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    A comprehensive review of miscellaneous heat transfer enhancement designs of phase change material integrated heat exchanger
    (Elsevier Ltd, 2025) Erdinç, M. Tahir; Dalgıç, İrem; Kutlu, Cagri; Dik, Abdullah; Tokgoz, Nehir; Su, Yuehong; Riffat, Saffa
    This comprehensive review focuses on the specific investigation of heat transfer enhancement with a primary objective of achieving more uniform melting/solidification within heat exchangers employing phase change materials (PCM). The paper begins highlighting the crucial role of heat exchangers and introduces the unique studies associated with achieving uniform phase changes. The main body of the paper seeks to explore heat transfer enhancement strategies, particularly within shell-and-tube structures and plate heat exchanger (PHE). Moreover, the study discusses the role of these strategies in achieving more uniform melting/solidification in phase change materials. Special attention is applied to examining advancements and methodologies aimed at optimizing heat transfer for improved performance in applications requiring control of phase changes. As a new contribution, the paper examines the application of PCM in PHEs, providing insights into their effectiveness in facilitating more uniform phase change and PCM usage in these heat exchangers. Notable improvements were also observed from literature studies with specific fin geometries, where longitudinal and spider-web-like structures reduced solidification times by as much as 63 % and enhanced melting uniformity by 47.9 %. Operational parameter optimization, particularly through increasing heat transfer fluid (HTF) inlet temperature by 10 °C, resulted in a 35 % decrease in charging time, underscoring the importance of temperature control in Thermal energy storage (TES) applications. The literature studies mentioned that enhanced PHE configurations, including corrugated and zigzag plate designs, have demonstrated up to nine times faster charging and discharging rates compared to traditional concentric systems due to increased surface area. This study provides essential insights for researchers and practitioners aiming to enhance heat exchanger designs for critical applications in thermal energy storages. © 2025 Elsevier Ltd
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    Investigations of flow structures and performances of heat transfer in semi-circular grooved ducts by applying field synergy principal analysis: An experimental and numerical study
    (Pergamon-Elsevier Science Ltd, 2023) Tokgoz, Nehir; Erdinc, Mehmet Tahir; Kaska, Onder; Sahin, Besir
    The present study aimed at investigating the flow structure and heat transfer mechanism through the corrugated channel experimentally and numerically. Particle imaging velocimetry (PIV), which can give detailed information about the wake and shear flow regions, was used for the experiments. The experimental and numerical works were performed considering Reynolds numbers in the range of 6 x 103 <= Re <= 12 x 103 and 3 x 103 <= Re <= 2 x 104, respectively. In the numerical part, aspect ratios (R/hp) of examined grooves have been chosen as 0.1, 0.2, and 0.3, and for the experiment, only one aspect ratio was chosen which was 0.3. The experimental studies were conducted regarding different Reynolds numbers as well as the distributions of instantaneous and timeaveraged velocity contours, Turbulence Kinetic Energy, Reynolds shear stress, and vorticity. The standard SST k-omega turbulent method was employed for the case of numerical study to predict the thermal performance (eta) along with Nusselt numbers (Nu) the friction factors (f) and local field synergy angles (alpha, beta) were calculated. As a result, the Nusselt number (Nu) values of the corrugated channels were higher than the parallel plate, and the increment in the Nusselt number initially increased and later decreased with Reynolds numbers for all aspect ratios considered.