103 research outputs found
Combustion chamber analysis code
A three-dimensional, time dependent, Favre averaged, finite volume Navier-Stokes code has been developed to model compressible and incompressible flows (with and without chemical reactions) in liquid rocket engines. The code has a non-staggered formulation with generalized body-fitted-coordinates (BFC) capability. Higher order differencing methodologies such as MUSCL and Osher-Chakravarthy schemes are available. Turbulent flows can be modeled using any of the five turbulent models present in the code. A two-phase, two-liquid, Lagrangian spray model has been incorporated into the code. Chemical equilibrium and finite rate reaction models are available to model chemically reacting flows. The discrete ordinate method is used to model effects of thermal radiation. The code has been validated extensively against benchmark experimental data and has been applied to model flows in several propulsion system components of the SSME and the STME
Development Toward a Ground-Based Interferometric Phased Array for Radio Detection of High Energy Neutrinos
The in-ice radio interferometric phased array technique for detection of high
energy neutrinos looks for Askaryan emission from neutrinos interacting in
large volumes of glacial ice, and is being developed as a way to achieve a low
energy threshold and a large effective volume at high energies. The technique
is based on coherently summing the impulsive Askaryan signal from multiple
antennas, which increases the signal-to-noise ratio for weak signals. We report
here on measurements and a simulation of thermal noise correlations between
nearby antennas, beamforming of impulsive signals, and a measurement of the
expected improvement in trigger efficiency through the phased array technique.
We also discuss the noise environment observed with an analog phased array at
Summit Station, Greenland, a possible site for an interferometric phased array
for radio detection of high energy neutrinos.Comment: 13 Pages, 14 Figure
Design and Bolometer Characterization of the SPT-3G First-year Focal Plane
During the austral summer of 2016-17, the third-generation camera, SPT-3G,
was installed on the South Pole Telescope, increasing the detector count in the
focal plane by an order of magnitude relative to the previous generation.
Designed to map the polarization of the cosmic microwave background, SPT-3G
contains ten 6-in-hexagonal modules of detectors, each with 269 trichroic and
dual-polarization pixels, read out using 68x frequency-domain multiplexing.
Here we discuss design, assembly, and layout of the modules, as well as early
performance characterization of the first-year array, including yield and
detector properties.Comment: Conference proceeding for Low Temperature Detectors 2017. Accepted
for publication: 27 August 201
Optimization of transition edge sensor arrays for cosmic microwave background observations with the South Pole Telescope
In this paper, we describe the optimization of transition-edge-sensor (TES) detector arrays for the third-generation camera for the South Pole Telescope. The camera, which contains ~16 000 detectors, will make high-angular-resolution maps of the temperature and polarization of the cosmic microwave background. Our key results are scatter in the transition temperature of Ti/Au TESs is reduced by fabricating the TESs on a thin Ti(5 nm)/Au(5 nm) buffer layer and the thermal conductivity of the legs that support our detector islands is dominated by the SiOx dielectric in the microstrip transmission lines that run along the legs
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