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Davood Toghraie - One of the best experts on this subject based on the ideXlab platform.
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The thermal performance of five different viscosity models in the kidney blood vessel with multi-Phase Mixture of non-Newtonian fluid models using computational fluid dynamics
Archive of Applied Mechanics, 2021Co-Authors: Shahab Naghdi Sedeh, Davood ToghraieAbstract:Computational hemodynamic (CHD) is an engineering tool and a good approach that helped many physicians to obtain much information about the situation of the patient in a lot of diseases like cardiovascular disease, even surgery, etc. The dispersion of blood cells in the plasma is heterogeneous. Therefore, the blood fluid is a multi-Phase Mixture of non-Newtonian fluid. Numerical calculation of non-Newtonian viscosity models of blood flow parameter includes Reynolds number; different wall heat fluxes in three situations of the body (sleeping, standing and running), etc. are investigated. To construct a 3D model of the kidney blood vessel, an open-source software program using Digital Imaging and Communications in Medicine (DICOM) and Magnetic Resonance Image (MRI) is used. Additionally, the vessel wall is considered solid. The finite volume approach and SIMPLE scheme are used. The non-Newtonian blood flow is considered as a laminar flow. All of these heat fluxes generated by the body in different situations have their impact on the reported parameters in this paper. The reported parameters included dimensionless numbers like pressure drop, average wall shear stress, heat transfer coefficient, and temperature. The power-law non-Newtonian viscosity model makes the velocity gradient more than other non-Newtonian viscosity models. Also, the power-law model represents a higher heat transfer.
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numerical investigation of heat and mass transfer of water silver nanofluid in a spiral heat exchanger using a two Phase Mixture method
Journal of Thermal Analysis and Calorimetry, 2020Co-Authors: Erfan Khodabandeh, Reza Boushehri, Omid Ali Akbari, Soheil Akbari, Davood ToghraieAbstract:This study numerically investigates the heat and mass transfer characteristics of water—silver nanofluid flowing in a spiral heat exchanger (HX) using the two-Phase Mixture model. The hot side of the HX is pure water at the temperature of 343 K and Re = 500, while the cold side is nanofluid with volume fraction up to 5% at 305 K and Re number ranging from 500 to 2000. The cold and hot tubes are concentrically twisted 3.5, 5.5 and 7.5 turns in order to explore the heat transfer effectiveness of the heat exchanger as a function of the spiral turns. The results indicate that increasing the volume fraction of nanoparticles, Re number and the number of turns increases the overall heat transfer coefficient, heat rate absorbed by the cold fluid and pumping power of the HX noticeably. The above-mentioned factors also improve the temperature stability of the input fluid along with the heat exchanger. The effectiveness of the HX decreases by increasing the Re number, the volume fraction of nanoparticles and turning rounds due to the greater pressure drop of the coolant fluid. At a constant Re number, increasing the volume fraction and number of turns enhances the NTU parameter to a great extent.
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Numerical investigation of heat and mass transfer of water—silver nanofluid in a spiral heat exchanger using a two-Phase Mixture method
Journal of Thermal Analysis and Calorimetry, 2020Co-Authors: Erfan Khodabandeh, Reza Boushehri, Omid Ali Akbari, Soheil Akbari, Davood ToghraieAbstract:This study numerically investigates the heat and mass transfer characteristics of water—silver nanofluid flowing in a spiral heat exchanger (HX) using the two-Phase Mixture model. The hot side of the HX is pure water at the temperature of 343 K and Re = 500, while the cold side is nanofluid with volume fraction up to 5% at 305 K and Re number ranging from 500 to 2000. The cold and hot tubes are concentrically twisted 3.5, 5.5 and 7.5 turns in order to explore the heat transfer effectiveness of the heat exchanger as a function of the spiral turns. The results indicate that increasing the volume fraction of nanoparticles, Re number and the number of turns increases the overall heat transfer coefficient, heat rate absorbed by the cold fluid and pumping power of the HX noticeably. The above-mentioned factors also improve the temperature stability of the input fluid along with the heat exchanger. The effectiveness of the HX decreases by increasing the Re number, the volume fraction of nanoparticles and turning rounds due to the greater pressure drop of the coolant fluid. At a constant Re number, increasing the volume fraction and number of turns enhances the NTU parameter to a great extent.
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A numerical investigation on the influence of nanoadditive shape on the natural convection and entropy generation inside a rectangle-shaped finned concentric annulus filled with boehmite alumina nanofluid using two-Phase Mixture model
Journal of Thermal Analysis and Calorimetry, 2019Co-Authors: Amin Shahsavar, Davood Toghraie, Milad Rashidi, Mostafa Monfared Mosghani, Pouyan TalebizadehsardariAbstract:The goal of this work is to numerically study the hydrothermal and entropy generation specifications of boehmite alumina (γ-AlOOH) nanofluid flowing in a finned concentric annulus using the two-Phase Mixture model. Different shapes for the nanoadditives are examined including cylindrical, brick, blade, platelet and spherical. The impacts of nanoadditive shape and volume concentration $$(\varphi )$$ , Rayleigh number $$({\text{Ra}})$$ and application of fins on the streamlines, isotherms, Nusselt number as well as both the local and global rates of entropy generation due to the heat transfer and fluid friction are examined. The results indicated that the addition of fins and employing a higher $${\text{Ra}}$$ and $$\varphi$$ cause a higher average Nusselt number and generation rate of thermal entropy. Moreover, it was found that, except for $${\text{Ra}} = 10^{3}$$ , the generation rate of frictional entropy intensifies by utilizing fins. Moreover, the frictional entropy generation rate was enhanced using a higher $${\text{Ra}}$$ and $$\varphi$$ . The results depicted that the impact of fins on the Nusselt number and entropy generation is not varied by the nanoadditive shape and concentration. Furthermore, it was concluded that the best nanoadditive shape is cylindrical and platelet, respectively, based on the first and the second laws of thermodynamics.
Amin Shahsavar - One of the best experts on this subject based on the ideXlab platform.
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Two-Phase Mixture modeling of turbulent forced convective flow of water–silver nanofluid inside a rifled tube: hydrothermal characteristics and irreversibility behavior
Journal of Thermal Analysis and Calorimetry, 2020Co-Authors: Amin Shahsavar, Majid Jafari, Fatih SelimefendigilAbstract:This work aims to present a numerical evaluation of the turbulent forced convective flow of water–silver nanofluid (NF) inside a horizontal internally spiral-ribbed heat exchanger tube using the two-Phase Mixture model. The considered NF is prepared using an environmentally friendly method. The influences of the volume concentration of silver nanoadditives ( $$\varphi$$ φ ), Reynolds number (Re), rib width ( W ), rib height ( H ) and rib pitch ( P ) on the convection coefficient, pressure loss, irreversibility in fluid friction ( $$\dot{S}_{{{\text{g}},{\text{f}}}}$$ S ˙ g , f ) and heat transfer ( $$\dot{S}_{{{\text{g}},{\text{h}}}}$$ S ˙ g , h ) and total irreversibility ( $$\dot{S}_{{{\text{g}},{\text{t}}}}$$ S ˙ g , t ) are assessed. The outcomes disclosed that the hydrodynamic characteristics and irreversibility behavior of NF flow in the ribbed tube are better than that of the water flow in the plain tube. In addition, it was found that the best first-law performance belongs to the case $$\varphi = 1\%$$ φ = 1 % , $${\text{Re}} = 5000$$ Re = 5000 , $$W = 2$$ W = 2 mm, $$H = 2$$ H = 2 mm, $$P = 4$$ P = 4 mm, while the best second-law performance occurs at $$\varphi = 0\%$$ φ = 0 % , Re = 20,000, $$W = 2$$ W = 2 mm, $$H = 1$$ H = 1 mm, $$P = 5$$ P = 5 mm.
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Numerical investigation of laminar flow of biological nanofluid in a rifled tube using two-Phase Mixture model: first-law and second-law analyses and geometry optimization
Journal of Thermal Analysis and Calorimetry, 2020Co-Authors: Amin Shahsavar, Majid Jafari, Sara RostamiAbstract:The impetus of this numerical investigation is to explore the performance aspects of laminar forced convection flow of biologically synthesized water–silver nanofluid inside an internally spiral-ribbed heat exchanger tube from both the first and second laws of thermodynamics perspectives. The two-Phase Mixture model is used to perform the required simulations. The impacts of the volume concentration of nanoadditives ( φ ), Reynolds number (Re) as well as the width ( W ), height ( H ) and pitch ( P ) of the ribs on the hydrothermal aspects and irreversibility behavior of the nanofluid are assessed, and the results are compared with the findings of smooth tube. It was found that the use of nanofluid and the use of rifled tube instead of water and smooth tube, respectively, are suitable ways to improve system performance from both the first and second laws of thermodynamics perspectives. Moreover, it was reported that the best hydrothermal performance of the nanofluid through the rifled tube occurs at φ = 1%, Re = 2000, W = 3 mm, H = 1 mm, P = 4 mm, while the minimum total irreversibility in the flow of water–silver nanofluid inside a rifled tube occurs at φ = 1%, Re = 2000, W = 3 mm, H = 0.5 mm, P = 4 mm.
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A numerical investigation on the influence of nanoadditive shape on the natural convection and entropy generation inside a rectangle-shaped finned concentric annulus filled with boehmite alumina nanofluid using two-Phase Mixture model
Journal of Thermal Analysis and Calorimetry, 2019Co-Authors: Amin Shahsavar, Davood Toghraie, Milad Rashidi, Mostafa Monfared Mosghani, Pouyan TalebizadehsardariAbstract:The goal of this work is to numerically study the hydrothermal and entropy generation specifications of boehmite alumina (γ-AlOOH) nanofluid flowing in a finned concentric annulus using the two-Phase Mixture model. Different shapes for the nanoadditives are examined including cylindrical, brick, blade, platelet and spherical. The impacts of nanoadditive shape and volume concentration $$(\varphi )$$ , Rayleigh number $$({\text{Ra}})$$ and application of fins on the streamlines, isotherms, Nusselt number as well as both the local and global rates of entropy generation due to the heat transfer and fluid friction are examined. The results indicated that the addition of fins and employing a higher $${\text{Ra}}$$ and $$\varphi$$ cause a higher average Nusselt number and generation rate of thermal entropy. Moreover, it was found that, except for $${\text{Ra}} = 10^{3}$$ , the generation rate of frictional entropy intensifies by utilizing fins. Moreover, the frictional entropy generation rate was enhanced using a higher $${\text{Ra}}$$ and $$\varphi$$ . The results depicted that the impact of fins on the Nusselt number and entropy generation is not varied by the nanoadditive shape and concentration. Furthermore, it was concluded that the best nanoadditive shape is cylindrical and platelet, respectively, based on the first and the second laws of thermodynamics.
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the effects of tape insert material on the flow and heat transfer in a nanofluid based double tube heat exchanger two Phase Mixture model
International Journal of Mechanical Sciences, 2019Co-Authors: Ali Reza Karimi, Omid Mahian, Abdullah A A A Alrashed, Masoud Afrand, Somchai Wongwises, Amin ShahsavarAbstract:Abstract The present study dealt with the numerical simulation of nanofluid flow in a double tube heat exchanger equipped with twisted tape. Alumina/water nanofluid and pure water are considered to be working fluids. A two-Phase Mixture model was employed for nanofluid flow simulation. The effect of nanofluid and twisted tape on the hydrodynamic and thermal performance of the heat exchanger was studied. Next, the focus was placed on the effect of the surface roughness (material type) of twisted tape on heat transfer and pressure drop in the heat exchanger. The results are presented as the temperature distribution, velocity field, Nusselt number, and pressure drop for various Reynolds numbers, nanofluid concentrations, pitch ratios, and tape insert materials. The results revealed that the use of twisted tape improved the Nusselt number up to 22%; also, adding alumina particles to water augmented heat transfer up to 30% and increased pressure drop up to 40%. Tapes with more roughness provided heat transfer enhancement of up to 16%, whereas the friction factor increased up to 21%.
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hydrothermal analysis of turbulent boehmite alumina nanofluid flow with different nanoparticle shapes in a minichannel heat exchanger using two Phase Mixture model
Physica A-statistical Mechanics and Its Applications, 2019Co-Authors: Jalal Alsarraf, Masoud Afrand, Amin Shahsavar, Alireza Moradikazerouni, Hamzeh Salehipour, Minhduc TranAbstract:Abstract Exploring the effect of nanoparticle shape on the fluid flow characteristics of boehmite alumina nanofluid in a horizontal double-pipe minichannel heat exchanger is the goal of this study. The proposed boehmite alumina nanofluid could consist of dispersed cylindrical, brick, blade, platelet, and spherical shape nanoparticles in a Mixture of water/ethylene glycol. In this study, the water and nanofluid pass through the annulus and tube side of the heat exchanger, respectively. To accurately simulate the behavior of nanofluid, the two Phase Mixture model is utilized in the simulation. In this investigation, the effect of different Reynolds numbers, nanoparticle concentrations and shapes versus important hydrothermal properties are investigated. The results show that, the spherical and platelet shape lead to the highest and lowest performance index of heat exchanger, respectively. Moreover, it is found that the rates of heat transfer, overall heat transfer coefficient, pressure drop, and pumping power increases with increase in Reynolds number and nanoparticle concentration, while the opposite trend is observed for performance index of the heat exchanger. For instance, at the Reynolds number of 20 000, by boosting the nanoparticle concentration from 0.5 to 2%, the performance index for nanofluid containing platelet shape and spherical shape nanoparticles reduces by 130.63 and 3.88%, respectively.
Erfan Khodabandeh - One of the best experts on this subject based on the ideXlab platform.
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numerical investigation of heat and mass transfer of water silver nanofluid in a spiral heat exchanger using a two Phase Mixture method
Journal of Thermal Analysis and Calorimetry, 2020Co-Authors: Erfan Khodabandeh, Reza Boushehri, Omid Ali Akbari, Soheil Akbari, Davood ToghraieAbstract:This study numerically investigates the heat and mass transfer characteristics of water—silver nanofluid flowing in a spiral heat exchanger (HX) using the two-Phase Mixture model. The hot side of the HX is pure water at the temperature of 343 K and Re = 500, while the cold side is nanofluid with volume fraction up to 5% at 305 K and Re number ranging from 500 to 2000. The cold and hot tubes are concentrically twisted 3.5, 5.5 and 7.5 turns in order to explore the heat transfer effectiveness of the heat exchanger as a function of the spiral turns. The results indicate that increasing the volume fraction of nanoparticles, Re number and the number of turns increases the overall heat transfer coefficient, heat rate absorbed by the cold fluid and pumping power of the HX noticeably. The above-mentioned factors also improve the temperature stability of the input fluid along with the heat exchanger. The effectiveness of the HX decreases by increasing the Re number, the volume fraction of nanoparticles and turning rounds due to the greater pressure drop of the coolant fluid. At a constant Re number, increasing the volume fraction and number of turns enhances the NTU parameter to a great extent.
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Numerical investigation of heat and mass transfer of water—silver nanofluid in a spiral heat exchanger using a two-Phase Mixture method
Journal of Thermal Analysis and Calorimetry, 2020Co-Authors: Erfan Khodabandeh, Reza Boushehri, Omid Ali Akbari, Soheil Akbari, Davood ToghraieAbstract:This study numerically investigates the heat and mass transfer characteristics of water—silver nanofluid flowing in a spiral heat exchanger (HX) using the two-Phase Mixture model. The hot side of the HX is pure water at the temperature of 343 K and Re = 500, while the cold side is nanofluid with volume fraction up to 5% at 305 K and Re number ranging from 500 to 2000. The cold and hot tubes are concentrically twisted 3.5, 5.5 and 7.5 turns in order to explore the heat transfer effectiveness of the heat exchanger as a function of the spiral turns. The results indicate that increasing the volume fraction of nanoparticles, Re number and the number of turns increases the overall heat transfer coefficient, heat rate absorbed by the cold fluid and pumping power of the HX noticeably. The above-mentioned factors also improve the temperature stability of the input fluid along with the heat exchanger. The effectiveness of the HX decreases by increasing the Re number, the volume fraction of nanoparticles and turning rounds due to the greater pressure drop of the coolant fluid. At a constant Re number, increasing the volume fraction and number of turns enhances the NTU parameter to a great extent.
Yasuo Koizumi - One of the best experts on this subject based on the ideXlab platform.
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Initiation conditions of liquid ascent of the countercurrent two-Phase flow in vertical pipes (in the presence of two-Phase Mixture in the lower portion)
International Journal of Multiphase Flow, 1996Co-Authors: Yasuo Koizumi, Tatsuhiro UedaAbstract:Abstract Experiments on the countercurrent two-Phase flow of air and water were conducted using vertical pipes of 10–26 mm in diameter to investigate the initiation conditions of liquid ascent. When a liquid film flowed down to a bubbling two-Phase Mixture in the lower portion of the pipe, liquid ascent began at much lower gas velocities than usual flooding velocities without the bubbling two-Phase Mixture. In most cases, liquid ascent occurred in a slug flow state. The initiation conditions of the liquid ascent were analyzed physically by considering the level swell of the two-Phase Mixture fluctuating around the mean height.
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Two-Phase Mixture level swell in vertical pipes
International Journal of Multiphase Flow, 1993Co-Authors: Tatsuhiro Ueda, Yasuo KoizumiAbstract:Abstract The behavior of the two-Phase Mixture level was examined in the case of bubbling of a stagnant liquid column in vertical pipes and also in the case of bubbling of a liquid column to which liquid is supplied as a falling film. In a range of low air flow rates where the flow pattern is of bubbly type, the Mixture level swell and its fluctuation amplitude were small. However, these values increased sharply as the air flow rate was increased and the flow pattern turned into a slug type. The mean height of the two-Phase Mixture level and the level fluctuation amplitude were analyzed physically and compared with the experimental results.
Tatsuhiro Ueda - One of the best experts on this subject based on the ideXlab platform.
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Initiation conditions of liquid ascent of the countercurrent two-Phase flow in vertical pipes (in the presence of two-Phase Mixture in the lower portion)
International Journal of Multiphase Flow, 1996Co-Authors: Yasuo Koizumi, Tatsuhiro UedaAbstract:Abstract Experiments on the countercurrent two-Phase flow of air and water were conducted using vertical pipes of 10–26 mm in diameter to investigate the initiation conditions of liquid ascent. When a liquid film flowed down to a bubbling two-Phase Mixture in the lower portion of the pipe, liquid ascent began at much lower gas velocities than usual flooding velocities without the bubbling two-Phase Mixture. In most cases, liquid ascent occurred in a slug flow state. The initiation conditions of the liquid ascent were analyzed physically by considering the level swell of the two-Phase Mixture fluctuating around the mean height.
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Two-Phase Mixture level swell in vertical pipes
International Journal of Multiphase Flow, 1993Co-Authors: Tatsuhiro Ueda, Yasuo KoizumiAbstract:Abstract The behavior of the two-Phase Mixture level was examined in the case of bubbling of a stagnant liquid column in vertical pipes and also in the case of bubbling of a liquid column to which liquid is supplied as a falling film. In a range of low air flow rates where the flow pattern is of bubbly type, the Mixture level swell and its fluctuation amplitude were small. However, these values increased sharply as the air flow rate was increased and the flow pattern turned into a slug type. The mean height of the two-Phase Mixture level and the level fluctuation amplitude were analyzed physically and compared with the experimental results.
