This document discusses using graphene silicone grease to improve heat dissipation for an Intel Core i5 processor. Graphene nanoplatelets were functionalized with carboxyl groups and dispersed in silicone grease using high-energy ball milling. Testing showed the graphene was well-dispersed in the grease and increased its thermal conductivity by up to 234%. When used between the processor and heatsink, the graphene grease reduced the processor's saturation temperature by 4°C compared to plain silicone grease. The graphene grease improved heat transfer for the processor.
Experimental Investigation of Graphene coated Al cuboid crammed with PCM`s fo...IRJET Journal
1. Researchers developed a composite cuboid made of aluminum with its top surface coated with graphene to increase heat absorption. The hollow interior was filled with paraffin wax pellets for latent heat storage.
2. Experiments tested the cuboid with and without the graphene coating and wax pellets. With both, the cuboid reached a maximum temperature of 105°C after 80 minutes and took 148 minutes to cool to room temperature, absorbing and releasing heat for a longer period than the non-coated aluminum box.
3. Scanning electron microscope images of the graphene-coated surface showed spherical structures of varying grain size, with some areas of larger lumps and other areas of smaller grain structures with less agglomer
Recent advances in semiconductor technology show the improvement of fabrication on
electronics appliances in terms of performance, power density and even the size. This great achievement
however led to some major problems on thermal and heat distribution of the electronic devices. This
thermal problem could reduce the efficiency and reliability of the electronic devices. In order to minimize
this thermal problem, an optimal cooling techniques need to be applied during the operation. There are
various cooling techniques have been used and one of them is passive pin fin heat sink approach. This
paper focuses on inline pin fin heat sink, which use copper material with different shapes of pin fin and a
constant 5.5W heat sources. The simulation model has been formulated using COMSOL Multiphysics
software to stimulate the pin fin design, study the thermal distribution and the maximum heat profile.
1) Carbon foam was produced with 2-8% aluminum powder added to improve thermal and mechanical properties. During carbonization, aluminum reacted with carbon to form Al4C3 and AlN, increasing conductivity and strength.
2) Samples with 6% aluminum showed a density of 0.5-0.58 g/cm3, porosity of 64-68%, conductivity of 0.043-0.385 W/mK, and compressive strength of 17-32 MPa.
3) Carbon foam with 8% aluminum self-destructed after 2 weeks due to formation of Al4C3 and Al(OH)3 from reaction with atmospheric moisture, starting from the core and proceeding out
Experimental Investigation on Thermal Properties of Bagasse Fly Ash Reinforce...IRJET Journal
This document experimentally investigates the thermal properties of epoxy composites reinforced with bagasse fly ash at different volume fractions. Bagasse fly ash is an industrial waste obtained from sugar cane bagasse combustion. Epoxy composites were fabricated with 0-50% bagasse fly ash by volume. Thermal conductivity, specific heat capacity, thermal diffusivity, and coefficient of thermal expansion were experimentally determined. Results showed that thermal properties generally increased with higher bagasse fly ash content, enhancing the thermal insulation capabilities of the composites. Finite element analysis was also conducted to model temperature distribution across the composites.
CHARACTERIZATION AND EMISSION ANALYSIS OF PREMIXED AND PREHEATED POROUS RADIA...BIBHUTI BHUSAN SAMANTARAY
This document summarizes an experimental study on the characterization and emission analysis of premixed and preheated porous radiant burners during LPG combustion. Experiments were conducted on 13 different burners made of brass and cast iron with varying geometric parameters like diameter, thickness, pore size, number of pores, and pore distribution. The maximum thermal efficiency obtained was 64.59% for a cast iron burner with the largest diameter and pore distribution. Material, pore geometry, and firing rate significantly affected thermal efficiency and emissions. Burner material, precise pore design, and optimal firing rate are important to improve efficiency while meeting emission standards.
Numerical Model and Experimental Validation of the Hydrodynamics in an Indust...IJERA Editor
This paper describes a development of a numerical model and experimental validation of the hydrodynamics in industrial-scale sewage sludge bubbling fluidized bed incinerator. The numerical model and simulations are performed using commercial CFD software package ANSYS Fluent 14.5. The complex geometry of the developed numerical model represents the actual industrial-scale bubbling fluidized bed combustor. The gassolid flow behaviour inside the bed was described using the Eulerian-Eulerian multiphase model. The momentum exchange coefficients between the gas phase and solid particles were described by the Syamlal and O’Brien drag model equations. The CFD transient simulations were run for 350 seconds at the optimum operating conditions of the used fluidized bed with bed temperature of 850°C. The experiments were carried out using quartz sand with three different particle sizes having a diameters ranging from 0.5 mm to 1.5 mm and a density of 2650 kg/m³. The industrial-scale furnace was filled with bed material to a bed height of 0.85 m. The same operating parameters have been applied for both experimental and numerical studies. The hydrodynamics of the gas-solid industrial-scale bubbling fluidized bed at operating conditions are investigated in the CFD numerical model and simulations of this three-dimensional (3D) complex geometry. To estimate the prediction quality of the simulations based on the developed numerical model, the minimum fluidization gas velocity and pressure drop results obtained from the CFD simulations are validated with the experimental measurements. The generated simulation results of the pressure drop and minimum fluidization gas velocity of the industrial-scale sewage sludge incinerator based the Eulerian-Eulerian method and Syamlal and O’Brien drag model are in good agreement with the experimental measured data.
Enhanced thermal conductivity of epoxy matrix composites filled with boron ni...IAEME Publication
This document summarizes research on enhancing the thermal conductivity of epoxy composites by adding boron nitride (BN) microparticles. Epoxy composites containing 0-11.3% BN by volume were prepared and their thermal conductivities were measured experimentally. Numerical simulations using ANSYS found the effective thermal conductivity increased by 27.82% for 11.3% BN and 440% for 30% BN, compared to neat epoxy. The results showed BN particles exhibited a percolation behavior, with a sudden jump in thermal conductivity occurring at 20% BN volume.
Enhanced thermal conductivity of epoxy matrix composites filled with boron ni...IAEME Publication
This document summarizes research on enhancing the thermal conductivity of epoxy matrix composites by filling them with boron nitride (BN) particles. The researchers prepared epoxy composites with BN content ranging from 0-11.3% by volume and measured their thermal conductivities experimentally. They also used finite element analysis to model heat transfer in the composites and validate the simulated effective thermal conductivities. Their results showed that an 11.3% BN filling increased thermal conductivity by 27.82% while a 30% filling increased it by 440%, demonstrating BN's ability to significantly improve an epoxy matrix's heat dissipation capabilities.
Experimental Investigation of Graphene coated Al cuboid crammed with PCM`s fo...IRJET Journal
1. Researchers developed a composite cuboid made of aluminum with its top surface coated with graphene to increase heat absorption. The hollow interior was filled with paraffin wax pellets for latent heat storage.
2. Experiments tested the cuboid with and without the graphene coating and wax pellets. With both, the cuboid reached a maximum temperature of 105°C after 80 minutes and took 148 minutes to cool to room temperature, absorbing and releasing heat for a longer period than the non-coated aluminum box.
3. Scanning electron microscope images of the graphene-coated surface showed spherical structures of varying grain size, with some areas of larger lumps and other areas of smaller grain structures with less agglomer
Recent advances in semiconductor technology show the improvement of fabrication on
electronics appliances in terms of performance, power density and even the size. This great achievement
however led to some major problems on thermal and heat distribution of the electronic devices. This
thermal problem could reduce the efficiency and reliability of the electronic devices. In order to minimize
this thermal problem, an optimal cooling techniques need to be applied during the operation. There are
various cooling techniques have been used and one of them is passive pin fin heat sink approach. This
paper focuses on inline pin fin heat sink, which use copper material with different shapes of pin fin and a
constant 5.5W heat sources. The simulation model has been formulated using COMSOL Multiphysics
software to stimulate the pin fin design, study the thermal distribution and the maximum heat profile.
1) Carbon foam was produced with 2-8% aluminum powder added to improve thermal and mechanical properties. During carbonization, aluminum reacted with carbon to form Al4C3 and AlN, increasing conductivity and strength.
2) Samples with 6% aluminum showed a density of 0.5-0.58 g/cm3, porosity of 64-68%, conductivity of 0.043-0.385 W/mK, and compressive strength of 17-32 MPa.
3) Carbon foam with 8% aluminum self-destructed after 2 weeks due to formation of Al4C3 and Al(OH)3 from reaction with atmospheric moisture, starting from the core and proceeding out
Experimental Investigation on Thermal Properties of Bagasse Fly Ash Reinforce...IRJET Journal
This document experimentally investigates the thermal properties of epoxy composites reinforced with bagasse fly ash at different volume fractions. Bagasse fly ash is an industrial waste obtained from sugar cane bagasse combustion. Epoxy composites were fabricated with 0-50% bagasse fly ash by volume. Thermal conductivity, specific heat capacity, thermal diffusivity, and coefficient of thermal expansion were experimentally determined. Results showed that thermal properties generally increased with higher bagasse fly ash content, enhancing the thermal insulation capabilities of the composites. Finite element analysis was also conducted to model temperature distribution across the composites.
CHARACTERIZATION AND EMISSION ANALYSIS OF PREMIXED AND PREHEATED POROUS RADIA...BIBHUTI BHUSAN SAMANTARAY
This document summarizes an experimental study on the characterization and emission analysis of premixed and preheated porous radiant burners during LPG combustion. Experiments were conducted on 13 different burners made of brass and cast iron with varying geometric parameters like diameter, thickness, pore size, number of pores, and pore distribution. The maximum thermal efficiency obtained was 64.59% for a cast iron burner with the largest diameter and pore distribution. Material, pore geometry, and firing rate significantly affected thermal efficiency and emissions. Burner material, precise pore design, and optimal firing rate are important to improve efficiency while meeting emission standards.
Numerical Model and Experimental Validation of the Hydrodynamics in an Indust...IJERA Editor
This paper describes a development of a numerical model and experimental validation of the hydrodynamics in industrial-scale sewage sludge bubbling fluidized bed incinerator. The numerical model and simulations are performed using commercial CFD software package ANSYS Fluent 14.5. The complex geometry of the developed numerical model represents the actual industrial-scale bubbling fluidized bed combustor. The gassolid flow behaviour inside the bed was described using the Eulerian-Eulerian multiphase model. The momentum exchange coefficients between the gas phase and solid particles were described by the Syamlal and O’Brien drag model equations. The CFD transient simulations were run for 350 seconds at the optimum operating conditions of the used fluidized bed with bed temperature of 850°C. The experiments were carried out using quartz sand with three different particle sizes having a diameters ranging from 0.5 mm to 1.5 mm and a density of 2650 kg/m³. The industrial-scale furnace was filled with bed material to a bed height of 0.85 m. The same operating parameters have been applied for both experimental and numerical studies. The hydrodynamics of the gas-solid industrial-scale bubbling fluidized bed at operating conditions are investigated in the CFD numerical model and simulations of this three-dimensional (3D) complex geometry. To estimate the prediction quality of the simulations based on the developed numerical model, the minimum fluidization gas velocity and pressure drop results obtained from the CFD simulations are validated with the experimental measurements. The generated simulation results of the pressure drop and minimum fluidization gas velocity of the industrial-scale sewage sludge incinerator based the Eulerian-Eulerian method and Syamlal and O’Brien drag model are in good agreement with the experimental measured data.
Enhanced thermal conductivity of epoxy matrix composites filled with boron ni...IAEME Publication
This document summarizes research on enhancing the thermal conductivity of epoxy composites by adding boron nitride (BN) microparticles. Epoxy composites containing 0-11.3% BN by volume were prepared and their thermal conductivities were measured experimentally. Numerical simulations using ANSYS found the effective thermal conductivity increased by 27.82% for 11.3% BN and 440% for 30% BN, compared to neat epoxy. The results showed BN particles exhibited a percolation behavior, with a sudden jump in thermal conductivity occurring at 20% BN volume.
Enhanced thermal conductivity of epoxy matrix composites filled with boron ni...IAEME Publication
This document summarizes research on enhancing the thermal conductivity of epoxy matrix composites by filling them with boron nitride (BN) particles. The researchers prepared epoxy composites with BN content ranging from 0-11.3% by volume and measured their thermal conductivities experimentally. They also used finite element analysis to model heat transfer in the composites and validate the simulated effective thermal conductivities. Their results showed that an 11.3% BN filling increased thermal conductivity by 27.82% while a 30% filling increased it by 440%, demonstrating BN's ability to significantly improve an epoxy matrix's heat dissipation capabilities.
IRJET- Literature Review on Energy Storage MaterialsIRJET Journal
The document summarizes research on phase change materials (PCMs) that can store and release large amounts of thermal energy during melting and freezing. It reviews several studies on developing PCMs for thermal energy storage applications in construction. Some key findings discussed include nanoencapsulating organic PCMs like n-octadecane to improve stability and thermal properties; adding micro-PCM and TiO2 nanoparticles to polyvinyl chloride films to control temperature ranges in buildings; incorporating fatty acid-based nano-PCM and graphite sheets into gypsum boards to significantly reduce energy demands; and using materials like polyethylene glycol and nanoparticles to create nanofibers with improved thermal conductivity for storing thermal energy in construction.
Experimental Heat Transfer Analysis of Different PCM Material used in Concret...Swapnil Shahade
This document summarizes an experimental study on heat transfer of different phase change materials (PCMs) used in concrete walls. Paraffin wax and beewax were used as PCMs integrated into concrete blocks. A testing setup with temperature sensors measured the surface and internal temperatures of the concrete blocks and PCMs when exposed to sunlight over several hours. Results showed that the average temperature of paraffin wax-integrated concrete was reduced by 5.98°C compared to only 2.9°C for hollow concrete, indicating paraffin wax more effectively stores thermal energy through its phase change process. The study concludes PCMs like paraffin wax can significantly reduce wall temperatures and energy required for building heating and
Development of advanced materials and manufacturing technologies for high eff...naveenchandra103
This document discusses the development of advanced materials and manufacturing technologies for high efficiency gas turbines. It focuses on turbine blades, which are subjected to extreme heat, corrosion, and centrifugal forces. Nickel-based superalloys are commonly used for turbine blades and discs due to their high strength at high temperatures. The document also discusses research into single crystal turbine blades and thermal barrier coatings to allow higher turbine inlet temperatures, improving engine efficiency.
Energy Recovery of Biomass: Study Comparative Experimental of Fixed Bed Combu...AJSERJournal
Energy recovery of biomass is considered as an important source of energy. The main objective of this
experimental study is to validate the use of olive pomace as an alternative fuel using a comparison with that of wood.
Therefore a biomass boiler was designed and fabricated based on two separate compartments. Experiments tests
showed that the average temperature in the boiler is around 700 °C for pomace and 670 °C for sawdust with variations
up to 100 °C depending on fuel supply. In this study, the temperature distributions within of the combustion chamber of
pomace and sawdust of wood are presented, evaluated and analyzed. The removal of combustion gas is produced via a
probe of a multi-gas analyzer placed at the smoke outlet. Analysis of combustion gases such as NO, CO, CO2 and O2 are
illustrated and discussed. The results showed that low values of nitrogen oxides NOx have been observed, well below
standard limit values and absence SOx
Energy Recovery of Biomass: Study Comparative Experimental of Fixed Bed Combu...AJSERJournal
Energy recovery of biomass is considered as an important source of energy. The main objective of this
experimental study is to validate the use of olive pomace as an alternative fuel using a comparison with that of wood.
Therefore a biomass boiler was designed and fabricated based on two separate compartments. Experiments tests
showed that the average temperature in the boiler is around 700 °C for pomace and 670 °C for sawdust with variations
up to 100 °C depending on fuel supply. In this study, the temperature distributions within of the combustion chamber of
pomace and sawdust of wood are presented, evaluated and analyzed. The removal of combustion gas is produced via a
probe of a multi-gas analyzer placed at the smoke outlet. Analysis of combustion gases such as NO, CO, CO2 and O2 are
illustrated and discussed. The results showed that low values of nitrogen oxides NOx have been observed, well below
standard limit values and absence SOx.
Experimentation on heat pipe and cfd analysis for performance enhancementeSAT Journals
Abstract
Heat Pipe is a heat transfer device used in many applications and it is very similar in some respects to the thermosyphon. Since there were several limitations of thermosyphon, heat pipe was developed. The idea of the heat pipe was first suggested in 1942, since then over a several decades the serious development of a heat pipe took place. Heat pipe mainly consists of three regions viz. evaporator, adiabatic and condenser section. The heat pipe differs from the thermosyphon by virtue of its ability to transport heat against gravity by an evaporation-condensation cycle. This research work includes experimentation on available heat pipe, development of CFD model and its validation with experimental results using CFD Tool. The results obtained by CFD are in good agreement with an experimental results. Since the heat pipe is used for transferring the heat, this research work focuses on increasing the heat transfer by modified model, modifications in terms of increased surface area, is proposed. From CFD analysis it was found that the proposed modified heat pipe shows enhancement in performance in terms of heat transfer rate by 19% when it is simulated for without heat sink case and 45% while with heat sink case, compared to conventional heat pipe. The mixture multiphase model from CFD too is used for simulation of heat pipe.
Experimentation on heat pipe and cfd analysis for performance enhancementeSAT Journals
Abstract
Heat Pipe is a heat transfer device used in many applications and it is very similar in some respects to the thermosyphon. Since there were several limitations of thermosyphon, heat pipe was developed. The idea of the heat pipe was first suggested in 1942, since then over a several decades the serious development of a heat pipe took place. Heat pipe mainly consists of three regions viz. evaporator, adiabatic and condenser section. The heat pipe differs from the thermosyphon by virtue of its ability to transport heat against gravity by an evaporation-condensation cycle. This research work includes experimentation on available heat pipe, development of CFD model and its validation with experimental results using CFD Tool. The results obtained by CFD are in good agreement with an experimental results. Since the heat pipe is used for transferring the heat, this research work focuses on increasing the heat transfer by modified model, modifications in terms of increased surface area, is proposed. From CFD analysis it was found that the proposed modified heat pipe shows enhancement in performance in terms of heat transfer rate by 19% when it is simulated for without heat sink case and 45% while with heat sink case, compared to conventional heat pipe. The mixture multiphase model from CFD too is used for simulation of heat pipe.
Effect of Separator Thickness and Preheating Temperature on the Development o...CrimsonPublishersRDMS
Effect of Separator Thickness and Preheating Temperature on the Development of Microwave Processed Composite Clads by Sarbjeet Kaushal* in Crimson Publishers: Peer Reviewed Material Science Journals
The use of Cooking Gas as Refrigerant in a Domestic RefrigeratorIJERA Editor
The application of cooking gas refrigerants in refrigeration system is considered to be a potential way to improve
energy efficiency and to encourage the use of environment-friendly refrigerants. Refrigeration operation has
been met with many challenges as it deals with environmental impact, how it affects humans and how it
contributes to the society in general. Domestic refrigerators annually consume several metric tons of traditional
refrigerants, which contribute to very high Ozone Depletion Potential (ODP) and Global Warming Potential
(GWP). The experiment conducted employs the use of two closely linked refrigerants, R600a (Isobutene) and
cooking gas which is varied in an ideal refrigerant mixture of 150 g of refrigerant and 15 ml of lubricating oil (to
a rating of 40 wt % expected in the compressor). The Laboratory process involved the use of Gas
Chromatography machine to ascertain the values of the mole ratio, molecular weight and critical temperatures.
Prode properties and Refprop softwares were used to ascertain other refrigerant properties of the mixture. The
results indicated that the mixture of R600a with lubricant confirm mineral oil as being the most appropriate for
the operation. The experimental results indicated that the refrigeration system with cooking gas refrigerant
worked normally and was found to attain high freezing capacity and a COP value of 2.159. It is established that
cooking gas is a viable alternative refrigerant to replace R600a in domestic refrigerators. Hence, its application
in refrigerating systems measures up to the current trend on environmental regulations with hydrocarbon
refrigerants
EXPERIMENTAL INVESTIGATION ON THERMAL PERFORMANCE OF POROUS RADIANT BURNER AN...BIBHUTI BHUSAN SAMANTARAY
This paper presents the heat transfer characteristics of a
self-aspirating porous radiant burner (SAPRB) that operates
on the basis of an effective energy conversion method between
flowing gas enthalpy and thermal radiation. The temperature
field at various flame zones was measured experimentally by
the help of both FLUKE IR camera and K-type thermocouples.
The experimental setup consisted of a two layered domestic
cooking burner, a flexible test stand attached with six K-type
thermocouples at different positions, IR camera, LPG setup
and a hot wire anemometer. The two layered SAPRB consisted
of a combustion zone and a preheating zone. Combustion zone
was formed with high porosity, highly radiating porous
matrix, and the preheating zone consisted of low porosity
matrix. Time dependent temperature history from
thermocouples at various flame zones were acquired by using
a data acquisition system and the temperature profiles were
analyzed in the ZAILA application software environments. In
the other hand the IR graphs were captured by FLUKE IR
camera and the thermographs were analyzed in the
SMARTView software environments. The experimental results
revealed that the homogeneous porous media, in addition to
its convective heat exchange with the gas, might absorb, emit,
and scatter thermal radiation. The rate of heat transfer was
more at the center of the burner where a combined effect of
both convection & radiation might be realized. The maximum
thermal efficiency was found to be 64% which was having a
good agreement with the previous data in the open literature.
it contain some primary information about carbon black and its manufacturing process... not in detail but just overview...
hope you will find it helpful...
This research paper investigates the thermal properties of beeswax/graphene as a phase change material for energy storage applications in buildings. Differential scanning calorimetry was used to measure the melting temperature, thermal capacity, and latent heat of beeswax and beeswax/graphene samples. Thermal conductivity was measured using a thermal conductivity apparatus. Viscosity was also tested to analyze the effect of nanoparticles. Results showed that the addition of 0.3 wt% graphene increased the latent heat of beeswax by 22.5% and increased the thermal conductivity to 2.8 W/m K. Scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction analysis confirmed compatibility between the beeswax
The document discusses the synthesis and characterization of cost-effective hybrid silica-cellulose aerogels for thermal insulation, acoustic absorption, energy storage, and oil absorption applications. The aerogels were synthesized through a sol-gel process involving the preparation of silica and cellulose aerogels followed by the addition of cellulose to the silica gel to form hybrid aerogels. The hybrid aerogels were characterized through various techniques and showed improved properties like low density, high porosity, and surface area, making them suitable for thermal and acoustic insulation as well as oil absorption. The document aims to optimize the synthesis parameters to develop hybrid aerogels for efficient energy and environmental applications.
CFD investigation on heat transfer enhancement in shell and tube heat exchang...IRJET Journal
The document discusses a computational fluid dynamics (CFD) investigation of heat transfer enhancement in a shell and tube heat exchanger using graphene oxide (GO) nanofluid. A 3D model of a shell and tube heat exchanger is developed and GO nanofluid is introduced. Governing equations are solved numerically to analyze heat transfer performance. Results show that incorporating GO nanofluid leads to enhanced heat transfer compared to traditional fluids due to GO's higher thermal conductivity and its ability to disrupt thermal boundary layers and promote mixing. Heat transfer rate increased 42% and convective heat transfer coefficient increased 62% with GO nanofluid. This suggests GO nanofluid can significantly improve heat exchanger efficiency for applications like power plants and HVAC systems. Further
Performance Improvement Of Self-Aspirating Porous Radiant Burner By Controlli...BIBHUTI BHUSAN SAMANTARAY
This document summarizes an experimental study on improving the performance of a self-aspirating porous radiant burner (SAPRB) by controlling process parameters such as gas velocity. The study used an experimental setup including a two-layer SAPRB, thermocouples, an IR camera, and data acquisition systems to measure temperature profiles at different flame zones. Results showed that the maximum temperature and heat transfer rate increased with higher gas velocity due to combined convective and radiative heat transfer. The maximum thermal efficiency achieved was 64% which agrees with previous literature. Process parameters like gas velocity can be controlled to improve SAPRB performance.
Review of Gas Turbine Combustion Chamber Designs to Reduce EmissionsIJAEMSJORNAL
Ensuring the environmental safety of aircraft engines is an important task for developers. This problem is becoming more urgent due to an increase in engine power, since an increase in power is achieved primarily by increasing the temperature in the combustion chamber, leading to an increase in NOx emissions. In this study, the problem of emission in the aviation industry and ways to solve it were considered. Separately, the method of reducing emissions by changing the design of combustion chambers was considered in more detail.
IRJET- Analysis of Engine Fin Body by Varying Geometry & MaterialsIRJET Journal
This document analyzes the thermal properties of fins on an engine cylinder by varying the fin geometry and materials. It discusses modeling cylinder fins with different geometries like rectangular, circular, and triangular in SOLID EDGE and analyzing them in ANSYS Workbench. The analysis shows that triangular fins made of aluminum alloy 6082 have the lowest temperature and highest heat transfer rate compared to other geometries and materials. The document concludes that fins with extensions provide more effective heat transfer than fins without extensions, with rectangular extensions providing the best performance. It recommends triangular fins made of aluminum alloy 6082 as the optimal design based on the thermal analysis.
IRJET- Assessment of Coal Through Analysis of Various Properties of Coal Samp...IRJET Journal
The document discusses assessing the properties of coal samples and using artificial neural networks to predict calorific value. It analyzes coal samples through proximate analysis methods like thermogravimetric analysis and bomb calorimetry. Proximate analysis is performed on samples from various mines to determine moisture, volatile matter, fixed carbon, and ash content. An artificial neural network model is developed using 49 samples and validated with 10 samples. The model aims to accurately predict calorific value based on proximate analysis data with an R2 of 0.9 and low error between predicted and analyzed values.
A Review on Coating of Titanium Alloy on Mild Steel using Thermal Spray Techn...IRJET Journal
This document reviews coating titanium alloy on mild steel using thermal spray techniques. It discusses several thermal spray coating processes including electric arc wire spraying, cold spraying, flame spraying, and high velocity oxy-fuel (HVOF) spraying. HVOF spraying is identified as particularly suitable for producing dense, adherent coatings with few oxides due to the high particle velocity and relatively cold flame compared to other thermal spray techniques. The document provides details on the operating principles and benefits of each thermal spray coating process.
Explore the essential graphic design tools and software that can elevate your creative projects. Discover industry favorites and innovative solutions for stunning design results.
IRJET- Literature Review on Energy Storage MaterialsIRJET Journal
The document summarizes research on phase change materials (PCMs) that can store and release large amounts of thermal energy during melting and freezing. It reviews several studies on developing PCMs for thermal energy storage applications in construction. Some key findings discussed include nanoencapsulating organic PCMs like n-octadecane to improve stability and thermal properties; adding micro-PCM and TiO2 nanoparticles to polyvinyl chloride films to control temperature ranges in buildings; incorporating fatty acid-based nano-PCM and graphite sheets into gypsum boards to significantly reduce energy demands; and using materials like polyethylene glycol and nanoparticles to create nanofibers with improved thermal conductivity for storing thermal energy in construction.
Experimental Heat Transfer Analysis of Different PCM Material used in Concret...Swapnil Shahade
This document summarizes an experimental study on heat transfer of different phase change materials (PCMs) used in concrete walls. Paraffin wax and beewax were used as PCMs integrated into concrete blocks. A testing setup with temperature sensors measured the surface and internal temperatures of the concrete blocks and PCMs when exposed to sunlight over several hours. Results showed that the average temperature of paraffin wax-integrated concrete was reduced by 5.98°C compared to only 2.9°C for hollow concrete, indicating paraffin wax more effectively stores thermal energy through its phase change process. The study concludes PCMs like paraffin wax can significantly reduce wall temperatures and energy required for building heating and
Development of advanced materials and manufacturing technologies for high eff...naveenchandra103
This document discusses the development of advanced materials and manufacturing technologies for high efficiency gas turbines. It focuses on turbine blades, which are subjected to extreme heat, corrosion, and centrifugal forces. Nickel-based superalloys are commonly used for turbine blades and discs due to their high strength at high temperatures. The document also discusses research into single crystal turbine blades and thermal barrier coatings to allow higher turbine inlet temperatures, improving engine efficiency.
Energy Recovery of Biomass: Study Comparative Experimental of Fixed Bed Combu...AJSERJournal
Energy recovery of biomass is considered as an important source of energy. The main objective of this
experimental study is to validate the use of olive pomace as an alternative fuel using a comparison with that of wood.
Therefore a biomass boiler was designed and fabricated based on two separate compartments. Experiments tests
showed that the average temperature in the boiler is around 700 °C for pomace and 670 °C for sawdust with variations
up to 100 °C depending on fuel supply. In this study, the temperature distributions within of the combustion chamber of
pomace and sawdust of wood are presented, evaluated and analyzed. The removal of combustion gas is produced via a
probe of a multi-gas analyzer placed at the smoke outlet. Analysis of combustion gases such as NO, CO, CO2 and O2 are
illustrated and discussed. The results showed that low values of nitrogen oxides NOx have been observed, well below
standard limit values and absence SOx
Energy Recovery of Biomass: Study Comparative Experimental of Fixed Bed Combu...AJSERJournal
Energy recovery of biomass is considered as an important source of energy. The main objective of this
experimental study is to validate the use of olive pomace as an alternative fuel using a comparison with that of wood.
Therefore a biomass boiler was designed and fabricated based on two separate compartments. Experiments tests
showed that the average temperature in the boiler is around 700 °C for pomace and 670 °C for sawdust with variations
up to 100 °C depending on fuel supply. In this study, the temperature distributions within of the combustion chamber of
pomace and sawdust of wood are presented, evaluated and analyzed. The removal of combustion gas is produced via a
probe of a multi-gas analyzer placed at the smoke outlet. Analysis of combustion gases such as NO, CO, CO2 and O2 are
illustrated and discussed. The results showed that low values of nitrogen oxides NOx have been observed, well below
standard limit values and absence SOx.
Experimentation on heat pipe and cfd analysis for performance enhancementeSAT Journals
Abstract
Heat Pipe is a heat transfer device used in many applications and it is very similar in some respects to the thermosyphon. Since there were several limitations of thermosyphon, heat pipe was developed. The idea of the heat pipe was first suggested in 1942, since then over a several decades the serious development of a heat pipe took place. Heat pipe mainly consists of three regions viz. evaporator, adiabatic and condenser section. The heat pipe differs from the thermosyphon by virtue of its ability to transport heat against gravity by an evaporation-condensation cycle. This research work includes experimentation on available heat pipe, development of CFD model and its validation with experimental results using CFD Tool. The results obtained by CFD are in good agreement with an experimental results. Since the heat pipe is used for transferring the heat, this research work focuses on increasing the heat transfer by modified model, modifications in terms of increased surface area, is proposed. From CFD analysis it was found that the proposed modified heat pipe shows enhancement in performance in terms of heat transfer rate by 19% when it is simulated for without heat sink case and 45% while with heat sink case, compared to conventional heat pipe. The mixture multiphase model from CFD too is used for simulation of heat pipe.
Experimentation on heat pipe and cfd analysis for performance enhancementeSAT Journals
Abstract
Heat Pipe is a heat transfer device used in many applications and it is very similar in some respects to the thermosyphon. Since there were several limitations of thermosyphon, heat pipe was developed. The idea of the heat pipe was first suggested in 1942, since then over a several decades the serious development of a heat pipe took place. Heat pipe mainly consists of three regions viz. evaporator, adiabatic and condenser section. The heat pipe differs from the thermosyphon by virtue of its ability to transport heat against gravity by an evaporation-condensation cycle. This research work includes experimentation on available heat pipe, development of CFD model and its validation with experimental results using CFD Tool. The results obtained by CFD are in good agreement with an experimental results. Since the heat pipe is used for transferring the heat, this research work focuses on increasing the heat transfer by modified model, modifications in terms of increased surface area, is proposed. From CFD analysis it was found that the proposed modified heat pipe shows enhancement in performance in terms of heat transfer rate by 19% when it is simulated for without heat sink case and 45% while with heat sink case, compared to conventional heat pipe. The mixture multiphase model from CFD too is used for simulation of heat pipe.
Effect of Separator Thickness and Preheating Temperature on the Development o...CrimsonPublishersRDMS
Effect of Separator Thickness and Preheating Temperature on the Development of Microwave Processed Composite Clads by Sarbjeet Kaushal* in Crimson Publishers: Peer Reviewed Material Science Journals
The use of Cooking Gas as Refrigerant in a Domestic RefrigeratorIJERA Editor
The application of cooking gas refrigerants in refrigeration system is considered to be a potential way to improve
energy efficiency and to encourage the use of environment-friendly refrigerants. Refrigeration operation has
been met with many challenges as it deals with environmental impact, how it affects humans and how it
contributes to the society in general. Domestic refrigerators annually consume several metric tons of traditional
refrigerants, which contribute to very high Ozone Depletion Potential (ODP) and Global Warming Potential
(GWP). The experiment conducted employs the use of two closely linked refrigerants, R600a (Isobutene) and
cooking gas which is varied in an ideal refrigerant mixture of 150 g of refrigerant and 15 ml of lubricating oil (to
a rating of 40 wt % expected in the compressor). The Laboratory process involved the use of Gas
Chromatography machine to ascertain the values of the mole ratio, molecular weight and critical temperatures.
Prode properties and Refprop softwares were used to ascertain other refrigerant properties of the mixture. The
results indicated that the mixture of R600a with lubricant confirm mineral oil as being the most appropriate for
the operation. The experimental results indicated that the refrigeration system with cooking gas refrigerant
worked normally and was found to attain high freezing capacity and a COP value of 2.159. It is established that
cooking gas is a viable alternative refrigerant to replace R600a in domestic refrigerators. Hence, its application
in refrigerating systems measures up to the current trend on environmental regulations with hydrocarbon
refrigerants
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1. 222
Application of Graphene Silicone Grease in heat dissipation for the
Intel Core i5 Processor
Mai Thi Phuong#*
, Bui Anh Tuan#
, Trần Văn Hậu#*
, Pham Van Trinh#
, Nguyen Nang Dinh*
,
Phan Ngoc Minh**
, Bui Hung Thang#
#
Institute of Materials Science, Vietnam Academy of Science and Technology, Hanoi, Vietnam
*
VNU University of Engineering and Technology, Ha Noi, Vietnam
**
Graduate University of Science and Technology, Vietnam Academy of Science and Technology, Hanoi, Vietnam
E-mail: thangbh@ims.vast.ac.vn
Abstract— Graphene was known as the material that owning many superiority properties and high thermal conductivity. Thermal
conductivity of single-layer graphene was up to 5200 W/mK (compared to the thermal conductivity of Carbon nanotubes 2000 W/mK
and Silver 410 W/mK). This had suggested that graphene is the most potential material for heat dissipation applications for electronic
devices, such as a computer microprocessor, high power LED... To enhance the dispersion of the GNPs silicone matrix, we were
functionalized graphene nanoplatelets (GNPs) with carboxyl (-COOH) groups. The silicone thermal greases containing GNPs were
prepared by High- Energy Ball Milling method (8000D Mixer /Mill). The results of SEM, FTIR, Raman showed the presence of the
carboxyl groups in GNPs and GNPs uniform dispersion dispersed in grease. The results of thermal conductivity from Transient Hot
Bridge THB-100 showed that thermal conductivity enhancement was up to 234 % with Gr-COOH 1.0 vol.%. Thermal grease is used
as a thermal interface material to coolants for Intel Core i5 processor. The results of thermal dissipation efficiency shown the
saturation temperature of the processor using thermal grease containing 1.0 vol.% Gr-COOH decreased 4℃, compared to the silicone
grease.
Keywords— thermal grease, silicone grease, graphene, CPU, Intel Core i5 processor.
I. INTRODUCTION
Nowadays, the process of miniaturization with the
development of high-power electronic devices and
manufacturing processes developed at the nanometer-level.
The electronic devices allow higher transistor integration
density in the processor (CPU) [1-4]. However, computer
processors action for a long will consume energy and release
large amounts of heat. The excessive amount of heat
generated will reduce the lifespan, reliability and efficiency
of the CPU because the electronic devices only work into a
certain temperature limit [5]. Therefore, the heat generated
from high-power electronic devices should be dissipated as
quickly and effectively as possible, to maintain the operating
temperatures of the devices at the desired level. In the way
stated, the heat dissipation enhancement has become one of
the most crucial issues that raise the reliability, boosts
performance and stability of high-power electronic devices
such as microprocessors, and especially is Central
Processing Unit (CPU) [6,7].
Current cooling methods are only reaching a certain limit
due to the interface area between CPU and heatsink [8,9].
Therefore, the use of thermal grease in high-power
electronic devices of great interest by researchers and
manufacturers. Thermal grease is a typical thermal interface
material (TIM) [10], usually used to increase the thermal
conductivity between microprocessors and heat sinks [11].
The main materials of thermal grease consist of the matrix
polymer and filler [12,13]. The filler materials are key
thermal conductivity ingredient in silicone thermal grease. It
is sized particles µm with high thermal conductivity and
dispersed in the base silicone, often use inorganic or metal
nanomaterials with high thermal conductivity [14-18].
Thermal silicon grease fills the gaps between two solid
surfaces and establishes an efficient heat path, thereby
enhancing thermal conductivity [19-21]. The thermal
conductivity of fat increases with increasing filler content.
However, many factors have an effect on thermal
conductivity of grease, such as the size of particles, the
particle dispersion in base grease, and the thermal properties
of the dispersed particle [22,23]. In recent years, many
thermal greases have been reported using nanomaterials with
high conductivity for better performance. Researchers have
recently shown much interest in the issue of finding new
INTERNATIONAL JOURNAL ON INFORMATICS VISUALIZATION
VOL 3 (2019) NO 2-2
e-ISSN : 2549-9904
ISSN : 2549-9610
2. 223
materials for thermal grease in the heat dissipation future
issue[24,25].
Recently, Graphene is a two-dimensional nanocarbon
material with the hexagonally packed structure compromised
of sp2-hybridized carbon atoms, discovered by Andre Geim
and Kostya Novoselov in 2004 [26]. Baladin et al.’s research
showed that the in-plane thermal conductivity of single-layer
graphene was up to 5200 W/mK [27] (compared to the
thermal conductivity of CNTs 2000 W/mK and Ag 410
W/mK) [28]. This suggests an approach in applying
graphene in grease or liquid for thermal dissipation systems
for computer processors and other high-power electronic
devices.
In this paper, we report on the new results in the
fabrication of high thermal conductivity silicone grease
containing graphene, and application grease for enhancing
heat dissipation of Intel Core i5 processor [29].
II. THE MATERIAL AND METHOD
The graphene nanoplatelets materials (GNPs) were
purchased from ACS Material Company with a purity of
99.5%, thickness 20 nm, diameter 5-10 μm, density 2,3
g/cm3
, and specific surface area 20-40 m2
/g. GNPs was
functionalized by treatment with a mixture HNO3 and
H2SO4 acids at a ratio of 1:3 (v/v) at a temperature of 70℃
for 5h to form a carboxyl (-COOH) group, as schematically
shown in Figure 1. Raman spectroscopy was used to analyze
graphitic change the graphene materials after acid treatment.
Chemical bonds and elements in thermal grease were
characterized by Fourier-transform infrared spectroscopy
(FTIR).
Fig.1. The creative process of graphene functionalized by carboxyl (-
COOH) group
In order to disperse the Gr-COOH in the silicone grease,
we using by 8000D Mixer /Mill (High- Energy Ball Mill) at
a speed of 8000 rpm for 3 hours. Field-emission scanning
electron microscope (FESEM) was used to examine the size,
morphology, and distribution of Gr-COOH in the thermal
grease. Thermal conductivity of the grease is measured by
Transient Hot Bridge THB-100 (Linseis, Germany) at room
temperature. Figure 2 is a schematic view of the thermal
dissipation system for a computer processor using silicone
grease containing Gr-COOH. In this model, thermal grease
was painted on the interface between the CPU chip and the
heatsink. We use the air conditioner to keep the ambient
temperature at 28◦C for all measurements. Thermal grease
replaces the air gap with thermal conductivity of 0.026
W/m.K and fills the gap between the rugged surface and the
heat path setting, thereby increasing the heat transfer
efficiency. The thermal dissipation efficiency was evaluated
by using dedicated software and built-in temperature sensors
inside the microprocessor to measure the temperature of the
microprocessor directly.
The computer used in this study has the following
configuration: Intel Core i5 – 3570 K Processor, Corsair’s 4
GB DDR3 SODIMM Memory, Toshiba’s 1 TB Hard Disk
Drive, Asrock H61M-VS3 Mainboard, and Window 10
Ultimate Service Pack 1 Operating System for all
experiments. The temperature of the microprocessor was
measured by using the Core Temp 1.10.2- 64 bit software.
The microprocessor was pushed to the maximum (100%
usage of the processor) by using Prime95 32 bit 29.3 build 1
software.
Fig.2. Scheme of the cooling system using thermal grease containing Gr-
COOH
III. RESULTS AND DISCUSSION
Figure 3 shows a typical FESEM image of the GNPs
hight magnification. The thickness of nanosheets in the
range of 2–10 nm, the average diameter was about 5-10 µm
with high cleanliness and purity 99%.
Fig.3. FESEM image of graphene nanoplatelets
Raman scattering is a technique to examine the changes
in the surfaces and the structures of GNPs. Figure 4 clearly
shows that the G band (around 1582.87) and 2D band
(around 2678.2). The D-band intensity was appeared in the
functionalized GNPs compared to the pristine GNPs. The
intensity ratio of D lines to G lines was different, suggesting
some changes in the surfaces and the structures of the GNPs.
This result indicates that some of the sp2
carbon atoms
(C=C) were converted to sp3
carbon atoms (C−C) at the
surfaces of the MWCNTs after the acid treatment in
HNO3/H2SO4.
3. 224
Fig.4. Raman spectra of Graphene (red line), Gr-COOH (blue line)
Figure 5 presents the typical FTIR spectra of the pristine
GNPs and Gr-COOH. Some important peaks are seen after
the GNPs have been treated with a mixture of H2SO4 and
HNO3. The vibration of O-H bonding in the carboxyl group
is shown as a peak at 3446 cm-1
. It was expanded more than
that of the O-H bonding of H2O. The peak at 1708 cm-1
showed the existence of vibrations of the C=O bond in the
carboxyl group. This shows the importance of proving the
existence of carboxyl (COOH) functional groups due to the
oxidation resulting from the nitric and the sulfuric acids.
This clearly shows that the acids functionalized the surfaces
of the GNPs.
Fig.5. FTIR transmission spectra of pristine GNPs, Gr-COOH.
Fig. 6a shows the SEM images of silicone thermal grease.
As can be seen, the silicone thermal grease used in this
research contains some large and small filling particles
inequitably distributed in the grease. Fig. 6b shows the SEM
images of thermal grease containing 1.0 vol.% Gr-COOH as
prepared. This result shows the distribution of the metal
oxide particles of the grease and Gr-COOH inside thermal
grease after annealing. This indicates that silicone grease
clings to graphene. In other words, Gr-COOH were good
compatibility and well-dispersed in the silicone grease,
thereby enhancing the thermal conductivity of grease.
Fig.6. FESEM image of silicone thermal grease (a) and silicone thermal
grease containing Gr-COOH (b)
TABLE 1
THE RESULT THERMAL CONDUCTVITY OF THE GREASE
Thermal conductivity of grease containing GNP
0.25
vol.%
0.5
vol.%
0.75 vol.% 1.0 vol.%
k
3.210
W/m.K
4.281
W/m.K
5.012
W/m.K
6.172
W/m.K
k-k0
1.276
W/m.K
2.437
W/m.K
3.168
W/m.K
4.328
W/m.K
(k-k0)/k0 74% 130% 171% 234%
The statistic results of thermal conductivity and the
thermal conductivity enhancement of thermal grease with
different Gr-COOH concentration are reported in table 1. In
which, k and k0 are the thermal conductivity of the silicone
thermal grease and the thermal grease containing Gr-COOH,
respectively. The equations (k−k0)/k0 shown the thermal
conductivity enhancement. The result shows with 0.25, 0.5,
0.75 and 1 vol.% Gr-COOH the thermal conductivity of
thermal grease containing Gr-COOH was measured to be
3.210, 4.281, 5.012, 6.172 W/m.K. Similarly, the thermal
conductivity enhancement was calculated to be 74%, 130%,
4. 225
171%, 234% corresponding to the thermal grease containing
0.25, 0.5, 0.75 and 1.0 vol.%, respectively. Results showed
that Gr-COOH 1.0 vol.% had the highest thermal
conductivity enhancement of 234% compared with silicone
grease.
Fig.7. The measured temperature of the microprocessor as a function of the
operation time in the case of using thermal grease
The temperature microprocessor of the can be measured
directly when it during the operation of the computer at full
load mode. We use an air conditioner to kept well room
temperature at 28℃ for all measurements. We use thermal
grease to reduce the saturation temperature and slow down
the temperature increase of the processor. Figure 7 shows the
microprocessor's experimental temperature as a function of
working time when using thermal grease. At the initial time,
the temperature of the microprocessor was about 32℃, after
about 240 seconds the temperature reached saturation. The
saturation temperature of the microprocessor reached 62℃
when using silicone thermal grease and it reached 61℃,
60℃, 59℃, 58℃ with silicone thermal grease containing
Gr-COOH with 0.25 vol.%, 0.5 vol.%, 0.75% vol.%, 1
vol.%, respectively. Similarly, the saturation temperature
decrease of CPU was calculated to be 1, 2, 3, 4
correspondings to the thermal grease containing 0.25, 0.5,
0.75 and 1.0 vol.%, responding. The lowest saturation
temperature of CPU was 58℃ with grease containing 1
vol.% Gr-COOH.
IV.CONCLUSION
The successful functionalization Gr-COOH by a mixture
of the acid solution was proven by Raman and FTIR spectral
measurements. The SEM images proved that graphene
nanoplatelets dispersed in the based grease by high energy
ball mill method. The results thermal conductivity from
Transient Hot Bridge THB-100 showed that thermal
conductivity enhancement was up to 234 % with Gr-COOH
1.0 vol.%. The thermal dissipation efficiency of the PC’s
microprocessor examined and evaluated. Compared to the
silicone grease, the saturation temperature of the processor
using thermal grease containing 1.0 vol.% Gr-COOH
decreased 4 ℃ . The obtained results confirmed the
advantages of using Gr-COOH for thermal grease in
microprocessors and other high-power electronic devices.
ACKNOWLEDGMENT
This study was funded from: “For Inspiration and
Recognition of Science and Technology (FIRST) under
grant No.16/FIRST/1.a/IMS”.
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