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Articles 1 - 5 of 5
Full-Text Articles in Mechanical Engineering
Single-Phase Turbulent Enthalpy Transport, Bradley J. Shields
Single-Phase Turbulent Enthalpy Transport, Bradley J. Shields
Masters Theses
Vapor generation is central to the flow dynamics within fuel injector nozzles. Because the degree of atomization affects engine emissions and spray characteristics, quantification of phase change within diesel fuel injectors is a topic of design interest. Within the nozzle, the large pressure gradient between the upstream and downstream plena induce large velocities, creating separation and further pressure drop at the inlet corner. When local pressure in the throat drops below the fluid vapor pressure, phase change can occur with sufficient time. At the elevated temperatures present in diesel engines, this process can be dependent upon the degree of superheat, …
Simulation And Modeling Of The Decay Of Anisotropic Turbulence, Christopher J. Zusi
Simulation And Modeling Of The Decay Of Anisotropic Turbulence, Christopher J. Zusi
Doctoral Dissertations
The influence of turbulence structure, parameterized by two point correlations, on the return-to-isotropy process is examined under controlled conditions. In order to determine the influence of structure, direct numerical simulations (DNS) of return-to-isotropy in homogeneous, anisotropic turbulence is performed on meshes of 5123 and 512x512x1024. Isotropic turbulence is generated by mechanical stirring (as in a wind tunnel). Anisotropy is then generated by one of four fundamentally different mean strains, axisymmetric expansion and contraction, plane strain, and pure rotation. Each strain produces very different structure within the turbulence. The influence on the return-to-isotropy process of the initial structure (parameterized by …
Simulating High Flux Isotope Reactor Core Thermal-Hydraulics Via Interdimensional Model Coupling, Adam Ross Travis
Simulating High Flux Isotope Reactor Core Thermal-Hydraulics Via Interdimensional Model Coupling, Adam Ross Travis
Masters Theses
A coupled interdimensional model is presented for the simulation of the thermal-hydraulic characteristics of the High Flux Isotope Reactor core at Oak Ridge National Laboratory. The model consists of two domains—a solid involute fuel plate and the surrounding liquid coolant channel. The fuel plate is modeled explicitly in three-dimensions. The coolant channel is approximated as a two-dimensional slice oriented perpendicular to the fuel plate’s surface. The two dimensionally-inconsistent domains are linked to one another via interdimensional model coupling mechanisms. The coupled model is presented as a simplified alternative to a fully explicit, fully three-dimensional model. Involute geometries were constructed in …
Experimental And Numerical Study Of The Air Distribution In An Airliner Cabin, Wei Liu
Experimental And Numerical Study Of The Air Distribution In An Airliner Cabin, Wei Liu
Open Access Theses
Nowadays, more people, including those with impaired health or who are otherwise potentially sensitive to the cabin environment, are traveling by air than ever before. The flying public demands a higher comfort level and a cleaner environment because they encounter a combination of environmental factors including low humidity, low air pressure, and sometimes, exposure to air contaminants such as ozone, carbon monoxide, various organic chemicals, and biological agents. Moreover, international air travel has increased the potential risks associated with airborne disease transmission and the release, whether accidentally or intentionally, of noxious substances during flight. Many studies suggest that the risk …
There Can Be Turbulence In Microfluidics At Low Reynolds Number, Guiren Wang, F. Yang, Wei Zhao
There Can Be Turbulence In Microfluidics At Low Reynolds Number, Guiren Wang, F. Yang, Wei Zhao
Faculty Publications
Turbulence is commonly viewed as a type of macroflow, where the Reynolds number (Re) has to be sufficiently high. In microfluidics, when Re is below or on the order of 1 and fast mixing is required, so far only chaotic flow has been reported to enhance mixing based on previous publications since turbulence is believed not to be possible to generate in such a low Re microflow. There is even a lack of velocimeter that can measure turbulence in microchannels. In this work, we report a direct observation of the existence of turbulence in microfluidics with Re on the order …