Begell House Inc.
Heat Transfer Research
HTR
1064-2285
48
12
2017
EFFECTS OF FRACTIONAL ORDER ON CONVECTIVE FLOW OF AN OLDROYD-B FLUID ALONG A MOVING POROUS HOT PLATE WITH THERMAL DIFFUSION
1047-1068
Constantin
Fetecau
Academy of Romanian Scientists, Bucharest 050094, Romania; Department of Mathematics, Technical University of Iasi 700050, Romania
Dumitru
Vieru
Department of Theoretical Mechanics, Technical University of Iasi 700050, Romania
Corina
Fetecau
Department of Theoretical Mechanics, Technical University of Iasi 700050, Romania
Itrat Abas
Mirza
Abdus Salam School of Mathematical Sciences, GC University Lahore 54000, Pakistan
Time-fractional convective flow over a dusty incompressible Oldroyd-B fluid over a moving infinite porous vertical plate is investigated in the presence of a heat source. At time t = 0+ the plate, whose temperature is time-variable, begins to move in its plane with a time-dependent velocity uwf(t). Exact solutions for dimensionless temperature and Nusselt number are determined using Laplace transforms. The influence of fractional parameter on the fluid temperature is graphically emphasized for small and large values of time. Its effects on the Nusselt number are also brought to light. The fluid velocity, as well as the dust particles velocity, are determined by combining the Laplace transform technique with the homotopy analysis method, and the Stehfest numerical algorithm is used for the inverse Laplace transform. As a check of the results, a closed form solution for the fluid velocity in the transformed domain is determined by both methods. Finally, the influence of fractional parameter and Prandtl number on the fluid and dust particles velocities is graphically underlined and discussed. Generally, in practical problems, these results can be used to determine suitable values for the fractional parameter so that the theoretical results to be in agreement with the experimental data.
THERMOECONOMICAL OPTIMIZATION OF CROSS-FLOW HEAT EXCHANGERS
1069-1075
M.
Yildirim
University of Gaziantep, Vocational School 27310, Gaziantep, Turkey
M.S.
Söylemez
Department of Mechanical Engineering, Engineering Faculty, University of Gaziantep,
27310, Gaziantep, Turkey
A thermo economic optimization analysis is presented yielding simple algebraic formula for estimating the optimum area of cross-flow heat exchangers of both fluids unmixed-type which are applied in industrial applications. An economic analysis method is used in the present study, together with the thermal analyses of heat exchangers, for thermo economic optimization. The validity of the optimization formulations was checked.
WETTING BEHAVIOR OF WATER MICRODROPLETS IN NATURAL EVAPORATION
1077-1088
Yukihiro
Yonemoto
Priority Organization for Innovation and Excellence, Kumamoto University, 2-39-1 Kurokami, Chuo, Kumamoto 860-8555, Japan
Tomoaki
Kunugi
Department of Nuclear Engineering, Kyoto University, Kyoto Daigaku-Katsura, Nishikyo-ku, Kyoto, Japan
The wetting phenomenon is related to improvements in the energy efficiency of many industrial devices and processes,
including heat exchangers and nuclear power generation. However, despite the benefits of the application of the wetting phenomenon in many industrial devices, the theoretical description of the wetting phenomenon remains insufficient. Wettability is mainly related to an interaction between a liquid and a solid, and is characterized by a contact angle. When the volume of a droplet on a solid surface decreases due to a phase change such as evaporation, there are two stages in the droplet behavior. First, the contact angle decreases, with a constant contact area; this is known as contact angle hysteresis. Then, after reaching a certain contact angle, the contact line starts to recede with the size dependent on the contact angle. If a droplet is in a thermodynamic equilibrium state, this can oft en be explained using a modified Young equation in which the line tension is explicitly added. However, there are no adequate and convenient models to treat these phenomena in
the nonequilibrium state. In the present study, the droplet behavior in natural evaporation was considered experimentally. Semiempirical models were proposed and compared with experimental data.
EVALUATION OF NUMERICAL MODELS FOR THERMAL ANALYSIS OF PRISMATIC LITHIUM-ION BATTERIES
1089-1102
Hee Won
Lee
Department of Advanced Pouch Development, LG Chemical Research Park, 188, Munji-ro,
Yuseong-gu, Daejeon, Korea
Il Seouk
Park
School of Mechanical Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu,
702-701, South Korea
Lithium-ion batteries are a type of secondary cells composed of repeatedly stacked microscale plates consisting of electrodes and separators. Because the thermal behavior of a battery is closely connected with its performance and lifespan, investigation of the battery's thermal characteristics is crucial for the design of cell products. However, in numerical simulations, allocating separate computing grids to various microstructures within the cell is ineffective in terms of computational costs.
Thus, various numerical models have been introduced to predict the battery's thermal behavior, such as the lumped capacitance model (LCM), equivalent detailed model (EDM), equivalent simple model (ESM), and others. However, assessment of the pros and cons of each model has not been carried out as yet. Therefore, in this study, the thermal behavior of a prismatic 185.3Ah lithium-ion battery during a discharging process was simulated using the LCM, EDM, and ESM approaches, and the performances of each model are discussed on the basis of the corresponding estimates for the thermal behaviors of a unit cell and cell module.
APPLICATION OF THE BIOGEOGRAPHY-BASED OPTIMIZATION ALGORITHMS TO INVERSE TRANSIENT RADIATION PROBLEM
1103-1126
Kun
Yang
Tianjin Key Laboratory of Civil Aircraft Airworthiness and Maintenance, Civil Aviation
University of China, Tianjin, 300300, China
Hong
Qi
School of Energy Science and Engineering, Harbin Institute of Technology, 92, West Dazhi Street, Harbin 150001, PR China; Key Laboratory of Aerospace Thermophysics, Ministry of Industry and Information Technology, Harbin, China, 150001
Jun-You
Zhang
School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China
Chun-Yang
Niu
School of Energy Science and Engineering, Harbin Institute of Technology, Harbin, 150001, China
Wei
Wang
Tianjin Key Laboratory of Civil Aircraft Airworthiness and Maintenance, Civil Aviation
University of China, Tianjin, 300300, China
Liming
Ruan
School of Energy Science and Engineering, Harbin Institute of Technology 92 West Dazhi Street, Harbin, Heilongjiang, 150001, P.R. China; Key Laboratory of Aerospace Thermophysics, Ministry of Industry and Information Technology, Harbin, China, 150001
Three biogeography-based optimization (BBO) algorithms, i.e., the basic BBO, the improved biogeography-based optimization algorithm based on local search strategy (ILSBBO), and the hybrid ILSBBO combined with the Simplex Method based on the K-means clustering method (KSM-ILSBBO), were developed to solve the inverse transient radiation problem in nonhomogeneous multilayer participating media. The transmittance and reflectance on the boundaries simulated by the finite volume method were served as input for the inverse analysis. The absorption coefficients, scattering coefficients, and geometric position of the middle layer in a three-layer nonhomogeneous slab were estimated by these three BBO-based algorithms, respectively. The influence of measurement errors on the retrieval results was also investigated. The results demonstrate that the BBO, ILSBBO, and KSM-ILSBBO algorithms all could obtain reasonable results when one, two, or three unknown parameters are retrieved. The KSM-ILSBBO could get more accurate results even when four parameters are estimated simultaneously, and the retrieval accuracy of KSM-ILSBBO is higher than that of BBO and ILSBBO algorithms.
The KSM-ILSBBO is proved to be suitable for solving inverse radiation problems.
MATHEMATICAL MODELING OF HEAT TRANSFER PROBLEMS FOR THIN PLATES WITH TEMPERATURE-DEPENDENT CONDUCTIVITY
1127-1138
Rogério Martins Saldanha
da Gama
Mechanical Engineering Graduate Program (FEN), Rio de Janeiro State University, Rua São
Francisco Xavier 524, 20550-013, Rio de Janeiro, Brazil
Felipe Bastos de
Freitas Rachid
Mechanical Engineering Graduate Program (TEM-PGMEC), Universidade Federal Fluminense,
Rua Passo da Pátria, 156, 24210-240, Niterói, RJ, Brazil
Maria Laura
Martins-Costa
Universidade Federal Fluminense
In this paper, the steady-state heat transfer phenomenon in a flat plate with temperature-dependent thermal conductivity
is considered. The plate thickness is small enough in order to allow a two-dimensional description involving only the
mean value of temperature over the plate thickness. A nonuniform, but known, internal heat supply and a convective heat exchange between the plate and the environment according to Newton's law of cooling are assumed. The resulting mathematical description consists of a nonlinear partial differential equation subjected to a Neumann boundary condition. The thermal conductivity is assumed to be a piecewise constant function of the temperature, and the Kirchhoff transformation is employed for constructing a new mathematical approach with an equivalent minimum principle. Proofs of existence and uniqueness of the solution are presented.