Power Harness Research Articles

Comparatives Studies in Molten Salt Reactor FUJI-U3 with Various Power

Indonesia has a resource of nuclear fuel which spread around the country, especially in Bangka Belitung, West Kalimantan, West Sulawesi, and Papua. Therefore, Indonesia has a potential in the nuclear energy development. The Generation IV nuclear power system has been developed by the Generation IV Forum (GIF) with its benefits such as highly economical, enhanced safety, low waste production, and proliferation resistant. MSR is one of Generation IV nuclear power system which uses molten salt as a fuel and a coolant. Based on RUPTL (Electricity Supply Business Plan) PLN 2018-2027, Indonesia needs 100 MWe power harness from nuclear energy. This study focuses on a FUJI-U3 reactor, a type of MSR which developed in Japan. Power operation varied from 120-150 MWth 60-100 MWe and using FLiBe as molten salt. The calculation was performed with PIJ and CITATION modules in SRAC 2006 and JENDL 4.0 as nuclear data library.

Analysis of Time-resolved Spectra of Ejecta from Hypervelocity Impacts

Ejecta from hypervelocity impact includes not only fragments but also luminous vapor cloud with plasma. The plasma (i.e. plasma density) is an important parameter for estimating the risk of discharge on solar array paddle or power harness of spacecraft. We carried out hypervelocity impact experiments using a two-stage light gas gun to analyze luminous vapor cloud and plasma from impacts of the different projectile and target materials. We measured luminous vapor cloud and plasma by using a high-speed video camera and a streak camera spectroscopy, which gives time-resolved spectra and a plasma probe. From the time-resolved spectra, the temperature of the luminous vapor cloud was calculated by fitting the black body radiation from a continuous spectrum of the luminous vapor cloud. Also, we compared and investigated the temporal change of each emission line spectrum from impacts of different target and projectile materials.

Numerical investigation on interactive FIO of two-tandem cylinders for hydrokinetic energy harnessing

Flow induced oscillations (FIO) of two rough, rigid, tandem-cylinders on springs are investigated for hydrokinetic power conversion at Reynolds number 30,000 ≤ Re ≤ 120,000. Passive turbulence control (PTC) in the form of roughness strips is applied to enhance FIO and increase the power harness efficiency of the VIVACE (Vortex Induced Vibration for Aquatic Clean Energy) converter. Numerical simulations are performed using two-dimensional, Unsteady Reynolds-Averaged Navier-Stokes equations with the Spalart-Allmaras turbulence model. The center-to-center spacing ratio d/D of the two cylinders is set as 2.0 or 2.57 with mass ratio m* = 1.343, damping ratio ζ = 0.26, and stiffness K = 1,200N/m. Amplitude response, frequency response, interaction, energy harvesting, and conversion efficiency are presented and discussed. Results are compared to experimental data for validation and reveal how the interaction of two tandem cylinders may enhance the harnessed power. CFD provides complementary valuable information on visualization of wake and vortex structures. The main conclusions are: (1) In the VIV region at Re = 60,000, the amplitude response, frequency response, harnessed power, and power conversion efficiency of the upstream cylinder is the same for the two spacing ratios tested. Due to the shedding effect, the motion of the downstream cylinder for spacing ratio d/D = 2.0 is more severely suppressed than spacing ratio d/D = 2.57, which reduces the harnessed power and conversion efficiency for the downstream cylinder. (2) In the galloping region at Re = 110,000, due to the different timing of impingement of the shed vortices on the downstream cylinder, the upstream cylinder harnesses more power and has higher energy conversion efficiency for spacing ratio d/D = 2.0 than d/D = 2.57.

Flow-Induced Vibration and Hydrokinetic Power Conversion of Two Staggered Rough Cylinders for 2.5 × 104 < Re < 1.2 × 105

Flow-induced vibration (FIV), primarily vortex-induced vibrations (VIV), and galloping have been used effectively to convert hydrokinetic energy to electricity in model-tests and field-tests by the Marine Renewable Energy Laboratory (MRELab) of the University of Michigan. It is known that the response of cylinders with passive turbulence control (PTC) undergoing vortex shedding differs from the oscillation of smooth cylinders in a similar configuration. Additional investigation on the FIV of two elastically mounted circular cylinders in a staggered arrangement with low mass ratio in the TrSL3 flow-regime is required and is contributed by this paper. The two PTC-cylinders were allowed to oscillate in the transverse direction to the oncoming fluid flow in a recirculating water channel. The cylinder model with a length of 0.895 m and a diameter of 8.89 cm, a mass ratio of 1.343 was used in the tests. The Reynolds number was in the range of 2.5 × 104 < Re < 1.2 × 105, which is a subset of the TrSL3 flow-regime. The center-to-center longitudinal and transverse spacing distances were T/D = 2.57 and S/D = 1.0, respectively. The spring stiffness values were in the range of 400 < K (N/m) <1200. The values of harnessing damping ratio tested were ζharness = 0.04, 0.12 and 0.24. For the values tested, the experimental results indicate that the response of the upstream cylinder is similar to the single cylinder. The downstream cylinder exhibits more complicated vibrations. In addition, the oscillation system of two cylinders with stiffer spring and higher ζharness could initiate total power harness at a higher flow velocity and obtain more power.

In-flight calibration of the NEAR magnetometer

The science objectives for the Near Earth Asteroid Rendezvous (NEAR) Magnetometer Experiment (MAG) are to measure a possible magnetic field of 433 Eros to 5 nT accuracy and secondarily to detect asteroid-solar wind interaction signatures. Because the MAG sensor is body mounted, achieving this accuracy required detailed analysis of spacecraft magnetic fields during cruise. Sources of magnetic contamination identified prior to launch and during cruise are: propulsion latch valves, fixed 190 nT residual held, solar arrays and power harness, variable 15 to 60 nT field, power distribution terminal board, /spl sim/30 nT field with 5 nT variations, power shunting circuitry, 1-5 nT variations, the MAG sensor survival heater, 6 nT steps and attitude control momentum wheels, and 1 nT amplitude at 0.5 to 10 Hz from each of four wheels. Analysis of cruise data was used to create accurate /spl plusmn/1 nT models for the fixed and variable fields with signals below 0.5 Hz to provide correction of the raw data. The spacecraft field corrections and MAG calibration were validated with data from the Earth swing-by of January 1997. Comparison of solar wind magnetic held measurements from the WIND spacecraft and NEAR from January 22-24, 1997, before and after the Earth swing-by maneuver, confirm that the resulting NEAR magnetic field measurements are accurate to 1-2 nT.

Summary of the CTS Transient Event Counter Data after One Year of Operation

A spacecraft electrical system transient detector has been operating on the joint Canadian-American Communications Technology Satellite (CTS), now called Hermes, since January 31, 1976. This detector, called the transient event counter (TEC), senses and counts transients having a minimum amplitude of 5 volts and a rise time of less than 0.3 μsec. The transients in three separate wiring harnesses are counted: the attitude control harness, the solar array instrumentation harness and the solar array power harness. Recently, anomalous behavior of geosynchronous satellites has been attributed to the electrostatic charging of spacecraft surfaces by the environment during geomagnetic substorms. Insulating surface materials subjected to high electrical stress by such charging can discharge through electrical arcing. It is believed that the electromagnetic pulses from such discharges can couple into the spacecraft wiring harnesses and result in uncommanded switching of logic circuits, which in turn is responsible for the observed anomalies. The function of the TEC is to count such transients. This report describes the TEC and presents the flight data for a year of operation. A large number of transients have occurred but these have not caused any anomalous electronic switching events in the satellite systems. The character of the transients seems to imply that additional sensors are required to understand the discharge phenomenon on large satellites. The results of this experiment indicate that satellite system immunity to discharge-related electronic switching anomalies can be obtained by filtering out the harness transients.