Article
Thermodynamics
Toygun Dagdevir, Veysel Ozceyhan
Summary: The effects of different twisted tapes on heat transfer and flow characteristics in a heat exchanger tube were experimentally investigated to enhance performance. Results showed that twisted tape inserts improved heat transfer performance, with the novel dimpled twisted tape insert providing the best performance. Addition of ethylene glycol did not significantly increase the friction factor, and higher ethylene glycol content led to decreased thermo-hydraulic performance.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Thermodynamics
Hazim Moria
Summary: This study investigated the effect of twisted tape turbulators and air injection on heat transfer enhancement. Results showed significant differences in flow patterns and notable increases in heat transfer and pressure drop with the presence of twisted tape turbulators. Air injection led to substantial increases in heat transfer coefficient and pressure drop, with the best cost per benefit ratio occurring at specific flow rates and turbulator configurations.
CASE STUDIES IN THERMAL ENGINEERING
(2021)
Review
Green & Sustainable Science & Technology
Mohamed H. Mousa, Nenad Miljkovic, Kashif Nawaz
Summary: Enhancing heat transfer between fluids and walls is crucial for improving performance. By utilizing features that enhance heat transfer, equipment size can be reduced, costs minimized, and safety risks mitigated.
RENEWABLE & SUSTAINABLE ENERGY REVIEWS
(2021)
Article
Thermodynamics
Aziz Hakan Altun, Haluk Nacak, Eyub Canli
Summary: The trapezoidal and twisted trapezoidal tape elements used for heat transfer enhancement in tubes were experimentally investigated, analyzing their effects on heat transfer, pressure drop, and overall performance factor. The experimental results showed that the twisted trapezoidal tape elements had excellent heat transfer performance and overall performance factor.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Amin Karamati, Ali Qasemian, Ali Keshavarz, Mozhgan Haddadi
Summary: In this paper, the effects of titanium dioxide nanoparticles and twisted tapes on the heat transfer and pressure characteristics of ATF flow were investigated experimentally. The results showed that increasing the nanoparticle mass concentration and Reynolds number led to an increase in pressure and heat transfer. Decreasing the twist ratio of the tapes also increased both the pressure and heat transfer. The nanofluid with a mass fraction of 1% and twisted tape 2 showed the best performance in terms of both heat transfer and pressure drop.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Thermodynamics
Zahra Azizi, Vahid Rostampour, Samad Jafarmadar, Saleh Khorasani, Behzad Abdzadeh
Summary: The study investigated the combined effect of twisted tape turbulator and air injection on heat transfer augmentation. It was found that the twisted tape turbulator significantly altered the flow structure of the two-phase flow. The twist ratio of the twisted tape had a significant impact on the Nusselt number and pressure loss.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2022)
Article
Thermodynamics
Kim Leong Liaw, Jundika C. Kurnia, Agus P. Sasmito
Summary: This study investigated the effect of inserting twisted tape into a helical tube on turbulent heat transfer, finding that the insertion of twisted tape increases the intensity of secondary flow in the radial direction, resulting in higher heat transfer performance. The results also showed that for all cases, higher inlet Reynolds numbers lead to a proportional increase in heat transfer, while the friction coefficient decreases with decreasing decrement amounts.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Li Shijie, Qian Zuoqin, Wang Qiang
Summary: This numerical investigation explores the heat transfer optimization effect of circular tube heat exchanger with L-shaped twisted tape insert and finds the optimal parameter design. The effects of twist pitch, inner diameter, tape width, and number of tape on thermohydraulic performance were studied. Response surface method was used to analyze the relationship between the Nusselt number and these parameters. The results show that the tube fitted with L-shaped twisted tape insert has a significant increase in Nu and friction factor compared to the smooth tube.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Letter
Engineering, Mechanical
Ahmad Abbas, Zahid Ayub, Adnan Ayub, Wei Li, Shehryar Khan
Summary: Experimental tests were conducted in a heat exchanger using two types of opposite twisted tapes, showing enhanced heat transfer and reduced pressure drop, which could have implications for the solar power industry.
JOURNAL OF THE BRAZILIAN SOCIETY OF MECHANICAL SCIENCES AND ENGINEERING
(2021)
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
Bhrant Kumar Dandoutiya, Arvind Kumar
Summary: This study investigates the use of W-cut twisted tape in a double pipe heat exchanger to enhance heat transfer rate and thermal performance. The results show that increasing the depth of the cut in the twisted tape leads to an improvement in the thermal performance factor. Additionally, the study finds that the thermal performance factor in this research is better compared to previous studies with different inserts.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Zhang Jie, Salina Binti Muhamad, Azher M. Abed, Ahmed Deifalla, S. P. Ghoushchi, Izyani Mat Rusni
Summary: Numerous studies have been conducted to evaluate the separate effect of using a V-cut twisted tape turbulator, bubble injection method, and CuO-water nanofluid as a working fluid on hydrothermal parameters. However, this study is the first to comprehensively evaluate the simultaneous effect of these three methods on a double-tube heat exchanger. The results showed that their simultaneous use significantly increased the effectiveness and thermal performance enhancement factor, while the friction factor also increased.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Mohammed Zafar Ali Khan, Muhammad Aziz, Agung Tri Wijayanta
Summary: The study uses artificial neural networks to predict the efficiency of a double-pipe heat exchanger, showing that the model can accurately predict experimental data with a low mean square error. The neural network method is also effective in predicting thermal parameters with low variability and high precision.
CASE STUDIES IN THERMAL ENGINEERING
(2021)
Article
Multidisciplinary Sciences
Md Tauhidur Rahman, Khairul Habib, Md Niamul Quader, Navid Aslfattahi, Kumaran Kadirgama, Likhan Das
Summary: This study investigates the impact of porosity density of twisted tape inserts on temperature distribution, fluid velocities, heat transfer coefficients, Nusselt numbers, turbulent kinetic energy, and performance. The results demonstrate that high porosity TTI significantly reduces temperature spans, increases fluid velocities, enhances heat transfer efficiency, and exhibits superior performance compared to low porosity and typical TTI, particularly at Re = 12500.
Article
Engineering, Chemical
Saeid Salimi, Mohammad Javad Mozoun, Reza Beigzadeh
Summary: This study investigates the impact of twisted tape insert geometrical variables on the thermal-hydraulic performance of heat exchangers and uses computational fluid dynamics simulation technique. Predictions by artificial neural network and genetic algorithm models show high accuracy in correlation.
CANADIAN JOURNAL OF CHEMICAL ENGINEERING
(2023)
Article
Thermodynamics
Cong Li, Jiali Wang, Chenhui Wang, Yanke Jin, Yina Yao, Rui Yang
Summary: This study investigates the impact of NaCl water droplets with various concentrations on a heated surface. The results show that the impact patterns can be categorized into different types, and models are established to predict the spreading behavior of droplets with different concentrations. Additionally, high concentration droplets exhibit more violent boiling and have lower residual energy and rebound time.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
C. Barrera, V. Castro, F. Escudero, J. J. Cruz, I. Verdugo, J. Yon, A. Fuentes
Summary: This study focuses on the characterization of soot maturity and sooting propensity of anisole fuel in a controlled laminar coflow diffusion flame. The results show that the spatial distribution of soot volume fraction is enhanced near the flame centerline, while soot production is promoted near the flame wings. The temperature increase also affects the maturity of soot particles.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Roman W. Morse, Jason Chan, Tiago A. Moreira, Jared J. Valois, Evan T. Hurlburt, Jean-Marie Le Corre, Arganthael Berson, Kristofer M. Dressler, Gregory F. Nellis
Summary: This study investigates the dryout of liquid film and the role of disturbance wave frequency. Experimental results indicate that the heat transfer coefficient associated with optimal boiling conditions is maximized when the surface is dry 5% of the time, independent of pulse amplitude and frequency. Liquid-film measurements, dryout statistics, and direct observation suggest that disturbance-wave frequency can be manipulated by density-wave oscillations in the flow field.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
E. J. Vega, J. M. Montanero
Summary: In this study, we experimentally investigated the bursting of a bubble covered with a surfactant. We found that the bubble bursting time is longer compared to a surfactant-free bubble due to interfacial elasticity. Furthermore, the Marangoni stress drives liquid flow that allows the jet to escape from the end-pinching mechanism within a certain surfactant concentration range.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Guofu Sun, Yi Zhan, Tomio Okawa, Mitsuhiro Aoyagi, Akihiro Uchibori, Yasushi Okano
Summary: Experiments were conducted on liquid jets ejected from oval nozzles to investigate the effects of nozzle orifice shape on jet behavior. The study found that the liquid jet exhibited different characteristics at different liquid flow rates. Correlations were established to predict the liquid jet state and characteristics of the secondary droplets produced during jet impact onto a solid surface. This research extended the available knowledge on liquid jet behavior.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Jeonghoon Lee, Laurent Zimmer, Takeshi Saito, Shinji Nakaya, Mitsuhiro Tsue
Summary: This study investigates the effects of spatial resolution on DMD amplitudes and spatial mode strengths, and proposes scaling factors to correct for the resolution differences. The results show that the proposed scaling factors successfully normalize the amplitudes and spatial modes, allowing for quantitative comparison of data obtained with different spatial resolutions. This study is significant for analyzing spatiotemporal data in various fields.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Yanli Zhao, Shibing Kuang, Xiaoliang Zhang, Mingjun Xu
Summary: This study experimentally investigates the dynamic process of water droplet impacting different wood surfaces and analyzes and discusses the impacting phenomena, phenomena distribution, droplet spreading dynamics, and maximum spread factor. The results show that the impacting process can be distinguished by Weber numbers and Reynolds numbers, and can be predicted by mathematical expressions.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Aakhash Sundaresan, Atul Srivastava, Callum Atkinson
Summary: This study presents the first-ever application of an advanced methodology, combining two-color laser-induced phosphorescence and particle image velocimetry, to investigate the heat transfer mechanisms on the surface of a cylinder placed inside a confined square duct. The technique allows for simultaneous measurement of velocity and temperature fields, reducing the complexity and costs associated with separately measuring temperature distributions. Experimental observations show that increasing the mass flow rate enhances heat removal from the cylinder surface, and increasing the cylinder heat input enhances heat transfer in the rear portion of the cylinder.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Harish K. Patel, Sukhjeet Arora, Rutuja Chavan, Bimlesh Kumar
Summary: This study experimentally analyzed the multiscale statistical assessment of scour depth surrounding spur dikes with downward seepage. The research found that seepage affects the morphological behavior and hydrodynamic characteristics of the channel bed, leading to changes in scour formation. The rate of scour depth changes initially increases with higher seepage velocity but eventually becomes constant over time.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Justas Sereika, Paulius Vilkinis, Gediminas Skarbalius, Algis Dziugys, Nerijus Pedisius
Summary: This study experimentally investigated the pulsatile flow structure based on a transitional-type cavity. It was found that the pulsation amplitude has a more significant effect on the dynamics of recirculation zone than the pulsation frequency. Pulsatile flow can reduce the size of the recirculation zone.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Merav Arogeti, Eran Sher, Tali Bar-Kohany
Summary: This study provides a detailed exploration of the events that occur when a droplet hits a dry solid surface of various small sizes, with a focus on the deposition, receding breakup, and prompt splash phases. By utilizing non-dimensional analysis and graphical representation, the boundaries between different events are defined, and criteria for differentiation based on target-to-drop ratio, Reynolds, and Webber numbers are presented.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Tianxiong Li, Fei Wen, Yingchun Wu, Botong Wen, Lei Wang, Jinxin Guo, Xuecheng Wu
Summary: This study investigates the structure of the flow field induced by a strut in a scramjet and its influence on flame stabilization. Experimental and numerical analyses reveal that the flow field exhibits features beneficial for flame stabilization, but the asymmetry of the flow poses a challenge to flame establishment.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Syed Ehtisham Gillani, Yasir M. Al-Abdeli
Summary: This study investigates the asymmetry in bluff-body stabilised annular jets and finds that swirl can significantly mitigate the asymmetry and restore the symmetry of the jets. Moreover, increasing the Reynolds number and the swirl intensity can both decrease the asymmetry of the jets.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Utsav Bhardwaj, Rabindra Kumar, Shyama Prasad Das
Summary: This study presents an experimental investigation on flooding phenomenon in a pulsating heat pipe (PHP) unit cell, and analyzes the impact of flooding on the performance of PHP. The study recognizes three different flooding mechanisms and finds that currently accepted correlations for predicting flooding velocity are inaccurate. The study emphasizes the need for further research on flooding in PHPs.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
Article
Thermodynamics
Yunpeng Xue, Yongling Zhao, Shuo-Jun Mei, Yuan Chao, Jan Carmeliet
Summary: This study investigates the impact of building morphology on local climate, air quality, and urban microclimate. The researchers conducted an experimental investigation in a large-scale water tunnel, analyzing heat and flow fields using Laser-induced Fluorescence (LIF) and Particle Image Velocimetry (PIV). The findings show that factors such as canyon configuration, buoyant force, and approaching flow magnitude significantly influence fluid flow in street canyons, and the morphology of the street canyon dominates ventilation rate and heat flux. For example, changing the aspect ratio of a street canyon can lead to a significant change in air ventilation rate, ranging from 0.02 to 1.5 under the same flow conditions.
EXPERIMENTAL THERMAL AND FLUID SCIENCE
(2024)
