Download or read book Capillary Flow in Containers of Polygonal Section Theory and Experiment written by and published by . This book was released on 2001 with total page 30 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Capillary Flow in Containers of Polygonal Section written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-19 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: An improved understanding of the large-length-scale capillary flows arising in a low-gravity environment is critical to that engineering community concerned with the design and analysis of spacecraft fluids management systems. Because a significant portion of liquid behavior in spacecraft is capillary dominated it is natural to consider designs that best exploit the spontaneous character of such flows. In the present work, a recently verified asymptotic analysis is extended to approximate spontaneous capillary flows in a large class of cylindrical containers of irregular polygonal section experiencing a step reduction in gravitational acceleration. Drop tower tests are conducted using partially-filled irregular triangular containers for comparison with the theoretical predictions. The degree to which the experimental data agree with the theory is a testament to the robustness of the basic analytical assumption of predominantly parallel flow. As a result, the closed form analytical expressions presented serve as simple, accurate tools for predicting bulk flow characteristics essential to practical low-g system design and analysis. Equations for predicting corner wetting rates, total container flow rates, and transient surfaces shapes are provided that are relevant also to terrestrial applications such as capillary flow in porous media. Weislogel, Mark M. and Rame, Enrique (Technical Monitor) Glenn Research Center NASA/CR-2001-210900, E-12777, NAS 1.26:210900
Download or read book Capillary Flow in Cylindrical Containers of Irregular Polygonal Section written by M. M. Weislogel and published by . This book was released on 2001 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book AIAA Journal written by American Institute of Aeronautics and Astronautics and published by . This book was released on 2004 with total page 954 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book 39th AIAA Aerospace Sciences Meeting and Exhibit written by and published by . This book was released on 2001 with total page 656 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Capillary Driven Flows Along Differentially Wetted Interior Corners written by Eric L. Golliher and published by BiblioGov. This book was released on 2013-07 with total page 34 pages. Available in PDF, EPUB and Kindle. Book excerpt: Closed-form analytic solutions useful for the design of capillary flows in a variety of containers possessing interior corners were recently collected and reviewed. Low-g drop tower and aircraft experiments performed at NASA to date show excellent agreement between theory and experiment for perfectly wetting fluids. The analytical expressions are general in terms of contact angle, but do not account for variations in contact angle between the various surfaces within the system. Such conditions may be desirable for capillary containment or to compute the behavior of capillary corner flows in containers consisting of different materials with widely varying wetting characteristics. A simple coordinate rotation is employed to recast the governing system of equations for flows in containers with interior corners with differing contact angles on the faces of the corner. The result is that a large number of capillary driven corner flows may be predicted with only slightly modified geometric functions dependent on corner angle and the two (or more) contact angles of the system. A numerical solution is employed to verify the new problem formulation. The benchmarked computations support the use of the existing theoretical approach to geometries with variable wettability. Simple experiments to confirm the theoretical findings are recommended. Favorable agreement between such experiments and the present theory may argue well for the extension of the analytic results to predict fluid performance in future large length scale capillary fluid systems for spacecraft as well as for small scale capillary systems on Earth.
Download or read book 40th AIAA Aerospace Sciences Meeting Exhibit written by and published by . This book was released on 2002 with total page 672 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book AIAA Aerospace Sciences Meeting and Exhibit 42nd written by and published by . This book was released on 2004 with total page 558 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Analysis of Tank PMD Rewetting Following Thrust Resettling written by and published by . This book was released on 2002 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Gravitational Effects in Physico chemical Processes written by Ranga Narayanan and published by . This book was released on 2003 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Capillary Flow and Collapse in Wedge Shaped Channels written by Jörg Klatte and published by Cuvillier Verlag. This book was released on 2012-01-16 with total page 164 pages. Available in PDF, EPUB and Kindle. Book excerpt: The forced, isothermal, and incompressible capillary channel flow has been studied theoretically, experimentally, and numerically in this work using the example of an open wedge-shaped channel with a finite length. The curvature of the interface at the open side of the channel is coupled to the pressure difference between the surrounding gas pressure and liquid pressure along the flow path, and thus, a flow rate limit exists, above which the interface collapses. This work investigates this collapse phenomenon as a function of the channel geometry. The derivation of a one-dimensional differential flow equation is based on the streamline theory. The local pressure loss and both principal mean radii of curvature at the free surface are considered. To approximate the local pressure loss, the fully-developed flow profiles were compared to the three-dimensional numerical flow profiles. The physical understanding of the collapse behavior is generalized with the detection of a second characteristic collapse phenomena. In the inertial limit, the interface chokes at the smallest cross-section. In the viscous limit, the interface collapses at the outlet. A dimensionless number has been introduced, which classifies the inertial and viscous regime. Three numerical methods are presented to solve the capillary flow problems. The first method is a fast numerical tool for design and parametric studies of steady capillary flows. The second numerical approach solves the complete three-dimensional equation system for validation of the theoretical assumptions and time-dependent flows. The third method is specialist and solves the governing one-dimensional equations within seconds. Unique experimental data for inertia dominated flow has been recorded using the microgravity environment of a drop tower. The steady flow configuration, the transient reorientation behavior of the interface, and the collapse behavior have been observed. Additional terrestrial experiments study the hydrostatic influence. The experimental results validate the theoretical work and benchmark the numerical codes. The evaluation of a three-dimensional numerical parametric study reveals the desired velocity scale for the critical flow rate in the inertial and viscous regime. The study improves the physical understanding of such capillary corner flows, which is beneficial for liquid management in space as well as for the development of microfluidic applications on the ground.
Download or read book Analytical Computational and Experimental Studies of Capillary Flow in Complex Geometries written by Yongqing Pent and published by . This book was released on 2009 with total page 538 pages. Available in PDF, EPUB and Kindle. Book excerpt: The dynamic processes of capillary flow in complex geometries have been studied analytically, computationally and experimentally in this research. A general approach for modeling the capillary flow in arbitrary irregular geometries with straight axis of symmetry is proposed. Using this approach, the governing equation to describe the dynamic capillary rising motion in capillaries with nonuniform elliptical cross-section is first derived under the assumptions of parabolic distribution of the axial velocity and constant angle. The calculation results for the capillary flow in different tubes with irregular wall show that, in comparison with existing models that have been tested, the present model can improve the underestimation of the nonuniformity effects. Using the perturbation method, an asymptotic solution of the flow field in nonuniform circular tubes is obtained and is shown to be superior to the traditional Hagen-Poisuille solutions in comparison to the numerical FLUENT results. A new DCA (dynamic contact angle) model, combining the current velocity-dependent model based on molecular-kinetic theory and empirical time-dependent model based experiments, is proposed to describe the dynamic transition process from the initial state to the equilibrium state. The capillary flow model is further developed by using the new velocity distribution and the DCA model. The proposed theoretical models are validated by a series of experiments of capillary flow in complex geometries. The industrial application of the research was explored by adopting the proposed model to describe the water flow through a multi-layer porous medium that is used in Procter & Gamble's dewatering device for the paper making industry. Comparing with the experimental data, the proposed model has good predictions on the dewatering performance of the device, and hence, can potentially be used as an industrial design optimization tool.
Download or read book On Cylindrical Container Sections for a Capillary Free surface Experiment written by Allen Chen and published by . This book was released on 1995 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Mechanics written by and published by . This book was released on 2002 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Assessment of Directions in Microgravity and Physical Sciences Research at NASA written by National Research Council and published by National Academies Press. This book was released on 2003-07-11 with total page 123 pages. Available in PDF, EPUB and Kindle. Book excerpt: For thirty years the NASA microgravity program has used space as a tool to study fundamental flow phenomena that are important to fields ranging from combustion science to biotechnology. This book assesses the past impact and current status of microgravity research programs in combustion, fluid dynamics, fundamental physics, and materials science and gives recommendations for promising topics of future research in each discipline. Guidance is given for setting priorities across disciplines by assessing each recommended topic in terms of the probability of its success and the magnitude of its potential impact on scientific knowledge and understanding; terrestrial applications and industry technology needs; and NASA technology needs. At NASA's request, the book also contains an examination of emerging research fields such as nanotechnology and biophysics, and makes recommendations regarding topics that might be suitable for integration into NASA's microgravity program.
Download or read book 04 2569 04 2733 written by and published by . This book was released on 2004 with total page 504 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Open Channel Microfluidics written by Jean Berthier and published by Morgan & Claypool Publishers. This book was released on 2019-09-04 with total page 171 pages. Available in PDF, EPUB and Kindle. Book excerpt: Open microfluidics, the study of microflows having a boundary with surrounding air, encompasses different aspects such as paper or thread-based microfluidics, droplet microfluidics and open-channel microfluidics. Open-channel microflow is a flow at the micro-scale, guided by solid structures, and having at least a free boundary (with air or vapor) other than the advancing meniscus. This book is devoted to the study of open-channel microfluidics which (contrary to paper or thread or droplet microfluidics) is still very sparsely documented, but bears many new applications in biology, biotechnology, medicine, material and space sciences. Capillarity being the principal force triggering an open microflow, the principles of capillarity are first recalled. The onset of open-channel microflow is next analyzed and the fundamental notion of generalized Cassie angle (the apparent contact angle which accounts for the presence of air) is presented. The theory of the dynamics of open-channel microflows is then developed, using the notion of averaged friction length which accounts for the presence of air along the boundaries of the flow domain. Different channel morphologies are studied and geometrical features such as valves and capillary pumps are examined. An introduction to two-phase open-channel microflows is also presented showing that immiscible plugs can be transported by an open-channel flow. Finally, a selection of interesting applications in the domains of space, materials, medicine and biology is presented, showing the potentialities of open-channel microfluidics.
