Past Research Projects

• A novel hybrid Eulerian/Lagrangian dual scale LES model for predicting atomization in realistic aircraft combustor fuel injectors (Funding: NASA): This is a collaborative project between Dr. Marcus Herrmann (ASU), Dr. Apte (OSU) and Cascade Technology. The goal of this project is to develop, verify, and validate a hybrid Eulerian/Lagrangian dual-scale LES model to predict atomization in realistic aircraft engine combustors. The model will significantly advance the predictive capabilities of aircraft engine simulations by avoiding the currently existing need to tune spray models with relevant experimental data that is difficult to obtain at best. The aircraft engine injector targeted in this proposal is a realistic high shear fuel injector containing 6 liquid fuel jets injecting into a swirling crossflow and an outer secondary swirling flow.

• Pulse Detonation Engine for Advanced Oxy-Combustion of Coal-Based Fuels: (DoE-NETL: DE-FOA-0001247): This project was led by Dr. David Blunck together with Dr. Apte and Dr. Niemeyer. The overall goal of the proposed research will be to develop and evaluate a pulse detonation combustion system for direct power extraction. The system will work on either gaseous (e.g., natural gas) or solid (e.g., coal) fuels. The long term vision is that such a pulse detonation combustor can be coupled with a MHD system and be used as a topping cycle.

• Advances in Understanding Pore-Scale Dispersion (Funding: NSF, #1521441): This research will combine theory, numerical computation, and experimental data to examine the process of dispersion in monodisperse and polydisperse porous media at an unprecedented level of detail. It has only recently become possible to conduct numerical simulations of flow within the geometry of a complex, three-dimensional porous medium of sufficient size and resolution to generate the kind of data needed to connect the microscale physical processes within a porous medium with the observable macroscopic behavior of the material as a whole. The goal is to bring new understanding about the dispersion process by: 1) experimentally measuring (via X-ray tomography) beds of random porous media at unprecedented resolution; 2) conducting direct numerical simulations of the flow and dispersion process in these porous media (up through the steady inertial flow range) using state-of-the art numerical methods; and 3) developing modified descriptive theory (via the method of volume averaging) to predict the macroscopic behavior of the dispersion process from representative structure of porous materials.

• Numerical Investigation of Potential Erosion Mechanisms in SCO2 Power Generation Cycles (Funding: ORISE, NETL-Albany): Supercritical Carbon Dioxide (sCO2) has been used for power generation in thermal solar, fossil energy and nuclear power plants. It is an ideal working fluid for closed-loop power generation as it is nontoxic,non-flammable, non-corrosive and low-cost fluid. There is also evidence that even for a fairly pure sCO2 flowing through small pipe bends or junctions
  causes erosion of the material. For pure supercritical CO2 flowing through pipe or duct bends, it is hypothesized that erosion may occur due to (i) large fluctuations in local temperature and pressure due to turbulence, secondary flow patterns, and property variations causing substantial shear stresses on the pipe walls, and (ii) surface or geometric irregularities impacting wall shear stresses and pressure variations. To test these hypotheses, numerical simulation of a single-phase, turbulent
  flow with heat transfer in pipe or duct bends at representative conditions and flow Reynolds numbers is proposed. Collaboration between Dr. Apte and Dr. Omer Dogan of NETL, Albany.

• High Flux Microchannel Solar Receiver Development (Funding: DoE's Apollo Concentrating Solar Power Program): This collaborative project is led by Dr. M. Kevin Drost brings together researchers from OSU, UC Davis, PNNL, and NETL. The proposed research aims to develop the microchannel solar receiver (MSR) from technology readiness level (TRL) 3 to TRL 5, culminating in an on-sun test of a commercial scale receiver module with a surface area of approximately 1 square meter.

• Sediment-Bed-Turbulence Coupling in Oscillatory Flows: Fully Resolved Numerical Experiments and Modeling (Funding: NSF, #1133363): Sediment transport, in rivers and coastal regions, affects large-scale geomorphic processes of dune formation, beach erosion and landform evolution that can displace human settlements, as well as destroy vegetation and agricultural infrastructure with strong socio-economic impact. In this new project we will look at quantifying effect of sediment-bed-turbulence interactions on the onset of erosion, entrainment, suspension, and deposition mechanisms of sediment. Specifically, high-fidelity numerical simulations resolving all scales of fluid flow and sediment motion will be employed to study oscillatory boundary layer dynamics and resultant sediment transport. The novelty of this research is in the development and use of a fully resolved simulation (FRS) approach based on first principles, without requiring models for drag and lift forces, for the study of sediment incipient motion. This research will also yield a Numerical Water/Wind Tunnel (NWT), a virtual educational tool for fluid-particle systems.

• Characterization of Turbulent Flow in Porous Media: Integrating Experiments, DNS, and Theory (Funding: NSF, #1336983): In this recently funded project, the primary objective of the proposed research is to examine fast (high Reynolds number) flows in porous media. A unified approach is proposed, which integrates three research elements (1) upscaling theory (the method of volume-averaging ) with closure, (2) direct numerical simulation (DNS) of flow in porous media, and (3) PIV experimental studies of flows in porous media. The study will cover a broad range of Reynolds numbers [Re ~O(100-4000)]. The overall goal of this work is to provide a cohesive theory (with extensive experimental validation) to describe rather high velocity flows in a packed bed in a way that is consistent with the widely-used empirical expression known as the Darcy-Ergun-Forchheimer equation.

• High-Flux Microchannel Solar Receiver (Funding: DoE's SunShot Concentrating Solar Power Program under EERE): This collaborative project is led by Dr. M. Kevin Drost together with co-PIs Vinod Narayanan and Sourabh Apte of OSU and Bob Wegeng of Pacific Northwest National Laboratory (PNNL). The main goal of this research is to develop a microchannel solar-receiver for liquid and gas-cooled receivers. Laboratory-scale designs will be developed using integrated computational modeling for liquid-cooled systems. Focus will also be on a gas-cooled receiver design and demonstration on a solar dish at Pacific Northwest National Laboratory. It is hypothesized that use of microchannels may help reduce the size, weight, and thermal loss from high-temperature receivers owing to high heat transfer rates possible in microchannels. Goal is to first use computational modeling techniques to help guide the receiver design, build, test, and demonstrate the feasibility of the design. A novel adaptive flow-control capable of redistributing the flow with solar flux variations is also being developed by the PNNL researchers.

• CC-NIE Networking Infrastructure: Network Infrastructure and DMZ for Oregon State University (Funding: NSF, #1341033): PI: Brett Tyler and Co-PIs: Sourabh Apte, Joseph Beckman, Richard Spinrad, and Soloman Yim. NSF's network infracstructure and engineering program invests in improvements to dynamic network services at the campus level for a range of data transfers supporting computational science and computer networks and systems research. Oregon State University is upgrading key components of the campus core network infrastructure, enabling 10-40 Gbps network connections between research units within a Science DMZ, with interconnects via the DYNES network and Internet2 to external research partners such as XSEDE and iPlant. This infrastructure based grant will help transform research in a wide diversity of disciplines at OSU that generate and analyze massive data sets produced, analyzed and disseminated on- and off-campus. The disciplines affected include genomics and computational biology, image processing and recognition, earthquake and ocean wave physics, landscape remote sensing, pharmacy, clinical veterinary medicine, and earth, atmospheric and ocean sciences.

• Surface Transient Storage (STS) in Dead Zones of Streams (Funding: NSF, #0943570): This new project is starting in Fall 2010 and is an inter-disciplinary collaborative work between mechanical engineers and hydro-geologists (Prof. Roy Haggerty and his group). Eddies in streams caused by flow separation and recirculation can retain solutes, heat, and pollutants. The bed topology and stream conditions influence these regions. However, there is no easy or reliable method to quantify the residence time distribution (RTD) and its relation to physical characteristics such as stream velocity, size of the dead zone, and number of eddies. In this work, we are conducting field studies in Oak Creek near OSU as well as large-eddy simulation studies of turbulent flow in rivers and streams with complex bed topology. The field data will be used to validate LES results, which in turn will be used to train cheaper models based on Reynolds-Averaged Navier Stokes equations. This work will advance CFD capabilities and their applicability to hydrology and allied sciences.

• Inertial Effects in Flow Through Porous Media (Funding: NSF, #0933857): This recently initiated project involves investigation of inertial effects on flow and scalar transport in porous media. In this work, we plan to perform direct numerical simulations and time-resolved three-component PIV measurements of flow and transport through a porous medium over a wide range of Reynolds numbers (10-200), with specific emphasis on quantifying the flow field and scalar dispersion. Inertial flows in porous media have significance in a wide array of applications in the field from predicting the performance of packed bed reactors to understanding subsurface groundwater remediation. In these applications, the Reynolds number is in the inertial range; however, a majority of the theoretical studies of flow and transport in porous media have assumed non-inertial Stokes flow. This work is a collobrative effort among Prof. Brian Wood, Dr. Apte, and Prof. James Liburdy. Direct numerical simulations of such flows pose considerable challenges due to extremely complex geometry. We are performing simulations with unstructured body fitted grids as well as structured body non-conforming grids using the hLE based immersed boundary approach. Some of the simulations will use around 200M grid cells and 512-1024 processors on Tegragrid supercomputers.

• Modeling of Particle-Laden Flows and Radiative Heat Transfer in Oxy-Coal Reactors (Funding: DoE): Clean combustion technology, extracting energy from fossil fuels, is of considerable importance to the US economy. Design of new coal-based reactors in oxygen rich environments with subsequent carbon capture and sequestration is an emerging technology for efficient and clean use of fossil fuels. In this project, we are developing a numerical tool for predictive simulations of oxy-fuel combustion and radiation transport in coal reactors. This involves two major parallel efforts.

  • Large-eddy simulation of gas-particle interactions in complex systems (Clean Oxy-Coal Reactors)
  • Implicit Monte-Carlo based radiative transport modeling (IMC)

We collaborate with Dr. Todd Palmer's group for radiative heat transfer as well as the National Energy Technology's (NETL) research staff.

• Solar-Energy Based Biofuel Reforming and Control (Funding: Oregon BEST, US Army Tactical Energy System through ONAMI): Chemical processing and production of hydrogen fuel using solar energy is a promising clean energy source of considerable economic importance. We are performing fundamental studies that will facilitate simulation-based design of solar receivers and microchannel reactors for effective conversion of solar energy into clean fuels. Our goal is to design a receiver and a reactor with an active control algorithm that will allow continuous production of solar-fuels from biomass-based products. This proof-of-concept project, is a collaboration with Dr. John Schmitt's group on the control algorithm and Dr. Vinod Narayanan's group working on experimental heat transfer and thermal imaging.

• Simulation and Modeling of Bubbly Flows and Cavitation (Funding: ONR): This work involves development of an integrated framework for large-eddy simulations (LES) of disperse bubbly flows such as those occurring in cavitating flow over a propeller or hydrofoil. Such flows require models for bubble dynamics including transport, growth and collapse of bubbles and bubble clusters. We are presently working on the following aspects with the goal of a unified framework for LES of separated bubbly flows:

  • A novel interface tracking scheme for fully resolved bubbles (hLE)
  • Discrete bubble dynamics for subgrid bubbles (LES-DBM)
  • Fictitious domain method for flow over moving boundaries (FRS)

• Modeling and Control of Flow Maldistribution Due to Microchannel Plugging (Funding: US Army): Clogging of branches of parallel microchannels due to particulates or nucleation and bubble formation is one of the key issues encountered in designing efficient heat sinks and heat exchangers for cooling of high heat loads encoutered in modern tactical energy systems. Nucleation and growth of bubbles in parallel microchannels can block passages resulting in flow maldistribution, increased pressure drop and inefficient heat transfer. The main feature of this work is to develop a simulation platform wherein fluid flow simulation software based on scientific computing (MPI-Fortran90) is efficiently integrated with a Matlab-based model-predictive control algorithm to actively control and mitigate flow maldistibution. We collaborate with Dr. John Schmitt's Research Group.

• Flow Feature Identification (Funding: OSU Internal): Identification of swirl regions and vortical structures in separated flows over immersed objects (such as airfoils and hydrofoils) is of crucial importance to gain fundamental understanding of the flow as well as correlating passage of large-scale vortical structures with the signature they leave on the immersed surface in terms of pressure variations. In this research on flow feature detection, we identify the swirl and vortical structures in unsteady separated flows, using the Hessian of the pressure field obtained from numerical simulations and develop a correlation between the surface pressure oscillations and passage of vortical structures. This work originated as part of a new graduate level course on Flow Feature Identification and Scientific Visualization co-taught by Prof. Jim Liburdy, Dr. Apte, and Dr. Eugene Zhang. The approach investigated is being extended to flow over airfoils with the goal of determining critical sensor locations for flow control.

• Modeling of Disperse Two-Phase Flow in Gas-Turbine Combustors (Funding: DoE) (LES-GT): This project involved development of predictive models and numerical algorithms for multiphase, multiphysics flow in realistic gas-turbine combustion chambers. This work resulted in new schemes for large-eddy simulation of variable-density reacting flows on unstructured grids and subgrid scale models based on stochastic theory and point-particle approach for fuel spray and droplet dynamics (dispersion, breakup, evaporation, etc.). The high-fidelity LES and associated subgrid models were applied to study realistic flow conditions in a gas-t urbine combustor to show good predictive capability. This work was part of the Department of Energy's Advanced Scientific Computing (ASC) program at Stanford University.

• Internal Flow Dynamics in Solid Rocket Motors (Funding: DoD) (LES-SRM): This doctoral thesis work by Dr. Apte was supported under the Department of Defense's Multi-University Research Initiative (MURI) program on Investigations of Novel Energetic Materials to Stabilize Rocket Motors. This work used an all-Mach number finite volume scheme based on preconditioning techniques for large-eddy simulation of compressible reacting flows. The combustion dynamics and internal flow in a solid rocket motor were investigated in detail. This work resulted in six archival journal articles, two book chapters, and led to the development of reduced-order models for rocket chamber combustion dynamics.