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
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
Hong-Jin Joo, Hee-Youl Kwak, Minsuk Kong
Summary: The present study experimentally investigates the effect of twisted tape inserts on the thermal performance of an eccentric inlet and outlet heat pipe evacuated-tube solar thermal collector (HP-ESTC). The results show that the addition of twisted tape inserts enhances heat transfer performance by eliminating stagnation flow, reducing flow skewness, and generating rotating flow. A comprehensive performance analysis considering both heat transfer and pressure drop characteristics confirms that using twisted tape inserts can improve overall performance by approximately 7.7%. To assess its applicability for commercial HP-ESTCs, an HP-ESTC containing twisted tape inserts was manufactured and tested outdoors.
Article
Thermodynamics
Yuxiang Hong, Lei Zhao, Yongchun Huang, Qing Li, Jiajie Jiang, Juan Du
Summary: Waste heat recovery technology is crucial for energy conservation and emission reduction, and the efficiency of heat exchangers plays a decisive role in waste heat recovery. In this study, a synergistic thermal enhancement technology was devised using a spiral corrugated tube (SCT) and multiple twisted tapes (TTs) to improve the heat transfer potential of conventional heat exchangers. Numerical investigations showed that fitting multiple TTs into the SCT homogenized flow fields and temperature distributions, and increased heat transfer efficiency. Perforations on the surface of the TTs reduced friction factor without compromising heat transfer efficiency. By simple perforations, the maximum overall thermal performance evaluation index could be enhanced by around 7.9%.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Engineering, Chemical
Daniel Aprile, Samer Al-Banna, Arraventhan Maheswaran, Joshua Paquette, Mohamad Ziad Saghir
Summary: Phase change materials are commonly used for energy storage, with the goals of heat transfer enhancement and heat storage. This study experimentally investigated different configurations for a cylindrical pipe covered with phase change material. Results showed that while heat transfer rates were higher for all designs compared to a reference straight pipe, increased friction factors were also observed. The helical pipe configuration outperformed others in terms of performance evaluation criterion (PEC) due to enhanced Nusselt number despite higher friction factors.
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
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
Ahmed Ramadhan Al-Obaidi, Issa Chaer
Summary: The study focused on analyzing the flow and heat transfer characteristics of water within a straight circular pipe with twisted-tape inserts, revealing that the inserts induced noticeable swirling of the flow and significant improvement in heat transfer performance. The wider twisted-tape inserts showed more prominent swirling effects and higher heat transfer enhancements, although accompanied by increased pressure drop along the pipe.
CASE STUDIES IN THERMAL ENGINEERING
(2021)
Article
Thermodynamics
Changgui Xie, Ibrahim B. Mansir, Ibrahim Mahariq, Pradeep Kumar Singh, Akbar Arsalanloo, Rehman Muhammad Shahzad, Fahd Jarad
Summary: This study experimentally investigates the influence of using twisted tape turbulator and changing the pitch on fluid flow and heat transfer inside a helical tube. The results show that the application of twisted tape can significantly enhance the heat transfer rate, especially with smaller twist pitch.
CASE STUDIES IN THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Jatoth Heeraman, Ravinder Kumar, Prem Kumar Chaurasiya, Hristo Ivanov Beloev, Iliya Krastev Iliev
Summary: This experiment studies the effect of twisted tape inserts on heat transfer and friction factor of liquid in a double pipe heat exchanger. The impact of different dimple configurations (dimple diameter and diameter-to-depth ratio) on heat transfer and friction factor characteristics are analyzed. The performance of twisted tapes with dimples is compared to plain tubes. It is found that the Nusselt number increases with increasing Reynolds number. The optimum Nusselt number is achieved at D/H = 3 for a diameter of 4 mm, while the optimum friction factor is achieved at D/H = 4.5 for the same diameter.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Toygun Dagdevir, Mahmut Uyanik, Veysel Ozceyhan
Summary: Experimental investigation on heat transfer enhancement using various twisted tape inserted tube configurations under turbulent flow conditions. Results show that DTTEs have better heat transfer performance compared to PTTEs, while PTTEs have less friction loss.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2021)
Article
Thermodynamics
Cancan Zhang, Songtao Han, Yuting Wu, Chunyu Zhang, Hang Guo
Summary: This study investigates the forced convection heat transfer performance of low melting point quaternary MSBNFs in circular tubes. The results show that inserting twisted tapes can enhance heat transfer performance and achieve more uniform temperature distribution.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Thermodynamics
Pongjet Promvonge, Sompol Skullong
Summary: The article experimentally studied the improved thermal-hydraulic performance in a constant heat-fluxed tube inserted with V-winglet-attached twin counter-twisted tapes. Results showed that the V-winglet-attached twin counter-twisted tapes considerably increased friction loss and Nusselt number, indicating good thermal-hydraulic performance.
CASE STUDIES IN THERMAL ENGINEERING
(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)
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
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
Thermodynamics
Ahmed Ramadhan Al-Obaidi
Summary: In this research, the effect of different geometrical parameters on the flow field and thermal heat transfer performance of a heat exchanger design were investigated. Computational simulations were used to analyze the hydraulic thermal fluid coupling, and the results were validated with experimental data. The study found that using corrugated tubes improved heat transfer compared to smooth pipes, and optimization of design parameters enhanced heat transfer rate. The findings suggest that corrugated pipes can be an effective passive device to improve heat transfer in pipes.
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
Multidisciplinary Sciences
Kul Pun, Faik Hamad, Tariq Ahmed, Johnson Ugwu, Safa Najim, James Eyers, Gary Lawson, Paul Russell
Summary: The critical design parameter for a separator is the size of oil droplets in the water phase. This study improves the design by investigating the parameters that control droplet size, frequency, and distribution. Experimental work was performed to examine the effects of flow rates and oil layer thickness on these parameters. The findings show that droplet properties are influenced by the interaction between oil flow rate and oil pad thickness, and the distribution of droplet sizes is controlled by oil layer thickness.
Article
Engineering, Chemical
F. A. Hamad, Kul Pun, Basso Alessio, S. A. Najim, P. B. Ganesan, D. Hughes
Summary: The aim of this paper is to develop a low-cost, low-power consumption microbubble generator to improve gas-to-liquid mass transfer. Microbubble aeration is used in aquaculture, dissolved air flotation (DAF), oil refinement, and reducing skin friction on ship hull. Single Venturi and 3 twin-Venturis microbubble generators are manufactured and tested, showing that twin-Venturi generators produce smaller microbubbles with higher dissolved oxygen concentration and narrower size distribution, reducing the probability of bubbles coalescing.
CHEMICAL ENGINEERING SCIENCE
(2023)
Article
Engineering, Mechanical
Lewis Wilke, Faik. A. Hamad
Summary: The main objective of this research is to increase a low water flow rate of 1 l/m up to a minimum of 6 l/m using TapBoost pump, which is developed without mechanical seals to achieve efficient water boosting. The paper presents the design, testing, and development stages of TapBoost pump. TapBoost is a cost-effective solution for improving water flow from weak outlets in domestic settings and can be easily installed on existing or new water mains. The main conclusions are: i) successful design, manufacture, testing, and launch of TapBoost in March 2022, meeting Salamander Pumps' specifications, ii) the pump delivers a boosted water flow rate of 6.75 l/m compared to the original flow rate of 1 l/m without the pump, iii) TapBoost outperforms the leading competitor in the market.
AUSTRALIAN JOURNAL OF MECHANICAL 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)
