Bulletin of the American Physical Society
66th Annual Meeting of the APS Division of Fluid Dynamics
Volume 58, Number 18
Sunday–Tuesday, November 24–26, 2013; Pittsburgh, Pennsylvania
Session R28: Industrial Applications II |
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Chair: John R. Buchanan Jr., Bechtel Marine Propulsion Corporation, Bettis Atomic Power Laboratory Room: Spirit of Pittsburgh Ballroom B/C |
Tuesday, November 26, 2013 1:05PM - 1:18PM |
R28.00001: Influence of Spatial Variations on the Flow Field and Power Production of a Model Wind Farm Angelisse Ramos, Nicholas Hamilton, Dominic DeLucia, Ra\'{u}l Bayo\'{a}n Cal Wind tunnel experiments of a 4 $\times$ 3 model wind turbine array are carried out to understand impact on the flow field and turbulence statistics due to the changes in turbine spacing. Stereo particle Image Velocimetry (SPIV) is used to obtain measurements in dual planes, fore and aft of wind turbine models in the centerline of the array. Variations in turbulence statistics are assessed by altering the streamwise and spanwise spacing. Spacing schemes tested include permutations of streamwise spacing, $S_x = [3D,6D]$, and spanwise spacing, $S_z = [1.5D,3D]$, where $D$ is the rotor diameter. Quantities in the mean kinetic energy equation are analyzed under these variations including the Reynolds stress tensor, $\langle u_i u_j \rangle$, kinetic energy flux, $-\langle uv \rangle U$, and turbulence production, $-\langle uv \rangle \partial U/ \partial y$. Furthermore, the mechanical power is measured for these turbines reflecting the influence of spatial variations. The analysis has consequences on land use $versus$ power output. [Preview Abstract] |
Tuesday, November 26, 2013 1:18PM - 1:31PM |
R28.00002: Wind Turbine Gust Prediction Using Remote Sensing Data Paul Towers, Bryn Jones Offshore wind energy is a growing energy source as governments around the world look for environmentally friendly solutions to potential future energy shortages. In order to capture more energy from the wind, larger turbines are being designed, leading to the structures becoming increasingly vulnerable to damage caused by violent gusts of wind. Advance knowledge of such gusts will enable turbine control systems to take preventative action, reducing turbine maintenance costs. We present a system which can accurately forecast the velocity profile of an oncoming wind, given only limited spatial measurements from light detection and ranging (LiDAR) units, which are currently operational in industry. Our method combines nonlinear state estimation techniques with low-order models of atmospheric boundary-layer flows to generate flow-field estimates. We discuss the accuracy of our velocity profile predictions by direct comparison to data derived from large eddy simulations of the atmospheric boundary layer. [Preview Abstract] |
Tuesday, November 26, 2013 1:31PM - 1:44PM |
R28.00003: Detecting Unsteady Blade Row Interaction in a Francis Turbine using a Phase-Lag Boundary Condition Alex Wouden, John Cimbala, Bryan Lewis For CFD simulations in turbomachinery, methods are typically used to reduce the computational cost. For example, the standard periodic assumption reduces the underlying mesh to a single blade passage in axisymmetric applications. If the simulation includes only a single array of blades with an uniform inlet condition, this assumption is adequate. However, to compute the interaction between successive blade rows of differing periodicity in an unsteady simulation, the periodic assumption breaks down and may produce inaccurate results. As a viable alternative the phase-lag boundary condition assumes that the periodicity includes a temporal component which, if considered, allows for a single passage to be modeled per blade row irrespective of differing periodicity. Prominently used in compressible CFD codes for the analysis of gas turbines/compressors, the phase-lag boundary condition is adapted to analyze the interaction between the guide vanes and rotor blades in an incompressible simulation of the 1989 GAMM Workshop Francis turbine using OpenFOAM. The implementation is based on the ``direct-storage'' method proposed in 1977 by Erdos and Alzner. The phase-lag simulation is compared with available data from the GAMM workshop as well as a full-wheel simulation. [Preview Abstract] |
Tuesday, November 26, 2013 1:44PM - 1:57PM |
R28.00004: Modified Design of Hydroturbine Wicket Gates to Include Liquid Control Jets Bryan Lewis, John Cimbala, Alex Wouden With the ever-increasing penetration of alternative electricity generation, it is becoming more common to operate hydroturbines under off-design conditions in order to maintain stability in the electric power grid. Improving the off-design performance of these turbines is therefore of significant importance. As the runner blades of a Francis hydroturbine pass though the wakes created by the upstream guide vanes (wicket gates and stay vanes), they experience significant changes in the instantaneous values of absolute velocity, flow angle, and pressure. The concept of adding water jets to the trailing edge of the guide vanes is proposed as a method for reducing the dynamic load on the hydroturbine runner blades, as well as modifying the flow angle of the water entering the runner to improve turbine efficiency during off-design operation. In order to add water jets that are capable of turning the flow, a modified beveled trailing edge design is presented. Computational experiments show that a $\pm5^{\circ}$ change in swirl angle is achievable with the new design, as well as up to 4\% improvement in turbine efficiency during off-design operation. This correlates to an overall improvement in machine efficiency of up to 2\%, when the losses through the jet channels are taken into account. [Preview Abstract] |
Tuesday, November 26, 2013 1:57PM - 2:10PM |
R28.00005: Mixing and transport in a liquid metal electrode Douglas Kelley, Donald Sadoway Adding large-scale energy storage to Earth's electrical grids would accommodate demand variations, reduce the need for gas-fired peakers, and enable broad deployment of wind and solar generation. Liquid metal batteries are currently being commercialized as a promising and economically viable technology for grid-scale storage. But because these batteries are entirely liquid, fluid flow and instabilities affect battery robustness and performance. We present ultrasound measurements of flow in a realistic liquid metal electrode. We find a critical electrical current density above which the convective flow organizes and gains speed, improving battery efficiency. We are also developing numerical models to simulate flow and transport in liquid metal batteries. [Preview Abstract] |
Tuesday, November 26, 2013 2:10PM - 2:23PM |
R28.00006: Fluid flow in discrete fractures in Enhanced/Engineered Systems, consequences of interconnected fractures, buoyancy, and fracture roughness Don Fox, Donald Koch, Jefferson Tester In Enhanced/Engineered Geothermal Systems (EGS), fluid flow in the discrete fracture network governs how thermal energy is ``farmed'' from the systems. The flow is created by an injection and production well but apart from pressure driven flow, temperature gradients will also cause natural convection in the system. Due to the roughness and shearing of the fractures, the aperture of fracture varies spatially and has been shown to be self-affine. Fracture roughness can lead to flow channeling where most of the flow is conducted through a single pathway. Knowing the flow regime is also important in understanding the behavior of tracers that are injected into the system. The tracer's residence time distribution is used to determine characteristics of the fractures and how they are possibly connected. This presentation will focus on how one would model the fluid flow in EGS and the consequences caused by interconnection, fracture roughness, and buoyancy have on fluid flow, how energy is extracted, and the behavior of tracers. [Preview Abstract] |
Tuesday, November 26, 2013 2:23PM - 2:36PM |
R28.00007: POD-Based Model Reduction toward Efficient Simulation of Flow in NuclearReactor Components Mohammad Ahmadpoor, Greg Banyay, Sagnik Mazumdar, Anirban Jana, Mark Kimber, John Brigham The long-term objective of this research is reduced-order modeling (ROM) to simulate and understand the turbulent mixing inside the lower plenum of a Very High Temperature Reactor, while the present study focuses on confined isothermal jet flow. In general, two steps are required to generate a basis for a ROM: (1) acquisition of an ensemble of possible solution fields for the system; and (2) extracting key features of the ensemble to create the basis. Proper Orthogonal Decomposition (POD) is one approach for extracting features from an ensemble. For this work POD is used to capture the parametric variation of a flow with Reynolds (Re) number and time. Two approaches are considered for model reduction: (1) a regression-based approach, which does not keep the mathematical structure of the modeling, but rather uses interpolation and/or extrapolation to predict flow fields at different Re number or different times and (2) a Galerkin-projection approach in which the Navier-Stokes equations are projected onto the POD modes to obtain low-dimensional ordinary differential equations to represent the fluid flow under conditions outside of the original ensemble. [Preview Abstract] |
Tuesday, November 26, 2013 2:36PM - 2:49PM |
R28.00008: Experimental study on spray characteristics of alternate jet fuels using Phase Doppler Anemometry Kumaran Kannaiyan, Reza Sadr Gas-to-Liquid (GTL) fuels have gained global attention due to their cleaner combustion characteristics. The chemical and physical properties of GTL jet fuels are different from conventional jet fuels owing to the difference in their production methodology. It is important to study the spray characteristics of GTL jet fuels as the change of physical properties can affect atomization, mixing, evaporation and combustion process, ultimately affecting emission process. In this work, spray characteristics of two GTL synthetic jet fuels are studied using a pressure-swirl nozzle at different injection pressures and atmospheric ambient condition. Phase Doppler Anemometry (PDA) measurements of droplet size and velocity are compared with those of regular Jet A-1 fuel at several axial and radial locations downstream of the nozzle exit. Experimental results show that although the GTL fuels have different physical properties such as viscosity, density, and surface tension, among each other the resultant change in the spray characteristics is insignificant. Furthermore, the presented results show that GTL fuel spray characteristics exhibit close similarity to those of Jet A-1 fuel. [Preview Abstract] |
Tuesday, November 26, 2013 2:49PM - 3:02PM |
R28.00009: Fouling of Air Cooled Condensers On the Air Side Hazel Marie, Nicholas Matune As the electrical power demand increases and water resources become more limited, fouling on the air side of Air Cooled Condensers (ACC) is a growing concern. The objective of this study was to experimentally and computationally calculate the convection heat transfer coefficient for both a clean and fouled condenser. Bee pollen was selected as the experimental fouling particle, and engineering data for similar particles were used for the computational model. Both the experimental and computational results showing the negative impact fouling has a on the heat transfer will be presented. [Preview Abstract] |
Tuesday, November 26, 2013 3:02PM - 3:15PM |
R28.00010: Reducing numerical costs for core wide nuclear reactor CFD simulations by the Coarse-Grid-CFD Mathias Viellieber, Andreas G. Class Traditionally complete nuclear reactor core simulations are performed with subchannel analysis codes, that rely on experimental and empirical input. The Coarse-Grid-CFD (CGCFD) intends to replace the experimental or empirical input with CFD data. The reactor core consists of repetitive flow patterns, allowing the general approach of creating a parametrized model for one segment and composing many of those to obtain the entire reactor simulation. The method is based on a detailed and well-resolved CFD simulation of one representative segment. From this simulation we extract so-called parametrized volumetric forces which close, an otherwise strongly under resolved, coarsely-meshed model of a complete reactor setup. While the formulation so far accounts for forces created internally in the fluid others e.g. obstruction and flow deviation through spacers and wire wraps, still need to be accounted for if the geometric details are not represented in the coarse mesh. These are modelled with an Anisotropic Porosity Formulation (APF). This work focuses on the application of the CGCFD to a complete reactor core setup and the accomplishment of the parametrization of the volumetric forces. [Preview Abstract] |
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