Begell House Inc.
Heat Transfer Research
HTR
1064-2285
51
3
2020
ANALYSIS OF CONVECTIVE HEAT TRANSFER IN NON-NEWTONIAN FLUIDS BY APPLYING THE FIELD SYNERGY PRINCIPLE APPROACH
193-206
10.1615/HeatTransRes.2019030200
Pamela
Vocale
Department of Engineering and Architecture, University of Parma, Parco Area delle Scienze
181/A I-43124 Parma, Italy
Andrea
Mocerino
Department of Engineering and Architecture, University of Parma, Parco Area delle Scienze
181/A I-43124 Parma, Italy
Fabio
Bozzoli
Department of Engineering and Architecture, University of Parma, Parco Area delle Scienze
181/A I-43124 Parma, Italy; SITEIA.PARMA Interdepartmental Centre, University of Parma, Parco Area delle Scienze 181/A I-43124 Parma, Italy
Sara
Rainieri
Department of Engineering and Architecture, University of Parma, Parco Area delle Scienze
181/A I-43124 Parma, Italy; SITEIA.PARMA Interdepartmental Centre, University of Parma, Parco Area delle Scienze 181/A I-43124 Parma, Italy
field synergy principle
non-Newtonian fluids
power-law fluids
circular channel
convective heat transfer
heat transfer enhancement
The present paper is intended to evaluate the local convective heat transfer of power-law fluids through a circular channel, accounting for the asymmetric heating that may occur in some practical applications. The temperature distribution within the fluid is analytically determined by assuming that the wall of the channel could be partially heated by a constant heat flux. The effects of asymmetric heating and the flow behavior index on the average performance of the heat transfer device are evaluated in terms of average Nusselt number, while the local phenomena are investigated by adopting the field sinergy principle approach. The results in terms of average Nusselt number highlight that the convective heat transfer coefficient decreases as the portion of the heated wall increases, while it increases as the flow behavior index decreases. This trend is motivated by analyzing the heat transfer phenomenon by means of the field sinergy principle approach; indeed, this analysis reveals that synergy between the velocity vector and the temperature gradient is better when the wall is heated only for a small portion and for shear thinning fluid.
THERMAL ANALYSIS OF PERLITE-REINFORCED CONCRETE PANELS AT VARYING MOISTURE CONTENTS
207-216
10.1615/HeatTransRes.2019025925
Serdar
Celik
Southern Illinois University Edwardsville, Edwardsville, IL, 62026, U.S.A.
M. Pinar
Menguc
Center for Energy, Environment and Economy (CEEE), Ozyegin University, Cekmekoy, 34794, Istanbul Turkey
perlite
concrete
thermal resistance
reverse heat leak method
thermal diffusivity
flash method
Research on composite materials to be used in building insulation is presented. Building energy efficiency gained much broader significance following the COP 21 Paris agreement. In light of this outcome, this study focuses on the analysis of a construction material with improved potential building energy performance. A composite material consisting of Portland cement and perlite was developed and tested. R-values of perlite-reinforced panels at different moisture levels were measured by using the reverse heat leak method. Results obtained by this method were verified by testing materials with known properties and compared to theoretical calculations. Verification of theory was achieved within 1.8% error range. Thermal diffusivity values of the developed samples were also measured using the flash method. It was observed that addition of perlite to cement increases the thermal insulation capacity while thermal resistance decreases with increasing moisture content in the panels. Thermal diffusivity was found to be increasing up to a critical moisture level beyond which it decreases due to the effect of density of water that dominates the increase in thermal conductivity. These findings are considered to be significant for the construction industries, especially for regions with abundant perlite reserves.
HEAT TRANSFER IN MAGNETITE (Fe3O4) NANOPARTICLES SUSPENDED IN CONVENTIONAL FLUIDS: REFRIGERANT-134A (C2H2F4), KEROSENE (C10H22), AND WATER (H2O) UNDER THE IMPACT OF DIPOLE
217-232
10.1615/HeatTransRes.2019029919
A.
Majeed
Department of Mathematics and Statistics, Bacha Khan University Charsadda, kpk, Pakistan
Ahmed
Zeeshan
Department of Mathematics and Statistics, FBAS, IIUI, Islamabad, Pakistan
Muhammad Mubashir
Bhatti
College of Mathematics and Systems Science, Shandong University of Science and Technology,
Qingdao, Shandong, 266590, China; Shanghai Institute of Applied Mathematics and Mechanics, Shanghai University Yanchang Road,
Shanghai 200072, China
R.
Ellahi
Department of Mathematics and Statistics, FBAS, IIUI, Islamabad, Pakistan; Center for Modeling & Computer Simulation, Research Institute, King Fahd University of Petroleum & Minerals, Dhahran, Saudi Arabia
heat transfer
ferrofluid
boundary layer flow
magnetite (Fe3O4)
porous media
partial slip
In this article, theoretical investigation has been performed to explore the heat transport characteristics of a magnetic nano-fluid (ferrofluid) with dipole field impact. We considered magnetite (Fe3O4) nanoparticles suspended in three base fluids such as kerosene (C10H22), Refrigerant-134a (C2H2F4), and water (H2O). Magnetic dipole is of importance as it controls the momentum and thermal boundary layer region. Also characterization of magnetothermomechanical (ferrohydrodynamic) interaction decelerates the motion of the fluid as compared to the hydrodynamic case. Governing flow problem is normalized into ordinary differential equation by adopting the similarity transform procedure and thereafter solving by an effective shooting algorithm. Flow is generated due to a linearly porous stretched surface. Impact of involved constraints, namely, ferromagnetic parameter, suction, porosity, slip, and volume concentration of nanoparticle on friction factor and heat transfer rate are explained by graphs and tables. From the results we infer that the influence of ferrohydrodynamics is to flatten the velocity profile, whereas the decreasing effect is seen for the temperature profile for large values of nanoparticle volume fraction. Also it is shown that the Nusselt number is higher for the case of Refrigerant-134a for large values of concentration of nanoparticles.
NUMERICAL INVESTIGATION OF THE EFFECTS OF A CONSTANT MAGNETIC FIELD ON THE CONVECTIVE HEAT TRANSFER OF A WATER-BASED NANOFLUID CONTAINING CARBON NANOTUBES AND Fe3O4 NANOPARTICLES IN AN ANNULAR HORIZONTAL TUBE IN A LAMINAR FLOW REGIME
233-252
10.1615/HeatTransRes.2019029838
Hadi
Samsam-Khayani
School of Mechanical Engineering, Pusan National University, Busan 609-735, South Korea
Mohsen
Saghafian
Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111,
Iran
Shabnam
Mohammadshahi
School of Mechanical Engineering, Pusan National University, Busan 609-735, South Korea
Kyung Chun
Kim
School of Mechanical Engineering, Pusan National University, Jangjeon-dong, Gumjung-ku, Busan 609-735, Korea
ferrofluid
carbon nanotube
magnetic nanoparticles
constant magnetic field
convective heat transfer
This study numerically examined the effects of a constant nonuniform magnetic field on the laminar forced convective heat transfer of a hybrid nanofluid flowing through a heated annular tube and containing Fe3O4 nanoparticles and carbon nanotubes (CNTs). The investigations were carried out in a wide range of parameters, such as the volume concentrations of Fe3O4 nanoparticles (0.5-0.9%) and carbon nanotubes (0.25-0.9%) Reynolds number (548-1643), magnetic field strength (300-1000 Gauss), heat flux ratio (0-1), and radii ratio (0.4-0.6). First, the magnetic field was simulated using a Maxwell software, and then the results were transferred to a custom-made numerical code. The results show that the Fe3O4/CNT hybrid nanofluid significantly improves the convective heat transfer coefficient and, hence, the local and mean Nusselt numbers. Maximum enhancements in the mean Nusselt number of 23.1% and 4.03% were achieved for 0.9Fe3O4 + 0.9CNT at Re = 1643 at the outer and inner walls, respectively. In addition, the heat transfer was enhanced in the presence of constant magnetic fields. The effects of the magnetic field were more noticeable in nanofluids with higher volume concentrations and lower Reynolds numbers. Moreover, the convective heat transfer coefficient and then the Nusselt number increased on increasing the magnetic field strength, the volume concentrations of Fe3O4 nanoparticles and CNTs, and the heat flux ratio, and on reducing the radii ratio and Reynolds number. In comparison with the case without a magnetic field, the highest enhancements of 34.35% and 2.95% in the mean Nusselt numbers were obtained at the outer and inner walls, respectively. These results were obtained with the hybrid nanofluid containing 0.9Fe3O4 + 0.9CNT when the Reynolds number and the magnetic field strength were 548 and 1000 Gauss, respectively.
EFFECT OF OPERATING TEMPERATURE ON INTERFACE DIFFUSION AND POWER GENERATION OF BISMUTH TELLURIDE THERMOELECTRIC MODULES
253-262
10.1615/HeatTransRes.2019030539
Luxin
Wang
Key Laboratory of Thermo-Fluid Science and Engineering, MOE, Xi'an Jiaotong University,
Xi'an, Shaanxi 710049, China
Xing
Lu
Key Laboratory of Thermo-Fluid Science and Engineering, MOE, Xi'an Jiaotong University, Xi'an, Shaanxi, China, 710049; Department of Mechanical Engineering, University of Colorado Boulder, 80309
Xingfei
Yu
Key Laboratory of Thermo-Fluid Science and Engineering, MOE, Xi'an Jiaotong University,
Xi'an, Shaanxi 710049, China
Qiuwang
Wang
Key Laboratory of Thermo-Fluid Science and Engineering, MOE, Xi'an Jiaotong University,
Xi'an, Shaanxi 710049, China
Dongliang
Zhao
Department of Mechanical Engineering, University of Colorado at Boulder, Boulder, CO 80309, USA
Wei
Ren
Department of Mechanical Engineering, University of Colorado, Boulder, CO 80309, USA
Ting
Ma
Department of Thermo-Fluid Science and Engineering, School of Energy and Power Engineering, Xi'an Jiaotong University, Xianning West Road 28, Xi'an, Shaanxi 710049, China
thermal treatment temperature
interface diffusion
Ni diffusion barrier
output power
high temperature
stability
High-temperature stability of interfaces between metal electrodes and thermoelectric (TE) materials is one of the main factors that restrict the reliability of TE modules. The interface diffusion behavior of the connector of copper (Cu), tin (Sn) solder, and bismuth telluride (Bi2Te3) TE material layers and its influence on the module-level Seebeck coefficient are investigated experimentally. The experimental results show that the thermal treatment temperature has a significant effect on the interface diffusion. In the service environment of thermoelectric modules at a high operating temperature, the interface diffusion occurs, resulting in lower carrier concentration in thermoelectric materials, lower Seebeck coefficient, and poorer module performance. The X-ray diffraction measurements show that the Ni concentration reduces as the thermal treatment temperature increases, and finally the compound of NiTe2 is formed, which results in the decrease of carrier concentration inside Bi2Te3. The scanning electron micrograph (SEM) of interface connection layer shows that Ni diffuses into Bi2Te3 TE materials and the thickness of interface connection layer increases significantly compared to the one without high-temperature thermal treatments. As the thermal treatment temperature increases, the layer thickness also increases. The output power of the TE modules degrades by 13.6% after 6-h thermal treatment at 200°C.
VORTEX-INDUCED VIBRATION CHARACTERISTICS AND HEAT TRANSFER MECHANISM OF AN OSCILLATING PLATE ATTACHED TO A CYLINDER IN A CONSTANT-TEMPERATURE CHANNEL
263-274
10.1615/HeatTransRes.2019030374
Shabnam
Mohammadshahi
School of Mechanical Engineering, Pusan National University, Busan 609-735, South Korea
Hadi
Samsam-Khayani
School of Mechanical Engineering, Pusan National University, Busan 609-735, South Korea
Mahdi
Nili-Ahmadabadi
Department of Mechanical Engineering, Isfahan University of Technology, Isfahan 84156-83111,
Iran
Kyung Chun
Kim
School of Mechanical Engineering, Pusan National University, Jangjeon-dong, Gumjung-ku, Busan 609-735, Korea
bluff body
convective heat transfer
vortex-induced vibration
fluid-structure interaction
In the present study, a passive technique for heat transfer enhancement was used to affect the turbulence and eddies via an oscillating plate in a flow. The movement of the plate in the fluid domain was solved by a two-way fluid-solid interaction analysis. The increase in heat transfer by this method caused an increase in the friction coefficient, and paying attention to the heat transfer and pressure loss simultaneously is important. The role of the cylinder shape, cylinder location, and the length of the flexible plate in the heat transfer and pressure loss were investigated. It can be concluded that a bluff body before the oscillating plate can improve the performance evaluation criterion (PEC) by 13.75%. In addition, reducing the length of the plate by half can reduce the PEC number by 8%. The shape of the cylinder also has a significant effect on the heat transfer ratio and pressure loss. The best case was one with a circular cylinder behind the oscillating plate with a larger length with a PEC of 0.8.
CONVECTIVE AND RADIATIVE THERMAL ANALYSIS OF COMPOSITE WALL WITH NONLINEAR TEMPERATURE-DEPENDENT PROPERTIES
275-296
10.1615/HeatTransRes.2019031349
Meenal
Singhal
School of Mathematics, Thapar Institute of Engineering and Technology, Patiala-147004,
Punjab, India
Rohit Kumar
Singla
Mechanical Engineering Department, Thapar Institute of Engineering & Technology,
Patiala-147004, Punjab, India
Kavita
Goyal
School of Mathematics, Thapar Institute of Engineering and Technology, Patiala-147004,
Punjab, India
Adomian decomposition method
thermal performance
Newton-Raphson method
steady state solution
composite walls
internal heat generation rate
thermal convective
thermal radiation
thermal conductivity
emissivity
Composite walls were investigated for thermal performance by the Adomian decomposition method (ADM). The thermal properties of a composite system, i.e., the thermal conductivity, heat transfer coefficient, and surface emissivity were considered temperature-dependent and hence were nonlinear. In addition, the internal heat generation was also assumed to be temperature-dependent. A thermal analysis was done, where the effects of conduction, convection, and radiation were involved. The analysis was carried out to evaluate the temperature within the walls using ADM, a semi-analytical technique. The results obtained from ADM were found to be in good agreement with that of differential transform method (DTM), present in the literature. The temperature distribution and performance parameter have been evaluated as explicit functions of input parameters. Furthermore, the variation of these outputs with respect to heating input parameters (such as conduction-convection parameter) was studied. The response of the functional form of temperature-dependent properties on the variation of output parameters has also been investigated. Last but not least, a case where convection and radiation sink temperatures were considered to be different has also been studied. The current work also reported the efficiency of the overall system. The critical parameters were determined which influence the efficiency of the current setup.