Journal of the Korean Society for Precision Engineering

A Numerical Investigation on Heat Transfer Enhancement of a Dual-impeller Heat Exchanger for Electro-optical Tracking System Cooling via System Structural Modification: Sungbin Lee, Manyul Jeon, Hyungpil Park, Donghyeok Park, Hoonhyuk Park, Jongin Bae, Heesung Park; J. Korean Soc. Precis. Eng. 2025;42(10):871-877.
Published online October 1, 2025; DOI: https://doi.org/10.7736/JKSPE.025.071

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This study presents a dual-impeller air-cooled heat exchanger aimed at improving thermal management in electro-optical tracking systems operating under high power density. Two geometric modifications were introduced to enhance flow characteristics and heat transfer performance: the curvature of the center plate and the integration of a pin-fin structure at the outlet. Through numerical simulation, the improved model demonstrated more efficient internal flow compared to the original model, achieved through enhanced inflow characteristics and reduced flow separation. The pin-fin structures induced localized turbulence and recirculation zones, contributing to an increased thermal exchange surface area and longer effective heat transfer time. Consequently, the outlet temperature of the internal system decreased by an average of 1.4°C across various rotational speeds, resulting in a 5.9% increase in heat exchanger efficiency compared to the original model. Overall, this study shows that structural enhancements in heat exchanger design can significantly improve the cooling performance of high-power electronic systems, suggesting practical applicability for advanced thermal management solutions.

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A Study on Improvement of Flow Characteristics of TPMS Heat Exchanger based on Mathematical Filtering: Seo-Hyeon Oh, Jeong Eun Kim, Ji Seong Yun, Do Ryun Kim, Jungwoo Kim, Chang Yong Park, Keun Park; J. Korean Soc. Precis. Eng. 2024;41(7):541-550.
Published online July 1, 2024; DOI: https://doi.org/10.7736/JKSPE.024.034

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Recent advancements in additive manufacturing (AM) have made it possible to create compact heat exchangers (HXs) with complex geometries. This study introduces a new approach that uses Triply Periodic Minimal Surface (TPMS)-based designs for HXs. Mathematical filtering techniques are incorporated to optimize the local morphology changes. The goal of the proposed mathematical filtering method is to improve the flow characteristics and heat exchange capability of TPMS HXs by modifying the structure’s morphology at the inlet and outlet regions. This modification facilitates flow selection and reduces pressure drop. The HX design includes cylindrical flow domains at the inlet and outlet regions. Three different HX designs with varying inlet/outlet domains (through-hole, half-hole, and taper-hole) were fabricated using polymer AM and DLP 3D printing. These designs were then tested for pressure drop. Among the three designs, the taper-hole configuration showed the best flow characteristics, with a 50% reduction in pressure drop compared to previous studies. The taper-hole design was then replicated using metal AM technology, resulting in a 70-125% improvement in heat exchange capacity compared to previous studies.

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Multifunctional gradations of TPMS architected heat exchanger for enhancements in flow and heat exchange performances
Seo-Hyeon Oh, Jeong Eun Kim, Chan Hui Jang, Jungwoo Kim, Chang Yong Park, Keun Park
Scientific Reports.2025;[Epub] CrossRef

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Design of Cooling Module with CO₂ for Rapid Cooling of Injection Mold: Hyung Sup Bae, Dong Hyun Park, Ho Sang Lee; J. Korean Soc. Precis. Eng. 2022;39(7):477-484.
Published online July 1, 2022; DOI: https://doi.org/10.7736/JKSPE.022.050

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The design of the injection mold cooling system is important. The cooling time consumes 70-80% of the injection molding cycle, so a well-designed cooling system can shorten the molding time and improve productivity significantly. Recently, many studies have been conducted for rapid cooling of a hot-spot area using CO₂ in injection molding. In this study, a cooling module based on CO₂ was designed and manufactured for uniform and rapid cooling of an injection mold with a large cavity, and cooling characteristics were investigated through experiments. As the CO₂ supply pressure increased, the cooling effect increased significantly, while the cooling uniformity decreased relatively. In the case of using the heat exchanger, the cooling effect increased by 10oC on average compared to the case without the heat exchanger, whereas the effect on the cooling uniformity was insignificant. When the CO₂ was injected from both sides, the cooling effect increased by approximately 8oC on average compared to the case of injection from one side, and the cooling uniformity was approximately 10% higher. By using a heat exchanger and applying CO₂ bidirectional supply, a cooling rate of up to 5.78℃/s and an average of 4.9℃/s could be achieved.

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A Design and Fabrication Method of New Compact Heat Exchangers Using Triply Periodic Minimal Surface: Jiho Kim, Dong Jin Yoo; J. Korean Soc. Precis. Eng. 2020;37(7):509-518.
Published online July 1, 2020; DOI: https://doi.org/10.7736/JKSPE.020.025

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This paper describes a new design method for constructing a heat exchanger computational model comprising TPMS (Triply Periodic Minimal Surface) core structures. These TPMS-Based core structures cannot be designed using the existing CAD systems, especially for heat exchangers with a high level of geometric complexity. This paper introduces a new implicit design algorithm based on the VDF (Volumetric Distance Field) calculation. All geometric components, including the TPMS-based core structures, heat exchanger exterior shapes, a set of parts for inlets and outlets, are represented by the VDF in a given design area. This enables the efficient design of computational models for the arbitrary-complex heat exchangers. The proposed design method extends the 2D flow pattern of the existing CHE into the 3D flow pattern, providing high heat transfer efficiency and low-pressure drop. Investigation of the design results and manufactured prototypes using the AM (Additive Manufacturing) technology showed that the proposed TPMS CHE design method can open a new paradigm for generating high-performance next-generation CHEs which cannot be designed and manufactured with the existing CAD and CAM technologies.

Citations

Citations to this article as recorded by

A Study on Design and Fabrication Characteristics of TPMS Structures
Hyun Kim, Kwang-Kyu Lee, Dong-Gyu Ahn
Journal of the Korean Society of Manufacturing Process Engineers.2024; 23(2): 52. CrossRef
Triply Periodic Minimal Surface Structures: Design, Fabrication, 3D Printing Techniques, State‐of‐the‐Art Studies, and Prospective Thermal Applications for Efficient Energy Utilization
Mohamed G. Gado, Oraib Al‐Ketan, Muhammad Aziz, Rashid Abu Al‐Rub, Shinichi Ookawara
Energy Technology.2024;[Epub] CrossRef
A Study on the Dissolution Characteristics of 3D Printed Tablet with Lattice Structures
Sang Hoon Lee, Seung Min Oh, Seo Rim Park, Seok Kim, Young Tae Cho
Journal of the Korean Society for Precision Engineering.2023; 40(8): 633. CrossRef
Multi-objective optimization of TPMS-based heat exchangers for low-temperature waste heat recovery
Reza Attarzadeh, Seyed-Hosein Attarzadeh-Niaki, Christophe Duwig
Applied Thermal Engineering.2022; 212: 118448. CrossRef
Design analysis of the “Schwartz D” based heat exchanger: A numerical study
Reza Attarzadeh, Marc Rovira, Christophe Duwig
International Journal of Heat and Mass Transfer.2021; 177: 121415. CrossRef

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Structural Reliability Evaluation for Brazed Joints of Fine Tube Heat Exchanger on an Aero Engine: Na Hyun Kim, Jong Rae Cho, Yong Jae Ra, Seul Bi Lee, Yoon Seok Choi; J. Korean Soc. Precis. Eng. 2018;35(8):783-789.
Published online August 1, 2018; DOI: https://doi.org/10.7736/KSPE.2018.35.8.783

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The worsening environmental pollution has increased the interest in developing eco-friendly technologies. The purpose of this study is to develop an aero-heat exchanger to reduce the emission of environmental pollutants. The operating conditions of an aircraft are extremely harsh, leading to challenges with the determination of appropriate materials and structures that can withstand the severe conditions. In addition, since the tubes brazed to the tube-sheet are structurally fragile, it is essential to assess the structural integrity of tubes. In this study, the overall structural integrity of the tubular heat exchanger under development was evaluated. An appraisal of the junctions between tubes and tube-sheet, which are the most critical parts, was conducted. A finite element (FE) analysis was employed for the assessment of structural integrity. FE analysis was used to evaluate the brazed joint of tubes using a model in which specific tubes were designed to withstand the high temperature of the tube-sheet. The evaluation was carried out compared with the fatigue strength of Inconel 625, the material constituting the heat exchanger.