摘要:

A finite-difference formulation is presented for modeling conduction heat transfer in a generalized nonorthogonal curvilinear coordinate system. A control volume energy balance approach is taken in this work, and this leads to a formulation that permits direct physical interpretation. The inclusion of a convective boundary condition is demonstrated by example, and it is shown that this condition can be used to implement convective, Neumann, adiabatic, and Dirichlet boundary constraints. Three examples are examined to demonstrate the application of the generalized nonorthogonal formulation. For the three examples examined, the results agree well with previous solutions, where they are available. The examples are also used to provide the first application of the modified strongly implicit procedure for solving the algebraic equation system of a nonorthogonal coordinate formulation. The procedure is observed to perform well on all three test problems.

ISSN:0149-5720    

DOI:10.1080/10407788208913432

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

The study of radiative heat transfer with scattering usually leads to the solution of singular Fredholm integral equations. The present paper presents an accurate and efficient numerical method to solve certain integral equations that govern radiative equilibrium problems in plane-parallel geometry for both grey and nongrey, anisotropically scattering media. In particular, the nongrey problem is represented by a spectral integral of a system of nonlinear integral equations in space, which has not been solved previously. The numerical technique is constructed to handle this unique nongrey governing equation as well as the difficulties caused by singular kernels. Example problems are solved and the method's accuracy and computational speed are analyzed.

ISSN:0149-5720    

DOI:10.1080/10407788208913433

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Consideration is given to a system consisting of two parallel vertical channels that share a common wall across which heat is transferred from one channel to the other. The other walls of the system are characterized by prescribed surface temperatures that exceed the ambient temperature, and this induces a buoyancy-driven upflow in the channels. To cope with the strong interaction between the channels, a solution scheme was employed in which each channel was visited successively and iteratively. The single-channel solutions that were performed at each visitation were also iterative in character, with the computations carried out with a parabolic finite-difference method. Three parameters were varied during the course of the computations. These Included the dimensionless channel height, a dimensionless temperature difference, and the dimensionless position of the common wall between the channels. Results are presented for the surface-integrated heat transfer at each channel wall, the total system heat transfer, and the convective energy efflux from the respective channels. Local heat flux distributions are also presented, as are the distributions of the temperature along the common wall.

ISSN:0149-5720    

DOI:10.1080/10407788208913434

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Laminar natural convection of air along a vertical square duct open at both ends has been investigated for constant temperature and constant heat flux boundary conditions on the duct walls. The velocity of entering air at the bottom of the duct is assumed uniform at atmospheric pressure or the acceleration head of the entering fluid. The three-dimensional differential equations for momentum and energy have been solved numerically by a strongly implicit finite-difference procedure. The axial development of flow and heat transfer rates are presented, A curve fit for the mean heat transfer coefficient in the Rayleigh number range of 10 to 1000 results in the following relations:

ISSN:0149-5720    

DOI:10.1080/10407788208913435

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Numerical approximations to heat transfer rates for steady-state laminar free convection in rectangular cavities for Rayleigh numbers up to 107, angle of inclination varying up to ±90° with respect to the vertical direction, and aspect ratios 1, 5, and 10 are reported. These have been obtained with a penalty function finite-element algorithm using primitive fluid variables. The thermal structure and velocity fields of the flow are also presented for some of the most representative cases.

ISSN:0149-5720    

DOI:10.1080/10407788208913436

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

A few numerical analyses of the free convection between two heated parallel plates have been carried out without using the boundary-layer approximation. In this paper, an approach that can determine the flow rate with consideration of the pressure drop is proposed. As an example of the calculation, the method is applied to Kettleborough's model. In addition, a comparison is made with Kettleborough's and Aihara's results.

ISSN:0149-5720    

DOI:10.1080/10407788208913437

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor

摘要:

Numerical predictions have been made of heat transfer to low-Prandtl-number fluids in pipes with constant wall heat flux. The turbulence model employed is of the two-equation (k-)c kind in the core and the one-equation (k) kind in the near-wall region.

ISSN:0149-5720    

DOI:10.1080/10407788208913438

出版商:Taylor & Francis Group    

年代:1982

数据来源: Taylor