Article
Energy & Fuels
Boonsong Samutpraphut, Smith Eiamsa-ard, Varesa Chuwattanakul, Chinaruk Thianpong, Naoki Maruyama, Masafumi Hirota
Summary: This article explores the use of sawtooth twisted tapes to enhance heat transfer rate by generating swirling flow and interrupted flowing disturbance. The effects of sawtooth angles on heat transfer rate, friction factor, and aerothermal performance index are analyzed. The results show that the sawtooth twisted tape improves heat transfer rate and introduces varying levels of pressure loss based on the sawtooth angles. The recommended sawtooth twisted tape outperforms the typical twisted tape and plain tube in terms of Nusselt number.
Article
Thermodynamics
Kadir Bilen, Nehir Tokgoz, Ismail Solmaz, Tuba Balta
Summary: This study experimentally and numerically investigated the effects of swirl generators with different swirl angles on heat transfer and fluid flow characteristics in a pipe flow. The findings showed that increasing swirl angle and Reynolds number led to higher heat transfer rates, and decaying swirl flow resulted in enhanced Nu and f values compared to smooth pipe flow. Experimental and numerical results for swirl flow were in good agreement within a mean deviation of +/- 7.1% and +/- 8.4%, indicating the effectiveness of the swirl generators in improving heat transfer and fluid flow characteristics.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Yong Luan, Yu Rao, Bernhard Weigand
Summary: This paper presents a comparative study of heat transfer and pressure loss in a swirl cooling system with multi-convergent tubes. The results show that a small change in the swirl tube structure can significantly improve the heat transfer rates and uniformity. The multi-convergent structure offers better resistance against cross flow and improves the heat transfer rates.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Yaxia Li, Qingping Yu, Sanchuan Yu, Bin Gong, Jing Zhang
Summary: This study applies the innovative technology of a square wave pulsating flow combined with a spherical corrugated wall structure in a helical tube to enhance heat transfer. The unsteady flow structure and heat transfer characteristics are numerically investigated, and the effects of pulsating parameters on heat transfer enhancement performance are explored. The results show that the disturbance induced by the pulsating flow improves the local flow field and enhances the secondary flow and turbulent kinetic energy. The Nusselt number is significantly greater than that in steady flow, and the optimum dimensionless pulsation frequency and amplitude are determined.
APPLIED THERMAL ENGINEERING
(2022)
Article
Engineering, Multidisciplinary
Shi ChunYu, Yu MinJie, Liu Wei, Liu ZhiChun
Summary: This study optimized the design profile of corrugated tubes using machine learning techniques, finding that multi-objective optimization can transition the shape of corrugated tubes from double-trough to single-trough, striking a balance between comprehensive performance and thermal efficiency. The optimal solution increases flow resistance while decreasing thermal performance at specific Reynolds numbers.
SCIENCE CHINA-TECHNOLOGICAL SCIENCES
(2022)
Article
Energy & Fuels
Ramin Zarei, Kiyanoosh Razzaghi, Farhad Shahraki
Summary: This experimental study focused on heat transfer enhancement in laminar flow using different blade crossing angles of mixers in a tube. Results revealed that the 90 degrees blade mixer provided higher Nusselt numbers compared to the 120 degrees mixer, with higher pressure drop as a trade-off. Moreover, the heat transfer enhancement was correlated with the Graetz number, showing that heat transfer effects significantly dominated pressure drop effects.
CHEMICAL ENGINEERING AND PROCESSING-PROCESS INTENSIFICATION
(2021)
Article
Thermodynamics
Mohammad Zaboli, Mehdi Nourbakhsh, Seyed Soheil Mousavi Ajarostaghi
Summary: This study numerically evaluates heat transfer and fluid flow in a corrugate coil tube with different lobe-shaped cross-sections. Spiral twisted tapes with various geometries are used as turbulators in the tube. The results show that a five-lobe cross-section increases the Nusselt number and pressure drop, and increasing the area of the twisted tape also increases these parameters. Additionally, a spiral twisted tape with cleared center improves thermal efficiency in certain cases.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2022)
Article
Thermodynamics
M. G. Rizk, O. G. Kaoud, A. M. T. A. Eldein Hussin, W. Aboelsoud
Summary: An innovative method was proposed to enhance convective heat transfer by using a swirl jet to suppress the boundary layer over a flat plate. The parameter study showed that the heat transfer coefficient was significantly enhanced when using a combination of swirl jet and crossflow.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Zenan Yang, Meiyuan Lu, Ben Guan, Haiwei Yang, Weiqiang Pu, Ge Wang
Summary: This paper first proposes a new mechanism of heat transfer deterioration (HTD) in supercritical water (SCW) based on the pseudo boiling theory, and then numerically investigates the mitigation effects of nanoparticles and corrugations on the HTD. The study reveals that the low turbulence intensity and thermal conductivity of the pseudo film induce the HTD, and the pseudo two-phase flow instability affects the growth and dissipation of the pseudo film. With the presence of nanoparticles and corrugations, the wall temperature can decrease by 348 K, the wall temperature peak mitigation ratio is 33.5%, and the maximum heat transfer enhancement is 164%. However, when the corrugations in the corrugated tube have a large pitch, HTD cycles occur and further deteriorate the overall heat transfer performance. The coupling effect of nanoparticles and corrugations effectively suppresses the HTD and HTD cycles.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Wenling Liao, Shuaimei Lian
Summary: This study investigates the impact of compound corrugation on the heat transfer performance of corrugated tubes using computational fluid dynamics. The results show that compound corrugation induces stronger fluid mixing and provides greater heat transfer improvement compared to simple corrugation. The heat transmission efficacy of compound corrugation improves with increasing width and depth. This research supports the design of compound corrugations to enhance the heat transfer performance of corrugated tubes, but further studies are needed to understand the influence of compound corrugation in detail.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Ahmad Shafee, M. Sheikholeslami, M. Jafaryar, Houman Babazadeh
Summary: Incorporating hybrid nanopowders into a turbulator can disrupt the boundary layer, improving thermal treatment but also causing a greater pressure drop. As the revolution of swirl flow device decreases, frictional resistance reduces and secondary flow weakens. An increase in inlet velocity can enhance temperature gradient but at the expense of a greater pressure loss.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2021)
Article
Thermodynamics
Juan He, Qinghua Deng, Zhenping Feng
Summary: This paper investigates the use of corrugated target surfaces for impingement cooling, with results showing that the full-corrugated target surface improves heat transfer performance significantly at high Reynolds numbers, while the semi-corrugated target surface reduces friction loss.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Thermodynamics
J. D. Moya-Rico, A. E. Molina, J. I. Corcoles, J. A. Almendros-Ibanez
Summary: The aim of this study was to investigate the impact of a double tube heat exchanger on thermo-hydraulic performance. Through experimental tests, 21 different shell-tube configurations were examined. The results showed that using a light groove depth in the outer tube significantly enhanced heat transfer rate and efficiency, while a higher groove depth did not improve performance. Among the different shells, the inner tubes with the highest groove depth demonstrated the best results.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Thermodynamics
Yan Cao, Hamdi Ayed, Ali E. Anqi, Omid Tutunchian, Hamed Sadighi Dizaji, Samira Pourhedayat
Summary: This paper introduces and investigates a helical tube-in-tube heat exchanger with both inner tube and outer tube corrugated. The fabrication process and performance analysis show that this structure can significantly boost the thermal capacity of the heat exchanger, with the relative position of the corrugations playing a crucial role in performance improvement.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Thermodynamics
Wei Wang, Yong Shuai, Liang Ding, Bingxi Li, Bengt Sunden
Summary: This paper investigates the enhanced heat transfer performance and mechanism of a multi-tube heat exchanger with outward helically corrugated tubes using a numerical approach. The results show that rotational and secondary flows have an impact on heat transfer performance, with TTA exhibiting outstanding performance in terms of Nu, f, and PEC indices.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Thermodynamics
Pongjet Promvonge, Pitak Promthaisong, Sompol Skullong
Summary: The article investigates the effect of insertion of louvered V-winglet (LVW) vortex generators on convection heat transfer and pressure loss in a tubular heat exchanger. The experimental result shows that among the LVWs, the case of R-P=0.5, theta=10 degrees provides the largest friction factor and Nusselt number.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Energy & Fuels
Pongjet Promvonge, Pitak Promthaisong, Sompol Skullong
Summary: A numerical and experimental study was conducted on a solar receiver heat exchanger equipped with a newly designed longitudinal-vortex generator. The experimental results showed improved thermal-hydraulic performance under specific parameters. Further enhancements were achieved through design modifications and optimization conditions. Flow computation and validation of the results provided a better understanding of the system behavior.
Article
Thermodynamics
Smith Eiamsa-Ard, Arnut Phila, Monsak Pimsarn, Naoki Maruyama, Masafumi Hirota
Summary: The aim of this study is to investigate the effect of wing position on heat transfer rate and pressure drop characteristics in a channel with square-wing perforated transverse baffles. Two types of baffles, solid and square-wing, were tested at various Reynolds numbers. The results showed that square-wing baffles have lower pressure losses and higher thermal performance compared to solid baffles.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Thermodynamics
Pongjet Promvonge, Arnut Phila, Varesa Chuwattanakul, Suriya Chokphoemphun, Smith Eiamsa-ard, Naoki Maruyama, Masafumi Hirota
Summary: In this study, the use of arc-shaped twisted-baffles (T-ABs) in a rectangular air channel was experimentally investigated to improve the thermal performance factor (TPF). The effects of pitch ratio (p/w), arc-shape angle (alpha), and Reynolds number (Re) were explored. The results showed that the channel with arc-shaped twisted-baffles achieved higher Nusselt numbers compared to a smooth channel, likely due to the presence of multiple-impinging jets near the surface. Baffles with larger attack angles exhibited superior heat transfer enhancements. The optimal condition was found at alpha = 90o, p/w = 4.0, and Re = 4000, resulting in significant improvements in heat transfer rate, friction factor, and TPF.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Nuthvipa Jayranaiwachira, Pongjet Promvonge, Chinaruk Thianpong, Pitak Promthaisong, Sompol Skullong
Summary: The study investigates the enhancement of convection in a tube heat exchanger using louvered curved-baffle vortex generator (VG). The results show that the LCB-inserted tube has larger Nu and f values compared to a plain tube, with Nu and f increasing as PR and theta decrease. The LCB increases Nu and f by approximately 2.59-4.66 and 3.8-39.37 times, respectively. Empirical correlations for Nu and f fit the measured data well, with discrepancies of +/- 9% and +/- 10%, respectively.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Thermodynamics
V. Chuwattanakul, K. Wongcharee, P. Ketain, S. Chamoli, C. Thianpong, S. Eiamsa-ard
Summary: An experimental investigation on the aerothermal performance of a heat exchanger tube equipped with newly designed broken V-ribbed twisted tapes (B-VRT) was conducted. The results showed that the B-VRT provided enhanced heat transfer due to increased mixing caused by longitudinal vortices from the ribs and swirling flow from the twisted tapes. The B-VRT with forward facing ribs at an attack angle alpha of 45 degrees exhibited the best performance.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Energy & Fuels
Smith Eiamsa-ard, Arnut Phila, Khwanchit Wongcharee, Monsak Pimsarn, Naoki Maruyama, Masafumi Hirota
Summary: The influences of perforated-baffles on local Nusselt number and thermo-hydraulic behaviors were comprehensively studied using thermochromic liquid crystal sheet. The study found that perforated-baffle with square wings offered better results compared to regular perforated-baffles, and caused less pressure loss.
Article
Energy & Fuels
Prachya Samruaisin, Rangsan Maza, Chinaruk Thianpong, Varesa Chuwattanakul, Naoki Maruyama, Masafumi Hirota, Smith Eiamsa-ard
Summary: The influences of V-shaped delta-wing baffles on the thermohydraulic performance in a round tube were experimentally tested. The V-shaped delta-wing baffles with a set number of wings (N=4, 6, and 8) and various pitch ratios (P/D=2.0, 2.5, and 3.0) were studied. The results showed that the V-shaped delta-wing baffles can significantly enhance the Nusselt number and improve the heat transfer rate.
Article
Thermodynamics
S. Sirikasemsuk, N. Naphon, S. Eiamsa-ard, P. Naphon
Summary: The operating temperature of the battery has a significant impact on the performance, reliability, and safety of electric vehicles. A 3D Eulerian model is used to study the battery's thermal behavior under different coolant flow directions. The results show that the coolant flow direction and thermophysical properties have a significant effect on the maximum operating temperature and temperature gradient of the battery. The proposed battery nanofluid cooling pack can optimize the thermal management system of electric vehicle packs.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Pongjet Promvonge, Smith Eiamsa-ard, Sompol Skullong, Naoki Maruyama, Masafumi Hirota
Summary: An experiment was conducted to investigate the effectiveness of inserting a louver-punched trapezoidal-winglet into a heat-fluxed tube to create a longitudinal vortex generator. The study aimed to optimize thermal performance and reduce heat exchanger sizes. The experimental results showed significant improvements in friction factor and Nusselt number compared to a plain tube.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Smith Eiamsa-ard, Naoki Maruyama, Masafumi Hirota, Sompol Skullong, Pitak Promthaisong
Summary: This paper investigates the fluid flow and heat transfer mechanisms in ribbed twisted-oval tubes. Simulations were conducted to find the optimal conditions for uniform heat-flux wall condition in turbulent flow. The results show that the ribbed twisted-oval tubes generate stronger swirl flow and have higher turbulent kinetic energy compared to conventional twisted-oval tubes. With increasing rib height ratios, spiral depth ratios, and number of ribs, the turbulent kinetic energy increases significantly while it decreases with larger twist pitch ratios. The optimal parameters for maximal thermal performance factor (TPF) of 1.32 were found to be a twist pitch ratio of 3.5, a spiral depth ratio of 0.1, a rib height ratio of 0.075, a number of ribs of 4, and a Reynolds number of 5000.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
K. Nanan, S. Eiamsa-ard, S. Chokphoemphun, Manoj Kumar, M. Pimsarn, V. Chuwattanakul
Summary: The aim of this study was to investigate the shrimp drying process in a fluidized-bed dryer in order to develop a more efficient method compared to traditional sun drying. The influence of shrimp size, bed height, and air temperature on the drying rate was studied, with the moisture content of boiled shrimp decreasing at higher drying temperatures. Reducing bed height and shrimp size both increased shrimp moisture removal. The highest dried shrimp production rate was achieved at a bed height of 1.0 and drying temperature of 80 degrees C.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Arnut Phila, Warin Keaitnukul, Smith Eiamsa-ard, Paisarn Naphon, Naoki Maruyama, Masafumi Hirota, Varesa Chuwattanakul
Summary: The proper designs of modified heat transfer surfaces or turbulence enhancement inserts are crucial for improving the efficiency of thermal systems. The use of transverse baffles with rectangular notches can effectively enhance heat transfer while minimizing pressure loss. The smaller the ratio of notch height to baffle height, the higher the heat transfer enhancement, friction factor, and aerothermal performance.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Engineering, Aerospace
P. Eiamsa-ard, K. Wongcharee, K. Kunnarak, M. Kumar, S. Eiamsa-ard, M. Pimsarn
Summary: Thermal visualization was performed to study and compare the heat transfer behavior of different types of jets. The results showed that the swirling impinging jet with a triple spiral-corrugated nozzle and twisted tape inserts had stronger recirculation, leading to reduced heat transfer between the stagnation region and surroundings.
THERMOPHYSICS AND AEROMECHANICS
(2022)
