摘要:

An improved computational analysis is presented for the detailed prediction of heat transfer, phase change, and fluid flow during welding with a moving heat source. The governing equations are formulated in a reference frame attached to the heat source. A special feature in the formulation is that the primary unknown velocity is the convective velocity of the fluid with the motion of the heat source, resulting in additional source terms in the equations. The equations are solved using a control-volume-based computational method. The temperature and velocity fields and the time-temperature data are presented for two welding velocities to demonstrate the results using the new technique.

ISSN:1040-7782    

DOI:10.1080/10407789608913782

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Computer simulation is conducted to study vertical zone-melting crystal growth. Hie model, which is governed by momentum and heat transfer in the system, is solved by a finite volume/ Newton method with an implementation of the pseudo-arclength continuation. Single crystal growth of NaNO3in a computer-controlled transparent multizone furnace is simulated as examples. The calculated results show that natural convection induced by the buoyancy force affects melt-solid interfaces significantly, which is consistent with the observation during crystal growth experiments. Along the solution branch, multiple steady states are observed, and they are accompanied by the inversion of the upper melt-feed interface.

ISSN:1040-7782    

DOI:10.1080/10407789608913783

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

This article presents the application of the control volume finite element (CVFE ) numerical solution technique to the analysis of drying-induced stresses in timber. Two stress formulations are presented: first, a plane strain elastic analysis and, second, a mechano-sorptwe creep analysis, which models the well-known behavior of stress reversal in timber, In order to highlight the applicability of the CVFE method in stress analysis problems, the numerical solutions to two problems are compared against an analytical solution and previously published numerical simulation results.

ISSN:1040-7782    

DOI:10.1080/10407789608913784

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A three-dimensional unsteady numerical simulation was carried out to unravel the buoyancy-induced flow in a bottom-heated shallow rectangular box with perfect conducting side walls. The Navier-Stokes and energy equations were discretized by the higher order finite difference approximations and solved by the explicit projection method. Computations were specifically carried out for water Pr = 3.5 ) and air (Pr = 0.71) in a box of aspect ratios 10.6 X 5.3. The results for the water layer indicated that in raising the Rayleigh number (Ra) suddenly from zero to a value slightly above that for onset of convection, square cells were induced that later gradually merge to form parallel rolls along the short sides. Soft patterns were induced where Ra was abruptly raised from 0 to 4 Racr. The augmentation of wavelength in a parallel roll system was found to result from the disappearance of the rolls near the short sides and the expansion of the other rolls. In an air layer the increase in the roll size resulted from the skew-varicose instability and the combination of the adjacent rolls.

ISSN:1040-7782    

DOI:10.1080/10407789608913785

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The radiative-cancective heat transfer around a circular cylinder in a cross flow of a radiating gas has been numerically analyzed using the finite volume radiation solution method in a nonorthogonal coordinate system. The cross-flow Reynolds number based on the cylinder diameter is 40, and the fluid Prandtl number is assumed to be 0.7. The radiative heat transfer coupled with convection is reasonably predicted by the finite volume radiation solution method. Distributions of the local Nusselt number are investigated according to the variation of radiation parameters such as conduction-to-radiation parameter, optical thickness, scattering albedo, and cylinder wall emissivity.

ISSN:1040-7782    

DOI:10.1080/10407789608913786

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

The performance of a penalty-Galerkin finite element method with quartic triangular elements when applied to laminar natural convection in a square cavity with differentially heated vertical walk and adiabatic horizontal walls is studied. The numerical calculations were carried out for Rayleigh numbers of 104105, 106, and 107on several successively refined meshes. The computational results are presented in terms of velocity components, temperature, stream function, and Nusselt number. The numerical procedure adopted in the present study yields consistent performance with respect to mesh refinement, and comparisons with previously published results indicate fairly close agreements.

ISSN:1040-7782    

DOI:10.1080/10407789608913787

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A numerical study is performed for natural confection cooling of a discrete isothermal heater located on one vertical wall of a partially open two-dimensional enclosure. The governing equations are solved using the SIMPLER algorithm. Studies are performed for 103<Ra <106with air as the cooling medium for different heater locations and barrier heights. The primary circulation is stronger for higher Ra and lower heater positions. The barrier strongly affects the size and the strength of the recirculation formed near the barrier, although its effect on the bulk circulation and heat transfer is negligible. Correlations of average Nusselt number are developed for different heater locations and barrier heights.

ISSN:1040-7782    

DOI:10.1080/10407789608913788

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor