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Full-Text Articles in Engineering
Numerical Investigation Of Boiling In A Sealed Tank In Microgravity, Sonya Lynn Hylton
Numerical Investigation Of Boiling In A Sealed Tank In Microgravity, Sonya Lynn Hylton
ETD Archive
NASA's missions in space depend on the storage of cryogenic fluids for fuel and for life support. During long-term storage, heat can leak into the cryogenic fluid tanks. Heat leaks can cause evaporation of the liquid, which pressurizes the tank. However, when the tanks are in a microgravity environment, with reduced natural convection, heat leaks can also create superheated regions in the liquid. This may lead to boiling, resulting in much greater pressure rises than evaporation at the interface between the liquid and vapor phases. Models for predicting the pressure rise are needed to aid in developing methods to control …
Cfd And Heat Transfer Models Of Baking Bread In A Tunnel Oven, Raymond Matthew Adamic
Cfd And Heat Transfer Models Of Baking Bread In A Tunnel Oven, Raymond Matthew Adamic
ETD Archive
The importance of efficiency in food processing cannot be overemphasized. It is important for an organization to remain consumer- and business-oriented in an increasingly competitive global market. This means producing goods that are popular, of high quality and low cost for the consumer. This research involves studying existing methods of baking bread in a common type of industrial oven - the single level bread baking tunnel oven. Simulations of the oven operating conditions and the conditions of the food moving through the oven are performed and analyzed using COMSOL, an engineering modeling, design and simulation software. The simulation results are …
Free Convection Along A Vertical Wavy Surface In A Nanofluid, Deepak Ravipati
Free Convection Along A Vertical Wavy Surface In A Nanofluid, Deepak Ravipati
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The study of this paper is to introduce a boundary layer analysis for the fluid flow and heat transfer characteristics of an incompressible nanofluid along a vertical wavy surface in a nanofluid. The Resulting transformed governing equations are solved numerically by an implicit finite-difference scheme (Keller-Box method). The results are presented for the major parameters including the wave amplitude , buoyancy ratio parameter , Brownian motion parameter , Thermophoresis parameter and Lewis number. A systematic study on the effects of the various parameters of the local frication factor, surface heat transfer rate (Nusselt number) and mass transfer rate (Sherwood number) …
Computational Analyses For Fluid Flow And Heat Transfer In Different Curved Geometries, Carlin Miller Lucente
Computational Analyses For Fluid Flow And Heat Transfer In Different Curved Geometries, Carlin Miller Lucente
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Three-dimensional Computational Fluid Dynamics (CFD) models were developed to simulate fluid flow and heat transfer in a variety of helical channel geometries: circular and elliptical. Laminar flow was observed for Reynolds number between 200 and 1000. Code validation was done for developing steady laminar flow in a circular curved channel. The CFD results were compared to previous numerical results to verify that the model was producing valid results. The curve of the channel has a centrifugal effect on the fluid flow creating secondary flow known as Dean cells. This secondary flow moves the location of the maximum axial velocity towards …
Fabrication And Testing Of A Nonstandard Thin-Film Heat Flux Sensor For Power System Applications, Scott D. Wilson
Fabrication And Testing Of A Nonstandard Thin-Film Heat Flux Sensor For Power System Applications, Scott D. Wilson
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Stirling convertors are being operated by NASA Glenn Research Center for many years to demonstrate a Radioisotope Power System (RPS) capable of providing reliable power for potential multi-year space missions. Techniques used to monitor Stirling convertors for change in performance include measurements of temperature, pressure, energy addition, and power output. It is difficult to measure energy addition to Stirling convertors due to the complex geometries of the hot components, temperature limits of sensor materials, and invasive integration of sensors. A thin-film heat flux sensor was used to directly measure heat energy addition to a Stirling convertor. The one micron thick, …
Heat Transfer In A Nanofluid Flow Past A Permeable Continuous Moving Surface, Sarvang D. Shah
Heat Transfer In A Nanofluid Flow Past A Permeable Continuous Moving Surface, Sarvang D. Shah
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The main purpose of this paper is to introduce a boundary layer analysis for the fluid flow and heat transfer characteristics of an incompressible nanofluid flowing over a permeable isothermal surface moving continuously. The resulting system of non-linear ordinary differential equations is solved numerically using Runge-Kutta method with shooting techniques. Numerical results are obtained for the velocity, temperature and concentration distributions, as well as the friction factor, local Nusselt number and local Sherwood number for several values of the parameters, namely the velocity ratio parameter, suction/injection parameter and nanofluid parameters. The obtained results are presented graphically and in tabular form …
Heat Transfer In Electroosmotic Flow Of Power-Law Fluids In Micro-Channel, Omkareshwar Rao Bakaraju
Heat Transfer In Electroosmotic Flow Of Power-Law Fluids In Micro-Channel, Omkareshwar Rao Bakaraju
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The present study examines heat transfer in electro-osmotic flow of power-law fluids in a micro-channel analytically. The boundary layer equations governing the flow of power-law fluids in a micro-channel have been solved. Heat transfer characteristics such as the temperature distribution and Nusselt number are presented for parametric values of electro-kinetic parameter kH(where k-1 is the Debye length and H is semi-channel height of the micro-channel) and Brinkman number. Uniform surface heat flux boundary condition has been considered. The effects of the Brinkman number on the Nusselt number for specific values of the flow behavior index (n) are analytically determined. This …
Effect Of Rib Turbulators On Heat Transfer Performance In Stationary Ribbed Channels, Aravind Rohan Sampath
Effect Of Rib Turbulators On Heat Transfer Performance In Stationary Ribbed Channels, Aravind Rohan Sampath
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The thermal performance was examined computationally for the stationary channels with rib turbulators oriented at 90 degrees. Ribs were placed on opposite walls and the heat transfer coefficients and frictional loss were calculated. Three stationary channels with aspect ratios (W/H) 1, 2 and 4 were considered for the analysis. The thermal performance was measured by calculating the Nusselt number and frictional losses. Square ribs (w/e = 1) were considered as the baseline configuration. The rib width and rib spacing varies while the rib height is maintained constant. Rib spacing (P/e) of 10 and 20 and rib width to rib height …
Probabilistic Finite Element Heat Transfer And Structural Analysis Of A Cone-Cylinder Pressure Vessel, Omar Haddad
Probabilistic Finite Element Heat Transfer And Structural Analysis Of A Cone-Cylinder Pressure Vessel, Omar Haddad
ETD Archive
Stress analysis of a cone-cylinder pressure vessel was computationally simulated by a finite element method and probabilistically evaluated in view of the several uncertainties in the performance parameters. Cumulative distribution functions and sensitivity factors were computed for overall Von Mises stresses due to the structural and thermodynamic random variables. These results can be used to quickly identify the most critical design variables in order to optimize the design and make it cost effective. The analysis leads to the selection of the appropriate measurements to be used in structural and heat transfer analysis and to the identification of both the most …