Study of the cooling effects of nanofluids on electronic components and a sensitivity analysis of the most influential variable on the heat transfer

Date
2011
Authors
Lingo, Stephanie E.
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Abstract

In the past decade, there has been a significant increase in the amount of research being done on nanofluids, which are fluids containing minute concentrations of particles. Several experimental and computational studies have shown nanofluids have enhanced thermo-physical properties compared to pure fluid. The properties include thermal conductivity, specific heat, viscosity, and overall heat transfer ability. This makes nanofluids attractive for use in a wide range of heat transfer applications, some of which include electronic cooling, solar energy, and fluidized bed reactors.

This project computationally simulates a single particle flowing through a channel. The motion of the particle is described by the two-dimensional momentum equations. These include forces due to gravity, drag, lift, and Brownian motion. The heat transfer which occurs during the movement of the particle through the channel is modeled using the transient energy equation which includes the Lagrangian term, conduction, and history term. For this project, the original first-order integrodifferential energy equation is transformed into a second-order ordinary differential equation. This helped reduce the computational time up to an order of 10--15.

The simulations using water as the working fluid show a great deal of particle movement up and down in the channel. The overall heat transfer due to convection and the aggitation from the particle using various concentrations of particles was up to 400% more than pure water. The simulations conducted with oil as the working fluid had similar heat transfer capabilities, but the motion of the particle was very limited. This could be due to the higher viscosity of oil.

The last portion of this project included a sensitivity analysis to determine which variables have the largest influence on the overall heat transfer capabilities of the nanofluid. The four analyses conducted for the water simulations showed that the Brownian motion has the biggest impact on the overall heat transfer. Further research is being continued to study the same project with oil as the working fluid to determine if there is a difference in the most influential variable compared to result found for water.

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Keywords
electronic cooling, heat transfer, multiphase flow, particle
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Department
Mechanical Engineering