摘要:

A numerical model has been developed to predict the confined swirling spray-combusting flows. The governing gas phase equations in Eulerian coordinates are solved by a lime-marching multiple pressure-correction procedure based on the operator-splitting technique. The droplet dispersion by turbulence is handled by a stochastic discrete particle-tracking technique. The droplet / wall impingement process is modeled by adopting the jet treatment method and the empirical correlation approach. To appraise the relative performance of turbulence models, computations are carried out by the k-e model and the algebraic stress model. The present numerical results for the swirling spray-combusting flows show qualitative agreement with experimental data. In terms of overall local flow properties, the algebraic stress model improves conformity to the experimental data due to its ability to introduce nonisotropic turbulence effects.

ISSN:1040-7782    

DOI:10.1080/10407789408955933

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A numerical model has been developed to predict the fast transient spray-combusting flows. This method is pressure based, noniterative, and applicable to flows at all speeds. Special emphasis is given to the overall behavior of nonlinear combustion instabilities in the liquid-fueled rocket engines. Computations were carried out for various combustion parameters such as initial spray conditions and baffle lengths. The present numerical model successfully predicts high-frequency combustion instability as well as fast transient flow. The baffle length as well as variations in droplet size have significant effects on engine stability. The numerical results indicate that the baffle can effectively suppress pressure oscillations.

ISSN:1040-7782    

DOI:10.1080/10407789408955934

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A low Reynolds number k-e model has been used to predict the wind-induced entrainment in a double-diffusive system. The calculated results are compared with experimental results from wind-induced entrainment in a finite length tank and with shear-induced entrainment in an annular tank. Overall agreement is good for wind speeds less than 10 m / s. Above this value, multidimensional effects tend to dominate. The scale of the turbulence at the surface is found to significantly affect the entrainment rate. This indicates that the suppression of waves on the surface can significantly reduce the rate of entrainment.

ISSN:1040-7782    

DOI:10.1080/10407789408955935

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Numerical investigations are conducted into steady laminar combined convection flows of a power taw fluid between vertical parallel plates with constant wall temperatures. The parabolic boundary layer equations are written in an implicit finite difference form and are then solved using a marching technique. The governing parameters are Gr/ Re, Pr, and the non-Newtonian power law index n. Various values of Gr/Re and n are considered, including the forced convection solution, Gr/Re = 0, and the Newtonian case, n = /. Pr is set at a value of unity in order to present the numerical method. Under certain circumstances, reverse flow regions appear, either at the center or adjacent to the wall of the duct, and these are dealt with using an iterative technique. Results are presented in terms of velocity profiles, local and average Nusselt numbers, and friction factors.

ISSN:1040-7782    

DOI:10.1080/10407789408955936

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

A general analysis of steady laminar mixed convection heat transfer between a quiescent fluid and a rotating or nonrotating cone is presented. A new mixed convection parameter, which also represents a dimensionless streamwise coordinate, is proposed to serve as an index of the relative contributions of free convection and rotational (forced) convection. Appropriate coordinate transformations yield computationally efficient numerical solutions which are uniformly valid over the entire range of mixed convection from the pure free convection limit (nonrotating cone) to the pure forced convection limit (rotating cone). Of particular interest are the effects of the fluid Prandtl number, the power function index (nonisothermal factor), and mixed convection parameter on the local skin friction coefficient and the local Nusselt number.

ISSN:1040-7782    

DOI:10.1080/10407789408955937

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

This study involves simulation of separated, laminar forced convection in a heated cavity located on a flat plate. The velocity vector plots indicate that a single large vortex occupies the entire cavity but has no effect outside the cavity. The temperature distributions along the cavity length show a remarkable similarity in their profiles. The havgand hmaxare calculated on the cavity floor, and a correlation is derived between Nu¯s, based on havg( on the cavity floor, and Re, as Nu¯s, = 0.0031(Res)0.52. The results are compared with experimental values in the literature.

ISSN:1040-7782    

DOI:10.1080/10407789408955938

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

摘要:

Two-dimensional natural convection of a fluid of low Prandtl number (Pr = 0.02) in an annulus between two concentric horizontal cylinders is numerically investigated in a wide range of gap widths. For low Grashof numbers, a steady unicellular convection is obtained. Above a transition Grashof number that depends on the gap width, a steady bicellular flow occurs. With further increase of the Grashof number, steady or time-periodic multicellular convection occurs, and finally, complex unsteady convective flow appears. A plot is presented that predicts the type of flow patterns for various combinations of gap widths and Grashof numbers.

ISSN:1040-7782    

DOI:10.1080/10407789408955939

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor

ISSN:1040-7782    

DOI:10.1080/10407789408956356

出版商:Taylor & Francis Group    

年代:1994

数据来源: Taylor