Ratchagaraja Dhairiyasamy | Aksum University (original) (raw)
Papers by Ratchagaraja Dhairiyasamy
This study examines the effects of particle size and heat pipe angle on the thermal effectiveness... more This study examines the effects of particle size and heat pipe angle on the thermal effectiveness of a cylindrical screen mesh heat pipe using silver nanoparticles as the test substance. The experiment investigates three different particle sizes (30nm, 50nm, and 80nm) and four different heat pipe angles (0°, 45°, 60°, and 90°) on the heat transmission characteristics of the heat pipe. The results show that the thermal conductivity of the heat pipe increased with an increase in heat pipe angle for all particle sizes, with the highest thermal conductivity attained at a 90° heat pipe angle. Furthermore, the thermal resistance of the heat pipe decreased as the particle size decreased for all heat pipe angles. The thermal conductivity measurements of the particle sizes - 30, 50, and 80 nm - were 250 W/mK, 200 W/mK, and 150 W/mK, respectively. The heat transfer coefficient values for particle sizes 30nm, 50nm, and 80nm were 5500 W/m2K, 4500 W/m2K, and 3500 W/m2K, respectively. The study also found that the heat transfer coefficient increased with increased heat pipe angle for all particle sizes, with the highest heat transfer coefficient obtained at a 90° heat pipe angle.
Materials Research Express
This study investigates the heat transfer performance and thermo-hydraulic characteristics of nan... more This study investigates the heat transfer performance and thermo-hydraulic characteristics of nanofluids containing graphene nanoparticles in a water and ethylene glycol mixture. Results show that both nanofluid samples, with concentrations of 0.15% and 0.10% by volume, experience increased heat transfer coefficients (h) compared to the base fluid under various operating conditions, with average reductions of approximately 21% and 26%, respectively. Additionally, the nanofluids exhibit higher friction losses and pressure drops compared to the base fluid. The friction factor and head loss increased by 8.7% and 7.7% for the 0.15% concentration sample and 12.7% and 12.4% for the 0.10% concentration sample. These findings indicate that the thermo-hydraulic performance of the nanofluids is unsatisfactory, offering limited advantages over the base fluid. Surprisingly, the sedimentation of nanoparticles in the test section leads to unexpected results. Contrary to typical observations, the ...
This study examines the effects of particle size and heat pipe angle on the thermal effectiveness... more This study examines the effects of particle size and heat pipe angle on the thermal effectiveness of a cylindrical screen mesh heat pipe using silver nanoparticles as the test substance. The experiment investigates three different particle sizes (30nm, 50nm, and 80nm) and four different heat pipe angles (0°, 45°, 60°, and 90°) on the heat transmission characteristics of the heat pipe. The results show that the thermal conductivity of the heat pipe increased with an increase in heat pipe angle for all particle sizes, with the highest thermal conductivity attained at a 90° heat pipe angle. Furthermore, the thermal resistance of the heat pipe decreased as the particle size decreased for all heat pipe angles. The thermal conductivity measurements of the particle sizes - 30, 50, and 80 nm - were 250 W/mK, 200 W/mK, and 150 W/mK, respectively. The heat transfer coefficient values for particle sizes 30nm, 50nm, and 80nm were 5500 W/m2K, 4500 W/m2K, and 3500 W/m2K, respectively. The study a...
Journal of Thermal Analysis and Calorimetry
Energy Sources, Part A: Recovery, Utilization, and Environmental Effects
Scientific Reports
Steel fiber reinforced concrete (SFRC) offers improved toughness, crack resistance, and impact re... more Steel fiber reinforced concrete (SFRC) offers improved toughness, crack resistance, and impact resistance. Nano-silica enhances the strength, durability, and workability of concrete. This study investigated the combined effect of nano-silica and steel microfibers, termed micro-concrete reinforced with steel fibers embedding nano-silica (MRFAIN), on the mechanical properties of concrete. The aim was to determine the influence of different percentages of nano-silica and steel microfibers on fresh state properties, mechanical strength, and mechanical performance of MRFAIN. MRFAIN mixtures were prepared with cement, sand, water, superplasticizer, varying dosages of nano-silica (0–2%), and steel microfibers (0–2% by volume). Mechanical properties evaluated at 28 days included compressive strength, flexural strength, modulus of elasticity, and fracture energy. Incorporating steel microfibers reduced workability but enhanced mechanical properties like strength and ductility. Nano-silica ad...
Inorganic and Nano-Metal Chemistry, Sep 26, 2021
International journal of ambient energy, Jun 7, 2021
Thermal Science, 2016
Orig i nal sci en tific pa per
Journal of Thermal Analysis and Calorimetry
Energy & Environment
The emission of greenhouse gases is widely acknowledged as the primary driver of global warming. ... more The emission of greenhouse gases is widely acknowledged as the primary driver of global warming. The adoption of renewable energy sources is paramount to address the dependence on fossil fuels, which contribute significantly to this issue and account for 84.3% of current energy production. Solar thermal energy stands out as a prominent option, representing 54.1% of the world's solar energy derived from solar collectors. However, solar thermal energy encounters challenge due to the suboptimal thermal properties of the liquids used in these collectors. Incorporating particles into the liquids offers a potential solution to enhance absorption and thermal properties. Nanofluids, formed by reducing solid particles to nanoscale dimensions, provide an avenue for improvement. This study aimed to produce an Ag nanofluid through mechanical exfoliation and assess its impact on radiation absorption compared to a GO nanofluid. Under a simulated power of 1 unit, the Ag nanofluid demonstrated ...
Lecture notes in mechanical engineering, Sep 30, 2022
Inorganic and Nano-Metal Chemistry, 2021
Chemical Engineering and Processing - Process Intensification, 2020
Innovative heat elimination technologies from the radiator are needed for weight reduction in an ... more Innovative heat elimination technologies from the radiator are needed for weight reduction in an automotive vehicle to increase the overall performance. The fluids used nowadays are based on a combination of distilled water (DW) and ethylene glycol (EG), and also using nanofluids for improving heat transfer performance has been increased within the last couple of years. The use of aluminum oxide (Al 2 O 3) doped with unmilled silicon carbide (SiC UM) nanoparticles and milled Silicon carbide (SiC M) nanoparticles dispersed in DW and EG at 50:50 volumetric proportions experimented in this work. The focus for the important characterization of the nf which includes thermophysical properties is elaborated in this paper. The outcomes showed an optimum improvement regarding the overall thermal performance of 28.34 % making use of Al 2 O 3 doped with milled Silicon carbide (SiC M) at a volume concentration of 0.8 %. This might be due to the size reduction of SiC nanoparticles by the milling process involved in this experiment.
Powder Technology, 2020
The demand for the materials required for manufacturing automotive vehicles is increasing due to ... more The demand for the materials required for manufacturing automotive vehicles is increasing due to the increased production of vehicles in the automotive industry. To satisfy these demands, researchers are focusing to reduce the overall weight of the vehicle by finding alternate solutions to maintain the same efficiency. In this experimental and statistical investigation, Silicon carbide (SiC) nanofluids of different sizes are analyzed to enhance the heat transfer properties of an automotive radiator so that the size of the radiator can be reduced. Results showed that low sized nanoparticles of 24 nm have higher heat transfer properties than large-sized nanoparticles of 110 nm. The settling velocity of 2.075 is obtained for 24 nm-SiC at a 3% volume concentration by using Response Surface Methodology. The higher Brownian velocity of 9.453 was obtained by using 24 nm-SiC at a 3% volume concentration proving that low sized nanoparticles have a high impact than large-sized nanoparticles. It is concluded that utilizing lower sized nanoparticles with the base fluid will enhance heat transfer and can reduce the size of radiators compared with the conventional coolants.
Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2019
In this paper, the heat transfer coefficient and the heat transfer rate of a heat exchanger is ev... more In this paper, the heat transfer coefficient and the heat transfer rate of a heat exchanger is evaluated by using nanofluids. The silicon carbide nanoparticles, milled and sonificated as nanofluids with volume fractions of 0.01499(%) and 0.01399(%) are used. The heat transfer characteristics of SiC(P)/water, SiC(M)/water, SiC(P)/EG, and SiC(M)/EG are measured in a concentric tube heat exchanger under laminar flow condition. The consequence of nanoparticle physiognomies and Reynolds number, on the heat transfer characteristics are evaluated. It has been found that the addition of milled nanoparticle in the base fluids enhances the heat transfer characteristics rather than the normal nanoparticle. The experimental results shows that the heat transfer coefficient rate of SiC(M) is higher than that of SiC(P) in both the case of water and EG. Further the Reynolds number and Nusselt number for SiC (M) was found higher than SiC (P), which is essential for heat transfer flow.
This study examines the effects of particle size and heat pipe angle on the thermal effectiveness... more This study examines the effects of particle size and heat pipe angle on the thermal effectiveness of a cylindrical screen mesh heat pipe using silver nanoparticles as the test substance. The experiment investigates three different particle sizes (30nm, 50nm, and 80nm) and four different heat pipe angles (0°, 45°, 60°, and 90°) on the heat transmission characteristics of the heat pipe. The results show that the thermal conductivity of the heat pipe increased with an increase in heat pipe angle for all particle sizes, with the highest thermal conductivity attained at a 90° heat pipe angle. Furthermore, the thermal resistance of the heat pipe decreased as the particle size decreased for all heat pipe angles. The thermal conductivity measurements of the particle sizes - 30, 50, and 80 nm - were 250 W/mK, 200 W/mK, and 150 W/mK, respectively. The heat transfer coefficient values for particle sizes 30nm, 50nm, and 80nm were 5500 W/m2K, 4500 W/m2K, and 3500 W/m2K, respectively. The study also found that the heat transfer coefficient increased with increased heat pipe angle for all particle sizes, with the highest heat transfer coefficient obtained at a 90° heat pipe angle.
Materials Research Express
This study investigates the heat transfer performance and thermo-hydraulic characteristics of nan... more This study investigates the heat transfer performance and thermo-hydraulic characteristics of nanofluids containing graphene nanoparticles in a water and ethylene glycol mixture. Results show that both nanofluid samples, with concentrations of 0.15% and 0.10% by volume, experience increased heat transfer coefficients (h) compared to the base fluid under various operating conditions, with average reductions of approximately 21% and 26%, respectively. Additionally, the nanofluids exhibit higher friction losses and pressure drops compared to the base fluid. The friction factor and head loss increased by 8.7% and 7.7% for the 0.15% concentration sample and 12.7% and 12.4% for the 0.10% concentration sample. These findings indicate that the thermo-hydraulic performance of the nanofluids is unsatisfactory, offering limited advantages over the base fluid. Surprisingly, the sedimentation of nanoparticles in the test section leads to unexpected results. Contrary to typical observations, the ...
This study examines the effects of particle size and heat pipe angle on the thermal effectiveness... more This study examines the effects of particle size and heat pipe angle on the thermal effectiveness of a cylindrical screen mesh heat pipe using silver nanoparticles as the test substance. The experiment investigates three different particle sizes (30nm, 50nm, and 80nm) and four different heat pipe angles (0°, 45°, 60°, and 90°) on the heat transmission characteristics of the heat pipe. The results show that the thermal conductivity of the heat pipe increased with an increase in heat pipe angle for all particle sizes, with the highest thermal conductivity attained at a 90° heat pipe angle. Furthermore, the thermal resistance of the heat pipe decreased as the particle size decreased for all heat pipe angles. The thermal conductivity measurements of the particle sizes - 30, 50, and 80 nm - were 250 W/mK, 200 W/mK, and 150 W/mK, respectively. The heat transfer coefficient values for particle sizes 30nm, 50nm, and 80nm were 5500 W/m2K, 4500 W/m2K, and 3500 W/m2K, respectively. The study a...
Journal of Thermal Analysis and Calorimetry
Energy Sources, Part A: Recovery, Utilization, and Environmental Effects
Scientific Reports
Steel fiber reinforced concrete (SFRC) offers improved toughness, crack resistance, and impact re... more Steel fiber reinforced concrete (SFRC) offers improved toughness, crack resistance, and impact resistance. Nano-silica enhances the strength, durability, and workability of concrete. This study investigated the combined effect of nano-silica and steel microfibers, termed micro-concrete reinforced with steel fibers embedding nano-silica (MRFAIN), on the mechanical properties of concrete. The aim was to determine the influence of different percentages of nano-silica and steel microfibers on fresh state properties, mechanical strength, and mechanical performance of MRFAIN. MRFAIN mixtures were prepared with cement, sand, water, superplasticizer, varying dosages of nano-silica (0–2%), and steel microfibers (0–2% by volume). Mechanical properties evaluated at 28 days included compressive strength, flexural strength, modulus of elasticity, and fracture energy. Incorporating steel microfibers reduced workability but enhanced mechanical properties like strength and ductility. Nano-silica ad...
Inorganic and Nano-Metal Chemistry, Sep 26, 2021
International journal of ambient energy, Jun 7, 2021
Thermal Science, 2016
Orig i nal sci en tific pa per
Journal of Thermal Analysis and Calorimetry
Energy & Environment
The emission of greenhouse gases is widely acknowledged as the primary driver of global warming. ... more The emission of greenhouse gases is widely acknowledged as the primary driver of global warming. The adoption of renewable energy sources is paramount to address the dependence on fossil fuels, which contribute significantly to this issue and account for 84.3% of current energy production. Solar thermal energy stands out as a prominent option, representing 54.1% of the world's solar energy derived from solar collectors. However, solar thermal energy encounters challenge due to the suboptimal thermal properties of the liquids used in these collectors. Incorporating particles into the liquids offers a potential solution to enhance absorption and thermal properties. Nanofluids, formed by reducing solid particles to nanoscale dimensions, provide an avenue for improvement. This study aimed to produce an Ag nanofluid through mechanical exfoliation and assess its impact on radiation absorption compared to a GO nanofluid. Under a simulated power of 1 unit, the Ag nanofluid demonstrated ...
Lecture notes in mechanical engineering, Sep 30, 2022
Inorganic and Nano-Metal Chemistry, 2021
Chemical Engineering and Processing - Process Intensification, 2020
Innovative heat elimination technologies from the radiator are needed for weight reduction in an ... more Innovative heat elimination technologies from the radiator are needed for weight reduction in an automotive vehicle to increase the overall performance. The fluids used nowadays are based on a combination of distilled water (DW) and ethylene glycol (EG), and also using nanofluids for improving heat transfer performance has been increased within the last couple of years. The use of aluminum oxide (Al 2 O 3) doped with unmilled silicon carbide (SiC UM) nanoparticles and milled Silicon carbide (SiC M) nanoparticles dispersed in DW and EG at 50:50 volumetric proportions experimented in this work. The focus for the important characterization of the nf which includes thermophysical properties is elaborated in this paper. The outcomes showed an optimum improvement regarding the overall thermal performance of 28.34 % making use of Al 2 O 3 doped with milled Silicon carbide (SiC M) at a volume concentration of 0.8 %. This might be due to the size reduction of SiC nanoparticles by the milling process involved in this experiment.
Powder Technology, 2020
The demand for the materials required for manufacturing automotive vehicles is increasing due to ... more The demand for the materials required for manufacturing automotive vehicles is increasing due to the increased production of vehicles in the automotive industry. To satisfy these demands, researchers are focusing to reduce the overall weight of the vehicle by finding alternate solutions to maintain the same efficiency. In this experimental and statistical investigation, Silicon carbide (SiC) nanofluids of different sizes are analyzed to enhance the heat transfer properties of an automotive radiator so that the size of the radiator can be reduced. Results showed that low sized nanoparticles of 24 nm have higher heat transfer properties than large-sized nanoparticles of 110 nm. The settling velocity of 2.075 is obtained for 24 nm-SiC at a 3% volume concentration by using Response Surface Methodology. The higher Brownian velocity of 9.453 was obtained by using 24 nm-SiC at a 3% volume concentration proving that low sized nanoparticles have a high impact than large-sized nanoparticles. It is concluded that utilizing lower sized nanoparticles with the base fluid will enhance heat transfer and can reduce the size of radiators compared with the conventional coolants.
Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2019
In this paper, the heat transfer coefficient and the heat transfer rate of a heat exchanger is ev... more In this paper, the heat transfer coefficient and the heat transfer rate of a heat exchanger is evaluated by using nanofluids. The silicon carbide nanoparticles, milled and sonificated as nanofluids with volume fractions of 0.01499(%) and 0.01399(%) are used. The heat transfer characteristics of SiC(P)/water, SiC(M)/water, SiC(P)/EG, and SiC(M)/EG are measured in a concentric tube heat exchanger under laminar flow condition. The consequence of nanoparticle physiognomies and Reynolds number, on the heat transfer characteristics are evaluated. It has been found that the addition of milled nanoparticle in the base fluids enhances the heat transfer characteristics rather than the normal nanoparticle. The experimental results shows that the heat transfer coefficient rate of SiC(M) is higher than that of SiC(P) in both the case of water and EG. Further the Reynolds number and Nusselt number for SiC (M) was found higher than SiC (P), which is essential for heat transfer flow.