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 共查询到20条相似文献,搜索用时 125 毫秒
1.
ExperimentalInvestigationoftheInternalFlowFieldofRotatingImpellerPassagewithInletBox¥WuKeqi(HuazhongUniversityofScienceandTec...  相似文献   

2.
ANumericalAnalysisoftheForcedConvectionCondensationofSaturatedVaporFlowingAxiallyOutsideaHorizontalTube¥WeizhongLi,WeichengWa...  相似文献   

3.
TheStudyoftheDamageLawsofPoolFires¥YuDeming;FengChanggen;ZengQingxuan;GuoXinya(Mechanics&EngineeringDepartment,BeijingInstitu...  相似文献   

4.
IgnitionandExtinctionofMonopropellantDropletwithLewisNumberDifferentfromUnity¥FernandoF.Fachini(InstitutoNacionaldePesquisasE...  相似文献   

5.
ComparisonofaReactionFrontModelandaFiniteDifferenceModelfortheSimulationofSolidAbsorptionProcess¥ZikangWu;ArneJakobsen;Xiugan...  相似文献   

6.
InfluenceofHeatingRateontheOnsetofOscillationinLiquidBridgeofHalfFloatingZone¥Jing-ChengXie;Wen-RuiHu(InstituteofMechanics,Ch...  相似文献   

7.
ControllingMechanismandResultingSprayCharacteristicsofInjectionofFuelContaining DissolvedGasHuangZhen(DepartmentofPowerMachin?..  相似文献   

8.
ExperimentalStudyonHeatTransferandPressureDropCharacteristicsofFourTypesofPlateFin-and-TUbeHeatExchangerSurfaces¥H.J.Kang;W.L...  相似文献   

9.
Numerical Solution of Flow Field Diagnosis Problem in Multistage Axial CompressorsNumericalSolutionofFlowFieldDiagnosisProble...  相似文献   

10.
NumericalSimulationofMultistoryBuildingFirewithZone-ModelingMethodFuZhuman;FanWeicheng(StateKeyLabofFireScience,UniversityofS...  相似文献   

11.
To monitor and control its thermal state, a rotor’s temperature and thermal stress fields must be calculated in real time. After some reasonable assumptions and simplification, iterative models of the rotor’s temperature and thermal stresses were obtained with an integral transform based on a two-dimensional axis-symmetry thermal conduction differential equation. The models can deal with some nonlinear factors such as material and boundary condition. An example is given to compare results computed by the finite element method (FEM) and one-dimensional models. The result shows that the analytical model gained has high quality and the computing course is very short. The iterative formulas could be used not only to analyze the rotor’s thermal states of turbine, but to monitor and control them online. The method adopted can be used to analyze the thermal state of other axis-symmetry objects having similar boundary conditions. Translated from Proceeding of the CSEE, 2006, 26(1): 21–25 [译自:中国电机工程学报]  相似文献   

12.
The present work aims to investigate the transient thermoelastic diffusive response for a half-space with variable thermal conductivity and diffusivity in the context of the generalized thermoelastic diffusion theory. The boundary plane of the half-space is assumed to be traction free and subjected to a time-dependent thermal and chemical shock. The governing equations of the problem are formulated by using Kirchhoff’s transformation. Due to the complexity of the equations, Laplace transformation method is applied to solve them. Numerical results are obtained and illustrated graphically. Parameter studies are performed to evaluate the effects of variable thermal conductivity and diffusivity on the response. The present investigation could be helpful for better understanding the multifield coupling effect of mechanical and thermal fields in real materials.  相似文献   

13.
J. J. Han  N. Hasebe 《热应力杂志》2013,36(12):1147-1160
Green's function of a point heat source is derived for a mechanical mixed boundary value problem of an infinite plane with an arbitrary hole, for which zero-displacement and traction-free boundary conditions are prescribed to its boundary. As the thermal boundary condition on the hole, either an adiabatic or isothermal condition is considered. By employing the mapping technique and complex variable method, an explicit solution including a hypergeometrical function is obtained. Stress distributions are shown in illustrative examples for a square hole.  相似文献   

14.
We consider the inverse problem of determining the time-dependent thermal conductivity and the transient temperature satisfying the heat equation with initial data, Dirichlet boundary conditions, and the heat flux as overdetermination condition. This formulation ensures that the inverse problem has a unique solution. However, the problem is still ill-posed since small errors in the input data cause large errors in the output solution. The finite difference method is employed as a direct solver for the inverse problem. The inverse problem is recast as a nonlinear least-squares minimization subject to physical positivity bound on the unknown thermal conductivity. Numerically, this is effectively solved using the lsqnonlin routine from the MATLAB toolbox. We investigate the accuracy and stability of results on a few test numerical examples.  相似文献   

15.
The problem of seepage flow through a dam is free boundary problem that is more conveniently solved by a meshless method than a mesh-based method such as finite element method (FEM) and finite difference method (FDM). This paper presents method of fundamental solutions, which is one kind of meshless methods, to solve a dam problem using the fundamental solution to the Laplace's equation. Solutions on free boundary are determined by iteration and cubic spline interpolation. The numerical solutions then are compared with the boundary element method (BEM), FDM and FEM to display the performance of present method.  相似文献   

16.
Abstract

The hybrid scheme of the Laplace transform technique and the central difference approximation is applied to estimate the temperature-dependent thermal conductivity by utilizing temperature measurements inside the material at an arbitrary specified time. In the present study the functional form of the thermal conductivity is not known a priori. Thus, this problem can be regarded as the functional estimation in inverse calculation. The accuracy of the predicted results is examined from various illustrated cases using simulated exact and inexact temperature measurements obtained within the medium. Results show that a good estimation on the thermal conductivity can be obtained with any arbitrary initial guesses of the thermal conductivity. The advantage of the present method in the inverse analysis is that, for most types of boundary conditions, the relation between the thermal conductivity and temperature at any specified time can be determined without measuring the early temperature data.  相似文献   

17.
An inverse problem is solved for simultaneously estimating the convection–conduction parameter and the variable thermal conductivity parameter in a conductive–convective fin with temperature dependent thermal conductivity. Initially, the temperature field is obtained from a direct method using an analytical approach based on decomposition scheme and then using a simplex search minimization algorithm an inverse problem is solved for estimating the unknowns. The objective function to be minimized is represented by the sum of square of the error between the measured temperature field and an initially guessed value which is updated in an iterative manner. The estimation accuracy is studied for the effect of measurement errors, initial guess and number of measurement points. It is observed that although very good estimation accuracy is possible with more number of measurement points, reasonably well estimation is obtained even with fewer number of measurement points without measurement error. Subject to selection of a proper initial guess, it is seen that the number of iterations could be significantly reduced. The relative sensitiveness of the estimated parameters is studied and is observed from the present work that the estimated convection–conduction parameter contributes more to the temperature distribution than the variable conductivity parameter.  相似文献   

18.
The boundary geometry shape is identified by the finite element method (FEM) without iteration and mesh reconstruction for two-dimensional (2-D) and three-dimensional (3-D) inverse heat conduction problems. First, the direct heat conduction problem with the exact domain is solved by the FEM and the temperatures of measurement points are obtained. Then, by introducing a virtual boundary, a virtual domain is formed. By minimizing the difference between the temperatures of measurement points in the exact domain and those in the virtual domain, the temperatures of the points on the virtual boundary are calculated based on the least square error method and the Tikhonov regularization. Finally, the objective geometry shape can be estimated by the method of searching the isothermal curve or isothermal surface for 2-D or 3-D problems, respectively. In the process, no iterative calculation is needed. The proposed method has a tremendous advantage in reducing the computational time for the inverse geometry problems. Numerical examples are presented to test the validity of the proposed approach. Meanwhile, the influences of measurement noise, virtual boundary, measurement point number, and measurement point position on the boundary geometry prediction are also investigated in the examples. The solutions show that the method is accurate and efficient to identify the unknown boundary geometry configurations for 2-D and 3-D heat conduction problems.  相似文献   

19.
The paper deals with the non-iterative inverse determination of the temperature-dependent thermal conductivity in 2-D steady-state heat conduction problem. The thermal conductivity is modeled as a polynomial function of temperature with the unknown coefficients. The identification of the thermal conductivity is obtained by using the boundary data and additionally from the knowledge of temperature inside the domain. The method of fundamental solutions is used to solve the 2-D heat conduction problem. The golden section search is used to find the optimal place for pseudo-boundary on which are placed the singularities in the frame of method of fundamental solutions.  相似文献   

20.
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