국외 학회

Viscoelastic fluids have attracted considerable attention as a means of modifying flow structures in thermalfluid systems. However, the pressure-drop characteristics of such fluids in straight rectangular ducts, which are commonly used in practical heat exchangers and cooling channels, remain insufficiently understood. In this study, we experimentally investigated the effects of polymer addition on pressure-drop behavior and pressurefluctuation characteristics in pressure-driven rectangular duct flows. A dilute polyacrylamide (PAAm) solution at 600 ppm, corresponding to approximately twice the overlap concentration, was compared with pure water over a Reynolds number range from 1,000 to 6,000. In the laminar regime, the polymer solution exhibited an increased pressure drop accompanied by pressure fluctuations dominated by low-frequency components whose time scales were comparable to the polymer relaxation time. In the transitional regime, the pressure-drop and pressure-fluctuation characteristics of the polymer solution became similar to those of water. In the higher- Reynolds-number regime, a clear drag-reduction effect emerged as polymer chains absorbed turbulent kinetic energy. These results show that polymer-induced elasticity significantly modifies hydraulic behavior across flow regimes in a straight rectangular duct. While the present study focuses on hydraulic behavior rather than direct thermal measurements, the findings are relevant to convective heat transfer because they clarify how polymer addition changes the balance between flow unsteadiness and pressure-drop penalty. The present results therefore provide a useful hydraulic basis for future thermal-hydraulic studies under imposed heat-flux conditions.

18th International Heat Transfer Conference (IHTC-18)

Rio de Janeiro, Brazil

2026.08.02~2026.08.07

Brazilian Society of Mechanical Engineering and Sciences (ABCM) / Assembly for International Heat Transfer Conferences (AIHTC)

To address the imbalance between energy supply and demand, thermal energy storage (TES) systems have emerged as an efficient solution for storing and releasing thermal energy [1]. Among various TES systems, latent heat thermal energy storage (LHTES) systems utilize phase change materials (PCMs) to ensure stable temperature control during phase transitions. Particularly, they provide higher energy storage densities compared to sensible heat storage systems [2]. However, the inherently low thermal conductivity of PCMs limits both heat storage and release rates. Enhancing heat transfer between the heat transfer fluid (HTF) and PCMs is therefore crucial for improving system performance [3]. Cascaded LHTES systems have been developed to overcome this limitation by strategically arranging multiple PCMs with distinct phase change temperatures in series, aligning with the temperature gradient of HTF as it flows downstream. This configuration optimizes heat exchange efficiency by ensuring effective thermal energy abso

The 35th International Symposium on Transport Phenomena (ISTP-35)

Busan. Korea

2025.09.21-2025.09.24

Pacific Center of Thermal Fluids Engineering (PCTFE), The Korean Society of Visualization (KSV)

Thermochemical heat storage (TCHS) technology presents an effective approach to address energy demand-supply imbalances. TCHS systems leverage adsorption heat to achieve a high energy storage density up to 200–400 kWh/m³, ensuring prolonged storage with minimal thermal losses [1]. Given these advantages, TCHS holds promise in advancing sustainable energy transitions. Enhancing the efficiency and reliability of TCHS systems requires optimizing reactor design and operational strategies, an area of extensive research. Understanding adsorption and desorption behavior is critical, as these processes govern heat and mass transfer efficiency in TCHS systems. Several experimental techniques have been utilized to characterize adsorption-desorption dynamics [2,3]. However, resolving localized adsorption-desorption phenomena in porous media remains challenging due to the inherently rapid and spatially confined nature of heat and mass transfer during these processes. This difficulty is compounded by the spatial and temporal resolution constraints of experimental measurements. This study aims to systematically investigate the non-linear desorption behavior and re-adsorption effects in a zeolite 13X-based TCHS system through combined experimental and numerical approaches, providing insights into heat and mass transfer dynamics within porous media. To achieve this, we conducted adsorption equilibrium experiments to characterize the adsorption-desorption behavior of zeolite 13X and performed a lab-scale TCHS system experiment to evaluate system performance under practical operating conditions. based on these experimental findings, we developed a three-dimensional numerical model capable of accurately capturing the desorption rate and local re-adsorption dynamics within a TCHS reactor during desorption. By integrating experimentally obtained results into the numerical framework, we refined the model’s predictive accuracy and reliability, leading to a more comprehensive understanding of transient heat and mass transfer dynamics.

The 35th International Symposium on Transport Phenomena (ISTP-35)

Busan. Korea

2025.09.21-2025.09.24

Pacific Center of Thermal Fluids Engineering (PCTFE), The Korean Society of Visualization (KSV)

Pulsed operation is a key operational scenario for near-term fusion reactors, involving fluctuating neutron loads on plasma-facing components (PFCs) that affect radioactivity and decay heat. The transient behavior of radioactive parameters is critical for tokamak safety and requires thorough investigation. In this study, we examined the transient behavior of specific activity and decay heat in one of the major PFCs—a water-cooled breeder blankets module for a DEMO reactor—under both pulsed and continuous operation. A coupled MCNP/FISPACT-II model was verified with previous research. Under pulsed operation (2h burn/0.5h dwell), the shutdown specific activity was 34.8% lower than in steady-state operation. Analysis of regulated hazardous nuclides confirmed this reduction, indicating specific activity is proportional to total neutron irradiation time. Pulsed operation also induces decay heat fluctuations during operational cycles. Post-shutdown, decay heat was up to 55% lower for pulsed operation. Analysis of the tungsten, RAFM steel, and pebble bed layers identified that short-lived isotopes are the primary drivers of decay heat variations. Our findings can contribute to safer tokamak designs under pulsed conditions.

2025 Symposium on Fusion Engineering (SOFE 2025)

Boston, United States

2025.06.23-2025.06.26

IEEE Nuclear and Plasma Sciences Society, MIT Plasma Science & Fusion Center

A breeding blanket, a key subsystem of fusion tokamak, converts fusion energy into thermal energy. Poloidal and toroidal variations in the solid angle between blanket modules and plasma cause non-uniform neutron wall loading (NWL), leading to spatial gradients in volumetric heat generation. This study investigates the impact of poloidal NWL non-uniformity on nuclear heat deposition and resulting temperature distributions in breeding blanket modules. The NWL profiles were quantified based on the preliminary conceptual design of K-DEMO (Fusion power: 2.2 GW). Nuclear heat deposition was calculated using MCNP, and the corresponding thermal responses were evaluated using ANSYS Fluent. The results showed that assuming a uniform NWL profile led to an underestimation of ~94.5°C in the local peak temperature of the uppermost blanket module’s pebble bed layer, primarily due to a steep poloidal NWL gradient. In contrast, for the module near the equatorial plane, where NWL is relatively uniform, temperature differences were negligible, supporting a clear link between NWL gradient and thermal response deviation. These findings underscore the importance of incorporating poloidal heat source variations into blanket thermal design to ensure materials remain within allowable temperature limits.

2025 Symposium on Fusion Engineering (SOFE 2025)

Boston, United States

2025.06.23-2025.06.26

IEEE Nuclear and Plasma Sciences Society, MIT Plasma Science & Fusion Center

Thermochemical heat storage (TCHS) system offers an efficient solution for minimizing energy loss caused by the mismatch between energy supply and demand in existing energy grid systems. By converting energy into heat and releasing it when needed, TCHS systems enhance overall energy efficiency. Additionally, they can store waste heat using materials such as zeolite in a porous media and transport it to locations where heat is required, releasing it upon interaction with water. This study investigates the effect of initial water uptake in zeolite 13X on the charging characteristics of TCHS systems. Experimental isotherm measurements were conducted at various temperatures, and lab-scale experiments analyzed the charging process using dry air at 220°C. A numerical model was developed to simulate physical adsorption on local heat transfer and system performance characteristics under different initial adsorption conditions. The results indicate that while initial adsorption differences do not impact the desorption reaction rate, they significantly influence the total energy required for desorption, thereby affecting the charging time. This finding underscores the importance of storage conditions of the porous zeolite media post-heat release for optimizing charging efficiency. This study provides valuable insights into improving the charging process in TCHS systems, supporting sustainable energy transition efforts.

Thermal energy storage; Physical adsorption; Porous media; Zeolite 13X; Water uptake

The 1st. International Conference on Heat and Mass Transfer inside Porous Media: Fundamentals and Applications (ICHMT-PM2024)

Gran Meliá Xian, Xi\\\\\\\'an,Shaanxi Province,China

2024.11.07-2024.11.10

Xi\\\\\\\'an Jiaotong University

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The 37th International Electric Vehicle Symposium & Exhibition (EVS37)

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2024.04.26

World Electric Vehicle Association (WEVA) Electric Vehicle Association of Asia Pacific (EVAAP)

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The 37th International Electric Vehicle Symposium & Exhibition (EVS37)

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2024.04.23-2024.04.26

World Electric Vehicle Association (WEVA) Electric Vehicle Association of Asia Pacific (EVAAP)

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2nd International Fusion and Plasma Conference (IFPC) & 13th International Conference on Open Magnetic Systems for Plasma Confinement (OS 2023)

Busan. Korea

2023.08.21-2023.08.25

IFPC Committee

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32nd Symposium on Fusion Technology (SOFT)

Dubrovnik, Croatia

2022.09.18-2022.09.23

SOFT Committee

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31st Symposium on Fusion Technology (SOFT2020)

Croatia

2020.09.20-2020.09.25

Ruđer Bošković Institute

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Network Meeting of the Alexander von Humboldt Foundation

Augsburg, Germany

2015.10.28-2015.10.30

Alexander von Humbold Foundation

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The 7th Asia-Pacific Conference on Transducers and Micro/Nano Technologies

Daegu, Korea

2014.06.29-2014.07.02

The Korean Sensors Society, The society of Micro and Nano Systems

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The 23rd International Symposium on Transport Phenomena (ISTP)

Auckland, New Zealand

2012.11.19-2012.11.22

ISTP, The University of Auckland

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2012 MRS Spring Meeting

San Francisco, USA

2012.04.09-2012.04.13

Materials Research Society

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2nd Nanotoday Conference

Hawaii, USA

2011.12.11-2011.12.15

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2nd Nanotoday Conference

Hawaii, USA

2011.12.11-2011.12.15

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