Results for “INTERFERENCE - PROPELLER BLADES”

DOE OSTI2022

Rotor blade damping structures

A rotor blade assembly includes a first rotor blade and a second rotor blade positioned adjacent to one another. The first rotor blade and the second rotor blade each include a platform and an airfoil extending radially outward from a root coupled to the platform to a tip. The airfoil includes a part-span shroud. The part-span shroud extends from the airfoil and is disposed between the root and the tip. The part-span shroud includes a pressure side portion extending from the pressure side surface and a suction side portion extending from the suction side surface. A damper is in contact with both the part span shroud of the first rotor blade and the part span shroud of the second rotor blade at an interference joint. The damper is movable relative to the part span shroud of both the first rotor blade and the second rotor blade.

Chakrabarti, Suryarghya↗

DOE OSTI2020

Impact of control blade insertion on the deformation behavior of SiC-SiC channel boxes in BWRs

This article describes the analysis of distortion of a silicon carbide fiber-reinforced, silicon carbide matrix (SiC-SiC) composite channel box under in-reactor conditions of a boiling water reactor (BWR). The BWR core has significant gradients in the fast neutron flux across the channel box due to the presence of water rods within the fuel assemblies, and these gradients increase further with the insertion of control blades. As a result of the temperature and neutron flux dependent irradiation-induced swelling of SiC, the SiC-SiC composite channel box can undergo distortion. In this work, we evaluate the SiC-SiC channel box distortion for three different control blade positions. This analysis is based on the neutron flux and temperature distributions in the BWR core calculated using the neutronics code MPACT and thermal-hydraulics code CTF. This calculation is coupled through temperature feedback. Subsequently, we have performed structural analysis based on the calculated neutron flux and temperature distributions to determine the deformation and stress development in the channel box. The structural analysis was performed using the fuel performance modeling code BISON and the commercial finite element analysis software Abaqus. The results indicate that large gradients in fast neutron flux (up to 35–40% across a single axial level) will develop across the channel box. Due to these gradients, the channel box will undergo time-dependent bending for all the control blade positions in the assembly. The time-dependent bowing behavior is dominated by the transient swelling of SiC-SiC material under non-uniform neutron flux, and changes with variation in the control blade position. The bending will cause temporary interference between the channel box and control blade, and the interference is expected to be most severe for the fully inserted control blade position. The developed stresses due to differential swelling in the channel box exceed the proportional limit stress of the material, which may cause matrix microcracking in the channel box. However, the stresses remain below the tensile strength of the material, and therefore, development of a full, through-thickness crack in the channel box is not expected. Finally, further work is recommended to explore and evaluate the mitigation strategies.

42 ENGINEERING↗

DOE OSTI2021

HFIR SiC Bowing Test Ready to Insert

This report describes the successful assembly of a High Flux Isotope Reactor (HFIR) irradiation experiment designed to assess radiation-induced lateral bowing of silicon carbide fiber–reinforced, silicon carbide matrix composite (SiC/SiC) components under a radial fast neutron flux gradient. Excessive bowing of a SiC/SiC channel box in a boiling water reactor could potentially interfere with control blade movements. Similar concerns exist for SiC/SiC fuel cladding in light water reactors. The experiment described herein will provide experimental validation of the structural response of a miniature SiC/SiC channel box and tube specimens with pressurized water reactor diameters during irradiation. The significant radial fast neutron flux gradients that exist in the permanent reflector of HFIR were characterized using detailed three-dimensional neutronic calculations. The three-dimensional displacement damage dose rate profile and the resulting volumetric swelling in SiC were used as inputs to structural analyses that predicted the deformation and stresses in the channel box specimen. The specimens were thoroughly characterized prior to irradiation using traditional dimensional inspection and surface profilometry so that these measurements can later be compared with similar measurements that will be made post-irradiation to determine radiation-induced deformations. Furthermore, fine engraving markers were inscribed along all outer surfaces of the specimen and mapped using a digital microscope and a three-dimensional stage. This technique allowed for accurate measurements of the marker spacings, which can be compared with similar measurements that will be made post-irradiation to provide local radiation-induced strain mapping. The experiment was successfully assembled and is scheduled for insertion during HFIR cycle 492, which is currently scheduled to run from May 25, 2021 to June 18, 2021.

22 GENERAL STUDIES OF NUCLEAR REACTORS↗

DOE OSTI2022

Blade and airfoil damping configurations

The present embodiments set forth a blade including an airfoil, the airfoil including a tip cap, a pressure sidewall and a suction sidewall extending axially between corresponding leading and trailing edges and radially between the base and the tip cap. The blade, including the airfoil and base, being formed in at least two airfoil parts, each of the two airfoil parts including contacting edges engaging each other respective contacting edges, the contacting edges defining a joint for preloading each of the at least two parts with each other and with the base. The at least two airfoil parts forming the airfoil being retained to each other by an interference fit at the joint. The interference fit providing frictional damping of vibrations in the blade during blade operation.

Hart, Andrew Clifford↗

DOE OSTI2022

UAE6 - Wind Tunnel Tests Data - UAE6 - Sequence 8 - Raw Data

Sequences 8 and 9: Downwind Sonics (F,P) and Downwind Sonics Parked (P) This test sequence used an upwind, rigid turbine with a 0° cone angle. The wind speed ranged from 5 m/s to 25 m/s. Yaw angles of 0° to 60° were achieved. The blade tip pitch was 3°. The rotor rotated at 72 RPM during Sequence 8, but it was parked during Sequence 9. Blade pressure measurements were collected. The five-hole probes were removed and the plugs were installed. Plastic tape 0.03-mm-thick was used to smooth the interface between the plugs and the blade. The teeter dampers were replaced with rigid links, and these two channels were flagged as not applicable by setting the measured values in the data file to –99999.99 Nm. The teeter link load cell was pre-tensioned to 40,000 N. During post-processing, the probe channels were set to read -99999.99. Sonic anemometers were mounted on a strut downwind of the turbine. The strut was mounted to the T-frame, which was rotated to align the anemometers aft of the 9% and 49% radius locations at hub height. Because of this configuration, the tunnel balance data are considered invalid. Sequence 9 was designed to compare the downwind sonic anemometer readings with the upwind sonic anemometers without interference from the turbine. The rotor was parked with the instrumented blade at 0° azimuth. All pressure measurements obtained in Sequence 9 are invalid because sufficient time for temperature stabilization did not occur, thus all associated data values were flagged as not applicable by setting the measured values in the data file to 0.0000 Pa. This test is further described in Appendix G.

17 WIND ENERGY↗

DOE OSTI2022

UAE6 - Wind Tunnel Tests Data - UAE6 - Sequence 9 - Raw Data

Sequences 8 and 9: Downwind Sonics (F,P) and Downwind Sonics Parked (P) This test sequence used an upwind, rigid turbine with a 0° cone angle. The wind speed ranged from 5 m/s to 25 m/s. Yaw angles of 0° to 60° were achieved. The blade tip pitch was 3°. The rotor rotated at 72 RPM during Sequence 8, but it was parked during Sequence 9. Blade pressure measurements were collected. The five-hole probes were removed and the plugs were installed. Plastic tape 0.03-mm-thick was used to smooth the interface between the plugs and the blade. The teeter dampers were replaced with rigid links, and these two channels were flagged as not applicable by setting the measured values in the data file to –99999.99 Nm. The teeter link load cell was pre-tensioned to 40,000 N. During post-processing, the probe channels were set to read -99999.99. Sonic anemometers were mounted on a strut downwind of the turbine. The strut was mounted to the T-frame, which was rotated to align the anemometers aft of the 9% and 49% radius locations at hub height. Because of this configuration, the tunnel balance data are considered invalid. Sequence 9 was designed to compare the downwind sonic anemometer readings with the upwind sonic anemometers without interference from the turbine. The rotor was parked with the instrumented blade at 0° azimuth. All pressure measurements obtained in Sequence 9 are invalid because sufficient time for temperature stabilization did not occur, thus all associated data values were flagged as not applicable by setting the measured values in the data file to 0.0000 Pa. This test is further described in Appendix G.

17 WIND ENERGY↗

DOE OSTI2020

Wind Turbine Lightning Mitigation System Radar Cross Section Reduction

Modern wind turbines employ Lightning Mitigation Systems (LMSs) in order to reduce costly damages caused by lightning strikes. Lightning strikes on wind turbines occur frequently making LMS configurations a necessity. An LMS for a single turbine includes, among other equipment, cables running inside each blade, along the entire blade length. These cables are connected to various metallic receptors on the outside surface of the blades. The LMS cables can act as significant electromagnetic scatterers which may cause interference to radar systems. This interference may be mitigated by reducing the Radar Cross-Section (RCS) of the wind turbine's LMS. This report investigates proposed modifications to LMS cables in order to reduce the RCS when illuminated by Re locatable Over the Horizon Radar (ROTHR) systems which operate in the HF band (3 - 30 MHz). The proposed modifications include breaking up the LMS cables using spark gap connections, and changing the orientation of the LMS cable within the turbine blade. Both simulated analyses of such RCS mitigation techniques is provided as well as recommendations on further research.

17 WIND ENERGY↗

DOE OSTI2024

3D printable polymeric lightning strike protection system for fiber reinforced composites

The current embodiments include all-polymeric protective material for mitigating lightning strike damage. The protective material includes a hybrid matrix comprising PANI and MXene dispersed within a thermosetting epoxy resin. This hybrid matrix can be painted, printed, or applied as a conductive polymeric layer to a FRCP structure, for example an aircraft fuselage, wing, empennage, control surface (aileron, flap, slats, rudder, elevator) or a wind turbine blade. The protective material not only withstands lightning strikes, but also functions as shielding against electromagnetic interference and is corrosion-resistant and lightweight.

Kumar, Vipin↗