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Full-Text Articles in Mechanical Engineering
Design Of A Heat Exchanger For A Supercritical Co2 Turbine System, Kehinde Oluwatobi Adenuga
Design Of A Heat Exchanger For A Supercritical Co2 Turbine System, Kehinde Oluwatobi Adenuga
Graduate Theses, Dissertations, and Problem Reports
This research aims at designing a shell and tube heat exchanger which will drive a turbine operated on supercritical CO2. Hot gases from boiler (simulated using air) at 1500 K is introduced into the shell to heat up the supercritical CO2 at 10 MPa flowing within tubes from 450 K to 1050 K. The design was done using selected shell and tube heat exchanger empirical equations at predefined boundary conditions. The effect of shell and tube diameter on other design parameters was examined. It was observed that the number of tubes, tube external and internal side surface …
Enhanced Heat Transfer Performance By Shape Optimization Of A Non-Axisymmetric Droplet Evaporating On A Heated Micropillar, Haotian Wu
McKelvey School of Engineering Theses & Dissertations
Abstract
Enhanced Heat Transfer Performance by Shape Optimization of a Non-axisymmetric Droplet Evaporating on a Heated Micropillar
By
Haotian Wu
Department of Mechanical Engineering and Materials Science
Washington University in St. Louis, 2019
Research Advisor: Professor Damena Agonafer
The stacked multilayer 3D IC structure used in next generation high-powered electronics poses great challenges in dissipating their large heat flux, which causes extreme difficulties for traditional cooling technologies. In response, more advanced two-phase liquid cooling technologies, such as droplet evaporation, which utilizes the latent heat of vaporization to remove excessive heat, have been widely investigated. Compared to traditional single-phase cooling techniques, …
Conjugate Heat Transfer And Average Versus Variable Heat Transfer Coefficients, Tyler James Macbeth
Conjugate Heat Transfer And Average Versus Variable Heat Transfer Coefficients, Tyler James Macbeth
Theses and Dissertations
An average heat transfer coefficient, h_bar, is often used to solve heat transfer problems. It should be understood that this is an approximation and may provide inaccurate results, especially when the temperature field is of interest. The proper method to solve heat transfer problems is with a conjugate approach. However, there seems to be a lack of clear explanations of conjugate heat transfer in literature. The objective of this work is to provide a clear explanation of conjugate heat transfer and to determine the discrepancy in the temperature field when the interface boundary condition is approximated using h_bar compared to …
Entry Flow And Heat Transfer Of Laminar And Turbulent Forced Convection Of Nanofluids In A Pipe And A Channel, Yihe Huang
McKelvey School of Engineering Theses & Dissertations
This thesis presents a numerical investigation of laminar and turbulent fluid flow and convective heat transfer of nanofluids in the entrance and fully developed regions of flow in a channel and a pipe. In recent years, nanofluids have attracted attention as promising heat transfer fluids in many industrial processes due to their high thermal conductivity. Nanofluids consist of a suspension of nanometer-sized particles of higher thermal conductivity in a liquid such as water. The thermal conductivity of nanoparticles is typically an order-of-magnitude higher than the base liquid, which results in a significant increase in the thermal performance of the nanofluid …
The Effects Of Asymmetric Micro Ratchets On Pool Boiling Performance, Lance Austin Brumfield
The Effects Of Asymmetric Micro Ratchets On Pool Boiling Performance, Lance Austin Brumfield
LSU Doctoral Dissertations
Nucleate boiling is an attractive method for achieving high heat flux at low superheat temperatures. It is frequently used for industrial applications such as heat exchangers and is being considered to cool advanced central processing units (CPU) which produce heat fluxes on the order of 1 MW/m2 and are becoming increasingly less efficient to cool via forced conduction of air. The issue with implementing nucleate boiling as a cooling mechanism lies in the difficulty of quantifying the numerous and complex mechanisms which control the process. A comprehensive nucleate boiling model has yet to be formulated and will be required in …
Sub-Cooled Pool Boiling Enhancement With Nanofluids, Elliott Charles Rice
Sub-Cooled Pool Boiling Enhancement With Nanofluids, Elliott Charles Rice
USF Tampa Graduate Theses and Dissertations
Phase-change heat transfer is an important process used in many engineering thermal designs. Boiling is an important phase change phenomena as it is a common heat transfer process in many thermal systems. Phase change processes are critical to thermodynamic cycles as most closed loop systems have an evaporator, in which the phase change process occurs. There are many applications/processes in which engineers employ the advantages of boiling heat transfer, as they seek to improve heat transfer performance. Recent research efforts have experimentally shown that nanofluids can have significantly better heat transfer properties than those of the pure base fluids, such …