Article
Thermodynamics
Morteza Hangi, Alireza Rahbari, Xiaolin Wang, Wojciech Lipinski
Summary: The study demonstrates that inserting free rotating axial-turbine-types swirl generators (ATTSGs) in a circular tube can significantly enhance convective heat transfer, with a maximum enhancement of around 75%. The analysis of the net torque applied on the ATTSGs and their angular velocity reveals an efficient way to improve heat transfer efficiency.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2022)
Article
Thermodynamics
N. N. M. Zawawi, W. H. Azmi, Z. A. A. Majid, R. A. Rahim, H. M. Ali
Summary: Due to the depletion of conventional energy sources, solar energy is being considered as a viable alternative, especially for water heating systems. This study demonstrates the use of hybrid nanofluids in heating systems to improve the thermal performance of multilayer absorber solar collectors. The SiO2-TiO2 hybrid nanofluids at volume concentrations up to 2.0% were tested and showed significant improvements in temperature difference, efficiency, and fluid temperature in the solar collector.
BUILDING SIMULATION
(2023)
Article
Thermodynamics
B. Singh, W. A. N. W. Mohamed, M. N. F. Hamani, K. Z. N. A. Sofiya
Summary: The research demonstrates that using swirl flows can significantly enhance the power output of a thermoelectric generator module in converting waste heat from a low temperature Polymer Electrolyte Membrane fuel cell into electricity. The swirl strength and cooling modes have a nonlinear impact on power enhancement under different fuel cell power and vehicle drive speeds.
Review
Thermodynamics
Suvanjan Bhattacharyya, Devendra Kumar Vishwakarma, Adithya Srinivasan, Manoj K. Soni, Varun Goel, Mohsen Sharifpur, Mohammad Hossein Ahmadi, Alibek Issakhov, Josua Meyer
Summary: The objective of this article is to study the work carried out in heat transfer augmentation using active and passive techniques. The study reviews research done in various areas such as electrohydrodynamic, magnetic field, corona wind, vortex generators, tape and coil inserts, roughness, and modified duct. It was found that passive methods are more investigated than active methods due to their safe and sound operation along with no additional requirement of power. The results show that duct modification is an effective and efficient way for heat transfer enhancement.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2022)
Article
Thermodynamics
Hussein M. Maghrabie, A. G. Olabi, Enas Taha Sayed, Tabbi Wilberforce, Khaled Elsaid, Mohammad Hossein Doranehgard, Mohammad Ali Abdelkareem
Summary: Nowadays, cooling electronic components is considered a critical issue. This study focuses on fluid flow, heat transfer, and thermal performance to avoid hot spots in electronic devices. It discusses the use of nanofluids in microchannels for cooling electronics, considering the thermophysical properties and future prospects of nanofluids in electronic components.
THERMAL SCIENCE AND ENGINEERING PROGRESS
(2023)
Article
Thermodynamics
Nabeel Abed, Imran Afgan, Andrea Cioncolini, Hector Iacovides, Adel Nasser
Summary: The thermal performance of parabolic trough collectors can be significantly improved by using swirl generator inserts and nanoparticles in the solar receiver, leading to increased energy capture and reduced thermal losses. Testing different strip shapes with and without nanofluids showed that the straight large conical strips with nanofluid had the highest enhancement in Nusselt number, thermal efficiency, and thermal exergy efficiency.
APPLIED THERMAL ENGINEERING
(2022)
Article
Energy & Fuels
Ahmed Elminshawy, Kamal Morad, Nabil A. S. Elminshawy, Yasser Elhenawy
Summary: The study demonstrated that cooling with Al2O3 nanofluid can significantly reduce the temperature of LCPV modules, improve both electrical and thermal efficiency, and enhance power output compared to uncooled modules.
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
(2021)
Review
Thermodynamics
Norhazwani Abd Malek, Siti Ujila Masuri, R. Saidur, Che Nor Aiza Jaafar, Eris Elianddy Supeni, Muhammad Anis Khaliquzzama
Summary: This paper reviews the effect of morphology on heat transfer enhancement in nanofluids containing low-dimensional nanomaterials. The impact of morphology on heat transfer in nanofluids is still unclear. By examining experimental and theoretical studies on the effect of morphology on heat transfer enhancement in nanofluids, a better understanding of heat transfer mechanisms can be achieved.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Thermodynamics
Mohammad Jafari, Amir Farajollahi, Heshmatollah Gazori
Summary: The study reveals that the swirl generator significantly enhances the heat transfer rate while also increasing the pressure drop, especially at lower Reynolds numbers.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2021)
Article
Thermodynamics
Nemat Mashoofi Maleki, Saman Pourahmad
Summary: This study proposes an active method, the electromagnetic vibration method, to enhance heat transfer in a heated copper tube. A stretched wire turbulator with a designed vibrational frequency is installed in the middle of the tube. Different nanofluids are utilized as working fluids and tests are conducted under various conditions. The results demonstrate that the vibrating wire turbulator has a significant impact on the heat transfer rate of the nanofluids.
INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER
(2023)
Article
Thermodynamics
Faizan Ahmed
Summary: The study investigates the use of nanofluids to externally cool a refrigerator's condenser. The experiments show that the use of copper and aluminum nanofluids significantly improves the efficiency of the refrigerator. The refrigerator's performance increases as the volume fraction of the nanofluid increases.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2022)
Article
Engineering, Chemical
Wang Li, Shiliang Dai, Hanqing Wang, Jinping Zhao
Summary: By optimizing the structural parameters and operating conditions of the axial flow cyclone separator, the separation efficiency can be improved, pressure drops reduced, and it is suitable for industrial gas-solid separation applications.
ADVANCED POWDER TECHNOLOGY
(2022)
Review
Energy & Fuels
Olga Arsenyeva, Leonid Tovazhnyanskyy, Petro Kapustenko, Jiri Jaromir Klemes, Petar Sabev Varbanov
Summary: A plate heat exchanger (PHE) is a modern and efficient heat transfer equipment, capable of enhancing heat recuperation and energy efficiency. This paper reviews the construction and exploration developments of PHEs, as well as the methods of heat transfer intensification. The use of inclined corrugations on the surface of PHE plates is a common method to improve performance.
Article
Chemistry, Multidisciplinary
Yun-Seok Choi, Youn-Jea Kim
Summary: The study analyzed the heat transfer performance of a fin-tube heat exchanger using ferrofluid as a coolant under external magnetic fields, observing changes in the thermal boundary layer and formation of vortices that activate thermal diffusion, enhancing heat transfer efficiency.
APPLIED SCIENCES-BASEL
(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
Energy & Fuels
Jefferson Raja Bose, Stephen Manova, Appadurai Anitha Angeline, Lazarus Godson Asirvatham, Sneha Gautam
Summary: A numerical simulation was conducted to study the convective heat transfer coefficient (h(conv)) of Cu-Water and TiO2-Water nanofluids in a circular tube under laminar and turbulent flow conditions. The analysis involved four different concentrations of nanofluids and varying Reynolds numbers. The study found that the enhancements of h(conv) for both nanofluids were higher in turbulent flow compared to laminar flow, and were mainly influenced by the random motion and heat diffusion of the nanoparticles.
Article
Thermodynamics
Sanjaykumar A. Borikar, Dilipkumar A. Borikar, Hitesh Panchal, Erdem Cuce, Ahmet Selim Dalkilic, Ali Jawad Alrubaie, Mustafa Musa Jaber
Summary: The study investigates the role of the condenser and condenser geometry in enhancing the performance of mid-sized refrigerators in the future. Experimental and statistical methods were used to analyze the influence of ambient temperature, condenser geometry, and heat load on refrigerator performance. The evaluations showed a significant increase in coefficient of performance and sub-cooling through improved factor fixation, with the combination of ambient temperature and condenser geometry having the greatest impact. The analysis of variance confirmed the accuracy of the second-order quadratic model used, with a root mean square value of 0.994 and an adjusted root mean square value of 0.954.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2023)
Article
Thermodynamics
Aykut Bacak, Ali Pinarbasi, Ahmet Selim Dalkilic
Summary: This paper develops a validated three-dimensional fluid-structure interaction model to study the oscillation motion, compression power, and mass flow rate of a hermetic reciprocating compressor under different operating conditions. Unlike previous studies, the entire compression cycle is explored, and detailed diagrams are shown.
INTERNATIONAL JOURNAL OF REFRIGERATION
(2023)
Article
Thermodynamics
Tamer Calisir, Andac Batur Colak, Devrim Aydin, Ahmet Selim Dalkilic, Senol Baskaya
Summary: An artificial neural network model is proposed to predict the heat transfer and weight values of a panel radiator based on design parameters. The model shows high accuracy in predicting the heat transfer rate and weight. This study fills a significant gap and potentially contributes to the manufacturing industry.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Nuclear Science & Technology
Alisan Gonul, Andac Batur Colak, Nurullah Kayaci, Abdulkerim Okbaz, Ahmet Selim Dalkilic
Summary: In this study, four different artificial neural network models were used to predict the heat transfer characteristics in a microchannel. The results showed that these models have a high prediction performance and accuracy compared to empirical correlations.
Article
Nuclear Science & Technology
Andac Batur Colak, Hatice Mercan, Ozgen Acikgoz, Ahmet Selim Dalkilic, Somchai Wongwises
Summary: The average flow velocity in heat exchangers is often overlooked and requires further investigation due to its significant impact on overall thermal performance. The use of nanofluids has similar effects to finned tube designs, and it is necessary to evaluate the optimal operating velocity considering heat transfer and pressure drop. However, there is a lack of experimental, parametric, or numerical investigations in this area.
Article
Physics, Multidisciplinary
Tamer Calisir, Andac Batur colak, Devrim Aydin, Ahmet Selim Dalkilic, Senol Baskaya
Summary: In this study, the impacts of different factors on the heat output and total weight of panel radiators have been investigated using a machine learning algorithm. An artificial neural network model with 10 neurons in the hidden layer has been created and trained using numerical data. The accuracy of the model has been validated by comparing the results with computational data and examining various performance parameters.
EUROPEAN PHYSICAL JOURNAL PLUS
(2023)
Article
Thermodynamics
Safak Metin Kirkar, Alisan Gonul, Ali Celen, Ahmet Selim Dalkilic
Summary: This study numerically investigates the use of corrugated surfaces as a passive heat transfer improvement method on straight tubes. Nusselt number, friction factor, and performance evaluation criteria are determined. Sensitivity analyses and multi-objective optimization analyses are performed to maximize heat transfer and minimize pressure drops. The thermal-flow augmentation created by corrugated surfaces in laminar flow conditions is higher than that in turbulent region of smooth tubes. The maximum value of the performance evaluation criteria is 2.48 compared to the use of equivalent smooth and corrugated tubes. Nusselt number and friction factor equations are suggested with deviation bands of +/- 10% and +/- 15% respectively, based on 220 data points.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Thermodynamics
Muhammet Camci, Yakup Karakoyun, Ozgen Acikgoz, Ahmet Selim Dalkilic
Summary: With the increasing demand for energy-efficient air conditioning systems, the research on innovative systems combining displacement ventilation and radiant heating is becoming more relevant. This study discusses the local mixed convection heat transfer coefficients over a radiant heated wall in an experimental room with displacement ventilation provided by a floor level nozzle. The obtained data were analyzed and four correlations were developed for the local mixed convective heat transfer coefficients along the heated wall.
JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY
(2023)
Article
Engineering, Mechanical
Aykut Bacak, Ali Pinarbasi, Ahmet Selim Dalkilic
Summary: The most popular method to determine compressor losses is to generate pressure-volume indication diagrams. Experimental results for a hermetic reciprocating compressor used in household refrigerators operating with R600a were obtained under specific working conditions. The experiments showed that compressor losses increased with decreasing condensation pressure.
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART E-JOURNAL OF PROCESS MECHANICAL ENGINEERING
(2023)
Article
Engineering, Multidisciplinary
Gokberk Yalcin, Semiha Oztuna, Ahmet Selim Dalkilic, Somchai Wongwises
Summary: This experimental study investigated the impact of ZnO particle size on the viscosity of water-based nanofluids. Nanofluid samples with different volume concentrations and ZnO particle sizes were prepared and their viscosity was measured at various temperatures. The study found that the maximum relative viscosity was observed for 1% ZnO (50 to 150 nm) nanofluid, which was 1.35 times that of water. The stability of the samples was evaluated using Zeta potential values, and the correlation for dynamic viscosity showed a high level of accuracy.
ALEXANDRIA ENGINEERING JOURNAL
(2023)
Article
Thermodynamics
Safak Metin Kirkar, Alisan Gonul, Ahmet Selim Dalkilic
Summary: This study investigates the effect of coil diameter on the heat transfer and flow characteristics of single-phase liquid water flowing in corrugated coiled tubes using numerical simulations. The results show that the use of corrugation in coiled tubes significantly enhances the thermal-hydraulic performance, with an improvement of up to 270% compared to smooth straight tubes at Reynolds numbers below 2300.
INTERNATIONAL JOURNAL OF THERMAL SCIENCES
(2023)
Article
Nuclear Science & Technology
Dogan Akgul, Hatice Mercan, Ozgen Acikgoz, Ahmet Selim Dalkilic
Summary: Triple concentric-tube heat exchangers are widely used in various industries due to their superior heat transfer characteristics compared to double tube heat exchangers. They achieve better heat transfer performance by increasing the heat transfer surface area. In addition, advanced surfaces and flow turbulence can enhance heat transfer efficiency. However, further research is needed to fully analyze the heat transfer characteristics of triple enhanced surfaces.
Article
Nuclear Science & Technology
Dogan Akgul, Hatice Mercan, Ozgen Acikgoz, Ahmet Selim Dalkilic
Summary: This study focuses on the heat transfer and hydrodynamic properties of triple concentric-tube heat exchangers. The use of advanced surfaces and nanofluids positively affect heat transfer characteristics. More research is needed on pressure drop features and two-phase flows.
Article
Chemistry, Multidisciplinary
Thi To Nguyen Vo, Dong-In Yu, Ho Seon Ahn
Summary: A practical approach to designing 3D porous materials with new functionalities for oil spill clean-up attracts widespread attention. The carbonized seaweed-coated melamine sponge (CMS) can selectively absorb oil immediately due to its countless pores using capillary-driven force to absorb oil. The microstructure and behaviors of the CMS are thoroughly investigated in relation to the unique porous structure, mechanical stability, wetting response, and in-depth processing of the high-speed visualization experiment to determine its promising abilities. The theoretical models proposed based on quantitative analysis of optically analyzed oil interface phenomena are shown to be a reliable approach for describing volumetric absorption rate and effective CMS thickness. It is expected that this research will hold tremendous potential strategies for environmental remediation.
ADVANCED MATERIALS INTERFACES
(2023)