Article
Thermodynamics
Aparesh Datta, Santosh Sah, Arindam Majumder, Nirmalendu Biswas, Dipankar Sanyal
Summary: This study discusses the potential of the IMCHS-CR design in improving thermal performance and demonstrates the effectiveness of the design through numerical solutions and optimization methods. The results indicate a significant impact of controlling the relative discharges and passes through the rib pair on thermal performance.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2021)
Article
Thermodynamics
Chunquan Li, Xuebin Li, Hongyan Huang, Yuanhao Zheng
Summary: A new microchannel heat sink with embedded modules with ribs and pin-fins is proposed for efficient microchannel heat dissipation. Strategies such as microchannel cooling within low-temperature co-fired ceramic substrates, embedding modules in the substrate, and creating ribs and pin-fins are employed to enhance heat transfer. The study investigates the effects of relative rib height, relative pin-fin height, and relative number of auxiliary channels on heat transfer performance, temperature uniformity, and pressure drop. The performance of the proposed design is compared to other similar designs, showing significant improvements in heat transfer and temperature uniformity with a slight increase in pressure drop.
APPLIED THERMAL ENGINEERING
(2023)
Article
Thermodynamics
Mohammad Shamsoddini Lori, Kambiz Vafai
Summary: This study conducts a detailed numerical analysis to evaluate the effect of using periodic vertical porous and solid ribs with different geometrical shapes on the fluid flow and heat transfer in a three-dimensional microchannel. The results show that the use of porous ribs leads to higher Nusselt numbers and better Figure of Merit compared to solid ribs.
APPLIED THERMAL ENGINEERING
(2022)
Article
Thermodynamics
Zhenfei Feng, Yongqi Lan, Zhenjun Hu, Siyao Zheng, Yanjuan Zhang, Zuqiang Huang, Jinxin Zhang
Summary: This study introduces a novel interrupted microchannel heat sink with longitudinal vortex generator (LVG) pairs in transverse microchambers. The effects of LVG pairs on thermal-hydraulic performance and entropy generation in the microchannel were analyzed, revealing that certain parameters can lead to optimal performance.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2022)
Article
Materials Science, Multidisciplinary
Xiaobin Hao, Benjian Liu, Yicun Li, Jiwen Zhao, Sen Zhang, Dongyue Wen, Kang Liu, Bing Dai, Jiecai Han, Jiaqi Zhu
Summary: This study proposes a novel heat sink strategy based on a diamond single crystal-polycrystalline hybrid microchannel for directional heat dissipation of hot spots in power integrated circuits. Numerical simulation results show that the distribution of radiator materials in different heat flux regions can significantly improve the overall temperature uniformity. Compared with other heat sinks, the diamond single crystal-polycrystalline hybrid microchannel radiator demonstrates a heat dissipation performance improvement of 61.8% and 16.9% respectively. In high heat flux and large hot spot size conditions, the maximum surface temperature of the hybrid heat sink is significantly lower than the device failure temperature.
DIAMOND AND RELATED MATERIALS
(2023)
Article
Thermodynamics
M. Mohamed Souby, Mohammad Salman, Rajendran Prabakaran, Sung Chul Kim
Summary: Recently, hybrid nanofluids have been proposed to enhance the cooling performance of microchannel heat sinks (MCHSs) and improve heat dissipation in electronic devices. However, there are limited studies comparing the hydrothermal performance and irreversibility characteristics of hybrid nanofluids (HNFs) and water as coolants for MCHSs. This study numerically evaluates the hydrothermal performance and entropy generation of various hybrid nanofluids in an MCHS for cooling a central processing unit (CPU). The results show that increasing the concentration of hybrid nanofluids significantly enhances heat transfer and reduces CPU temperature and thermal resistance but leads to increased pressure drop and pumping power.
CASE STUDIES IN THERMAL ENGINEERING
(2023)
Article
Energy & Fuels
Sadiq Ali, Faraz Ahmad, Kareem Akhtar, Numan Habib, Muhammad Aamir, Khaled Giasin, Ana Vafadar, Danil Yurievich Pimenov
Summary: The study found that adding trefoil ribs to any wall improves heat transfer characteristics but increases friction factor. Pressure drop and heat transfer coefficient show similar trends, with highest values for MC-AWTR, followed by MC-SWTR, and lowest for MC-BWTR. The thermal enhancement factor is highest for MC-SWTR, followed by MC-BWTR, and lowest for MC-AWTR, with an increase with Reynolds number in each case.
Article
Engineering, Civil
Helin Wang, Xueye Chen
Summary: With the use of Koch fractal structure and nanofluid, a new type of microchannel heat sink is developed in this study. Numerical simulations are conducted to investigate the flow and heat transfer properties of TiO2-water nanofluids in microchannels and optimize the structure with Koch fractal baffles. The results show that the Nusselt number (Nu) of nanofluids increases with the increase of Reynolds number (Re) and the flow resistance decreases by 1.79 times.
Article
Chemistry, Physical
Kaijie Lu, Chunju Wang, Changrui Wang, Haidong He, Xueliang Fan, Feng Chen, Fei Qi
Summary: Diamond/copper composites with fin structures were prepared by hot-pressing sintering and their relative density and thermal conductivity were analyzed under different conditions. The results showed that the relative density of the composites decreased with increasing diamond particle size and volume fraction. The composite achieved a maximum thermal conductivity of 564.2 W/m·K at a sintering pressure of 1400 N and a sintering temperature of 900°C with a diamond particle size of 230 μm and a volume fraction of 60%. The heat dissipation experiment showed that the surface temperature of the heat source could be controlled at 59.9°C when the inlet velocity was 0.4 m/s, achieving a cooling of 40.1°C.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Thermodynamics
Yifei Cheng, Xiangyu Luo, Pengfei Wang, Zhehao Yang, Jin Huang, Jiaxin Gu, Wensheng Zhao
Summary: The influence of four geometrical parameters on the performance of microchannel heat sinks was analyzed using orthogonal experimental design and fuzzy grey relational analysis. A novel offset rib structure was proposed to enhance the performance, and the optimal offset rib structure was studied at different Reynolds numbers. The results showed significant improvement in performance at high Reynolds numbers with the optimal offset rib structure.
APPLIED THERMAL ENGINEERING
(2022)
Article
Chemistry, Analytical
Miaolong Cao, Shi Cao, Jincheng Zhao, Jiayi Zhu
Summary: This paper proposes a microchannel heat sink model and investigates the impact of built-in ribs on the flow and heat transfer characteristics. Numerical simulation results show that the rectangular rib plate enhances heat transfer, but the comprehensive evaluation factor decreases with increasing rib length. The angle of the rib plate has little influence on heat transfer, while the thickness variation has the largest impact on the comprehensive evaluation factor. The optimal parameter combination is an angle of 0 degrees, a length of 7.5 mm, and a thickness of 0.2-0.3 mm.
Article
Engineering, Chemical
I. Aguirre, A. Gonzalez, E. Castillo
Summary: This study numerically investigated the effects of vortex generators and changes in pin shape on flow characteristics in microchannel heat sinks. The results showed that the use of vortex generators significantly increased heat transfer rates, but also increased pressure drops in Newtonian fluids, while reducing pumping costs in shear-thinning fluids.
JOURNAL OF THE TAIWAN INSTITUTE OF CHEMICAL ENGINEERS
(2022)
Article
Thermodynamics
Wei Wang, Yong Shuai, Wentao Su, Bingxi Li, Yufei Tan, Bengt Sunden
Summary: The study found that in the interrupted microchannel heat sink with rectangular ribs, heat transfer and flow resistance were mainly strengthened at the sudden converging area and narrow channels, while the secondary flow area did not have a positive effect on heat transfer. The best performance was observed at specific rib width and length ratios.
HEAT TRANSFER RESEARCH
(2021)
Article
Thermodynamics
Zhenfei Feng, Chuanlong Zhou, Fangwen Guo, Jinxin Zhang, Qingyuan Zhang, Zhenzhou Li
Summary: To dissipate heat in high flux microelectronic devices, an original microchannel heat sink with staggered triangular ribs induced vortex flow is designed. The impacts of rib width, height, and length on hydrothermal behavior and entropy generation are numerically analyzed. The results indicate that increasing width and height can improve thermal performance and reduce entropy generation.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
K. Derakhshanpour, R. Kamali, M. Eslami
Summary: The study conducted 3-Dimensional numerical simulations to analyze laminar fluid flow and forced convection heat transfer through novel designs of microchannel heat sinks with cylindrical ribs. Incorporation of cylindrical ribs significantly enhanced heat transfer coefficient and reducing rib pitch had a greater effect on improving hydrothermal performance. Additionally, double-layered microchannels showed higher convection heat transfer coefficient and double-layered-design 1 microchannels performed the best with increased mass flow rate.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2021)
Article
Engineering, Biomedical
Ashkan Vatani, Sam Liao, Aidan J. C. Burrell, Josie Carberry, Marjan Azimi, Ulrich Steinseifer, Jutta Arens, Julio Soria, Vincent Pellegrino, David Kaye, Shaun D. Gregory
Summary: This study aims to numerically investigate the effect of cannula design parameters on local fluid dynamics and thrombosis potential in ECMO drainage cannulas. By comparing the simulated flow dynamics of a control cannula with other designs, it was found that simple geometrical changes can significantly reduce the risk of thrombosis.
Article
Engineering, Chemical
Omer A. Alawi, Haslinda Mohamed Kamar, Omar A. Hussein, A. R. Mallah, Hussein A. Mohammed, Mehdi Khiadani, Ali B. Roomi, S. N. Kazi, Zaher Mundher Yaseen
Summary: This paper investigates the flow and heat transfer over a modulated surface using MWCNTs-TiO2 nanohybrids, exploring the functionalization and morphology analysis of nanomaterials, as well as the thermophysical properties at different weight concentrations to optimize the heat transfer performance. Numerical models are established based on the research findings to predict the average Nusselt number for the nanoparticles' weight concentrations.
Article
Green & Sustainable Science & Technology
K. Farhana, K. Kadirgama, Hussein A. Mohammed, D. Ramasamy, M. Samykano, R. Saidur
Summary: The study shows that using Al2O3 and CNC nanofluids can increase the efficiency of solar collectors, with good to moderate stability performance of the nanofluids. The thermal conductivity of nanofluids increases while viscosity decreases with increasing temperature. Nanofluids have the potential to enhance the efficiency of flat-plate solar collectors.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2021)
Article
Engineering, Biomedical
Marjan Azimi, Sam Liao, Ashkan Vatani, Aidan Burrell, Shaun D. Gregory
Summary: This study numerically investigated the effects of side holes in dual-lumen cannulas on blood flow dynamics during VV-ECMO. Improved cannulas with optimized side hole designs were found to reduce the maximum wall shear stress, potentially reducing the risk of thrombosis and bleeding.
Review
Biotechnology & Applied Microbiology
Parag P. Thakur, Shriram S. Sonawane, Hussein A. Mohammed
Summary: Renewable-energy sources, such as wind and solar power, are being explored to meet the global energy demand. Nanofluids have been proven effective in replacing conventional working fluids in solar collectors, improving their performance. However, stability and agglomeration issues are still major concerns in the application of nanofluids.
CURRENT NANOSCIENCE
(2023)
Article
Energy & Fuels
Mushtaq T. Al-Asadi, Hussein A. Mohammed, Mark C. T. Wilson
Summary: An effective method to enhance heat transfer in mini and micro electronic devices is to use micro-channels with different shapes and vortex generators. Nanofluids, considered to have great potential for heat transfer enhancement, are also a way to improve heat transfer. This article provides a comprehensive review of the research progress on the heat transfer and fluid flow characteristics of nanofluids in different types of micro-channels, both experimentally and numerically. The study found that the optimization of heat transfer enhancement should consider the reduction in pumping power.
Review
Materials Science, Multidisciplinary
Basel Almuallim, W. S. W. Harun, Ihab Jabbar Al Rikabi, Hussein A. Mohammed
Summary: This review presents the principles of designing high thermal conductive polymer nanocomposites and summarizes the factors affecting thermal conductivity. It also explores the potential applications of polymer nanocomposites in AM technologies.
JOURNAL OF MATERIALS SCIENCE
(2022)
Article
Green & Sustainable Science & Technology
Hussein A. Mohammed, Hari B. Vuthaluru, Shaomin Liu
Summary: This article presents a numerical analysis on the thermohydraulic and thermodynamic performance of a parabolic trough solar collector receiver tube equipped with wavy promoters. The results show that the utilization of wavy promoters inside the PTSC's receiver tube can significantly augment the thermal performance, thereby increasing the overall thermal efficiency.
Article
Green & Sustainable Science & Technology
Omer A. Alawi, Haslinda Mohamed Kamar, Ali H. Abdelrazek, A. R. Mallah, Hussein A. Mohammed, Aziz Ibrahim Abdulla, Hamed Alwan Gatea, Mehdi Khiadani, S. N. Kazi, Zaher Mundher Yaseen
Summary: This study focuses on the numerical simulation of a three-dimensional inclined tube-on-absorbing sheet solar collector and investigates the impact of different parameters on its thermal efficiency and performance. The results suggest that using distilled water as the working fluid leads to better heat transfer and energy efficiency. The size and volume concentration of the nanofluid also affect the performance, with nanosheet-shaped CuO nanofluids showing the best characteristics.
SUSTAINABLE ENERGY TECHNOLOGIES AND ASSESSMENTS
(2022)
Article
Engineering, Civil
Ahmad Zaki, Peter Richards, Rajnish Sharma
Summary: This article investigates the effect of turbulent onset flows on building ventilation through wind tunnel experiments and analytical modeling. The results suggest that mean flows can serve as an important indicator for designing ventilation. Unsteady analyses should be considered when building openings face indirect wind streams and when both a windcatcher opening and an opened window are present. Furthermore, the room window plays a crucial role in defining the performance of windcatcher ventilation systems and dominating interior flow behavior.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2022)
Article
Green & Sustainable Science & Technology
G. Kadirgama, Amit Kumar, Madderla Sandhya, L. Samylingam, D. Ramasamy, K. Kadirgama, Hussein A. Mohammed, M. Samykano, R. Saidur
Summary: Friction and wear are the main causes of energy dissipation in automobile engines. This study aims to enhance the tribological behavior and lubricant properties by using graphene nanoplatelets (GNPs) and cellulose nanocrystals (CNCs) as additives. The characterization is done using different techniques such as X-ray diffractometer (XRD) and field emission scanning electron microscope (FESEM). The results show that the graphene:CNC nano lubricant leads to a smoother surface and more uniform dispersion compared to SAE 40.
Article
Energy & Fuels
Mohammed Ahmed, Mohammed Muhana Meteab, Qusay Oglah Salih, Hussein A. Mohammed, Omer A. Alawi
Summary: This study investigates the thermal-physical and rheological properties of hexagonal boron nitride/carbon nanotubes nanoadditives in enhancing the efficiency of a flat plate solar collector with water-based working fluid. The results show that with optimal mass ratio and flow rate, the efficiency of the solar collector can be remarkably improved by up to 87%.
Article
Acoustics
Sung Tyaek Go, Michael J. Kingan, Yan Wu, Rajnish N. Sharma
Summary: This paper investigates the effect of an acoustically rigid shroud on the tonal noise produced by a UAV propeller. Enclosing the propeller with a shroud alters the steady loading on the blades and the time-average rotating pressure field on the shroud's inner surface also contributes significantly to the tonal noise. Computational fluid dynamics simulations were used to study the aerodynamics, and acoustic calculations and measurements were performed to evaluate the noise reduction effect of the shroud. The results show that the shroud decreases the tonal noise below the propeller's rotational plane.
Article
Construction & Building Technology
Ahmad Zaki, Rajnish Sharma
Summary: This paper presents a detailed experimental analysis of ventilation flows in a building with a windcatcher surrounded by building arrays. The study investigates different ventilation characteristics for inline and staggered building arrangements. The results show that the presence of building arrays can significantly reduce the ventilation rate, with the maximum reductions being 30% and 42% for inline and staggered arrays, respectively. The study also highlights the differences in ventilation flow fluctuations for different wind directions.
BUILDING AND ENVIRONMENT
(2023)
Article
Construction & Building Technology
Tao Deng, Stuart Norris, Rajnish N. Sharma
Summary: This paper presents a simplified model to study the effect of sprinkler water spray on stratified stability in tunnel smoke stratification. Numerical simulations were conducted using FDS code to investigate the dragging effects of sprinkler sprays with different K-factors. Experimental data validated the accuracy of the CFD method. The findings indicate that the dragging effect of water spray is dependent on droplet size.
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY
(2023)
