consequences on the relative trajectories for intermediate-sized drops. Some comments are made on the difficulty in experimentally reproducing the theoretical results, with a recommendation of centi- or milligravity conditions.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"36 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142410921","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":"Correlation Between Invariable Blood Proteins and Heart Rate Variability in Long-Duration Space Flights","authors":"Ludmila Pastushkova,&nbsp;Vasily Rusanov,&nbsp;Anna Goncharova,&nbsp;Darya Kashirina,&nbsp;Andrey Nosovsky,&nbsp;Elena Luchitskaya,&nbsp;Tatyana Krapivnitskaya,&nbsp;Irina Larina","doi":"10.1007/s12217-024-10139-3","DOIUrl":"10.1007/s12217-024-10139-3","url":null,"abstract":"<div><p>The article analyzes how long-duration space missions’ effect on the heart rate variability parameters and invariable blood proteins. The results are discussed taking into correlation between them. Seven Russian cosmonauts took part in the research during their missions to the International Space Station. Samples of dry blood drops were collected as part of the space experiment ''OMICs-DBS'', electrocardiogram samples were collected as part of the space experiment \"Cardiovector\". We have established a linear relationship between the concentrations of the following proteins: complement C1q subcomponent subunit A (encoded by the C1QA gene), complement C1r subcomponent (encoded by the C1R gene), fibrinogen gamma chain (encoded by the FGG gene),galectin-3 (encoded by the LGALS3 gene), interstitial collagenase or matrix metalloproteinase-1 (encoded by the MMP-1 gene), pigment epithelium-derived factor (encoded by the PEDF gene) and frequency-domain heart rate variability (HRV) parameters at some stages of space flight. Three proteins were associated with of total power parameters, and either positively correlated with the low-frequency (LF) domain as in the case of the C1QA (complement C1q subcomponent subunit A) or negatively - LGALS3, MMP-1 (galectin-3, matrix metalloproteinase-1) correlated with the high-frequency domain (HF). One of the proteins, the PEDF (pigment epithelium-derived factor), positively correlated with the HF, which correspondingly reflected the effect of vagal modulation on the SA node. The Complement C1r subcomponent had positive correlations with both HF and LF. The FGG (fibrinogen gamma chain) was negatively correlated with both individual components of the frequency-domain (HF, ms2 and LF ms2) also its total power. We assume that such statistical relationships reflect the tension of regulatory mechanisms, which is consistent with classical studies of autonomic regulation in space flight.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"36 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2024-09-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247809","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":"Numerical Investigation on Mechanism Analysis of Bubble Pinch–off","authors":"Meng Jia,&nbsp;Mingjun Pang","doi":"10.1007/s12217-024-10138-4","DOIUrl":"10.1007/s12217-024-10138-4","url":null,"abstract":"<div><p>The studies on bubble pinch–off deviates to some degree from the actual situation due to limitations in theoretical assumptions and experimental conditions, and physical details such as satellite bubbles inside the bubble cannot be observed. Even some of the published experimental results are divergent. To fully understand the dynamics of bubble pinch–off, the authors applied the volume of fluid (VOF) method to investigate the effect of liquid–phase viscosity on bubble pinch–off, and analyzed the pinch–off process and the surrounding flow field. It was found that in low–viscosity liquids, the process of bubble pinch–off is relatively fast and the position corresponding to <i>R</i>_<i>min</i> varies only in the axial direction; and satellite bubbles during pinch–off shows vertical distribution, which enter the upper and lower parts with the jet after bubble pinch–off. In intermediate and high viscosity liquids, a gas line is formed after bubble pinch–off, and the length and duration of the gas line increase with an increase in liquid–phase viscosity; and the position corresponding to <i>R</i>_<i>min</i> moves not only radially inward, but also axially upward. In liquids of different viscosities, the strength of annular flow and the radial pressure drop are different, which leads to different phenomena of bubble pinch–off.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"36 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2024-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142247806","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 on Startup Performance of a High-temperature Liquid Metal Heat Pipe with Fins","authors":"Zhi-Hu Xue,&nbsp;Wei Qu","doi":"10.1007/s12217-024-10137-5","DOIUrl":"10.1007/s12217-024-10137-5","url":null,"abstract":"<div><p>This paper presents the experimental results of a high-temperature heat pipe with fins at horizontal. The heat pipe tube is designed to Φ25 × 410 mm, two wraps of 100 mesh screen, and filling mass of 15 g sodium. The height and thickness of the fins are 13 mm and 1 mm, and the gap distance between two fins is 5 mm. The wall material of the tube container and fins both are stainless steel. In order to compare the impact of the fins on the startup performance of the heat pipe, a plain-tube high-temperature heat pipe without fins which has the same dimensions is also comparatively experimented. The experimental results show that the finned heat pipe can start successfully and its end of condenser behaves bright red color, which is roughly in accordance with the results of the plain-tube heat pipe. The comparative results also show that the startup time of full startup and the temperature difference between evaporator and condenser after fully starting for the finned heat pipe and plain-tube heat pipe are similarly same. However, adding fins in condenser have a great effect on the temperature rise-rate during starting process and the quasi-steady or equilibrium temperature after startup between the results of two heat pipes.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"36 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181792","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 Frontier of Space Medicine: The Nexus of Bone Regeneration and Astronautic Health in Microgravity Conditions","authors":"Behnaz Banimohamad-Shotorbani,&nbsp;Arezou Azizsoltani,&nbsp;Zahra Khalaj,&nbsp;Maryam Rafiei-Baharloo,&nbsp;Armita Ghotaslou,&nbsp;Sonia Fathi-karkan","doi":"10.1007/s12217-024-10136-6","DOIUrl":"10.1007/s12217-024-10136-6","url":null,"abstract":"<div><p>Microgravity, the near absence of gravity experienced in space, is a major health concern for astronauts, leading to significant bone loss. This weakens their skeletal system, impacting performance during missions and hindering post-mission rehabilitation. To address this challenge, this paper explores the potential of advanced cellular research and regenerative medicine for mitigating bone loss in astronauts. We analyze the biological mechanisms affecting bone turnover markers and their implications for space travel. By examining key studies on the effects of spaceflight on bone structure in rodents and humans, we highlight the complex relationship between bone density and the microgravity environment. While acknowledging limitations like limited spaceflight simulators and the early stage of extraterrestrial research facilities, we propose a strategic shift towards advanced cellular research specifically tailored to microgravity. This approach focuses on understanding how microgravity disrupts bone formation and resorption at the cellular level. Tailor-made cellular laboratories are crucial for this research. These specialized labs would simulate microgravity and incorporate advanced technology to study the behavior and function of bone-forming cells (osteoblasts) and stem cells under these conditions. By investigating cellular mechanisms and potential therapeutic targets, this research holds promise for developing novel bone regeneration strategies for astronauts. This could involve stimulating bone formation or promoting the activity of stem cells to repair and strengthen bones in space. The success of this approach relies on collaboration between clinical applications and molecular signaling research. It also underscores the need for a skilled team of scientist-astronauts to conduct in vivo bone regeneration research under microgravity conditions. This multifaceted approach has the potential to not only improve astronaut health and well-being, but also pave the way for a sustainable human presence in space. Furthermore, advancements in cellular therapies for bone health under microgravity could have applications on Earth for treating conditions like osteoporosis.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"36 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181793","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":"Study on the instability of FC-72 vapor–liquid interface in a rectangular channel under different gravity conditions","authors":"Leigang Zhang,&nbsp;Bo Xu,&nbsp;Zhenqian Chen,&nbsp;Guopei Li,&nbsp;Yonghai Zhang,&nbsp;Xuehong Wu","doi":"10.1007/s12217-024-10135-7","DOIUrl":"10.1007/s12217-024-10135-7","url":null,"abstract":"<div><p>This paper investigates the instability of FC-72 vapor–liquid interface in a rectangular channel under different gravity conditions employing short-term microgravity experimental systems designed based on the drop tower platform. Visual observations and numerical simulations were conducted to monitor the behavior of vapor–liquid interface. The study reveals significant fluctuations, with liquid climbing along both sides of the channel after drop cabin releases. Higher initial liquid levels result in increased maximum liquid phase heights and decreased minimum values, with noticeable fluctuations. In microgravity, the maximum height gradually rises with significant fluctuations, while minimum height remains relatively stable. Increasing contact angle leads to reduced variation in maximum and minimum heights, with a distinctive upward slope of vapor–liquid interface observed at a 90° contact angle. The temporal evolution of vapor–liquid interface observed in simulations closely aligns with experimental findings. This study highlights the importance of considering various factors in designing experiments involving fluid systems with low surface tension, particularly in aerospace applications, and calls for further research to develop more sophisticated models and techniques for understanding and controlling vapor–liquid interface instability.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"36 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181794","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":"Analytical Analysis of the Effects of the Porosity Distribution on Liquid–Water Management in the Cathode of a Polymer Electrolyte Membrane Fuel Cell","authors":"Faycel Khemili,&nbsp;Mustapha Najjari","doi":"10.1007/s12217-024-10134-8","DOIUrl":"10.1007/s12217-024-10134-8","url":null,"abstract":"<div><p>Proton Exchange Membrane Fuel Cell (PEMFC) technology has been receiving more attention recently and can play a more expanded role in space missions with low gravity or microgravity. The liquid water generation in the Gas Diffusion Layer (GDL) of a Proton Exchange Membrane Fuel Cell (PEMFC) increases the resistance to oxygen flow toward the catalyst layer. Water flooding inside the GDL can affect the PEMFC performance especially at higher current densities. Therefore, a good understanding of the effect of liquid water amount in the GDL is crucial to water management and, subsequently, to the performance of the fuel cell. The purpose of the present study is to investigate the effect of the microstructure characteristics of the GDL on the water flooding and liquid water distribution inside the GDL. A one-dimensional theoretical model has been developed. Results indicate that the porosity gradient has a significant effect on the liquid water saturation and the performance of the PEM fuel cell.</p></div>","PeriodicalId":707,"journal":{"name":"Microgravity Science and Technology","volume":"36 5","pages":""},"PeriodicalIF":1.3,"publicationDate":"2024-08-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142181797","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}