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1.
Abstract This paper models the response of a thin metallic plate that is subjected to a rapid heat input. In order to accurately model plate response, both the dynamic mechanical and transient heat transfer problems must be solved. The solution is complicated by nonlinearities due to radiation boundary conditions and material inelasticity. Furthermore, the viscoplastic constitutive equations that model the mechanical material behavior are numerically stiff. Nonlinear finite element algorithms are developed for both heat transfer and mechanical analyses. The algorithms are both stable and efficient for solving the problems considered herein. Example problems presented in the paper demonstrate the importance of including material nonlinearity in the model 相似文献
2.
Sutthisak Phongthanapanich Suthee Traivivatana Parinya Boonmaruth Pramote Dechaumphai 《Acta Mechanica Sinica》2006,22(2):138-147
Based on flux-based formulation, a nodeless variable element method is developed to analyze two-dimensional steady-state and
transient heat transfer problems. The nodeless variable element employs quadratic interpolation functions to provide higher
solution accuracy without necessity to actually generate additional nodes. The flux-based formulation is applied to reduce
the complexity in deriving the finite element equations as compared to the conventional finite element method. The solution
accuracy is further improved by implementing an adaptive meshing technique to generate finite element mesh that can adapt
and move along corresponding to the solution behavior. The technique generates small elements in the regions of steep solution
gradients to provide accurate solution, and meanwhile it generates larger elements in the other regions where the solution
gradients are slight to reduce the computational time and the computer memory. The effectiveness of the combined procedure
is demonstrated by heat transfer problems that have exact solutions. These problems are: (a) a steady-state heat conduction
analysis in a square plate subjected to a highly localized surface heating, and (b) a transient heat conduction analysis in
a long plate subjected to a moving heat source.
The English text was polished by Yunming Chen. 相似文献
3.
The forced monoharmonic vibrations and self-heating of a circular thermoviscoelastic plate with piezoelectric sensor and actuator
are studied. The viscoelastic behavior of the passive (without piezoeffect) and piezoactive materials is described using the
concept of complex moduli. The problems of electroelasticity and heat conduction are solved numerically, assuming that the
mechanical load is unknown. The effect of self-heating on the active damping of the vibrations of the plate is analyzed 相似文献
4.
Bikash Sahoo 《Meccanica》2010,45(3):319-330
The effects of partial slip on the steady flow and heat transfer of an electrically conducting, incompressible, third grade
fluid past a horizontal plate subject to uniform suction and blowing is investigated. Two distinct heat transfer problems
are studied. In the first case, the plate is assumed to be at a higher temperature than the fluid; and in the second case,
the plate is assumed to be insulated. The momentum equation is characterized by a highly nonlinear boundary value problem
in which the order of the differential equation exceeds the number of available boundary conditions. Numerical solutions for
the governing nonlinear equations are obtained over the entire range of physical parameters. The effects of slip, magnetic
parameter, non-Newtonian fluid characteristics on the velocity and temperature fields are discussed in detail and shown graphically.
It is interesting to find that the velocity and the thermal boundary layers decrease with an increase in the slip, and as
the slip increases to infinity, the flow behaves as though it were inviscid. 相似文献
5.
This paper presents an investigation of temperature, displacement, stress, and induced magnetic field in a half space perfectly-conductive plate. Finite element equations regarding generalized magneto-thermoelasticity problems with two relaxation times (i.e., the G-L theory) are derived using the principle of virtual work. For avoiding numerical complication involved in inverse Laplace and Fourier transformation and low precision thereof, the equations are solved directly in time-domain. As a numerical example, the derived equation is used to investigate the generalized magneto-thermoelastic behavior of a semi-infinite plate under magnetic field and subjecting to a thermal shock loading. The results demonstrate that FEM can faithfully predict the deformation of the plate and the induced magnetic field, and most importantly can reveal the sophisticated second sound effect of heat conduction in two-dimensional generalized thermoelastic solids, which is usually difficult to model by routine transformation methods. A peak can be observed in the distribution of stress and induced magnetic field at the heat wave front and the magnitude of the peak decreases with time, which can not be obtained by transformation methods. The new method can also be used to study generalized piezo-thermoelastic problems.The project supported by the National Natural Science Foundation of China (10132010 and 10472089)The English text was polished by Yunming Chen 相似文献
6.
C. A. Deavours 《Flow, Turbulence and Combustion》1974,29(1):69-76
An exact solution for the fluid temperature due to laminar heat transfer in parallel plate flow is found. The formulas obtained are valid for an arbitrary velocity profile. The basic problem encountered involves finding certain expansion coefficients in a series of nonorthogonal eigenfunctions. This problem is solved by passing to a vector system of equations having orthogonal eigenvectors. The method is applicable to more general problems. 相似文献
7.
This paper presents a combined finite element method for solving conjugate heat transfer problems where heat conduction in
a solid is coupled with heat convection in viscous fluid flow. The streamline upwind finite element method is used for the
analysis of thermal viscous flow in the fluid region, whereas the analysis of heat conduction in solid region is performed
by the Galerkin method. The method uses the three-node triangular element with equal-order interpolation functions for all
the variables of the velocity components, the pressure and the temperature. The main advantage of the proposed method is to
consistently couple heat transfer along the fluid-solid interface. Three test cases, i.e. conjugate Couette flow problem in
parallel plate channel, counter-flow in heat exchanger, and conjugate natural convection in a square cavity with a conducting
wall, are selected to evaluate the efficiency of the present method.
The English text was polished byYunming Chen. 相似文献
8.
Results of experimental investigations of the heat exchange of a flat plate in the transition region are reported for low and high Mach numbers. Data are obtained about the heat transfer and the equilibrium temperatures of an infinitely thin plate and a finite-thickness plate at zero angle of attack. The effect of the edges is clarified. 相似文献
9.
采用近场动力学微分算子(Peridynamic Differential Operator, PDDO)理论建立正交各向异性板热传导的非局部模型。通过构造近场动力学函数,将边界条件和热传导方程由局部微分形式转化为非局部积分形式,引入Lagrange乘子,采用变分分析对含裂纹正交各向异性板温度及裂纹尖端的热通量分布进行求解。通过对比算例,验证了该模型具有较好的收敛性和有效性。分析了正交各向因子、材料铺设角、裂纹倾角及间距对裂纹尖端热通量的影响。结果表明,基于PDDO建立的含裂纹正交各向异性板热传导模型,考虑了热传导问题中的非局部性,能有效提高计算精度,预测含裂纹板中裂纹尖端出现的奇异性。 相似文献
10.
Norio Hasebe Christian Bucher Rudolf Heuer 《International Journal of Solids and Structures》2010,47(1):138-147
A uniform electric current at infinity was applied to a thin infinite conductor containing an elliptical hole with an edge crack. The electric current gives rise to two states, i.e., uniform and uneven Joule heat. These two states must be considered to analyze the heat conduction problem. The uneven Joule heat gives rise to uneven temperature and thus to heat flux, and to thermal stress.Using a rational mapping function, problems of the electric current, the Joule heat, the temperature, the heat flux, the thermal stress are analyzed, and each of their solutions is obtained as a closed form. The distributions of the electric current, the Joule heat, the temperature, the heat flux and the stress are shown in figures.The heat conduction problem is solved as a temperature boundary value problem. Solving the thermal stress problem, dislocation and rotation terms appear, which complicates this problem. The solutions of the Joule heat, the temperature, the heat flux and the thermal stress are nonlinear in the direction of the electric current. The crack problems are also analyzed, and the singular intensities at the crack tip of each problem are obtained. Mode II (sliding mode) stress intensity factor (SIF) is produced as well as Mode I (opening mode) SIF, for any direction of the electric current. The relations between the electric current density and the melting temperature and between the electric current density and SIF are investigated for some crack lengths in an aluminum plate. 相似文献
11.
Analytical study on the freezing and thawing processes of biological skin with finite thickness 总被引:1,自引:0,他引:1
The moving heat source model and the Green's function method were applied to solve for the phase change problems involved
in the freezing and thawing processes of biological skins with finite thickness. The transient temperature distributions,
the cooling and warming rates, etc. inside the skin subject to two typical boundary conditions (the convective or plate cooling)
often encountered in skin cryo-preservation are analytically predicted. And the heat transfer performances of these two freezing
(or thawing) approaches are comparatively discussed. Implications of the present closed form analytical solution to the other
biological phase change problems such as the skin cryosurgery or rewarming by microwave were also suggested.
Received on 4 May 2000 / Published online: 29 November 2001 相似文献
12.
Theoretical analyses which incorporate one-dimensional heat conduction along a plate and transverse heat conduction approximations are presented to predict the net heat transfer between laminar film condensation of a saturated vapour on one side of a vertical plate and boundary layer natural convection on the other side. It is assumed that countercurrent boundary layer flows are formed on the two sides. The governing boundary layer equations of this problem and their corresponding boundary conditions are all cast into dimensionless forms by using a non-similarity transformation. Thus the resulting system of equations can be solved by using the local non-similarity method for the boundary layer equations and a finite difference method for the heat conduction equation of the plate. The plate temperature and the heat flux through the plate are repetitively determined until the solutions for each side of the plate match. The predicted results show that the effect of Prc is not negligible for larger values of A* (thermal resistance ratio between natural convecti on side and condensing film side) and the approximation of transverse heat conduction overpredicts the plate temperature for lower values of Rt (thermal resistance ratio between plate and condensing film). However, no significant differences are observed between the two different approximations for higher values of Rt. © by 1997 John Wiley & Sons, Ltd. 相似文献
13.
The present paper reports the parametric studies and correlations for the problem of combined conduction-mixed convection–radiation
from a non-identically and discretely heated vertical plate. Three discrete heat sources of non-identical heights but with
identical volumetric rate of heat generation are assumed to be flush-mounted in a thin vertical plate. The longest and the
shortest heaters are provided at the leading and trailing edges of the plate, while the remaining heater is located centrally.
The governing fluid flow and heat transfer equations are considered in their full strength without the boundary layer approximations
and are solved using the finite volume method. A computer code is written to solve the problem and various parametric studies
have been performed. The relative roles of free convection, forced convection and radiation in various fluid flow and heat
transfer results have been elucidated. In conclusion, based on a large set of data generated from the code, correlations for
maximum non-dimensional plate temperature, average non-dimensional plate temperature and mean friction coefficient have been
evolved. 相似文献
14.
Summary Green's function approach is adopted for analyzing the deflection and the transient temperature distribution of a plate made
of functionally graded materials (FGMs). The governing equations for the deflection and the transient temperature are formulated
into eigenvalue problems by using the eigenfunction expansion theory. Green's functions for solving the deflection and the
transient temperature are obtained by using the Galerkin method and the laminate theory, respectively. The eigenfunctions
of Green's function for the deflection are approximated in terms of a series of admissible functions that satisfy the homogeneous
boundary conditions of the plate. The eigenfunctions of Green's function for the temperature are determined from the continuity
conditions of the temperature and the heat flux at interfaces.
Received 9 October 2000; accepted for publication 3 April 2001 相似文献
15.
Heat and Mass Transfer in MHD Micropolar Flow Over a Vertical Moving Porous Plate in a Porous Medium
Youn J. Kim 《Transport in Porous Media》2004,56(1):17-37
An analysis is presented for the problem of free convection with mass transfer flow for a micropolar fluid via a porous medium bounded by a semi-infinite vertical porous plate in the presence of a transverse magnetic field. The plate moves with constant velocity in the longitudinal direction, and the free stream velocity follows an exponentially small perturbation law. A uniform magnetic field acts perpendicularly to the porous surface in which absorbs the micropolar fluid with a suction velocity varying with time. Numerical results of velocity distribution of micropolar fluids are compared with the corresponding flow problems for a Newtonian fluid. Also, the results of the skin-friction coefficient, the couple stress coefficient, the rate of the heat and mass transfers at the wall are prepared with various values of fluid properties and flow conditions. 相似文献
16.
Numerical simulations of unsteady radiative-convective heat transfer in a turbulent flow of a mixture of gases and solid particles
past a semi-transparent plate are performed. An ablation process is demonstrated to occur on the plate surface in the case
of intense radiative heating of the plate by an external source with emission in a limited spectral range. Temperature fields
and distributions of heat fluxes in the boundary layer and in the plate are calculated. Calculation results are presented,
which allow determining the effect of ablation and reflecting properties of the plate surface on the thermal state of the
medium in the system containing the boundary layer and the plate under conditions of plate heating by a high-temperature source
of radiation.
__________
Translated from Prikladnaya Mekhanika i Tekhnicheskaya Fizika, Vol. 50, No. 3, pp. 140–146, May–June, 2009. 相似文献
17.
S. S. Kutateladze N. A. Rubtsov 《Journal of Applied Mechanics and Technical Physics》1968,9(6):667-673
An examination is made of the thermal state of a plane layer of gray gas injected into a turbulent stream of high temperature gas flowing over a permeable flat plate.Similarity-type formulations of problems are encountered both in examination of flow near a stagnation point, and also in analysis of the lifting of the boundary layer by intense injection through a porous plate [1]. The examination described relates to the following idealized formulation of the problem (Fig. la).In a plane layer of gray absorbing medium, formed by plane-parallel diffusely radiating surfaces (1-porous plate; 2-boundary of high temperature turbulent gas stream), heat transfer is accomplished by radiation and convection of the layer normal to the surfaces and by molecular heat conduction. All the physical and optical properties of the medium and of the boundary surfaces are assumed to be constant, independent of temperature.The temperature of the wetted surface of the specimen and also that of the fictitious surface determining the upper bound of the lift-off region, are given.Also assumed given is the velocity of the injected medium, which is constant throughout the entire lift-off layer. This idealization appreciably facilitates our examination without in principle changing its features.A very simplified examination of this problem was given in [2]. The special case of a medium with low optical thickness was examined in [3,4].The problem was examined in [5] under the assumption that molecular heat conduction in the medium is negligibly small.In the formulation considered the generalized energy equation has the form 相似文献
18.
An experimental investigation is performed to study the effect of the finned surfaces and surfaces with vortex generators on the local heat transfer coefficient between impinging circular air jet and flat plate. Reynolds number is varied between 7000 and 30,000 based on the nozzle exit condition and jet to plate spacing between 0.5 and 6 nozzle diameters. Thermal infrared imaging technique is used for the measurement of local temperature distribution on the flat plate. Fins used are in the form of cubes of 2 mm size spaced at a pitch of 5 mm on the target plate and hexagonal prism of side 2.04 mm and height of 2 mm spaced at a pitch of 7.5 mm. Vortex generators in the form of a equilateral triangle of side 4 mm are used. Effect of number of rows of vortex generators, radius of a row, number of vortex generators in a row and inclination angle (i.e., the angle between the plane of the target plate and the plane of the vortex generators) on Nusselt number is studied. It is observed that the heat transfer coefficient between the impinging jet and the target plate is sensitive to the shape of the fin. The increase in the heat transfer coefficient up to 77% depending on the shape of the fin, nozzle plate spacing and the Reynolds number is observed. The augmentation in the heat transfer for the surfaces vortex generators are higher than that of the finned surfaces. The heat transfer augmentation in case of vortex generator is as high as 110% for a single row of six vortex generators at a radius of 1 nozzle diameter as compared to the smooth surface at a given nozzle plate spacing of 1 nozzle diameter and a Reynolds number of 25,000 at extreme radial location. 相似文献
19.
Presented in this paper are the results of natural convection heat transfer between inclined parallel plates. Lower plate is heated isothermally while the upper plate is both unheated and insulated. Plate inclinations were 0°, 30°, 45° measured from vertical position. Experiments were carried out for different temperature differences in air to determine the effect of plate spacing and plate inclination on heat transfer. It was found that heat transfer rate depends on plate spacing and inclination. 相似文献
20.
燃气射流冲击传热特性的数值模拟 总被引:2,自引:0,他引:2
针对射流传热问题,利用基于RNGk-ε湍流模型的数值方法模拟了射流垂直冲击平板的流动过程,并与实验数据比较,验证了模型的可行性。在此基础上,以火箭喷管入口参数为入口条件,建立了超音速燃气射流垂直冲击平板和冲击浸没平板的计算模型,分析了不同冲击条件下努塞尔数分布规律和温度分布规律, 论述了超音速射流传热的特性及影响传热特性的因素。得到了冲击距离为(14~18)D的努塞尔数取值范围,并表明冲击距离和射流温度是影响传热效率的关键因素;冲击距离增加,传热效率降低,冲击平板表面的射流温度越高,传热效率越高。 相似文献