Uses of impinging jet devices for heat transfer are described, with a focus on cooling applications within turbine systems. Numerical simulation techniques and results the relative strengths drawbacks k-ε,k-ω, Reynolds stress model, algebraic models, shear transport, v2f turbulence models flow compared. Select model equations provided as well quantitative assessments errors judgments suitability.

To increase the storage capacity of hard disk drives, Heat-Assisted Magnetic Recording (HAMR) takes advantage laser heating to temporarily reduce coercivity recording media, enabling writing very small data bits on materials with high thermal stability. One key challenge in implementing HAMR is effective management, which requires reliable determination properties over their range operating temperature. This work reports dielectric (amorphous silica, amorphous alumina, and AlN), metallic...

To better understand and facilitate design of an impinging jet device, the heat transfer on a cylindrical target exposed to radial slot jets was investigated using numerical methods. Numerical models were created test performance shear stress transport, standard realizable k-e, v 2 f, Reynolds model turbulence vs published data. Based validation study, f ultimately selected for further work. Models then constructed simulate cylinder array jets. Parametric variations conducted produce...

Acoustic phonon scattering from isolated nanometer-scale impurity particles embedded in anisotropic media is investigated using molecular dynamics simulation. The spectral-directional dependence of the scattering, for both longitudinal and transverse modes, found through calculation cross sections three-dimensional phase functions inclusions varying sizes, shapes, stiffnesses waves different wave numbers. technique enables direct observation effects mode conversion, lattice mismatch strain,...

Abstract A conjugate heat transfer investigation was conducted to better understand the effects of an impinging radial slot jet cooling device on both rates and temperature fields in fluid, especially cylindrical solid cooled by this device. The study used numerical methods model a configuration which set four radially positioned jets steel target using air with Reynolds number 20,000. steady-state v 2 f averaged Navier-Stokes representative two-dimensional section axisymmetric flow domain....

A thermistor-based proximity sensor enables identification of head-disk contact in a hard disk drive, allowing the setting clearance. This also provides thermal information, permitting validation computational models used to design recording heads. We describe here set models, and related experiments probe mechanical characteristics at interface. Example results are shown, leading conclusion that with diffusive-ballistic equations capable simulating heat transfer through gas bearing.

To better understand and facilitate design of an impinging jet device, the heat transfer on a cylindrical target exposed to radial slot jets was investigated using numerical methods. Numerical models were created test performance Shear Stress Transport (SST), Standard Realizable k-epsilon, v2f, Reynolds Model (RSM) turbulence versus published data. Based validation study v2f model ultimately selected for further work. Models then constructed simulate cylinder array jets. Parametric...

Presented here is a new molecular dynamics simulation approach for visualizing multidimensional acoustic wave-packet propagation in anisotropic materials. This allows examination of longitudinal wave selected frequency range and may also be extended to track transverse motions. The obtained results agree with analytical predictions experimental measurements quasilongitudinal front the literature. Additionally, spectral analysis reveals minor levels redistribution as packet propagates, which...

Heat transfer in solid materials at short time scales, length and low temperatures is governed by the transport of ballistic phonons. In anisotropic crystals, energy carried these phonons strongly channeled into well-defined directions a phenomenon known as phonon focusing. Presented here new molecular dynamics simulation approach for visualizing acoustic focusing crystals. An advantage this over experimental imaging techniques that it allows examination propagation selected modes...

In this work we show the structure and application of a two carrier thermal model applied to near field transducer, representative that used in Heat Assisted Magnetic Recording (HAMR). As part HAMR device operation, high energy non-thermalized electrons are initially excited by laser incidence on gold nanostructure. The can travel ballistic fashion over longer distances than optical thickness gold, resulting spreading local heat. During their hot collide with lower-energy electrons,...

A conjugate heat transfer investigation was conducted to better understand the effects of an impinging radial slot jet cooling device on both rates and temperature fields in fluid, especially cylindrical solid cooled by this device. Such nonuniformities are practical interest as they may result phenomena such nonuniform material properties, residual thermal stresses, distortion target shape, several metrics for nonuniformity were defined evaluated. The study used numerical methods model a...

A new kinetic Monte Carlo method for modeling phonon transport in quantum dot superlattices is presented. The uses scattering phase functions and cross sections to describe collisions between phonons dots. are generated using molecular dynamics simulation, which capable of including atomistic effects otherwise unavailable approaches. demonstrated a test case featuring Si-Ge superlattice, the model compared against published experiments. It found that dynamics-derived must be weighted by...

The calculation of heat transport in nonmetallic materials at small length scales is important the design thermoelectric and electronic materials. New designs with quantum dot superlattices (QDS) other nanometer-scale structures can change thermal conductivity ways that are difficult to model predict. Boltzmann Transport Equation describe propagation energy via mechanical vibrations an analytical fashion but remains solve for problems interest. Numerical methods simulation scattering high...

Dependent scattering of acoustic phonons by multiple nanometer-scale inclusions in anisotropic media is investigated using a new molecular dynamics simulation technique. The spectral-directional characteristics the are found calculation three-dimensional phase functions and cross sections for varying sizes various spatial arrangements. technique enables computation effects reflected wave interference sequential scattering, mode conversion, lattice strain, elastic anisotropy, atomic-scale...