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Single-phase Flow (single-phase + flow)
Selected AbstractsSingle-phase flow in composite poroelastic mediaMATHEMATICAL METHODS IN THE APPLIED SCIENCES, Issue 2 2002R. E. Showalter The mathematical formulation and analysis of the Barenblatt,Biot model of elastic deformation and laminar flow in a heterogeneous porous medium is discussed. This describes consolidation processes in a fluid-saturated double-diffusion model of fractured rock. The model includes various degenerate cases, such as incompressible constituents or totally fissured components, and it is extended to include boundary conditions arising from partially exposed pores. The quasi-static initial,boundary problem is shown to have a unique weak solution, and this solution is strong when the data are smoother. Copyright © 2002 John Wiley & Sons, Ltd. [source] The dynamic characteristics of a thermal control system using latent heat: Comparison between analytical and experimental resultsHEAT TRANSFER - ASIAN RESEARCH (FORMERLY HEAT TRANSFER-JAPANESE RESEARCH), Issue 8 2005Terushige Fujii Abstract The two-phase flow thermal control system, using latent heat of the internal fluid, has received a great deal of research interest as a method for heat removal on the space station and the Space Solar Power System (SSPS). The system has a much lower weight than the single-phase flow, and the temperature can be accurately controlled by changing the saturated pressure inside the loop. To date, this system has not been put into practical use. Numerical analyses were therefore used to investigate the dynamic responses of the loop and to investigate the operational characteristics of the thermal control system. A simulation model was constructed, and the results of the numerical analysis were compared with the experimental results. Good agreement was obtained between analytical and experimental results. © 2005 Wiley Periodicals, Inc. Heat Trans Asian Res, 34(8): 564,578, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.20090 [source] COMPUTATIONAL FLUID DYNAMICS MODELING OF FLUID FLOW IN HELICAL TUBESJOURNAL OF FOOD PROCESS ENGINEERING, Issue 2 2002T. KORAY PALAZOGLU ABSTRACT The effect of different processing parameters on the degree of mixing and axial and radial pressure drops, during single-phase flow in helical tubes was investigated by using CFD software. Correlations were developed to calculate axial and radial pressure drops, and also the ratio of maximum to average fluid velocities. All of these quantities were found to be dependent on curvature ratio (ratio of tube diameter to coil diameter). Flow visualization experiments were performed to assess the degree of mixing in different configurations. At identical conditions, the degree of mixing was higher in the system with the large curvature ratio, which is in agreement with the simulation results. A minimum ratio of maximum to average fluid velocities of 1.61 was achieved, representing a 20% reduction in hold tube length for Newtonian fluid in laminar flow. [source] Three-Dimensional CFD Simulation of Stratified Two-Fluid Taylor-Couette FlowTHE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2006Sreepriya Vedantam Abstract Two-fluid Taylor-Couette flow, with either one or both of the co-axial cylinders rotating, has potential advantages over the conventional process equipment in chemical and bio-process industries. This flow has been investigated using three-dimensional CFD simulations. The occurrence of radial stratification, the subsequent onset of centrifugal instability in each phase, the cell formation and the dependency on various parameters have been analyzed and discussed. The criteria for the stratification, Taylor cell formation in each phase have been established. It can be stated that the analysis of single-phase flow acts as the base state for the understanding of radial stratification of the two-fluid flows. The extent of interface deformation also has been discussed. A complete energy balance has been established and a very good agreement was found between dissipation rate by CFD predictions and the energy input rate through the cylinder/s rotation. L'écoulement bifluide de Taylor-Couette, avec un des cylindres ou les deux cylindres coaxiaux en rotation, offre un avantage potentiel par rapport au système conventionnel utilisé dans les industries chimiques et des bio-procédés. Cet écoulement a été étudié à l'aide de simulations par CFD tridimensionnelles. On a examiné l'occurrence de la stratification radiale, l'apparition subséquente de l'instabilité centrifuge dans chaque phase, la formation des cellules et la dépendance des divers paramètres. Les critères pour la stratification et la formation des cellules de Taylor dans chaque phase ont été établis. On a trouvé que l'analyse de l'écoulement monophasique est à la base de la compréhension de la stratification radiale dans le cas bifluide. Le degré de déformation de l'interface a également été analysé. Un bilan d'énergie complet a été établi et un très bon accord a été trouvé entre la vitesse de dissipation par les prédictions CFD et le taux d'apport d'énergie dû à la rotation du ou des cylindres. [source] Fluid flow in an impacting symmetrical tee junction: I single-phase flow and experimentalASIA-PACIFIC JOURNAL OF CHEMICAL ENGINEERING, Issue 4 2009A. P. Doherty Abstract Experiments were conducted on single-phase fluid flow in a horizontal 90° symmetrical impacting tee junction of 0.026 m i.d. The impacting geometry was chosen because, unlike the combining tee, the pressure loss of the system was not amenable to modelling. Various methods of presentation of the junction pressure drop were attempted and a simple dimensionless model suggested based on the inlet Reynolds number and the equivalent length parameter le/d. Copyright © 2009 Curtin University of Technology and John Wiley & Sons, Ltd. [source] Aeration of Large Size Tanks by a Surface AgitatorCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 5 2005R. Sardeing Abstract A new device has been developed in order to achieve urban or industrial wastewater biological treatment. It has been designed specially for lagoon applications to oxygenate and mix with the same apparatus. The goal is both to achieve a high gas flooding rate and to reach a maximal depth with the bubble plume. Mass transfer measurements have allowed us to choose the most appropriate geometry. Considering the application of the device and the possible use of low-pressure O2 produced on-site, the agitation system is located close to the liquid surface and is composed of a gas-inducing turbine. The role of propellers in addition to the gas-inducing turbine, as well as the use of baffles and a shell, have been experimentally studied. Numerical simulations (CFD) of the whole apparatus in single-phase flow have been used to study the influence of the stator part of the geometry. [source] A Comparison of the Mixing Characteristics in Single- and Two-Phase Grid-Generated Turbulent Flow SystemsCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 6 2004J.S. Moghaddas Abstract The mixing process is studied in grid-generated turbulent flow for single- and bubbly two-phase flow systems. Concentration and mixing characteristics in the liquid phase are measured with the aid of a PLIF/PLIF arrangement. A nearly isotropic turbulent flow field is generated at the center of the vertical pipe by using a honeycomb, three grids and a contraction. In two-phase flow experiments, air bubbles were injected into the flow from a rectangular grid, with mesh size M = 6 mm, which is placed midway between two circular grids each with a mesh size of M = 2 mm. For single-phase flow, the normalized mean concentration cross-stream profiles have rather similar Gaussian shapes, and the cross-stream profiles of the normalized root-mean-square (RMS) values of concentration were found to be quite similar. Cross-stream profiles of the mean concentration, for bubbly two-phase flow, were also found to be quite similar, but they did not have the Gaussian shape of the profiles for single-phase flow. Almost self-similar behavior was also found for the RMS values of the concentration in two-phase systems. The turbulent diffusion coefficient in the liquid phase was also calculated. At the center of the plume, the flow was found to have a periodic coherent structure, probably of vortex shedding character. Observations showed that the period of oscillation is higher in the case of two-phase flow than in single-phase flow. [source] | ||||||||||