Article
Thermodynamics
Xu Wang, Huazhao Xu, Jianhua Wang, Wei Song, Lei Wang
Summary: This study investigated the internal cooling characteristics of turbine blades in a realistic rib roughened two-pass channel and found that the type of wall boundary conditions had a significant impact on blade internal cooling performance, with blade rotation leading to a significant increase in heat transfer on the trailing surface.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Inderjot Kaur, Youssef Aider, Karthik Nithyanandam, Prashant Singh
Summary: Gas turbine blade trailing edge cooling is a challenging task due to strict geometrical constraints and thermal stresses. Traditional pin-fin structures are commonly used for internal cooling, but lattice structures have shown better heat transfer performance. In this study, four different lattice unit cell topologies were additively manufactured in 420 Stainless Steel using Binder Jetting technology, and their heat transfer capabilities were evaluated.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Karthik Krishnaswamy, Suresh Sivan
Summary: The power output and efficiency of a gas turbine can be improved by using ribs that generate high Thermal Hydraulic Performance (THP) in cooling passages. Experimental results show that V and W-shaped ribs can effectively enhance heat transfer within a certain range of Reynolds numbers, with optimal performance observed at Reynolds number 40000.
CASE STUDIES IN THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Xing Yang, Florian Seibold, Zhenping Feng, Bernhard Weigand
Summary: This study numerically investigates the flow and heat transfer behavior of swirl cooling in leaned, convergent tubes. The results show that the unsteady RANS method effectively captures the flow characteristics and heat transfer performance of swirling flows. The use of leaned tubes with Dean vortices improves heat transfer and reduces flow loss compared to straight tubes.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Ran Yao, Hang Su, Yun Cheng, Jianhua Wang, Jian Pu
Summary: The study introduces a novel multistage swirl cooling configuration that can significantly enhance cooling performance and reduce surface temperature, but at the expense of increased total pressure loss. By modifying the bends connecting adjacent stages into round-shaped ones, the pressure loss can be significantly decreased, leading to higher thermal performance of the multistage swirl cooling models compared to the single-stage model.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Thermodynamics
Ning Sun, Wan-Ruo Lu, Yuan Ma, Meng-Zheng Zhang, Li Chen, Wen -Tao Ji, Ya-Ling He, Wen-Quan Tao
Summary: Two types of internal liquid cooling channels and a film cooling structure were designed for a static blade of a turbine engine. The cooling efficiency was investigated using numerical and experimental methods. The regular-sized internal channels showed higher heat transfer coefficient near the inner wall before the elbow and near the outer wall after the elbow. The micro-channel cooling structure, with its smaller diameter, could be mounted closer to the leading edge and cover a wider area. The film cooling method effectively reduced the leading edge temperature when the blowing ratio exceeded 1.3, with an optimal blowing ratio of 2.5 for this blade. Experimental results demonstrated that the micro-channel cooling structure reduced the blade temperature by over 230K, with an error of less than +/- 10% between simulation and experiment.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Shijie Jiang, Zhigang Li, Jun Li
Summary: The effects of rib design on the unsteady tip heat transfer amplitude for a turbine rotor blade with different rotating speeds are numerically investigated in this study. The results suggest that the ribbed tip has a lower averaged heat transfer coefficient and a lower amplitude of the heat transfer coefficient compared to the traditional squealer tip. The low-energy passing wake causes variations in flow field pressure near the tip clearance, resulting in fluctuations in the tip heat transfer coefficient.
JOURNAL OF THERMAL SCIENCE AND ENGINEERING APPLICATIONS
(2022)
Article
Thermodynamics
Jie Liu, Jiabing Wang, Kun Yang
Summary: A novel method is proposed to enhance heat transfer in a turbine blade internal cooling channel by inserting a radiation enhancement plate. Numerical investigations reveal that the model with a radiation enhancement plate roughed with W-shaped ribs exhibits the highest cooling performance. The method shows excellent self-enhancement effect and significantly reduces the heat transfer difference between the leading and trailing walls.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
W. Jin, Y. X. Jia, J. Lei, W. T. Ji, J. M. Wu
Summary: There is a lack of research on the coupled heat transfer characteristics of turbine blade cooling. This study numerically investigates the coupled heat transfer in a turbine blade by considering both internal and film cooling. The results show that the heat conduction through the dividing wall enhances the cooling effect, and adjusting the blowing ratio improves the blade cooling performance.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Minho Bang, Seungyeong Choi, Seok Min Choi, Dong-Ho Rhee, Hee Koo Moon, Hyung Hee Cho
Summary: This study investigates the cooling effectiveness and flow characteristics of a turbine blade tip using a special slot cooling scheme. The slot cooling exhibits significantly enhanced cooling performance compared to cooling holes, providing better thermal durability and reliability for the blade tip.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Ramy Abdelmaksoud, Ting Wang
Summary: This study investigates the effect of injecting mist into the cooling air for gas turbine blades through numerical simulation, finding that mist cooling enhancement is significant on the surface and internal cooling passages walls.
JOURNAL OF THERMAL SCIENCE AND ENGINEERING APPLICATIONS
(2021)
Article
Thermodynamics
I-Lun Chen, Izzet Sahin, Lesley M. Wright, Je-Chin Han, Robert Krewinkel
Summary: This study investigates the effects of different rib orientations on heat transfer and pressure loss in a rotating, blade-shaped cooling channel. The results show that the unusual and criss-cross rib orientations have higher heat transfer performance compared to the criss-cross ribs, while the criss-cross ribs have the lowest pressure loss. The findings provide valuable information for internal cooling of gas turbine blades.
JOURNAL OF THERMAL SCIENCE AND ENGINEERING APPLICATIONS
(2022)
Article
Thermodynamics
Jinfu Chen, Ran Yao, Jianhua Wang, Xu Wang
Summary: In this study, a multi-objective optimization is conducted to enhance the internal cooling strategies of gas turbine blade leading edges by maximazing the heat transfer rate and minimizing the friction loss. By adopting advanced internal cooling concepts, four geometrical parameters are determined as design variables. Validated numerical simulations based on Reynolds Averaged Navier-Stokes equations are performed to generate accurate surrogate models. The optimized cooling strategies achieve significant heat transfer enhancement, reduced friction loss, and improved aerothermal efficiency compared to previous cooling methods.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Jiajia Chen, Yucan Fu, Ning Qian, Huafei Jiang, Chan Y. Ching, Dan Ewing, Chenwei Dai
Summary: A new cooling method incorporating an axially rotating heat pipe (RHP) has been proposed for profile grinding, demonstrating great cooling advantages compared to traditional methods. The study analyzed the cooling behavior through simulation and experimental grinding of titanium alloys, providing insights for green machining in industrial products with complex profiles.
APPLIED THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Jie Liu, Jiabing Wang, Kun Yang
Summary: In this study, a novel method of employing an inserted plate in turbine blades internal cooling channel is proposed for the first time, which enhances heat transfer and improves heat transfer uniformity by extending cold surfaces for radiation. The coupled convective and radiative heat transfer in the rotating channel is numerically explored, and the mechanisms of heat transfer enhancement are revealed and investigated. The results demonstrate that the novel model with the inserted plate parallel to the leading and trailing walls and considering radiation significantly increases the total Nusselt number ratio, performance evaluation criterion and reduces maximum and average temperature.
CASE STUDIES IN THERMAL 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)
