31-35 of 35 results

  • Investigation of Bio-Inspired Cylinders for Enhanced Heat Transfer

    PI Anish Prasad

    CO-I Yogesh Pai

    CO-I Royce Fernandes

    CO-I Mark Ricklick

    This project investigates a novel cylinder design inspired from the Harbor Seal whisker, with the goal of reducing coolant pumping power requirements while maintaining heat transfer rates in pin-fin arrays. 

    Arrays of constant cross-section cylinders have been employed in many heat exchange applications. Increases in heat transfer rates characteristically result in an increase in the coolant pumping power requirements, which can be quite high for a circular cylinder array. Pin fin channels are often used at the trailing edge of the blades where they also serve an additional purpose of providing structural support. It has been found that the behavior of the flow around a wall-mounted cylinder significantly impacts the heat transfer. The boundary layer becomes broken up by the presence of the pin, creating a horseshoe vortex. This horseshoe vortex produces high wall shear stress beneath it, resulting in high heat transfer from the wall in this region. The resulting flow separation around the pin, however, results in large pressure losses. The pin fin channel has been heavily studied in the literature, in an effort to describe the heat transfer and flow behavior and improve prediction abilities. The circular cylindrical pins are relatively easy to manufacture and hence, this configuration is often found in commercial applications. However, the need to reduce pressure drop and maintain the heat transfer rates are a much needed requirement for a variety of industries to improve the cooling efficiency.

    One such prominent line of research is conducted on optimizing the design of the circular cylindrical pins to increase their cooling performance. In this line of research, it was found that bio-mimicked harbor seal whisker geometry leads to the reduction in the cooling system pumping power requirements, while maintaining or improving heat transfer rates. The seal whisker geometry consists of stream-wise and span-wise undulations which reduce the size of the wake and coherent structures shed from the body as a result of an added component of stream-wise vorticity along the pin surface. Also, the vortex shedding frequency becomes less pronounced, leading to significantly reduced lateral loading on the modified cylinder. Preliminary computational studies have shown that the modified wake and vortex shedding structures resulting from the geometry tend to reduce the total pressure loss throughout the system without degrading the cooling levels.

    Seal whisker and proposed bio-inspired cylinder:

    Three different cross-section types, one elliptical, one of circular cross section and a 0.25X axially scaled type of the bio inspired pin were created for further investigation along with two baseline circular cylindrical and elliptical pins. Computational analysis for an array of the above three shapes and a standard elliptical cross-section pin array was undertaken. The results obtained were compared with the baseline circular cylindrical pin array. The main purpose of this research is to describe the heat transfer and flow characteristics of 3 novel bio inspired pin designs using steady and unsteady Reynolds-Averaged-Navier-Stokes (RANS) based simulations, in an effort to better understand their performance. These findings are important to the gas turbine community as reduced penalties associated with cooling flows directly translate to improved thermodynamic and propulsive efficiencies.

    Pin-fin geometries analyzed:

    Further computational research is being conducted in these geometries, and later will be compared with the experimental results, which will be carried out in Embry-Riddle's Gas Turbine Laboratory.


    Categories: Graduate

  • Investigate Detect and Avoid Track Classification and Filtering

    PI Richard Prazenica

    CO-I Troy Henderson

    CO-I Morad Nazari

    CO-I Tyler Spence

    This research will identify key sources of uncertainty in representative detect and avoid architectures and assess the downstream risks and effects of spurious information on downstream system performance

    In this project, which is funded by the FAA ASSURE program, the research team consisting of The Ohio State University, Embry‑Riddle Aeronautical University, Mississippi State University, University of North Dakota and Cal Analytics will work together to:

    • Identify the key sources of misleading surveillance information produced by airborne and ground-based detect and avoid (DAA) systems. Develop risk modeling and analysis tools to assess the system-wide effects of false or misleading information on alerting and separation, as well as impacts on pilots in command (PIC) and air traffic operators.
    • Provide guidance and recommendations for track classification and filter performance and safety requirements to standards bodies, including Radio Technical Commission for Aeronautics (RTCA) and American Society for Testing and Materials (ASTM) DAA working groups, and inform Federal Aviation Administration (FAA) rulemaking on DAA operations.

    Current guidance provided by the Federal Aviation Administration has made beyond visual line of sight (BVLOS) missions an executive priority. Key to the success of these missions is the development of DAA systems capable of providing accurate pilot in the loop, or autonomous deconfliction guidance. Current standards for DAA services provided by RTCA and ASTM do not address the requirements for system performance with respect to generation of false or misleading information to the PIC or autonomous response services of the unmanned aircraft system. This research will identify key sources of uncertainty in representative DAA architectures and assess the downstream risks and effects of spurious information on downstream system performance. Additionally, recommendations will be developed for track classification accuracy requirements that provide sufficient safety margins for enabling DAA services in support of BVLOS missions.

    Categories: Faculty-Staff

  • Mixing of a supercritical jet in a supercritical cross-flow

    PI Neil Sullivan

    CO-I Mark Ricklick

    This project is focused on the exploration and validation of numerical modeling techniques, for the simulation of supercritical jets in crossflow. 

    ​The injection of fuels and oxidizers into combustion chambers is often performed at near-critical or supercritical (SC) temperatures and pressures. At the critical point, the surface tension and enthalpy of vaporization of a fluid approach zero. This means there is no droplet formation in a jet, and also no density change between phases. The fluid has in effect only one supercritical phase, and has both liquid-like and gas-like properties. Physical and thermodynamic properties of the fluid have large gradients near the critical point, and this has led to complications in numerical simulation of even simple flow phenomena at this condition.

    It is desired to simulate the mixing and subsequent combustion of certain supercritical fluids for application to the design of SC-CO combustion power generation. SC methane and oxygen will be burned in an atmosphere of SC carbon dioxide, allowing highly efficient power extraction using smaller turbomachinery than in traditional Brayton or Rankine cycles. The study of SC methane jets also has applications to liquid rocket propellant injection and jet impingement rocket nozzle cooling.

    Reynolds-Averaged Navier Stokes (RANS) and Large Eddy Simulation (LES) numerical studies are conducted to investigate the diffusion-driven mixing of one or more species in a SC jet, with another species in a SC cross-flow. Real-gas effects will be captured using the Peng-Robinson cubic equation of state. Benchmarking is performed against previous experimental and LES studies performed on near-critical and SC jets in quiescent fluids. The commercial code STAR-CCM+ is used for the simulation.

    Improved prediction of jet behavior at near-critical and SC pressures and temperatures will better inform combustor design, combustion efficiency and thermodynamic efficiency.

    Ideal gas axisymmetric simulation of a sub-critical nitrogen jet

    Categories: Graduate

  • Langrangian Wind Tunnel

    ERAU is supporting industry (i.e. Global Aerospace Corp.) in the development of a novel hypersonic wind tunnel by using high-fidelity computational fluid dynamcs.

    GAC is leading development of a wind tunnel in which the test article is propelled thru the test section at hypersonic speeds using a novel, proprietary approach.  Due to proprietary restrictions a simplistic version of the test article is illustrated below as it moves Mach 10 from right to left.  Shock waves may be observed reflecting off tunnel walls.  A Phase I Air Force STTR effort has been completed and Phase II is expected to begin in the near future.

    Categories: Faculty-Staff

  • GAANN

    CO-I William Engblom

    CO-I J. Gordon Leishman

    This project is sponsored by the Department of Education Graduate Assistance in Areas of National Need (GAANN) fellowship program to support six to 10 Ph.D. students of high ability and financial need in the Department of Aerospace Engineering at Embry-Riddle Aeronautical University.

    This project is sponsored by the Department of Education Graduate Assistance in Areas of National Need (GAANN) fellowship program to support six to 10 Ph.D. students of high ability and financial need in the Department of Aerospace Engineering at Embry-Riddle Aeronautical University. The purpose of the program is to enhance and diversify the pool of U.S. citizens who are qualified to teach and pursue research careers in the field of aerospace engineering.

    Embry-Riddle's Aerospace Engineering Department is among the top aerospace engineering programs in the nation. It is currently ranked 32nd for its graduate programs and 8th for its undergraduate program by U.S. News and World Report. The department currently has 34 faculty comprised of distinguished researchers and teachers in the fields of aerodynamics and propulsion, dynamics and control, as well as structures and materials.

    GAANN Fellows will participate in a formal training/teaching program, which will allow them to learn, observe experienced teachers and gain hands-on experience in teaching. Fellows will receive instruction on effective teaching techniques and will be evaluated formally on their teaching. A far-reaching recruitment plan will allow Embry-Riddle to identify outstanding and eligible students, especially from traditionally underrepresented groups. Embry-Riddle is contributing matching funds in the form of tuition and fee assistance. 

    If you are interested in being supported as a GAANN Fellow, please contact Dr. Lyrintzis at lyrintzi@erau.edu.

    Categories: Faculty-Staff

31-35 of 35 results