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Clement Roy^a,* , Prasanna Venuvanalingam^b , James F. Klausner^a , Renwei Mei^c
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-12, 2018, DOI:10.5098/hmt.11.1
Abstract This article presents both an experimental and numerical study of both stationary and sliding bubbles in a horizontal duct with forced convection heat transfer. An experimental facility was fabricated using a fully transparent, electrically-heated test section in which the bubble dynamics and the thermal field on the heated wall can be acquired using high-speed cameras and Thermochromic Liquid Crystals (TLC). Experiments were conducted using the working fluid HFE 7000 for two different turbulent Reynolds numbers. The experimental temperature field in the span-wise direction is first compared to the numerically calculated temperature field of a bubble sliding near a wall and… More >

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Junjie Chen^* , Baofang Liu, Longfei Yan, Deguang Xu
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-15, 2018, DOI:10.5098/hmt.11.2
Abstract The combustion and emissions characteristics of methane-air mixtures in high-temperature catalytic micro-combustors were studied numerically. Both the heterogeneous and homogeneous chemistry were modeled simultaneously using detailed reaction mechanisms in order to better understand the role of each pathway in determining the product distributions. Computational fluid dynamics simulations were performed at a variety of pressures, temperatures, compositions, and combustor dimensions to determine their effects on the combustion and emissions characteristics. Comparisons were made between the results obtained for a purely heterogeneous case, a purely homogeneous case, and a coupled homogeneousheterogeneous case. It was shown that homogeneous and heterogeneous chemistry take place… More >

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D. R. V. S. R. K. Sastry
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-7, 2018, DOI:10.5098/hmt.11.3
Abstract The present paper investigates the combined effects of melting phenomenon and viscous dissipation over a steady incompressible mixed convection boundary layer fluid flow along a vertical plate. Radiation and double dispersion are also taken into consideration. Further effect of homogeneous chemical reaction of order ’n’ is studied over the non-Darcy porous plate. Continuum equations that characterize fluid flow are transformed to a set of non linear ordinary differential equations through a suitable similarity transformation. These equations are then solved by MATLAB ’bvp4c’ iterative programming method. As a matter of accuracy and validation, available results are compared with the present study… More >

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Ralph Eismann^a,† , Robert Adams^b
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-7, 2018, DOI:10.5098/hmt.11.4
Abstract Convergence of numerical schemes for pipe network analysis requires continuous modelling of pressure losses in the transition region between laminar and turbulent regions. Several existing correlations for the friction factor of straight pipes and helical tubes are presented. Based on these correlations a new explicit correlation for helical tubes with arbitrary surface roughness is derived. The friction factor is expressed as a continuous function of the Reynolds number covering laminar, transitional, and turbulent flow regions. Potential sources of error are also discussed, including the effects of tube deformation caused by the bending process. More >

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P. Bala Anki Reddy^a , B. Mallikarjuna^b,*,K. Madhu Sudhan Reddy^a
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-10, 2018, DOI:10.5098/hmt.11.5
Abstract In this paper, a mathematical model has been developed to analyze the double diffusive convective flow of Casson fluid over an inclined stretching sheet with Cattaneo-Christov Heat Flux model. The velocity slip is considered over the surface of the stretching sheet as well. The governing equations for the pertinent model are transformed into non-dimensional highly coupled nonlinear differential equations using similarity transformations. The implicit finite difference method is used to carry out the numerical results and presented the graphs for different values of the physical parameter, Casson fluid parameter, and thermal relation time parameter, chemical reaction parameter for the cases… More >

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ARTICLE

G. Dharmaiah^a,* , CH. Baby Rani^b , N. Vedavathi^c , K.S. Balamurugan^d
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-8, 2018, DOI:10.5098/hmt.11.6
Abstract Analytical investigation is carried out to analyze the unsteady, two-dimensional, laminar, boundary layer flow of a viscous incompressible electrically conducting and heat absorbing fluid along a semi-infinite vertical permeable moving plate in the presence of Diffusion-thermo and radiation absorption effects. The set of ordinary differential equations are solved by using perturbation technique. The effects of the various fluid flow parameters on velocity, temperature and concentration fields with in the boundary layer have been analyzed with the help of graphs. Numerical values of local skin-friction coefficient, nusselt number and Sherwood number are tabulated. More >

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ARTICLE

Mo Yang^a,*, Xiaoming Wang^a, Zhiyun Wang^a, Zheng Li^b , Yuwen Zhang^b
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-6, 2018, DOI:10.5098/hmt.11.7
Abstract Turbulent convective heat transfer in an elliptical pipe are investigated numerically in this paper. The RSM model is employed in the simulations of elliptical tubes with different aspect ratio a/b and Reynolds numbers within the range of 10,000~120,000. It is found that the maximum deviation between the numerical result and the one from Dittus-Boelter equation contained a hydraulic diameter is 28.4%. Based on simulation results, the correlation between the Nusselt number and Reynolds number in the fully developed fluid section of the elliptical tube is obtained. More >

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Nidhal Hnaien^a , Salwa Marzouk^a , Lioua Kolsi^a,b,*, Abdullah A.A.A. Al-Rashed^c , Habib Ben Aissia^a , Jacques Jay^d
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-11, 2018, DOI:10.5098/hmt.11.8
Abstract The purpose of the present paper is to numerically investigate two plane turbulent parallel jets using CFD model. A parametric study was carried out to evaluate the simultaneous effect of the nozzle spacing and the velocity ratio on the merge point (MP), the combined points (CP) as well as the upper (UVC) and lower (LVC) vortices centers positions. Results show that the velocity ratio significantly affects twin-parallel jets flow structure. In fact, increasing the velocity ratio moves the MP, CP, UVC and LVC further upstream along the longitudinal direction while deflecting toward the stronger jet along the transverse direction. Due… More >

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M. Arun^a,*, M. Jose Prakash^b
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-10, 2018, DOI:10.5098/hmt.11.9
Abstract Prediction of heat transfer deterioration in rocket engine coolant channels with supercritical flow is essential while designing high pressure rocket engines. Three-dimensional conjugate heat transfer of cryogenic methane in rectangular engine cooling channels at supercritical pressures with asymmetric heating imposed on the bottom channel surface is numerically investigated, focusing on the effects of key parameters such as aspect ratio, heat flux and coolant pressure. Due to the similarity of the coolant channel with that of an actual rocket engine, the results obtained herein are beneficial for the design and optimization of rocket engine cooling systems. Heat flux is varied from… More >

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Amnart Boonloi^a, Withada Jedsadaratanachai^b,*
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-14, 2018, DOI:10.5098/hmt.11.10
Abstract Numerical analysis on flow configuration, heat transfer behavior and thermal performance in the heat exchanger tube equipped with various flow attack angles of the inclined wavy surface are presented. The laminar flow (Re = 100 – 1200) and turbulent flow (Re = 3000 – 10000) are considered for the present investigation. The flow attack angles of the inclined wavy surface are varied as 15o – 60o . The finite volume method with SIMPLE algorithm is selected to evaluate the current problem. The numerical results are reported in terms of flow and heat transfer mechanisms. The performance evaluations in forms of… More >

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Zoubair Boulahia^* , Abderrahim Wakif, Rachid Sehaqui
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-10, 2018, DOI:10.5098/hmt.11.11
Abstract A numerical study has been performed to investigate mixed convection flow in a vented square cavity with circular cooling obstacle. The governing equations such as two dimensional Navier-Stokes, continuity, and energy balance equations have been solved using a finite volume discretization method with SIMPLE algorithm. The effect of the Richardson number, outlet port location and volume fraction of nanoparticles were studied. The outlet port is varied from top to bottom in order to find the maximum heat transfer rate. The results indicated that by increasing the volume fraction of nanoparticles and reducing Richardson number, the heat transfer rate is enhanced.… More >

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Ammar Abdulkadhim^a,*, Azher Mouhsen Abed^a , Khaled Al-Farhany^b
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-7, 2018, DOI:10.5098/hmt.11.12
Abstract The conjugate natural convection heat transfer in a partially heated porous enclosure had been studied numerically. The governing dimensionless equations are solved using finite element method. Classical Darcy model have been used and the considering dimensionless parameters are modified Rayleigh number (10 ≤ Ra ≤ 10³), finite wall thickness (0.02 ≤ D ≤ 0.5), thermal conductivity ratio (0.1 ≤ K_r ≤ 10), and the aspect ratio (0.5 ≤ A≤ 10). The results are presented in terms of streamlines, isotherms and local and average Nusselt number. The results indicate that heat transfer can be enhanced by increasing the modified Rayleigh number,… More >

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R. Biswas^a , M. Afikuzzaman^b,*, M. Mondal^a , S.F. Ahmmed^a
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-10, 2018, DOI:10.5098/hmt.11.13
Abstract Present study concerns with the numerical investigation of the MHD free convection and heat transfer fluid flow through a semi-infinite vertical porous plate with the effects of chemical reaction. A boundary layer approximation is premeditated to develop a flow model representing time dependent momentum, energy and concentration equations. The governing model equations are governed as a form of coupled nonlinear dimensionless system of partial differential equations (PDEs) by the as usual mathematical procedure of mathematical transformation and which model equations are solved by using explicit finite difference method (EFDM). Then the numerical results have been calculated by Compaq Visual FORTRAN… More >

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G. Dharmaiah^a,†, N. Vedavathi^b , CH. Baby Rani^c , K.S. Balamurugan^d
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-7, 2018, DOI:10.5098/hmt.11.14
Abstract The time-dependent flow past an impulsively started vertical infinite plate in a viscous electrically conducting natural convective incompressible Nano-fluid is considered in this article by taking into account the effects of heat absorption, heat generation and radiation. An analytical study is performed to obtain exact solutions for water-based Nano-fluid TiO₂. The dimensionless governing equations for this investigation are solved analytically by using the small perturbation Technique. The effects of various physical parameters on velocity, temperature fields are presented graphically. With the aid of these, the expression for the skin-friction and Nusselt number profiles was done with the help of tables. More >

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Ravi Shankar Prasad^a , S.N. Singh^b , Amit Kumar Gupta^c,*
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-12, 2018, DOI:10.5098/hmt.11.15
Abstract A systematic approach for the optimal positioning of multiple isothermal heat sources mounted on the walls of a side vented open cavity filled with natural air (Pr = 0.70) under natural convection and surface radiation is discussed. A numerical investigation is performed for the different possible cases with the two isothermal heat sources of equal dimensions mounted on the walls of the cavity. The geometrical parameters like the aspect ratio (A = 2), side vent ratio (W1 = 0.50) and side port ratio (W2 = 0.50) along with the most pertinent parameters like Rayleigh Number (10⁴ ≤ Ra ≤ 10⁷… More >

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REVIEW

Naveen G. Patil, Tapano Kumar Hotta^*
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-13, 2018, DOI:10.5098/hmt.11.16
Abstract The manuscript deals with the critical review for cooling of discrete heated electronic components using liquid jet impingement. Cooling of electronic components has been a lead area of research in recent years. Due to the rapid growth of electronic industries, there is an enormous rise in the system power consumption, and the reduction in the size of electronic components has led to a rapid increase in the heat dissipation rate per unit volume of components. The present paper deals with the role of liquid jet impingement (heat flux removal rate 200 - 600 W/cm²) for cooling of electronic components. The… More >

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M. Mirmanto^*, I.W. Joniarta, I.M.A. Sayoga, N. Nurpatria, Y.A. Padang, I.G.N.K. Yudhyadi
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-9, 2018, DOI:10.5098/hmt.11.17
Abstract Due to rapid demand on the thermoelectric cooler box, an investigation concerning the effect of water volume on a thermoelectric cooler box performance and its COP has been conducted. The aim of this study is to know the performance and the COP of the cooler box with water volume variations. The conduction heat transfer rate flowing from the ambient to the cooler box space is discussed deeply as this type of heat transfer rate is seldom to be elucidated in the published literature and it can be the dominant of the heat load when there is no water volume inside… More >

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REVIEW

Xiang Zhang, Hadi Keramati, Martinus Arie, Farah Singer, Ratnesh Tiwari, Amir Shooshtari, Michael Ohadi^*
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-14, 2018, DOI:10.5098/hmt.11.18
Abstract Heat exchangers are key components of most power conversion systems, a few industrial sectors can particularly benefit from high temperature heat exchangers. Examples include conventional aerospace applications, advanced nuclear power generation systems, and high efficiency stationary and mobile modular fossil fuel to shaft power/electricity conversion systems. This paper provides a review of high temperature heat exchangers in terms of build materials, general design, manufacturing techniques, and operating parameters for the selected applications. Challenges associated with conventional and advanced fabrication technologies of high temperature heat exchangers are discussed. Finally, the paper outlines future research needs of high temperature heat exchangers. More >

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N. Vijaya^a,*, Y. Hari Krishna^a , K. Kalyani^b, G.V.R. Reddy^a
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-11, 2018, DOI:10.5098/hmt.11.19
Abstract The present paper deals with the thermo physical properties of a Casson fluid through an oscillating vertical wall embedded through porous medium under the influence transverse magnetic field, radiation, constant heat source and first order chemical reaction. The radiative heat loss is modelled by using Rosseland approximation. Similarity variables were used to convert the partial differential equations into ordinary differential equation. The transformed ordinary differential equations are solved numerically using Runge - Kutta -Fehlberg method with shooting technique. In order to get perfect perception of the flow pattern we obtain the graphs of axial velocity, temperature and concentrations profiles for… More >

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Shihong Zhang^* , Meixian Wei, Hui Yang
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-5, 2018, DOI:10.5098/hmt.11.20
Abstract This article discussed flow and temperature characteristics of the catalytic combustion furnace based the combustion of lean natural gas-air mixtures in catalytic honeycomb monoliths. Catalytic combustion as a developing technology could make the pollutant emissions (CO and NO_X) to near zero. Within the porous structure, the reactions then take place on the catalytic sites. A heterogeneous catalytic process includes more than one phase. Usually the catalyst is a solid and the reactants and products are in liquid or gaseous form. According to the applications of low- carbon catalytic combustion furnace, heating glazed tiles with pure solid texture, rich melodic style… More >

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ARTICLE

Mengchen Zhang^a , Hui Chen^b,*, Ming Shen^a
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-7, 2018, DOI:10.5098/hmt.11.21
Abstract The time fractional Cattaneo-Christov flux heat model is first introduced to investigate the flow and heat transfer of Maxwell viscoelastic fluid past a vertical flat plate. Fractional constitutive relation and Cattaneo-Christov heat flux model are applied to construct the governing boundary layer equations of momentum and energy, which are nondimensionalized by new dimensionless variables and solved numerically. The results indicate that there exist intersections on velocity and temperature profiles for different values of Prandtl number when the fractional Cattaneo-Christov flux heat model is considered. More >

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Weera Punin^*, Somchai Maneewan, Chantana Punlek
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-5, 2018, DOI:10.5098/hmt.11.22
Abstract In the present experimental investigation, ethylene glycol cooling in a plate-fin heat sink was attached inside an aluminum cooling block for the cooling unit of a thermoelectric (TE) power generator system. The plate-fin heat sink with two different fin heights was made from aluminum with length, width and base thickness of 300, 200, and 25 mm, respectively. The ethylene glycol was used as a coolant. The effects of fin height, coolant volume flow rate, and hot side surface temperature were considered for the temperature differences between the hot side surface and cold side surface of the TE power module. The… More >

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R. Rajaraman^a , L. Anna Gowsalya^b,*, R. Velraj^c
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-8, 2018, DOI:10.5098/hmt.11.23
Abstract To get accurate results in casting simulations, prediction of interfacial heat transfer coefficient (IHTC) is imperative. In this paper an attempt has been made for estimating IHTC during solidification process of a rectangular aluminium alloy casting in a sand mould. The cast temperature and mould temperature are measured during the experimental process at different time intervals during the process of solidification. Two different inverse methods, namely control volume and Beck’s approach are used to estimate the heat flux and temperature at the mould surface by using the experimentally measured temperatures. In the case of control volume technique, the partial derivative… More >

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Hong Hu^a,*, J. N. Chung^a,†
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-8, 2018, DOI:10.5098/hmt.11.24
Abstract A new architecture for absorption refrigeration systems (ARSs) that enables a significant enhancement of heat and mass transport processes has been proposed. This enhancement in performance is expected to translate into a significant reduction is size and cost of ARSs. The key innovation in the new approach is the use of ultrathin liquid films constrained by highly permeable nanostructured membranes. This approach enables far greater performance than those in the existing macroscale. For example, in the new absorber design, the thin film of LiBr solution is constrained by hydrophobic porous membranes and the inner wall of cooling water channel. The… More >

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Yongbin Zhang^*
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-7, 2018, DOI:10.5098/hmt.11.25
Abstract A tree-type cylindrical-shaped nanoporous filtering membrane is optimized with two levels of branches and a lot of branch pores. In this membrane, the branch pores are parallel with their trunk pore and their radius More >

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Yongbin Zhang_*
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-5, 2018, DOI:10.5098/hmt.11.26
Abstract The paper analytically studies the performance of the optimized tree-type cylindrical-shaped nanoporous filtering membranes with 9 or 10 branch pores in each pore tree. The optimum ratio of the radius of the trunk pore to the radius of its branch pore was found. The corresponding lowest flow resistances of the membranes were typically calculated respectively for weak, medium and strong liquid-pore wall interactions. For liquid-liquid separations, the optimum radii of the trunk pore in the membranes were calculated according to the weak liquid-pore wall interaction. The capability of the liquidliquid separation of the membranes was also studied. The obtained results… More >

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ARTICLE

Mohammed A. Tashkandi^a , Abdelkarim Aydi^b,*
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-6, 2018, DOI:10.5098/hmt.11.27
Abstract In this work, a computational study of convective heat transfer in a hybrid CNT-Al2O3/water nanofluid cavity filled. The main considered parameters are the Rayleigh number and nanoparticles volume fraction. Results are presented in terms of flow structure, temperature field, and average Nusselt number. Since CNT and Al₂O₃ have different shapes to models are used to evaluate the effective thermal conductivity. It was found that both increasing Rayleigh number and nanoparticles volume fraction increase the heat transfer intensify the flow and affect the temperature field. Adding nanoparticles enhances the heat transfer due to the enhancement of the effective thermal conductivity. The… More >

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Ravi Shankar Prasad^a , S.N. Singh^b , Amit Kumar Gupta^c,*
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-15, 2018, DOI:10.5098/hmt.11.28
Abstract This paper presents the results of numerical analysis of steady laminar natural convection and surface radiation in the two dimensional partially right side open square cavity filled with natural air (Pr = 0.70) as the fluid medium. The cavity has left isothermal hot wall with top, bottom and right adiabatic walls. In the present study, the governing equations i.e. Navier-Stokes Equation in the stream function – vorticity form and Energy Equation are solved for a constant thermophysical property fluid under the Boussinesq approximation. For discretization of these equations, the finite volume technique is used. For the radiation calculations, the radiosity-irradiation… More >

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ARTICLE

Amnart Boonloi^a, Withada Jedsadaratanachai^b,*
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-16, 2018, DOI:10.5098/hmt.11.29
Abstract Numerical predictions on flow and heat transfer in a square channel heat exchanger placed with V-baffle are examined. The gap spacing between the V-baffle and channel wall is varied for all baffle heights. The laminar regime with Re = 100 – 1000 is considered. The numerical model for the square channel heat exchanger placed with V-baffle is validated. The preliminary result reveals that the computational domain has reliability to predict flow and heat transfer in the channel. The mechanisms on flow and heat transfer in the heat exchanger channel are illustrated at the numerical result section. The thermal performance analysis… More >

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ARTICLE

Sanjib Sengupta^a,*, Amrit Karmakar^b
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-13, 2018, DOI:10.5098/hmt.11.30
Abstract In this paper an analysis on heat and mass transfer is made to study magnetohydrodynamic (MHD) mixed convective flow of an incompressible viscous fluid flowing past an inclined plate. A magnetic field of uniform strength is applied to the plate to influence the flow. Due to weak voltage differences caused by the very low polarization charges, the influence of electric field is considered to be neglected. Again large temperature gradient ensures cross diffusion effect like thermo-diffusion (Soret) in the field. The governed set of non-linear partial differential equations is solved by developing a multi-parameter asymptotic perturbation scheme. The influence of… More >

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M. S. Dada^∗ , S. A. Agunbiade, E. O. Titiloye
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-12, 2018, DOI:10.5098/hmt.11.31
Abstract Diffusion-thermo and thermal-diffusion effects on unsteady, incompressible Rivlin-Ericksen rotatory convective flow of a magnetic conducting electrical fluid with time dependent suction between two vertical plates of which one is permeable are investigated. The uniform angular velocity rotates about an axis normal to the plate. The equations governing the flow model are non-dimensionalised, perturbed for simplification and solved by Adomian decomposition method. Graphical illustrations of the fluid parameters on velocity, temperature, concentration are presented and discussed. The effect of skin-friction, Nusselt and Sherwood numbers are presented in tabular forms and it is discovered from the results that a rise in thermal-diffusion… More >

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Yongbin Zhang^*
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-5, 2018, DOI:10.5098/hmt.11.32
Abstract A tree-type nanoporous filtering membrane with complex pores is proposed. The membrane consists of three kinds of concentric cylindrical pores across the membrane thickness i.e. the four branch pores for filtration, the one flow-collecting pore and the one flow resistance-reducing pore. The ratio of the radius of the flow resistance-reducing pore to that of the filtration pore is optimized for yielding the highest flux of the membrane. The dimensionless lowest flow resistance of the membrane in the optimum condition was typically calculated for different filtration pore radii and different passing liquid-pore wall interactions. The capability of the membrane for a… More >

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Yashwant Singh^a , Rajesh Maithani^b , Sunil Kumar^a , Ehsan Gholamalizadeh^c , Anil Kumar^a,d,*
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-16, 2018, DOI:10.5098/hmt.11.33
Abstract Nanofluids play important roles in the heat transfer and flow characteristics in ribbed square channels. Systematic experiments are conducted to measure heat transfer enhancement and TiO₂-H₂O based nanofluid flow characteristics on a protruded with combined V-type ribbed square channel. Reynolds number studied in the channel range from 4000-18000. Investigational parameters of square channel contain, volume fraction range of 1.0- 4.0%, particle diameter range of 30nm-45nm, relative protruded rib height range of 0.10-0.25, ratio of protruded height to print diameter range of 0.8- 2.0, relative protruded rib pitch ratio range of 2.0-3.5 and angle of attack of 300 -750 respectively. Results… More >

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ARTICLE

Huan Zheng^a,*, Yuliang Ma^b , Huaping Mei^c , Xiaohong Xu^a , Xiguang Chen^d , Xunchen Cao^e
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-6, 2018, DOI:10.5098/hmt.11.34
Abstract The supersonic separator has proved to be an effective method to condense and separate CO₂ from natural gas, and the inlet temperature plays a vital role on condensation characteristics of CO₂ in the supersonic separator due to the instability temperature of wellhead natural gas. In this paper, the physical and mathematical models for the supersonic condensation process of CO₂ in the natural gas were established on the basis of CO₂ droplet surface tension, nucleation and growth model. The flow and condensation parameters were investigated under different temperature conditions. The results show that when the inlet gas pressure is 8.0 MPa,… More >

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C. Rajashekhar^a , G. Manjunatha^a,† , Hanumesh Vaidya^b , B. B. Divya^a , K. V. Prasad^c
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-8, 2018, DOI:10.5098/hmt.11.35
Abstract The primary objective of this paper is to examine the impact of variable viscosity and thermal conductivity on peristaltic transport of Casson liquid in a convectively heated inclined porous tube. The viscosity differs over the radial axis, and temperature dependent thermal conductivity is taken into account. The perturbation technique is utilized to solve the governing nonlinear equations under the assumption of long wavelength and small Reynolds number. The analytical solutions are obtained for velocity, streamlines, pressure rise, frictional force, and temperature when subjected to slip and convective boundary conditions. The impacts of related parameters on physiological quantities of interest are… More >

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Yun Whan Na^* , J. N. Chung^†
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-14, 2018, DOI:10.5098/hmt.11.36
Abstract Flow instabilities of convective two-phase boiling in a trapezoidal microchannel were investigated. using a three-dimensional numerical model. Parameters such as wall temperature and inlet pressure that characterize the instability phenomena of flow boiling with periodic flow patterns were studied at different channel wall heat fluxes and flow mass fluxes. Results were obtained for various wall heat flux levels and mass flow rates. The numerical results showed that large amplitude and short period oscillations for wall temperature and inlet pressure fluctuations are major characteristics of flow instability. The wall temperature fluctuations are mainly initiated by the transition from bubbly to slug… More >

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Michael Petrucci, Amir Faghri^*
Frontiers in Heat and Mass Transfer, Vol.11, pp. 1-9, 2018, DOI:10.5098/hmt.11.37
Abstract The results of integrating heat pipes into the vanes of a turbofan engine are presented. These Heat Pipe Turbine Vanes (HPTV) are integrated into the compressor exit, turbine inlet, and exhaust flow for vane cooling and waste heat recovery. Thermodynamic analysis of HPTV turbofan engines is done and comparisons are made between heat pipe turbine vane cooling and conventional film cooling techniques. Heat transfer through the vanes is analyzed using a thermal network model. Limitations on the heat transfer caused by various limiting phenomena within the heat pipe are also determined. More >

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