Design and performance characterization of novel heat exchanger geometries enabled by additive manufacturing

Heat exchangers (HX) with optimal geometries are of particular interest because of their potential for high performance beyond current limits. This dissertation presents design, fabrication, and characterization of additively manufactured (AM) HX, and investigates HX geometries that are difficult or impossible to fabricate using conventional manufacturing methods. First, we designed, fabricated, and characterized an energy storage device based on an AM HX that stores heat from a flowing liquid coolant in the channel in the form of latent heat in a phase change material (PCM). We developed a design with internal fins extending from the channel wall to the flowing fluid and the external fins extending from the channel wall to the PCM, and then we fabricated and tested the device. The HX has 4X higher power density compared to the state-of-the-art (SOA) thermal energy storage devices. Second, we also report the design, fabrication, and characterization of single-phase internal flow AM HX under uniform heat flux condition using shape optimization. We developed a genetic algorithm to optimize the internal fin geometry for both laminar and turbulent flow regimes. The fin geometries were evaluated using two-dimensional (2D) finite element method (FEM) for laminar flow or Nusselt number-fin geometry correlation. The genetic algorithm proposed an optimal geometry that was fabricated and tested. The optimized device decreased the total thermal resistance by 4.5X for laminar flow and 3X for turbulent flow compared to a smooth device without internal fins. Finally, we report design, fabrication, and characterization of an ultra-power-dense tube-in-tube HX. We designed optimal inner fins that extend from channel wall to the inner flow region and outer fins that extend from channel wall to outer flow region by using a genetic algorithm. The optimized device was fabricated and tested and was also investigated using finite element simulations. We demonstrated a 23X increase in power density and 21X increased specific power when compared to conventional and commercially available compact HX technologies.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Mechanical Engineering

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2021

Author dc:creator

• Moon, Hyunkyu

Contributors dc:contributor

• King, William P
• Jacobi, Anthony M
• Miljkovic, Nenad
• James, Kai

• Heat exchanger
• Heat transfer enhancement
• Heat transfer augmentation
• Genetic algorithm
• Generative design
• Shape optimization
• PCM
• Thermal energy storage

Statement dc:rights

• Copyright 2021 Hyunkyu Moon

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/110781

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/110781