摘要:

The performance of the PISO, SIMPLER, and SIMPLEC algorithms for the treatment of the pressure-velocity coupling in steady flow problems is examined by comparing the computational effort required to obtain the same level of convergence in four test problems. For problems in which the momentum equation is not coupled to a scalar variable the PISO algorithm is superior, but when the scalar variable is strongly coupled to the momentum equation SIMPLER and SIMPLEC exhibit better behavior and reasonable solutions with the PISO algorithm are obtained only for small time steps. Clear superiority of SIMPLER over SIMPLEC or vice versa is not observed, although the iterative formulations of these two algorithms exhibit more robust behavior than the corresponding time-marching formulations.

ISSN:0149-5720    

DOI:10.1080/10407788608913517

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Phase distribution of two-fluid flow in elbows is determined by the interaction of centrifugal forces with gravity and interphase friction. A method of computing flow and phase distribution by solving the three-dimensional two-fluid conservation equations is outlined and implemented in a computer program that is shown to be successful in predicting distributions measured in several different bend configurations, including C, L, and U bends.

ISSN:0149-5720    

DOI:10.1080/10407788608913518

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

The problem of transient droplet vaporization in a hot convective environment is examined. A model that accounts for liquid-phase internal circulation, transient droplet heating and species diffusion, and axisymmetric gas-phase convection is used. The coupled vaporization problem is formulated as a Volterra-type integral equation with the liquid-phase temperature and species concentration at the droplet surface being unknown functions of time. The integral equation formulation is subsequently transformed into a system of first-order ordinary differential equations, which are solved by the Runge-Kutta scheme. Since only the liquid-phase temperature and species concentration at the droplet surface are needed for determining the vaporization rate and the heat flux, the integral equation formulation has the advantage of eliminating the spatial dependence from the problem, thereby reducing the amount of compulation time.

ISSN:0149-5720    

DOI:10.1080/10407788608913519

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Numerical solutions are presented for steady laminar two-dimensional natural convection in annuli between concentric and vertically eccentric horizontal circular cylinders with specified (constant) heat flux at the boundaries. The results encompass streamline and isotherm contours, temperature distributions on both cylinder boundaries, and average Nusselt numbers as functions of the modified Rayleigh number.

ISSN:0149-5720    

DOI:10.1080/10407788608913520

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor

摘要:

Finite-difference calculations were used to characterize a periodic alternation of heating and nonheating of finite and semi-infinite regions. Heating with a fixed heat flux density and heating with a fixed temperature at the surface or surfaces were both examined. Theoretically based correlating equations were developed to generalize the computed values. Periodic on-off heating with a fixed heat flux density is shown to be particularly advantageous when deep and rapid penetration of energy is to be accomplished while constraining the maximum temperature at the surface.

ISSN:0149-5720    

DOI:10.1080/10407788608913521

出版商:Taylor & Francis Group    

年代:1986

数据来源: Taylor