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Design And Simulation Of Passive Thermal Management System For Lithium-Ion Battery Packs On An Unmanned Ground Vehicle, Kevin Kenneth Parsons

Master's Theses

The transient thermal response of a 15-cell, 48 volt, lithium-ion battery pack for an unmanned ground vehicle was simulated with ANSYS Fluent. Heat generation rates and specific heat capacity of a single cell were experimentally measured and used as input to the thermal model. A heat generation load was applied to each battery and natural convection film boundary conditions were applied to the exterior of the enclosure. The buoyancy-driven natural convection inside the enclosure was modeled along with the radiation heat transfer between internal components. The maximum temperature of the batteries reached 65.6 °C after 630 seconds of usage …

Measurement Of Thermal Diffusivities Using The Distributed Source, Finite Absorption Model, James B. Hall

Theses and Dissertations

Thermal diffusivity in an important thermophysical property that quantifies the ratio of the rate at which heat is conducted through a material to the amount of energy stored in a material. The pulsed laser diffusion (PLD) method is a widely used technique for measuring thermal diffusivities of materials. This technique is based on the fact that the diffusivity of a sample may be inferred from measurement of the time-dependent temperature profile at a point on the surface of a sample that has been exposed to a pulse of radiant energy from a laser or flash lamp. An accepted standard approach …

Silicon Wafer Temperature Distribution, Daniel Gonzalez, Nathan Jones, Dylan Justice

Mechanical Engineering

Applied Materials is a global company that designs equipment for use in the semiconductor manufacturing industry. The scope of this project covers process chambers used for depositing thin chemical films onto silicon wafers. These processes must take place in particularly specific environments– including extremely low pressures and high temperatures. One challenge engineers face when designing these processes is carefully controlling the thermal behavior of silicon wafers. Typically, behavior is predicted using time consuming and computationally expensive CFD simulations. We have been asked to address this issue with a simpler, faster model which will allow engineers to reduce the total number …

Integral-Balance Solution To The Stokes’ First Problem Of A Viscoelastic Generalized Second Grade Fluid, Jordan Hristov

Jordan Hristov

Integral balance solution employing entire domain approximation and the penetration dept concept to the Stokes’ first problem of a viscoelastic generalized second grade fluid has been developed. The solution has been performed by a parabolic profile with an unspecified exponent allowing optimization through minimization of the norm over the domain of the penetration depth. The closed form solution explicitly defines two dimensionless similarity variables and , responsible for the viscous and the elastic responses of the fluid to the step jump at the boundary. The solution was developed with three forms of the governing equation through its two dimensional forms …

Thermal Impedance At The Interface Of Contacting Bodies: 1-D Example Solved By Semi-Derivatives, Jordan Hristov

Jordan Hristov

Simple 1-D semi-infinite heat conduction problems enable to demonstrate the potential of the fractional calculus in determination of transient thermal impedances of two bodies with different initial temperatures contacting at the interface ( ) at . The approach is purely analytic and uses only semi-derivatives (half-time) and semi-integrals in the Riemann-Liouville sense. The example solved clearly reveals that the fractional calculus is more effective in calculation the thermal resistances than the entire domain solutions

An Investigation Of Mist/Air Film Cooling With Application To Gas Turbine Airfoils, Lei Zhao

University of New Orleans Theses and Dissertations

Film cooling is a cooling technique widely used in high-performance gas turbines

to protect turbine airfoils from being damaged by hot flue gases. Film injection holes are

placed in the body of the airfoil to allow coolant to pass from the internal cavity to the

external surface. The ejection of coolant gas results in a layer or “film” of coolant gas

flowing along the external surface of the airfoil.

In this study, a new cooling scheme, mist/air film cooling is proposed and

investigated through experiments. Small amount of tiny water droplets with an average

diameter about 7 μm (mist) is …

Flow Distribution And Heat Transfer Coefficients Inside Gas Holes Discharging, Amirhossein Eshtiaghi

LSU Master's Theses

Fluid flow and heat transfer coefficient associated with flow inside short holes (L/D=1) discharging orthogonally into a crossflow was investigated experimentally and numerically for (Re) ̅ ranging from 0.5×105 to 2×105, and blowing ratio ranging from 1.3 to 3.2. The basic configuration studied consists of a feed tube with five orthogonally located gas holes. Four different hole configurations were studied. The transient heat transfer study employs an IR-camera to determine the local heat transfer coefficient inside each hole. Velocity measurements and numerical flow simulation were used to better understand the measured heat transfer distribution inside the hole. The Nusselt number …