摘要:

A method is presented for solving the equations of motion in orthogonal curvilinear coordinates using a computational grid that conforms to the boundaries and is orthogonal in the interior. Details of the derivation are provided. The particular formulation proposed maintains simplicity, clarity, and flexibility by special treatment of the stresses and diffusive fluxes. Because the equations are simple generalizations of those that arise when specific analytic coordinates are used, standard solution methods are applicable. The method is demonstrated for two problems, one of which involves both heat and fluid flow.

ISSN:0149-5720    

DOI:10.1080/10407788608913469

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A numerical method for three-dimensional elliptic convection-diffusion problems is presented. The formulation is based on four-node tetrahedral elements and flow-oriented interpolation functions that respond appropriately to an element Peclet number and the direction of the element-average velocity vector. A control-Volume approach is used to derive the discretization equations. The method has been applied successfully to several test problems.

ISSN:0149-5720    

DOI:10.1080/10407788608913470

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The optimization of thermal insulation distribution over a conducting body is analyzed by an iterative numerical method. The sensitivity analysis of the optimization problem is done by using an augmented function method, in which the derivatives of the performance index and constraints with respect to the control functions are evaluated via Lagrange multiplier functions. For a numerical solution of the problem, the spatial discretizations of the system and adjoint equations are achieved by means of the boundary element method. Starting from a feasible initial guess for the discretized control function, the minimization of the performance index is performed by using an iterative constrained optimization routine.

ISSN:0149-5720    

DOI:10.1080/10407788608913471

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Mathematical models describing the operation of diabatic regenerators have been derived and solved numerically using finite-difference schemes for the prediction of system thermal performance. The present formulations include the effects of radial conduction and storage of heat in the regenerator walls as well as heat loss, which can be quite important in experimental situations but which were neglected in all previous investigations. The effects of the above phenomena are explored, and indications are given under what regenerator conditions these effects could be reduced. In addition, the models are used to examine the available experimental data for the contribution of such effects.

ISSN:0149-5720    

DOI:10.1080/10407788608913472

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A numerical model for pulsed turbulent ducted air flows and related heat transfer is presented. A mixing length hypothesis combined with the eddy viscosity and diffusivity model of Cebeci, Habib, and Na is used. Turbulent transport properties are assumed not to change with time. The equation set is solved by means of a finite-difference method coupled with asymptotic developments for the different physical quantities (pressure, velocity, temperature). Assuming a fully developed dynamic regime, the developing steady and unsteady thermal fluid fields, and thus the heat fluxes at the wall, are described for a condition of uniform temperature.

ISSN:0149-5720    

DOI:10.1080/10407788608913473

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

A finite-difference study has been made of steady-state natural convection in an enclosure with an off-center complete partition. Results are obtained for Rayleigh numbers in the range 104−107; inclination angles of 30°, 45°, 60°, and 90°; and dimensionless partition locations of 0.75 and 0.875. The results are compared with similar calculations for an enclosure with a centrally located partition. Results indicate that the partition location has a significant influence on flow and heat transfer characteristics. The partition temperature distribution is strongly influenced by the partition location at low Rayleigh numbers; this influence decreases with increasing Rayleigh numbers. The average Nusselt numbers along the thermally active surfaces are found to be significantly smaller than the corresponding values for a nonpartitioned enclosure.

ISSN:0149-5720    

DOI:10.1080/10407788608913474

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

ISSN:0149-5720    

DOI:10.1080/10407788608913475

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Computer time comparisons were performed between the eigenvalue method, the Crank-Nicolson method, and the fully implicit method for computing transient heat conduction in a two-and a three-dimensional problem. It was found that a large number of nodal points required excessive computer time for computation of the complete sets of eigenvalues and eigenvectors, as needed by the eigenvalue method.

ISSN:0149-5720    

DOI:10.1080/10407788608913476

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor