Article
Thermodynamics
Ahmed Ramadhan Al-Obaidi, Jassim Alhamid
Summary: This investigation used numerical simulation techniques to study the thermo-hydraulic flow behavior, heat transfer enhancement, and overall thermal performance of fluid passing within a corrugated pipe. The results showed that an increase in corrugated configurations led to a greater pressure drop and higher Nusselt number values. The study also developed correlation equations for the friction factor, Nusselt number, and thermal performance factor.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Thermodynamics
Wandong Bai, Wei Chen, Chang Zeng, Ge Wu, Xiaoming Chai
Summary: This study investigates the heat transfer and flow characteristics of densely longitudinal fin-equipped annular heat exchangers through experimental testing and numerical simulation. The results show that folded fins and arc-shaped fins have higher heat transfer efficiency and friction loss compared to long straight fins. The findings provide valuable insights for the design of heat exchangers in heat pipe-based thermal power conversion systems.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Merve Goltas, Baris Gurel, Ali Kecebas, Volkan Ramazan Akkaya, Onur Vahip Guler
Summary: In this study, a compact PHE with a lung patterned plate surface was fabricated using additive manufacturing. The design aimed to reduce pressure drop and improve heat transfer. Experimental and numerical results showed that the lung patterned PHE achieved good performance and pressure drop reduction.
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2022)
Article
Thermodynamics
Merve Goltas, Baris Gurel, Ali Kecebas, Volkan Ramazan Akkaya, Onur Vahip Guler, Karani Kurtulus, Emine Yagiz Gurbuz
Summary: This study improves the thermo-hydraulic performance of plate heat exchangers (PHEs) by designing fish gill grooves on the plate surface. The use of nano-fluids enhances heat transfer and reduces pressure drop.
Article
Thermodynamics
M. Muneeshwaran, Yun-Jin Lee, Chi-Chuan Wang
Summary: This study aimed to improve the heat transfer performance of heat sinks with vapor chamber heat spreader by developing parallelogram fins integrated with heat pipes. Results showed significant reduction in thermal resistance and chip temperature with the proposed design.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Prakash Batule, Prashant W. Deshmukh, R. M. Warkhedkar
Summary: The method of inserting curved circular spines for heat transfer augmentation increases fluid dwelling time and induces swirling motion, improving heat transfer coefficients in uniform and non-uniform channels. The study focuses on tubes with curved spines under turbulent fluid flow conditions. Results show that the enhancement ratios for heat transfer and friction, as well as the Nusselt number ratio, are significantly higher compared to smooth tubes at similar flow conditions.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2023)
Article
Thermodynamics
Duygu Yilmaz Aydin, Metin Guru
Summary: Nanofluids with better thermo-physical properties compared to conventional fluids are widely used in various systems. Studies on preparation techniques, stability improvement, and thermal performance evaluation are increasing. The use of nanofluids shows potential in enhancing heat transfer properties in thermal systems.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2022)
Article
Energy & Fuels
Xiuzhen Li, Shijie Liu, Xun Mo, Zhaoyang Sun, Guo Tian, Yifan Xin, Dongsheng Zhu
Summary: A numerical simulation was conducted to explore the hydraulic-thermal performance and convection heat transport development inside spirally corrugated pipes. It was found that the heat transport performance increases with the thread height and Reynolds number, but decreases with the thread pitch. The Nusselt number of the spirally corrugated pipe is 2.77 times that of the plain pipe, while the flow resistance coefficients are 89 to 324% higher. The overall heat transmission performance factor increases in the Reynolds number region of 4000 to 7000 and then decreases in the region of 7000 to 13000. The promotion of convection heat transport is attributed to the secondary flow and vortexes in the pipe.
Article
Engineering, Chemical
Haojie Zhang, Wenwen Guo, Long Guo, Guoneng Li, Youqu Zheng, Cong Dong, Haoxiang Zhou
Summary: The combination of nanofluids and pulsation was used to enhance heat transfer in a mini-channel corrugated tube, resulting in a maximum enhancement of 21.8% using distilled water as the medium. When 0.5% Al2O3/DW nanofluids were used as the heat transfer medium, Nunf/Nubf increased by 16% at Re = 1100. A pulsation wave generator was designed and the optimal St for each Re was determined, with lower Re values corresponding to higher optimum St values. The best heat transfer enhancement achieved in this study was 147% at St = 0.034, Re = 747, and A = 3.85.
Article
Thermodynamics
Manojkumar Gudala, Suresh Kumar Govindarajan, Bicheng Yan, Shuyu Sun
Summary: This study proposes an improved mathematical model to investigate the temperature variations and mechanical strain in the Puga geothermal reservoir. It is found that there are low-temperature regions within the fractures, and the number of hydraulic fractures and well patterns significantly influence the rock and fluid properties. The proposed mathematical model can effectively evaluate and predict the changes in the reservoir.
Article
Mechanics
Behzad Mohajer, Anshuman Dey, Ri Li
Summary: The research explores the formation of stagnation lines when two free liquid jets impinge on a planar surface, with a focus on factors such as jet flow conditions, fluid properties, and jet orientation. Experimental observations show that changing fluid characteristics, jet positions, and orientations leads to variations in stagnation lines. A theoretical model based on momentum analysis is utilized to predict the location of stagnation lines, demonstrating good agreement with experimental findings.
Article
Thermodynamics
Mehmet Tahir Erdinc, Arif Emre Aktas, Muhammet Nasif Kuru, Mehmet Bilgili, Orhan Aydin
Summary: This study investigated the thermo-hydraulic characteristics of circular and diamond shaped cross-sections in periodic flow using numerical methods and multi-objective genetic algorithm (MOGA) for optimization. The results showed that compared to circular geometries, the average Nusselt number of diamond shaped geometry increased by 10.11%, while pressure drop and volume decreased by 11.90% and 52.76%, respectively.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Thermodynamics
Ahmed Ramadhan Al-Obaidi
Summary: In this study, through numerical simulations, the flow behavior, pressure drop, and heat transfer enhancement in a corrugated pipe were analyzed. It was found that as the Reynolds number increased, the Nusselt number also increased, and with increased corrugated geometry, the pressure drop, turbulent kinetic energy, and vorticity also increased.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Thermodynamics
Zhigen Wu, Lan Qiu, Changchun Wu, Dan Zhou
Summary: This study focused on a double-pipe heat exchanger with corrugated inner tubes for cooling thermal-hydrolyzed sludge. A numerical model was used to analyze the effects of various parameters on the flow and heat transfer performance of the sludge, recommending an optimal sludge flow rate of 1.2-1.5 m/s for the studied corrugated tubes.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Thermodynamics
Junjun Chen, Leilei Yan, Hongbin Yan, Gongnan Xie
Summary: In this paper, an improved periodic cellular material (XCCH) that combines X-lattice with corrugated honeycomb is proposed. Comparisons with the X-lattice cored plate honeycomb (XCPH) show that the XCCH has higher compressive strength and convective heat transfer characteristics. Experimental and numerical results reveal that the XCCH has higher overall Nusselt number and better heat transfer performance. The introduction of corrugated fins improves turbulent kinetic energy and enhances heat transfer. Additionally, the XCCH has 20% higher compressive strength due to increased moment of inertia and improved energy absorption ability.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Engineering, Multidisciplinary
Ahmed Ramadhan Al-Obaidi, Ali Qubian
Summary: In this study, numerical calculations using CFD code were conducted to investigate the flow field and pressure fluctuations in a centrifugal pump under different outlet impeller diameters. The results provide valuable insights for optimizing pump performance and characteristics.
INTERNATIONAL JOURNAL OF NONLINEAR SCIENCES AND NUMERICAL SIMULATION
(2022)
Article
Thermodynamics
Ahmed Ramadhan Al-Obaidi
Summary: In this study, through numerical simulations, the flow behavior, pressure drop, and heat transfer enhancement in a corrugated pipe were analyzed. It was found that as the Reynolds number increased, the Nusselt number also increased, and with increased corrugated geometry, the pressure drop, turbulent kinetic energy, and vorticity also increased.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Thermodynamics
Ahmed Ramadhan Al-Obaidi, Jassim Alhamid, Hussam Ali Khalaf
Summary: The effects of mixing secondary, spiral, and swirl flows on heat transfer and pressure drop in internal corrugated tubes with varying Reynolds numbers were examined. The results showed that heat transfer enhancement can be attributed to the convective heat transfer transformation and the redevelopment of the boundary layer by pulsation. Different corrugated geometrical configurations were also investigated, and it was found that higher configurations led to increased heat transfer. Using different corrugated geometric configurations resulted in improved performance compared to smooth pipes.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Jassim Alhamid, Ahmed Ramadhan Al-Obaidi, H. Towsyfyan
Summary: This study successfully enhances the thermal performance of heat exchangers through the use of enhanced pipes, with the 4 mm dimple diameter model showing the highest heat transfer enhancement among other designs. The research demonstrates that perforated geometrical parameters can lead to high fluid mixing and flow perturbation between the pipe core region and the walls, improving thermal efficiency.
Article
Thermodynamics
Ahmed Ramadhan Al-Obaidi
Summary: The current investigation numerically evaluates the influence of various twisted tape configurations on heat transfer and thermal performance, with emphasis on the design optimization through Taguchi analysis and computational fluid dynamics numerical methodology. The best design of twisted tape is identified to enhance heat transfer and overall performance.
Article
Thermodynamics
Ahmed Ramadhan Al-Obaidi, Jassim Alhamid
Summary: This investigation used numerical simulation techniques to study the thermo-hydraulic flow behavior, heat transfer enhancement, and overall thermal performance of fluid passing within a corrugated pipe. The results showed that an increase in corrugated configurations led to a greater pressure drop and higher Nusselt number values. The study also developed correlation equations for the friction factor, Nusselt number, and thermal performance factor.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Engineering, Mechanical
Ahmed Ramadhan Al-Obaidi, Jassim Alhamid
Summary: This study investigates the mixed-flow dynamics of axial pumps under five operational conditions, from optimal to the QBEP plus value. In addition, the effects of blade angle on pump performance are examined by considering three angles. The results show that the flow stability of the axial pump deteriorated as the flow decreased, and increasing the blade angle influenced the machine's flow and pressure field characteristics. This study contributes to a more thorough understanding of pump flow dynamics, benefiting researchers and engineers.
IRANIAN JOURNAL OF SCIENCE AND TECHNOLOGY-TRANSACTIONS OF MECHANICAL ENGINEERING
(2023)
Article
Energy & Fuels
Ahmed Ramadhan Al-Obaidi
Summary: The existing numerical research focuses on studying the effects of dimples on the inner wall of heat exchanger pipes. Computational calculations and optimization techniques are used to analyze the influence of various geometrical parameters and improve heat transfer performance. The results show that the use of dimples on the inner pipe surface can enhance heat performance and increase the area of heat transfer. Hydrodynamic analysis, optimization, and improvement of heat transfer performance are necessary for different design applications.
ENERGY SOURCES PART A-RECOVERY UTILIZATION AND ENVIRONMENTAL EFFECTS
(2023)
Article
Engineering, Mechanical
A. R. Al-Obaidi
Summary: In this research, the impact of guide vanes on flow analysis in axial pumps is investigated using unsteady numerical turbulence simulations. The results show that the addition of guide vanes significantly affects the flow field and performance of the pump, leading to improved pump performance and increased pressure, kinetic energy, shear stress, and velocity. This study provides important information and guidance for enhancing and improving the design and operation of axial flow pumps.
EXPERIMENTAL TECHNIQUES
(2023)
Article
Chemistry, Multidisciplinary
Ahmed Ramadhan Al-Obaidi
Summary: Numerical simulation was used to analyze the behavior of a flow field, pressure drop and hydraulic thermal performance. The results showed that the insertion of twisted tape in the pipe increased the pressure difference and flow resistance, resulting in a higher temperature difference. The twisted tape created vortex motion and different radial velocities, altering the behavior of the fluid. The geometric parameters of the twisted tape had an influence on the results, but the temperature difference increased less compared to a smooth pipe.
KOREAN JOURNAL OF CHEMICAL ENGINEERING
(2023)
Article
Acoustics
Ahmed Ramadhan Al-Obaidi
Summary: Condition monitoring in centrifugal pumps is important and the acoustic method is used to detect cavitations. The acoustic technique provides detailed information on cavitation detection under different conditions. Time domain analysis and fast Fourier method are used to analyze signals, which have shown to be effective in predicting future events. The experimental investigation aims to establish a correlation between noise characteristics and cavitation detection in a pump, as well as find a good method for estimating cavitation levels in a pump.
ARCHIVES OF ACOUSTICS
(2023)
