摘要:

The control volume finite-element method in conjunction with the vorticity stream function formulation is used to produce a numerical solution of the confined turbulent diffusion flame. The turbulence is described by the k-t model with wall functions near solid boundaries. The combustion kinetics are defined by a one-step infinite rate chemical reaction. The validity of the numerical method is assessed by a comparison between present numerical results and experimental data from the literature for a laboratory turbulent diffusion flame.

ISSN:1040-7782    

DOI:10.1080/10407789308913672

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This paper presents a comparative study of the standard k-t model, the nonlinear k-∈ model, and the modified k-∈ model utilizing the double-pass procedure. The three models are used to predict the flow and heat transfer past a backstep, and the predictions are compared with selected experimental data. The comparison indicates that the modified and nonlinear k-t models agree better with measurements than the standard k-t model predictions.

ISSN:1040-7782    

DOI:10.1080/10407789308913673

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

In the chemical vapor deposition process, the objective is to grow a crystal film as fast as possible, while at the same time ensuring Us chemical uniformity and crystal graphic perfection, This paper studies the possible enhancement of diffusion-controlled mass transfer by rotating a cylindrical substrate, which is used in the manufacture of superconductor materials. To preserve the free-stream properties, a numerical technique bearing a strong conservation property is described. The solutions are validated against previously published data on the drag and lift coefficients for a rotating cylinder. The numerical inaccuracy associated with the use of the conventional weak conservation form of the Navier-Stokes equations in polar coordinates is shown to be around 15%. It is found that rotation has minor influence on the average mass transfer rate and it generally increases the uniformity of the transport process.

ISSN:1040-7782    

DOI:10.1080/10407789308913674

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

An analytical/numerical analysis is made of the hydrodynamic and heat transfer characteristics of a fluid flow through internal, longitudinal finned tubes. Employing control volume discretization in the cross section of the tube only, the two-dimensional momentum equation is solved numerically, whereas the three-dimensional energy equation is solved analytically. The pressure gradients are numerically determined, and Ike heat transfer rates, in terms of the tube length, are expressed in analytical form. The computed results are presented for different configurations corresponding to selected combinations of relative fin heights and the number of equally spaced fins in the array.

ISSN:1040-7782    

DOI:10.1080/10407789308913675

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

This work deals with Ike problem of transient conjugated forced convection heat transfer with fully developed laminar flow in an infinitely long pipe, in which the external surface over a finite length of pipe is subject to a constant wall temperature. The effects are presented of Pécles number, ratios of pipe radii, wall-to-fluid diffusivity, and conductivity on the interfacial heat flux. The predicted results show that the unsteady heat transfer characteristics depend strongly on the ratios of outside and inside radix, wall-to-fluid conductivity, and thermal diffusivity. Additionally, the decrease in diffusivity ratio A from 10 to 0.1 results in a longer time for the system to reach the steady state condition from τ = 6.4 to τ = 265.

ISSN:1040-7782    

DOI:10.1080/10407789308913676

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor

摘要:

Non-Darcian effects, including the effects of boundary and inertia, are examined on the flow and vortex instability of a horizontal mixed convective boundary layer flow in a high-porosity medium. In the base flow, the governing conservation equations are solved by using a suitable variable transformation and employing an implicit finite-difference scheme. The stability analysis is based on linear stability theory, and the resulting equations are solved on the basis of the local similarity approximations. The results show that the flow becomes more susceptible to the vortex mode of disturbances as buoyancy force is increased. In addition, both the boundary and inertia effects reduce the heat transfer rate and stabilize the flow to the vortex mode of disturbances.

ISSN:1040-7782    

DOI:10.1080/10407789308913677

出版商:Taylor & Francis Group    

年代:1993

数据来源: Taylor