Article
Thermodynamics
Jiangbo Wang, Ting Fu, Liangcai Zeng, Fue-sang Lien, Guang Chen
Summary: The punched delta winglet (PDW) was found to enhance local heat transfer efficiency while slightly affecting overall heat transfer coefficient and reducing pressure loss in the channel. Among holes with the same area, the larger width and lower height of the hole resulted in the highest thermal enhanced factor (TEF).
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Thermodynamics
Yue Yang, JuiKui Mao, Pingting Chen, Feilong Wang, Zecan Tu
Summary: This study compares the heat transfer performance of different VGs configurations through numerical simulations, finding that the downstream common-flow-down configuration of VGs can achieve favorable heat transfer enhancement. By increasing the height of VGs and decreasing the spacing between VGs and the jet, the heat transfer efficiency can be further improved.
APPLIED THERMAL ENGINEERING
(2022)
Article
Mechanics
L. Xia, Y. Hua, J. G. Zheng
Summary: The study investigates leading edge flow separation control over a stalled airfoil using a fluidic oscillator, revealing the interaction between oscillating jet and external crossflow leads to the production of spanwise vortices, mitigating flow separation. It is found that a higher mass flow usually leads to a better flow control performance.
Article
Thermodynamics
Jiangbo Wang, Ting Fu, Liangcai Zeng, Fue-sang Lien, Xiaolei Deng, Feng Zhang
Summary: This article presents a novel arrangement of planar vortex generators (VGs) and punched VGs within a heated tube. The airflow and heat removal performance of VGs with this new configuration were investigated through numerical simulation and experimental methods. The results showed that the heat enhancement factor (TEF) values of tubes fitted with the three arrangements of VGs were similar when Re > 10,000. Additionally, the TEF value increased as the perforation index (PI) decreased and the pitch ratio (PR) decreased.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Jiangbo Wang, Ting Fu, Liangcai Zeng, Fue-sang Lien, Xiaolei Deng
Summary: This study investigated the thermal performance of punched rectangular winglet vortex generators in turbulent regime. The results showed that punching holes can reduce heat transfer and friction coefficients, enhance the thermal enhancement factor, and jet flow can improve heat transfer efficiency.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Thermodynamics
Zhiqiang Sun, Qiang Chen, Nianben Zheng
Summary: The study investigated the turbulent airflow and heat transfer characteristics in round pipes with curved wing vortex generators (CWVGs), showing that CWVGs induced counter-rotating vortex pairs at the trailing edge, resulting in thinning thermal boundary layer and improved fluid mixing with larger width ratio (WR) or smaller pitch ratio (PR). The thermal enhancement factor (TEF) peaked at WR = 0.20 for Re = 6023 and at PR = 1.0 for Re = 5962, with correlations derived for industrial applications based on experimental data.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Energy & Fuels
Yicong Li, Zuoqin Qian, Qiang Wang
Summary: The aim of this study was to improve the heat transfer performance by using rectangular winglet vortex generators (RWVGs) inserted into tubes. Numerical simulations were conducted to analyze the influence of geometric parameters of RWVGs on thermal-hydraulic performance. The results showed that tubes with RWVG inserts had significantly higher heat transfer capacity than ordinary circular tubes, with the case of α=135 degrees showing the greatest enhancement of thermal performance.
Article
Thermodynamics
Takumi Ohta, Akihiko Mitsuishi, Takaaki Shimura, Kaoru Iwamoto, Akira Murata
Summary: This study investigated the influence of mainstream angle on laminar boundary layer flow with arrays of tetrahedral vortex generators (VGs) through direct numerical simulations. It was found that the highest heat transfer effect was observed when the mainstream angle was 60 degrees. The analysis revealed that advection induced by vortex pairs was the dominant factor at zero yaw angle, while heat transfer was enhanced by a turbulent component as the mainstream angle increased. Additionally, installing multiple VGs in the longitudinal direction led to a higher heat transfer enhancement effect, which was remarkable when VGs were aligned in the mainstream direction.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Ruben Borrajo Perez, Alberto Menendez Perez, Daniel Sacasas Suarez
Summary: This study numerically investigates the impact of a pair of perforated vortex generators (VGs) punched on the surface of a rectangular channel on its thermohydraulic performance. The results show that VGs enhance heat transfer efficiency and produce lower pressure loss, especially for Reynolds numbers higher than 120, indicating significant advantages.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Ruben Borrajo-Perez, Alberto Menendez-Perez, Daniel Sacasas-Suarez
Summary: Heat transfer enhancement is a constant objective in heat exchanger design, and vortex generators are a passive technique that can improve heat exchanger performance by disrupting boundary layers and creating secondary flows. In this study, the influence of punched holes on rectangular channels with built-in vortex generators was numerically analyzed. The arrangement with punched holes in front of the vortex generators achieved the best overall performance, doubling the heat transfer enhancement while also increasing pressure drop.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Mehmet Dogan, Atila Abir Igci
Summary: Vortex generators (VGs) play a crucial role in enhancing heat transfer. An experimental comparison between a novel type of vortex generator (NTVG) producing longitudinal vortex (LV) and delta winglet pair (DWP) showed that the NTVG achieved higher thermal enhancement, indicating its effectiveness in improving heat transfer.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Alberto Menendez-Pereza, Carlos Fernandez-Aballi Altamirano, Daniel Sacasas Suarez, Cristian Cuevas Barraza, Ruben Borrajo-Pereza
Summary: In this study, a combined geometry of louvered fins and vortex generators is simulated to optimize the thermohydraulic behavior of a compact heat exchanger. The study analyzes the influence of eight parameters of the enhanced surface on its thermohydraulic performance and achieves improvements in convective heat transfer between 6.55% and 19.63% with an increase in pressure losses ranging from 10.95% to 20.67%, depending on the Reynolds number. The optimization is carried out using NSGA-II genetic algorithms and multi-objective optimization technique.
APPLIED THERMAL ENGINEERING
(2022)
Article
Mechanics
Pengcheng Quan, Gang Wang, Xiwang Xu, Ke Zhu, Yanguang Yang
Summary: This paper experimentally investigates the effects of herringbone riblets (HRs) on a turbulent boundary layer and shock wave/boundary layer interactions (SWBLIs) at Mach number 3. Three different lengths of HRs strips are applied upstream of the separation zone of SWBLIs on a compression ramp model. Various techniques like high-speed schlieren, oil-flow visualization, and planar laser scattering are used to examine the shock pattern and boundary layer over the model's surface. The experiments provide evidence that HRs make the separation line wavy and reduce the separation zone, and microscale HRs induce large-scale streamwise vortical structures in the boundary layer.
Article
Thermodynamics
Soheil Asaadi, Hamid Abdi
Summary: The heat transfer enhancement in plate-fin heat exchangers using vortex generators with different nanoparticle volume fractions was numerically simulated. Results showed that using nanofluid can increase heat transfer coefficient by 20% and pressure drop by 18% compared to pure water. Among the vortex generator types, MDWP2 exhibited the highest heat transfer performance but also led to the highest pressure drop in the studied range of Reynolds number.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2021)
Article
Thermodynamics
Huseyin Zahit Demirag, Mehmet Dogan, Atila Abir Igci
Summary: In this study, experimental and numerical investigations were conducted to examine the heat transfer enhancement and friction factor characteristics of a solar air heater with novel type conic vortex generators on the absorber plate. The experimental results showed that the geometrical parameters played a crucial role in the thermal enhancement factor, with the optimum attack angle, blade angle, and scale ratio achieving the highest thermal enhancement factor. The numerical studies used Fluent software to visualize the fluid velocity, vorticity distributions, temperature, and Nusselt number distributions, as well as the pressure distribution of the vortex generators.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Pongjet Promvonge, Sompol Skullong
Summary: The study experimentally examined the influences of V-shaped baffle vortex generator inserts in a heated tube, showing that increasing the relative baffle blockages leads to a significant increase in friction factor and heat transfer, while reducing the baffle pitches decreases them. The optimal thermal enhancement factor is found at P-R = 1.0, B-R = 0.15.
APPLIED THERMAL ENGINEERING
(2021)
Article
Engineering, Chemical
Pongjet Promvonge, Chitakorn Khanoknaiyakarn, Somchai Sripattanapipat, Sompol Skullong
Summary: The article presents an experimental study on the impact of multiple V-shaped ribs and delta-grooves on heat transfer and friction behaviors in a solar air duct. The results show that ribs and grooves with specific parameter settings can enhance heat transfer and thermal performance.
CHEMICAL ENGINEERING RESEARCH & DESIGN
(2021)
Article
Thermodynamics
Pongjet Promvonge, Sompol Skullong
Summary: The article focuses on enhancing the thermohydraulic performance of a solar heat exchanger duct with combined V-shaped baffle-and-groove vortex generators. Experimental results show that using the flapped-baffle and groove VG devices can achieve maximum heat transfer and friction effects, especially for the VU case.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(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
Thermodynamics
C. Thianpong, K. Wongcharee, H. Safikhani, S. Chokphoemphun, A. Saysroy, S. Skullong, S. Eiamsa-ard
Summary: This study utilized a hybrid technique involving TiO2/water nanofluid and loose-fit delta-wing twisted tape to enhance heat transfer efficiency. Experimental results showed that the combined enhancement technique significantly improved heat transfer rates, mainly due to the swirling flow effect and higher thermal conductivity. Furthermore, reducing the loose-fit ratio and increasing the nanofluid concentration can also enhance heat transfer rates and thermohydraulic performance.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(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
Pongjet Promvonge, Sompol Skullong
Summary: This study investigates the thermohydraulic performance, flow friction, and entropy generation analysis of a heated tube with louvered winglet tape inserts. The results show that different louver angles and pitch ratios have a significant impact on heat transfer rates and friction losses. Decreasing Reynolds number, pitch ratio, and louver angle can reduce entropy generation.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Thermodynamics
Nuthvipa Jayranaiwachira, Pongjet Promvonge, Chinaruk Thianpong, Sompol Skullong
Summary: This article presents an experimental study on turbulent airflow friction and thermal behaviors in a solar receiver heat exchanger duct. The experimental results show that the combination of rib-groove turbulators at β = 0 degrees and P-R = 1 gives the maximum heat transfer rate and friction loss, and the highest thermal enhancement factor was found at β = 45 degrees and P-R = 1.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Nuthvipa Jayranaiwachira, Pongjet Promvonge, Chinaruk Thianpong, Sompol Skullong
Summary: This article presents an experimental study on entropy generation analysis and thermohydraulic performance of a uniform heat-flux tube equipped with louvered corner-curved baffle tape (LCBT). The impacts of various parameters on the thermal enhancement factor, Nusselt number, friction factor, and total entropy generation were examined. The results indicate that the LCBT with smaller pitch ratios and angles performs better in terms of thermal performance, especially at higher Reynolds numbers.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Energy & Fuels
Pongjet Promvonge, Pitak Promthaisong, Sompol Skullong
Summary: A vortex generator was tested and investigated in this study to improve the thermal performance of a solar heat exchanger duct. Experimental and numerical methods were used to understand its flow and thermal patterns, and optimal configurations were determined.
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
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
Engineering, Chemical
Pongjet Promvonge, Sompol Skullong
Summary: This study investigates the thermal-hydraulic performance of a solar receiver channel equipped with a vortex flow generator. The use of square flaps on the V-baffle helps reduce pressure drag and friction loss. The optimum thermal performance is achieved with a flap angle of 45 degrees and a relative baffle pitch of 1.5.
CHEMICAL ENGINEERING RESEARCH & DESIGN
(2022)
Article
Energy & Fuels
Siddharth Sradhasagar, Omkar Subhasish Khuntia, Srikanta Biswal, Sougat Purohit, Amritendu Roy
Summary: In this study, machine learning models were developed to predict the bandgap and its character of double perovskite materials, with LGBMRegressor and XGBClassifier models identified as the best predictors. These models were further employed to predict the bandgap of novel bismuth-based transition metal oxide double perovskites, showing high accuracy, especially in the range of 1.2-1.8 eV.
Article
Energy & Fuels
Wei Shuai, Haoran Xu, Baoyang Luo, Yihui Huang, Dong Chen, Peiwang Zhu, Gang Xiao
Summary: In this study, a hybrid model based on numerical simulation and deep learning is proposed for the optimization and operation of solar receivers. By applying the model to different application scenarios and considering multiple performance objectives, small errors are achieved and optimal structure parameters and heliostat scales are identified. This approach is not only applicable to gas turbines but also heating systems.
Article
Energy & Fuels
Mubashar Ali, Zunaira Bibi, M. W. Younis, Muhammad Mubashir, Muqaddas Iqbal, Muhammad Usman Ali, Muhammad Asif Iqbal
Summary: This study investigates the structural, mechanical, and optoelectronic properties of the BaCuF3 fluoroperovskite using the first-principles modelling approach. The stability and characteristics of different cubic structures of BaCuF3 are evaluated, and the alpha-BaCuF3 and beta-BaCuF3 compounds are found to be mechanically stable with favorable optical properties for solar cells and high-frequency UV applications.
Article
Energy & Fuels
Dong Le Khac, Shahariar Chowdhury, Asmaa Soheil Najm, Montri Luengchavanon, Araa mebdir Holi, Mohammad Shah Jamal, Chin Hua Chia, Kuaanan Techato, Vidhya Selvanathan
Summary: A novel recycling system is proposed in this study to decompose and reclaim the constituent materials of organic-inorganic perovskite solar cells (PSCs). By utilizing a one-step solution process extraction approach, the chemical composition of each layer is successfully preserved, enabling their potential reuse. The proposed recycling technique helps mitigate pollution risks, minimize waste generation, and reduce recycling costs.
Article
Energy & Fuels
Peijie Lin, Feng Guo, Xiaoyang Lu, Qianying Zheng, Shuying Cheng, Yaohai Lin, Zhicong Chen, Lijun Wu, Zhuang Qian
Summary: This paper proposes an open-set fault diagnosis model for PV arrays based on 1D VoVNet-SVDD. The model accurately diagnoses various types of faults and is capable of identifying unknown fault types.