Home / Journals / FHMT / Vol.13, No.1, 2019
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  • Open AccessOpen Access

    ARTICLE

    STUDY OF THERMAL AND MECHANICAL PROPERTIES OF FIBERGLASS MULTI-WALL CARBON NANOTUBE/EPOXY

    Luay Hashem Abbuda,b,*, Hyder H. Ballac, Ammar F. Abdulwahidd , Zaid Sttar Karimd
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-8, 2019, DOI:10.5098/hmt.13.30
    Abstract This project aims at determining both numerical and experimental to some thermal properties and its thermal expansion coefficient, thermal conductivity and mechanical properties of reinforcement of fiber glass woven with matrix of multi wall carbon nanotube MWCNT / epoxy composite. First, this powder is known to have a very good thermal properties. So, the nanopartical combined with resin has poor thermal properties. Secondly, the development a complete solution for the manufacturing of multi wall carbon nanotube /epoxy composites different volume fraction from 1% to 10% with increment of 2% to compare the result of finite More >

  • Open AccessOpen Access

    ARTICLE

    EFFECT OF SEMI-CIRCLE RIB ON HEAT TRANSFER COEFFICIENT IN A RECTANGULAR CHANNEL

    Riyadh S. Al-Turaihi a , Doaa Fadhila,b,*, Azher M. Abedb
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-7, 2019, DOI:10.5098/hmt.13.29
    Abstract In this paper an experimental and numerical analysis has been conducted to study the effect of heat transfer and filed flow of two-phase flow (water and air) through a rectangular ribbed channel. The study has involved the several values of heat flux (120,140,160 Watts), air and water superficial velocity (1.096, 1.425, 1.644, 1.864, and 2.193 m/s) and (0.0421, 0.0842, and 0.1474 m/s), respectively. The distribution of temperature along the channel was photographed using thermal camera and compared with numerical results . The experimental test system was fabricated of vertical rectangular channel with cross section of… More >

  • Open AccessOpen Access

    ARTICLE

    INFLUENCE OF RING SIZE AND LOCATION ON FLOW TOPOLOGY, HEAT TRANSFER STRUCTURE AND THERMAL EFFICIENCY IN HEAT EXCHANGER SQUARE CHANNEL PLACED WITH 30-DEGREE INCLINED SQUARE RING

    Amnart Boonloia, Withada Jedsadaratanachaib,*
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-11, 2019, DOI:10.5098/hmt.13.28
    Abstract This paper presents the numerical investigations (finite volume method with SIMPLE algorithm) on flow structure, heat transfer behavior and performance assessment in heat exchanger square channel placed with 30o inclined square ring (ISR). The influences of ring size and placement on flow and heat transfer characteristics are considered for laminar flow region with the Reynolds number in the range around 100 – 2000. The purpose for the insertion of the ISR in the square channel is to induce the vortex flow and also increase the turbulent mixing. The numerical result reveals that the ring size More >

  • Open AccessOpen Access

    ARTICLE

    INFLUENCE OF THE FLUID-WALL INTERACTION ON THE MULTISCALE FLOW THROUGH A MICRO SLIT PORE CONSIDERING THE ADSORBED LAYER-FLUID INTERFACIAL SLIPPAGE

    Yongbin Zhang*
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-6, 2019, DOI:10.5098/hmt.13.27
    Abstract A multiscale analysis is carried out for the pressure driven flow rate through a micro/nano slit pore when the adsorbed layer-fluid interfacial slippage is considered. The flow of the adsorbed layer on the channel wall is described by the flow factor approach model for nanoscale flow, and the flow of the continuum fluid intermediate between the two adsorbed layers is described by a continuum fluid model. The adsorbed layer-fluid interfacial slippage is considered, while the adsorbed layer-wall surface interfacial slippage is ignored. The weak, medium-level and strong fluid-wall interactions and the solid adsorbed layer assumption… More >

  • Open AccessOpen Access

    ARTICLE

    NUMERICAL ANALYSES ON VAPOR PRESSURE DROP IN A CENTERED-WICK ULTRA-THIN HEAT PIPE

    Yasushi Koitoa,*
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-6, 2019, DOI:10.5098/hmt.13.26
    Abstract This paper describes extended numerical analyses on vapor pressure distribution in a centered-wick ultra-thin heat pipe. Analyses were conducted by using a three-dimensional model developed by the author. Numerical results were obtained changing design parameters and operating conditions of the heat pipe. Discussion was made on the heat transfer limit as well as the vapor pressure drop. Moreover, a simple method was also presented to evaluate the vapor pressure drop in the ultra-thin heat pipe. Calculated results with the simple method agreed in 10 % with the three-dimensional numerical results. More >

  • Open AccessOpen Access

    ARTICLE

    EFFECT OF CYLINDER DIAMETER ON STATE QUANTITIES FOR IRREVERSIBLE PROCESS IN PISTON-CYLINDER SYSTEM

    Siti Nurul Akmal Yusofa , Yutaka Asakoa,*,Mohammad Faghrib , Lit Ken Tana , Nor Azwadi bin Che Sidika, Wan Mohd Arif bin Aziz Japara
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-5, 2019, DOI:10.5098/hmt.13.25
    Abstract A numerical analysis for the effect of a cylinder diameter on the state quantities for the irreversible process in a piston-cylinder system was conducted using the LB1S model. The numerical method is based on the ALE method. The cylinder-diameter range of D=0.01 m to 0.10 m was chosen. The effect of the cylinder-diameter on the state quantities was slight in the single compression with the piston velocity of -10 m/s. The ratio of the average pressure to the pressure of the reversible process at the end of the first cycle ranged from 1.00023 to 1.00462 in More >

  • Open AccessOpen Access

    ARTICLE

    DATA CENTER ENERGY CONSERVATION BY HEAT PIPE BASED PRECOOLER SYSTEM

    Randeep Singh* , Masataka Mochizuki, Koichi Mashiko, Thang Nguyen*
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-6, 2019, DOI:10.5098/hmt.13.24
    Abstract In the present paper, data center energy conservation systems based on the heat pipe heat exchanger (HPHE) pre-cooler to downsize the chiller capacity and working time has analysed, designed and discussed. The proposed system utilizes thermal diode character of heat pipe to transfer waste heat from source (pre-cooler coolant) to ambient and have been analyzed as per metrological conditions in New York. HPHE Pre cooler with 118 heat pipes and designed for 30 °C ambient temperature has been designed to effectively dissipate 30 kW or more datacenter heat throughout the year. The payback period of More >

  • Open AccessOpen Access

    ARTICLE

    FLOW AND HEAT TRANSFER CHARACTERISTICS OF AIR IN SQUARE CHANNEL HEAT EXCHANGER WITH C-SHAPED BAFFLE: A NUMERICAL STUDY

    Amnart Boonloia, Withada Jedsadaratanachaib,*
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-18, 2019, DOI:10.5098/hmt.13.23
    Abstract The purpose of the present work is to study flow configuration and heat transfer behavior in a square channel heat exchanger equipped with C-shaped baffle. The influences of flow attack angle and baffle size on flow and heat transfer characteristics are considered for the laminar flow regime with the Reynolds number around 100 – 2000. The numerical study with finite volume method is selected for the present investigation. The SIMPLE algorithms is opted to solve the numerical problem. The numerical results are concluded in terms of flow and heat transfer mechanisms in the tested section.… More >

  • Open AccessOpen Access

    ARTICLE

    POWER LOSS IN MULTISCALE MASS TRANSFER

    Yongbin Zhang*
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-4, 2019, DOI:10.5098/hmt.13.22
    Abstract The power loss is calculated by a multiscale approach in the pressure driven mass transfer in a micro slit pore where there are the physical adsorbed layers respectively on the coupled walls and intermediate between them is a continuum fluid flow. The flow factor approach model for nanoscale flow is taken to simulate the flow of the adsorbed layer, and conventional hydrodynamic flow theory models the continuum fluid flow. The calculation shows that the adsorbed layer on the wall surface can have a very significant effect on the power loss in this multiscale mass transfer, More >

  • Open AccessOpen Access

    ARTICLE

    EXPERIMENTAL INVESTIGATION AND MATHEMATICAL MODELING OF CONVECTIVE DRYING KINETICS OF WHITE RADISH

    Abhishek Dasorea,*, Ramakrishna Konijetib , Naveen Puppalac
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-7, 2019, DOI:10.5098/hmt.13.21
    Abstract The influence of air temperature on drying kinetics of radish slices in a bench scale convective tray dryer was examined experimentally and suitable drying model was developed. The experiments of drying of radish slices were conducted at 40, 50 and 60 °C with an air velocity of 2 More >

  • Open AccessOpen Access

    ARTICLE

    PHYSICAL HEAT TRANSFER

    Hai-Dong Wanga , Zeng-Yuan Guoa,*
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-12, 2019, DOI:10.5098/hmt.13.20
    Abstract The classical heat transfer theory is established on the empirical models of Fourier’s heat conduction law and Newton’s cooling law. Although the classical theory has been successfully used in a wide range of industrial engineering applications, it lacks deep understanding of the physical mechanisms for energy transport and analytical methodology based on solid mathematical and mechanical principles. The rapid development of modern science and technology challenges the traditional heat transfer theory in two aspects: (1) Fourier’s law of heat conduction is no longer valid under the ultra-fast laser heating or nanoscale conditions; (2) The optimization… More >

  • Open AccessOpen Access

    ARTICLE

    A CHEBYSHEV SPECTRAL METHOD FOR HEAT AND MASS TRANSFER IN MHD NANOFLUID FLOW WITH SPACE FRACTIONAL CONSTITUTIVE MODEL

    Shina D. Oloniiju , Sicelo P. Goqo, Precious Sibanda
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-8, 2019, DOI:10.5098/hmt.13.19
    Abstract In some recent studies, it has been suggested that non–Newtonian fluid flow can be modeled by a spatially non–local velocity, whose dynamics are described by a fractional derivative. In this study, we use the space fractional constitutive relation to model heat and mass transfer in a nanofluid. We present a numerically accurate algorithm for approximating solutions of the system of fractional ordinary differential equations describing the nanofluid flow. We present numerically stable differentiation matrices for both integer and fractional order derivatives defined by the one–sided Caputo derivative. The differentiation matrices are based on the series More >

  • Open AccessOpen Access

    ARTICLE

    AN ITERTIVE DESIGN METHOD TO REDUCE THE OVERALL THERMAL RESISTANCE IN A CONJUGATE CONDUCTION-FREE CONVECTION CONFIGURATION

    Chadwick D. Sevart* , Theodore L. Bergman
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-18, 2019, DOI:10.5098/hmt.13.18
    Abstract A design approach is proposed and demonstrated to identify desirable two-dimensional solid geometries, cooled by natural convection, that offer superior thermal performance in terms of reduced overall (conduction-convection) thermal resistance. The approach utilizes (i) heat transfer modeling in conjunction with (ii) various novel shape evolution rules. Predictions demonstrate the evolution of the solid shape and associated reduction of the overall thermal resistance. Parametric simulations reveal the dependence of the predicted solid shape on the evolution rule employed, the thermal conductivity of the solid material, and the strength of advection within the fluid. More >

  • Open AccessOpen Access

    REVIEW

    MECHANICALLY DRIVEN OSCILLATING FLOW COOLING LOOPS-A REVIEW

    M.D. Alam, O.T. Popoola, Y. Cao*
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-16, 2019, DOI:10.5098/hmt.13.17
    Abstract The significant increase in the heat dissipation associated with the increased throughput in computing, renewable energy, and electric vehicles has become a limitation to the evolution of these technologies. The needs for more effective thermal-management methods for higher heat fluxes and more uniform temperature have resulted in the development of mechanically driven oscillating flow cooling systems. The objective of this paper is to review the state-of-the-art of mechanically driven oscillating flow loops (MDOFLs) in terms of several aspects such as heat transfer, fluid mechanics, and thermodynamic principles. In each aspect, essential formulas and related sciences More >

  • Open AccessOpen Access

    ARTICLE

    WALL HEAT FLUX PARTITIONING ANALYSIS FOR SUBCOOLED FLOW BOILING OF WATER-ETHANOL MIXTURE IN CONVENTIONAL CHANNEL

    B.G. Suhasa,* , A. Sathyabhamab, Kavadiki Veerabhadrappaa , R. Suresh Kumara, U. Kiran Kumara
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-8, 2019, DOI:10.5098/hmt.13.16
    Abstract In the present study, heat transfer coefficient of water-ethanol mixture in the subcooled boiling region is determined in a rectangular conventional channel (Channel size ≥3 mm). When the heat flux and mass flux increase it is observed that heat transfer coefficient increases. But the effect of heat flux is significant when compared with that of mass flux in the subcooled boiling region. It is found that maximum and minimum heat transfer coefficient are observed for mixture with 25% Ethanol volume fraction and 75% Ethanol volume fraction respectively. Wall heat flux partitioning analyses is carried out More >

  • Open AccessOpen Access

    ARTICLE

    EFFECTS OF NON-UNIFORM SLOT SUCTION/INJECTION AND CHEMICAL REACTION ON MIXED CONVECTIVE MHD FLOW ALONG A VERTICAL WEDGE EMBEDDED IN A POROUS MEDIUM

    M. Ganapathiraoa,∗ , Ali J. Chamkhab, N. Srinivasa Raoc
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-13, 2019, DOI:10.5098/hmt.13.15
    Abstract In this investigation, our objective is to study the effect of non-uniform slot suction or injection into a steady mixed convective MHD boundary layer flow over a vertical wedge embedded in a porous medium in the presence of chemical reaction. The wall of the wedge is embedded in a uniform porous medium in order to allow possible fluid wall suction or injection. The surface of the wedge is maintained at a variable wall temperature and concentration. The fluid is assumed to be viscous, incompressible and electrically conducting; and the magnetic field is applied transversally in… More >

  • Open AccessOpen Access

    ARTICLE

    INFLUENCE OF MHD ON FREE CONVECTION OF NON-NEWTONIAN FLUIDS OVER A VERTICAL PERMEABLE PLATE IN POROUS MEDIA WITH INTERNAL HEAT GENERATION

    Heng-Pin Hsua , Chuo-Jeng Huangb,*, Herchang Aya
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-8, 2019, DOI:10.5098/hmt.13.14
    Abstract The heat and mass transfer characteristics of the influence of uniform blowing/suction and MHD (magnetohydrodynamic) on the free convection of non-Newtonian fluids over a vertical plate in porous media with internal heat generation and Soret/Dufour effects are numerically analyzed. The surface of the vertical plate has a uniform wall temperature and uniform wall concentration (UWT/UWC). The numerical modeling of this problem attracts considerable attention, owing to its practical applications in biological sciences, electronic cooling, advanced nuclear systems, etc. The transformed governing equations are solved by Keller box method. Comparisons showed excellent agreement with the numerical More >

  • Open AccessOpen Access

    ARTICLE

    THERMAL TOPOLOGY OPTIMIZATION DESIGN OF SPINDLE STRUCTURE WITH A HYBRID CELLULAR AUTOMATON METHOD

    Xiaolei Denga,b,c,*, Jin Wangd , Hongcheng Shena, Jinyu Zhoua, Jianchen Wanga,c, Changxiong Xiea, Jianzhong Fub
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-6, 2019, DOI:10.5098/hmt.13.13
    Abstract A hybrid cellular automaton model combined with a finite element method for thermal topology optimization of spindle structure is developed. The higher order 8-node element and von Neumann strategy are employed for the finite element and the cellular element, respectively. The local sensitivity filtering algorithm and the weight approach are applied. The four validating studies of two-dimensional structure for thermal topology optimization are carried out. The structure evolution and thermal distribution evolution of thermal topology optimization are investigated. The results show the developed hybrid method is more efficient for thermal topology optimization. Meanwhile, the thermal More >

  • Open AccessOpen Access

    REVIEW

    REVIEW OF VARIOUS THIN HEAT SPREADER VAPOR CHAMBER DESIGNS, PERFORMANCE, LIFETIME RELIABILITY AND APPLICATION

    Masataka Mochizukia,*,†, Thang Nguyenb
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-6, 2019, DOI:10.5098/hmt.13.12
    Abstract The cooling device for computers and electronics is getting smaller and thinner year after year, especially for the mobile handheld device such as smartphone which is the most popular gadget and widely use nowadays. It seems that in the current trend every 6-12 months a new model of smartphone is introduced and it was packed with faster processing processor, memories, and graphics, higher density battery, higher resolution for camera and video and so on. The drawback is the device getting hotter due to the increase of heat dissipation caused by faster computing. The traditional method… More >

  • Open AccessOpen Access

    ARTICLE

    EFFECT OF ABSORBER TYPES OF CONVENTIONAL DISTILLERS ON THE AMOUNT OF DISTILLED WATER PRODUCTION

    M. Mirmanto*, M. Wirawan, I.M.A. Sayoga, S. Syahrul, M. Faisal, A. Abdullah
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-7, 2019, DOI:10.5098/hmt.13.10
    Abstract Due to clean water crisis in the dry season in some places in Indonesia, experiments to find the best distiller to provide distilled water were performed. The long-term goal of this study is to create a distiller that is cheap, simple, easy to make, durable, low maintenance, but produces plenty of distilled water. Three identical conventional distillers with different absorbers had been tested for about 6 days in May 2019. These three distillers were used to evaporate and condense seawater to be distilled water. The absorbers types employed were type A, B, and C. The More >

  • Open AccessOpen Access

    ARTICLE

    STUDY ON HEAT AND MASS TRANSFER AND NONLINEAR CHARACTERISTICS WITH THERMAL AND SOLUTAL SOURCE IN A CAVITY

    Yubing Lia , Mo Yanga,*, Jian Lib , Zhiyun Wanga
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-8, 2019, DOI:10.5098/hmt.13.11
    Abstract Thermalsolutal convection induced by mass and heat source in horizontal cavity is investigated numerically based on SIMPLE algorithm with QUICK scheme. The high-concentration heat source is placed in the square cavity, and the cavity wall is low temperature and low concentration. The smoke is used as the diffusion medium, and the flow field, temperature and concentration of the fluid under different Rayleigh number, buoyancy ratio Nc, Soret numbers and Dufour numbers are analyzed systematically. Parameter study demonstrates that heat and mass transfer of thermosolutal convection are enhanced with increasing Rayleigh number or buoyancy ratio, and More >

  • Open AccessOpen Access

    ARTICLE

    TURBINE BLADE LEADING EDGE IMPINGEMENT COOLING FROM NORMAL OR TANGENTIAL JETS WITH CROSSFLOW EFFECT

    Nian Wang, Mingjie Zhang, Sulaiman Alsaleem, Lesley M. Wright, Je-Chin Han*
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-13, 2019, DOI:10.5098/hmt.13.9
    Abstract This study investigates turbine blade, leading edge cooling from normal or tangential impinging jets. These jets impinging on a semi-cylindrical, inner surface are constrained to discharge in a single direction. The downstream jets are affected by the crossflow originating from the upstream jets. To understand the thermal flow physics, numerical simulations are performed using the realizable k- turbulence model. Both the experimental and numerical results show crossflow is more detrimental to normal impinging jets than the tangential jets. Furthermore, with a significant temperature drop across the jet plate, designers must correctly interpret jet impingement results. More >

  • Open AccessOpen Access

    ARTICLE

    OPERATING CHARACTERISTICS OF NAPHTHALENE HEAT PIPES

    B. Orra,* , R. Singha, A. Akbarzadehb , M. Mochizukic
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-7, 2019, DOI:10.5098/hmt.13.8
    Abstract Heat pipes that operate in the medium temperature range (550-700 K) are very rarely used in industry despite the potential demand of use. There is no consensus about suitable working fluids in this temperature range as research on possible working fluids is limited. One proposed working fluid is naphthalene. In this paper, a number of tests have been undertaken on both an individual naphthalene heat pipe and a naphthalene heat pipe heat exchanger. Unlike room temperature working fluids, medium temperature working fluids are solid at ambient temperature therefore they have unusual transient start up behaviour.… More >

  • Open AccessOpen Access

    ARTICLE

    NUMERICAL AND EXPERIMENTAL INVESTIGATIONS OF NATURAL CONVECTIVE HEAT TRANSFER FROM TWO-SIDED DIAGONALLY INCLINED SQUARE PLATES HAVING A FINITE THICKNESS

    Rafiq Manna* , Patrick H. Oosthuizen
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-12, 2019, DOI:10.5098/hmt.13.7
    Abstract Natural convective heat transfer from two-sided diagonally inclined square plates having various thicknesses has been numerically and experimentally investigated. The aim of this work is to determine the influence of the plate thickness and diagonal inclination angle on the heat transfer rate for various flow regimes. The mean heat transfer rate was numerically obtained using ANSYS FLUENT© and experimentally determined using the Lumped Capacity Method. The results indicate that the plate thickness does not have a significant influence on the heat transfer rate while the diagonal inclination angle significantly influences the heat transfer rate especially More >

  • Open AccessOpen Access

    ARTICLE

    MHD FLOW IN A CIRCULAR HORIZONTAL PIPE UNDER HEAT SOURCE/SINK WITH SUCTION/INJECTION ON WALL

    G. Nagarajua,∗ , Mahesh Garvandhab, J.V. Ramana Murthyc
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-8, 2019, DOI:10.5098/hmt.13.6
    Abstract This paper analyzes a hypothesis of the 2−dimensional thermal transport behavior of Newtonian axisymmetric, viscous heating flow in a horizontal pipe. The flow is subjected to an externally applied uniform suction across the pipe wall in the polar direction, a constant magnetic field perpendicular to the wall and a uniform heat source/sink on the surface of the cylinder. The thermal boundary condition is imposed as a uniform heat flux. The Velocity fields are expressed in terms of stream function and the solution is obtained using the homotopy analysis method (HAM). Graphs are designed to analyze More >

  • Open AccessOpen Access

    REVIEW

    INVESTIGATIONS OF WIRE-BONDED MICRO HEAT PIPES - A REVIEW

    C. B. SobhanaG. P. Petersonb,*
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-10, 2019, DOI:10.5098/hmt.13.5
    Abstract Micro heat pipes have found applications in numerous types of systems where effective heat dissipation in a limited space is required. One relatively new design/fabrication methodology for parallel micro heat pipes with high performance is referred to as “wire-bonded” micro heat pipe arrays. The following review analyzes the principles of operation of these devices and investigates the recent developments in the technology, along with their fabrication and application. The results indicate that these micro heat pipe arrays present an attractive alternative for a number of interesting applications, including many that have yet to be explored.   More >

  • Open AccessOpen Access

    ARTICLE

    THERMAL ANALYSIS OF HEAT TRANSFER ENHANCEMENT OF RIB HEAT SINK FOR CPU

    Ming Zhao* , Yang Tian
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-10, 2019, DOI:10.5098/hmt.13.4
    Abstract The field synergy principle and thermal resistance analysis were carried out for the heat transfer enhancement of a chip heat sink. Thermal analysis of the heat dissipation capacity is applied for setting up the gallery on the rib, changing the fan ventilation diameter, and changing the rib height. The results show that the analysis of field synergy principle agrees well with that of the thermal analysis, and setting up a gallery on the rib can improve the heat capacity of the heat sink. Meanwhile, the results also show that decreasing diameter of the ventilation causes More >

  • Open AccessOpen Access

    ARTICLE

    NATURAL CONVECTION OF NANOFLUIDS PAST AN ACCELERATED VERTICAL PLATE WITH VARIABLE WALL TEMPERATURE BY PRESENCE OF THE RADIATION

    H. Astutia, P. Srib, S. Kaprawia,†
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-8, 2019, DOI:10.5098/hmt.13.3
    Abstract The natural convection of the nanofluids from a vertical accelerated plate in the presence of the radiation flux and magnetic field is observed in this study. Initially, the plate with a temperature higher than the temperature of nanofluids is at rest and then it accelerates moving upward and then the wall temperature decreases. The governing unsteady equations are solved by the explicit method based on the forward finite difference. Three different types of water-based nanofluids containing copper Cu, aluminum oxide Al2O3 and titanium dioxide TiO2 are taken into consideration. The hydrodynamic and thermal performance of the More >

  • Open AccessOpen Access

    ARTICLE

    TRANSIENT MODELLING OF AN EV INVERTER HEAT SINK WITH PCM

    B. Orra,* , R. Singha, T. L. Phana , M. Mochizukib
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-6, 2019, DOI:10.5098/hmt.13.1
    Abstract One of the problems with cooling an IGBT inverter chip is that its heat generation is not constant. These chips tend to produce heat in pulses which results in high peak chip temperatures. Transient modelling is required to determine the suitability of a heat sink and to ensure the max peak temperature is not exceeded. This paper demonstrates a method of transient thermal analysis using a thermal resistance / capacitor network. A sample heat sink was modelled and then experimentally tested to validate the model. A novel method of modelling phase change materials (PCM) using More >

  • Open AccessOpen Access

    ARTICLE

    FLOW CHARACTERISTICS OF WET NATURAL GAS IN DIFFERENT THROTTLING DEVICES

    Xuewen Caoa,b,*, Qi Chua,b, Xiaodan Songa,b, Yuxuan Lia,b, Jiang Biana,b
    Frontiers in Heat and Mass Transfer, Vol.13, pp. 1-9, 2019, DOI:10.5098/hmt.13.2
    Abstract Wet natural gas widely exists in the natural gas industry, and the selection of throttling devices plays an important role in wet natural gas transportation. In order to study the flow field characteristics of different throttling devices in wet natural gas pipelines, a set of Laval nozzles, orifice plates, and plate valves have been designed. The standard k-ε model was selected for numerical simulation. By changing inlet pressure, inlet temperature or volume fraction of water-liquid, the pressure field and temperature fields of different throttling devices were obtained, and the influence of the presence of a More >

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