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Jason Velardo^a, Randeep Singh^a,*, Mohammad Shahed Ahamed^a, Masataka Mochizuki^b, Abhijit Date^c, Aliakbar Akbarzadeh^c
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-11, 2021, DOI:10.5098/hmt.17.1
Abstract Thermal solutions play an integral role in managing heat loads for electronic devices. As these electronics become more compact and portable, improved thermal management solutions need to be introduced. Thin flattened heat pipes (0.8mm – 2.0mm thick) and piezoelectric fans (1mm thick) have been proposed here for this purpose. The maximum heat carrying capacity of the flattened heat pipe was experimentally determined and found to be a function of the flattened heat pipe thickness. Reductions from 48W at 2.0mm to 7W at 0.8mm were observed. This was expected to be due to capillary limitations. The piezoelectric fan could be operated… More >

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K. Kranthi Kumar^1,*, CH. Baby Rani² , A. V. Papa Rao³
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-9, 2021, DOI:10.5098/hmt.17.2
Abstract MHD Casson flow fluid over an inclined plate with aligned magnetic, Hall current and thermal radiation in the presence of Chemical reaction is examined. The governing equations are solved using perturbation method. The effects of various physical parameters like as chemical reaction parameter, radiation parameter, Casson parameter, Schmidt number, Grashof number, modified Grashof number, Prandtl number, magnetic parameter, inclined angle, Hall parameter and Aligned parameter are discussed for velocity, temperature and concentration. The skin-friction, Nusselt number and Sherwood number are also obtained and are shown in tabular form. More >

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Yan-Juan Zhao^a,*, Yu-Liang Zhang^b,† , Chen-Liang Zhang^b
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-7, 2021, DOI:10.5098/hmt.17.3
Abstract Vortex flowmeter adopts advanced micro processing technology, which has the advantages of strong function, wide flow range, simple operation and maintenance, convenient installation and use. It is widely used in petroleum, chemical industry, electric power, metallurgy, urban gas supply and other industries to measure various gas flows. In order to study the characteristics of the inner flow passage of the vortex flowmeter and reach the normal working standard of the vortex flowmeter, this paper uses CFX to calculate the turbulent kinetic energy, eddy viscosity and flow velocity of the inner flow passage of the vortex flowmeter and analyze their distribution,… More >

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A. Sahaya Jenifer^a , P. Saikrishnan^a,*, J. Rajakumar^b
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-8, 2021, DOI:10.5098/hmt.17.4
Abstract This paper examines the steady magnetohydrodynamic (MHD) flow of water over a yawed cylinder with variable fluid properties and non-uniform mass transfer. The impact of viscous dissipation is taken into consideration. The velocity and temperature fields are governed by coupled nonlinear partial differential equations together with boundary constraints. These governing equations are converted to dimensionless form with suitable non-similar transformations and then solved using an implicit finite difference method and the quasi-linearization technique. The results indicate that the yaw angle enhancement declines the skin friction coefficient in the axial direction and the heat transfer coefficient. It is also ascertained that… More >

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Xiao Sun^a, Fan-Kang Zeng^a, Jia-Bing Yang^a, Feng-Lin Zhou^a, Yu-Liang Zhang^b,*
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-6, 2021, DOI:10.5098/hmt.17.5
Abstract In order to better study the internal flow characteristics of centrifugal pump as turbine, CFX software is employed to carry out numerical simulation to obtain flow field under different working conditions for pump as turbine based on the standard k - epsilon turbulence model and the SIMPLEC algorithm. The efficiency curves of the pump and pump as turbine are obtained under different working conditions. The results show that the effciency characteristics of the pump change greatly during the process of pumping. The efficiency of the turbine is higher than that of the pump under the respective optimal operating conditions. The… More >

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Hasan S. Majdi^a,*, Azher M. Abed^b, Laith J. Habeeb^c
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-7, 2021, DOI:10.5098/hmt.17.6
Abstract The present work presents and analyzes the results acquired from outdoor experimental measurements of a solar latent heat storage unit integrated with built-in thermal energy storage at the presence and absence of porous media. The tank consists of a porous media part, a packed of glass beds, and the fluid flowing through the void space surrounding the porous glass beds. The porous tanks were filled by 1.68 mm glass beds to form bed heights (h) of 10 and 20 cm. Results show that the maximum thermal storage of 110 min is achieved in hot flow rate qh=4 LPM, cold flow… More >

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Elyazid Flilihi^a,† , Mohammed Sriti^b, Driss Achemlal^a, Mohamed El haroui^c
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-6, 2021, DOI:10.5098/hmt.17.7
Abstract In this work, a numerical simulation of steady and laminar free convection flow over a heated vertical flat plate embedded in a saturated porous medium by a Newtonian fluid is presented and analyzed. The Brinkman-Forchheimer extension of Darcy’s law has been adopted to describe the movement of fluid within the porous matrix. A numerical solution of the governing continuity, momentum and energy equations was made with the appropriate boundary conditions using ANSYS/FLUENT software based on finite volume method. The found results are graphically presented and physically discussed for main controling parameters. Subsequently, we compared our CFD calculation by the results… More >

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O. M. Oyewola^a,b,*, O. S. Ismail^b, J. O. Bosomo^b
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-5, 2021, DOI:10.5098/hmt.17.8
Abstract This paper investigates possible inherent modifications of the radiative heat source term due to the influence of turbulence in the thermal radiation field of a gas turbine combustor flame. Adapting a flame temperature of 2000[K], COMSOL Multiphysics software was utilized to numerically simulate the process, assuming a gray gas participating medium with absorption coefficient of 0.03[m^-1]. The analysis of the results for five (5) different radial cut sections of the simulated combustor chamber shows that turbulence-radiation interactions cause radiative heat losses from the flame, with the divergence of the radiative heat flux having a deviation factor of 3.48, and a… More >

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Mian Wang¹, Yongbin Zhang^2,*
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-5, 2021, DOI:10.5098/hmt.17.9
Abstract There is the connexon between neighboring cells in human bodies, which normally has the cylindrical channels with the diameter about 1.5nm. The analysis is here derived for the water transport through such a narrow channel based on the nanoscale flow equation by considering the dynamic, interfacial slippage and non-continuum effects of the water. The calculation shows that when the intracellular fluids of the neighboring cells are not obviously different, there is no wall slippage in the connexon channel and the water flow rate through the channel is significantly smaller than that calculated from the classical continuum flow equation due to… More >

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Zhiyun Wang^*, Ziqing Wang, Mo Yang
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-7, 2021, DOI:10.5098/hmt.17.10
Abstract This paper presents a two-dimensional fluid-structure interaction numerical simulation of fluid flow over two horizontal heat exchange cylinders affected by a flapping reed in a domain. The reed is a thin flexible sheet made of elastic material with one end fixed on the trailing edge of the upstream cylinder. The effects of the reed length and the cylinder spacing on the periodic oscillations of the reed, the flow field and the heat transfer of the downstream cylinder. The results show that the oscillation of the reed in this paper is a single-period oscillate model. Compared to the case of cylinder… More >

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Olanrewaju M. Oyewola^a,b,*, Samuel I. Afolabi^b , Olawale S. Ismail^b
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-8, 2021, DOI:10.5098/hmt.17.11
Abstract The problem of natural convection in rectangular cavities with different aspect ratios has been numerically analyzed in this study. Cavities considered have their right vertical walls heated and cooled at the opposite with constant temperatures, while horizontal walls are kept adiabatic. The objective of this study is to ascertain the significant effects of Rayleigh numbers (Ra), Nusselt numbers (Nu) and aspect ratios (AR) on flow and heat transfer in rectangular cavities. The equations of Navier-Stokes and energy are solved by applying Galerkin weighted residual Finite Element Method. Parametric calculations are performed for Rayleigh numbers (Ra) ranging from 104 to 108… More >

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V. W. Bhatkar^a,*, Anirban Sur^b,*
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-5, 2021, DOI:10.5098/hmt.17.12
Abstract A jet pump or an ejector uses primary fluid flow as motive fluid to entrained secondary fluid. In this paper, the main intention is to find suction flow rate, primary flow rate, secondary flow rate, loss factors and ejector efficiency for an applied pressure. The values of the different loss factors estimated are primary nozzle loss factor (Kp)=0.06, suction loss factor (Ks)=0.04-0.1, mixing loss factor (Km)=0.07-0.1 and diffuser loss factor (Kd)=0.0289. It is found that with the increase in pressure across the ejector, efficiency increases with increase in flow ratio and decrease in pressure ratio. More >

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Matt Ghiji^a,*, Ian Burch^b, Brigitta Suendermann^b, Grant Gamble^b, Vasily Novozhilov ^a, Paul Joseph^a, Khalid Moinuddin^a
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-8, 2021, DOI:10.5098/hmt.17.13
Abstract Lithium-ion batteries (LiBs) have superior energy density and lifetime compared to battery technologies such as lead acid. Despite the widespread application of LiBs in energy storage systems, electronic devices, aerospace and the automotive industry, they present a fire risk. In this study, experiments were conducted to characterize the thermal behavior of the electrolyte (as the main contributor to LiB fires) using a cone calorimeter; investigate the interactions of water mist and a Bunsen burner, as a precursor to examining the effectiveness of a water mist suppression system in extinguishing a LiB fire. In the present work, we have endeavored to… More >

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Jingquan Zhang^a,b, Kun Zhang^a,b,*
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-6, 2021, DOI:10.5098/hmt.17.14
Abstract Detailed numerical analysis is presented for flow and heat transfer in sinusoidal-corrugated parallel channel with six discrete heat sources placed under the bottom surface. Three dimensional numerical model are applied for simulating the flow and heat transfer process and the Colburn j factor is applied to evaluate the overall performance of the corrugated liquid cooled channel. The results show that the maximum temperature in the middle section decreases and the pressure loss increases as the wavelength of sinusoidal surface on the bottom decreases, while the increasing wave amplitude of corrugated surface can enhance the heat transfer rate in the ranges… More >

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Ida Bagus Alit, I Gede Bawa Susana^*
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-7, 2021, DOI:10.5098/hmt.17.15
Abstract Rice husk is a cheap fuel source and it is abundantly available in Indonesia. The heat exchanger mechanism was used in other to, the dried material was not contaminated by the combustion gases. The drying system consists of three components which include the furnace, heat exchanger pipe, and drying chamber. The heat exchanger pipe connects the furnace with the drying chamber and transfers the heat generated from rice husk burning to the drying chamber. The drying chamber was the section for drying the jackfruit dodol. It consists of 4 shelves and is equipped with an exhaust fan. The results showed… More >

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Felix Schily^a,∗, Wolfgang Polifke^a
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-15, 2021, DOI:10.5098/hmt.17.16
Abstract A simple open-loop pulsating heat pipe model is proposed, which allows to analytically determine the start-up behavior by a linear stability analysis. Two distinct types of instability can occur in such a pulsating heat pipe: oscillatory and non-oscillatory. This paper demonstrates that for bubbles consisting of non-condensible gas, large temperature gradients along the wall are required to achieve start-up, whereas start-up is fairly easy to achieve when there is only a single working medium that forms bubbles from its vapor. The study also finds that surface tension as such only influences start-up indirectly, while contact angle hysteresis dampens out any… More >

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Shuang Cao^a,*, Hui Yang^a, Luxing Zhao^a, Tao Wang^a, Jian Xie^b,†
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-16, 2021, DOI:10.5098/hmt.17.17
Abstract Flow boiling heat transfer is an effective way to fulfill the energy transfer. The wettability of boiling surface influences the liquid spreading ability and the growth, departure, and release frequency of bubbles, which determines the heat transfer performance. According to the wettability and combination forms, boiling surface are classified into weak wetting surface, strong wetting surface, and heterogeneous wetting surface. Fabricating by physical, chemical method or coating the original surface with a layer of low surface energy, the weak wetting surface has more effective activation point and nucleation center density to improve heat transfer performance at low heat flux. The… More >

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Utpal Jyoti Das^a , Mira Das^b,*
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-8, 2021, DOI:10.5098/hmt.17.18
Abstract An unsteady mixed convection flow of an electrically conducting, viscous, incompressible fluid over an oscillating vertical surface in a Darcian porous regime in presence of heat generation/absorption and thermal radiation have been studied. The liquid and the surface is moving with constant angular velocity as a rigid body about an axis. The fluid is taken here to be gray, absorbing/emitting radiation but non scattering medium. Here firstorder chemical reaction and a transverse magnetic field have been considered. The presence of Hall current and Soret effect are considered. The governing coupled partial differential equations are solved by using Laplace transform technique… More >

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Emad D. Aboud¹ , Qusay Rasheed Al-Amir², Hameed K. Hamzah², Ammar Abdulkadhim³, Mustafa M. Gabir³, Salwan Obaid Waheed Khafaji², Farooq H. Ali^2,*
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-17, 2021, DOI:10.5098/hmt.17.19
Abstract The natural convection of nanofluid flow, which occurs between a sinusoidal-corrugated enclosure and a concentric inner cylinder has been numerically investigated. The two horizontal walls of this enclosure are considered adiabatic and two vertical corrugated walls are held at a constant value of the cold temperature while the inner concentric cylinder is heated isothermally. Different cylinder geometries (i.e, circular, square, rhombus, and triangular) located inside the enclosure are examined to find the best shape for optimum heat transfer. The physical and geometrical parameters influencing heat transfer are Rayleigh number (Ra=10³ -10⁶), undulation numbers (N=0,1 and 2), aspect ratios (AR=5, 2.5… More >

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Marwa M. Ibrahim^a,*, Mohamed Mahran Kasem^b,c
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-11, 2021, DOI:10.5098/hmt.17.20
Abstract Currently electricity generation technologies by thermal energy conversions become strong demand. The objective of this paper is to present a novel thermal study of absorber/receiver circular pipe of parabolic trough solar collector system for laminar and turbulent (k-ɛ model) fluids flow as well as two-dimensional numerical simulation is performed using CFD ANSYS FLUENT software. Significant improvements in heat transfer and velocity were discovered; the pattern of temperature distribution over the pipe absorber was displayed, and velocity vectors, pressure contours, and temperature contours were studied. The impact of increasing the heat flux towards the pipe wall is discussed. Heat transfer coefficient… More >

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Ammar Hassan Soheel, Omar Mahmood Jumaah, Ahmed Mustaffa Saleem^*
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-7, 2021, DOI:10.5098/hmt.17.21
Abstract This paper presents a simulation and investigation of the heat transfer coefficient, pressure drop, and thermal conductivity of two - phase flow. The simulation was performed of mixtures (Al₂O₃ nanoparticles with R134a refrigerant). The size of nanoparticles (Al₂O₃) which is used in this study is 30 nm and volume concentrations are 0.015 and 0.03. The two – phase flowing through a horizontal circular microchannel of (diameter 100 µm, and length 20 mm) under constant heat flux (3000 W/m²) and constant wall temperature (330 K), also in this study used the inlet temperature at -20 oC and mass flow rates are… More >

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Zahraa A. Faisal^*, Hassanain Ghani Hameed, Dhafer Manea H. Al-Shamkhee
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-9, 2021, DOI:10.5098/hmt.17.22
Abstract One of the common water desalination apparatuses in freshwater regimes is Single Slope Solar Still (SSSS). This paper numerically investigated the heat transfer processes that took place inside the still. Also, implementing an optimization process to explore the best sustainable feed water preheating tank design. Comsol Software package (v 5.4) was utilized to develop and validate the 3D Mathematical model. The investigation included comparing four different tank designs namely are sphere, half-sphere, cone, and flat plate. In addition, the influence of altering the volume of the tank has been considered. The study revealed that the half-sphere design with a volume… More >

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N.Vijaya^a,* , P. Krishna Jyothi^b, A. Anupama^c, R. Leelavathi^d, K. Ambica^e
Frontiers in Heat and Mass Transfer, Vol.17, pp. 1-8, 2021, DOI:10.5098/hmt.17.23
Abstract The main intention of this study is to explore Maxwell fluid under the influence of thermophoresis and buoyancy forces induced by exponentially stretching sheet under chemical reaction. Cattaneo –Christov heat flux model is used to explore heat and mass characteristics with variable magnetic field, and chemical reaction. Variables of similarity were induced to transmute partial differential equations into dimensionless equations and are resolved numerically by elegant method bvp 4c. Behavior of various critical parameters on velocity, temperature and concentrations is graphically presented and discussed. Non Newtonian nature of the Maxwell fluid is clearly explored by the Maxwell parameter, it was… More >

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