摘要:

AbstractThe complex variable boundary element method (CVBEM) for simply connected domains is extended to include the use of quadratic elements and interpolating functions. The derivation follows the format for linear elements given in the literature, with second‐degree Lagrange polynomials taken as the interpolating functions. The quadratic‐element CVBEM nodal‐ and interior‐point equations are given in detail, and the resulting formulation is successfully tested by solving example problems with available analytical solutions. Comparisons of computational efficiency and accuracy are made between the solutions obtained using linear and quadratic elements. Additional comparisons are made using published results from other boundary element

ISSN:0271-2091    

DOI:10.1002/fld.1650150802

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA numerical study was performed to investigate chemically reactive flows with sprays inside a staged turbine combustor (STC) using a modified version of the KIVA‐II code. This STC consists of a fuel nozzle (FN), a rich‐burn (RB) zone, a converging connecting pipe, a quick‐quench (QQ) zone, a diverging connecting pipe and a lean‐combustion (LC) zone. From the computational viewpoint, it is more efficient to split the STC into two subsystems, called FN/RB zone and QQ/LC zones, and the numerical solutions were obtained separately for each subsystem. This paper addresses the numerical results of the STC which is equipped with an advanced airblast fuel nozzle. The airblast nozzle has two fuel injection passages and four air flow passages. The input conditions used in this study were chosen similar to those encountered in advanced combustion systems. Preliminary results generated illustrate some of the major features of the flow and temperature fields inside the STC. Velocity, temperature and some critical species information inside the FN/RB zone are given. Formation of the co‐ and counter‐rotating bulk flow and the sandwiched‐ring‐shaped temperature field, typical of the confined inclined jet‐in‐cross‐flow, can be seen clearly in the QQ/LC zones. The calculations of the mass‐weighted standard deviation and the pattern factor of temperature revealed that the mixing performance of the STC is very promising. The temperature of the fluid leaving the LC zone is very uniform. Prediction of the NOxemission shows that there is no excessive thermal NOxproduced in the QQ/LC zones for the case studied. From the results obtained so far, it appears that the modified KIVA‐II code can be used to guide the low‐emis

ISSN:0271-2091    

DOI:10.1002/fld.1650150803

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractThree kinds of grid system based on C‐type grid are examined in order to reveal their relative flow characteristics of the turbomachinery cascade, especially near the trailing edge and wake. Here, a semi‐conservative interpolation technique to treat the discontinuous boundary condition along the periodic boundary is proposed and is applied on the patched‐type grid structure. Computational results are presented to see the influence of trailing‐edge grid structure on the Navier‐Stokes solutions for the high‐turning transonic turb

ISSN:0271-2091    

DOI:10.1002/fld.1650150804

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractA finite volume method for the calculation of laminar and turbulent fluid flows inside constricted tubes and ducts is described. The selected finite volume method is based on curvilinear non‐orthogonal co‐ordinates (body‐fitted co‐ordinates) and a non‐staggered grid arrangement. The grids are either generated by transfinite interpolation or an elliptic grid generator. The method is employed for calculation of laminar flows through a tube, a converging‐diverging duct and different constricted tubes by both a two‐ and a three‐dimensional computer program. In addition, turbulent flow through an axisymmetric constricted tube is calculated. Both the power law scheme and the second‐order upwind scheme are used. The calculated results are compared with the experimental data and with other nu

ISSN:0271-2091    

DOI:10.1002/fld.1650150805

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

摘要:

AbstractIn this paper a new approach to calculate transonic flows is developed. A set of full‐potential‐equivalent equations in the von Mises co‐ordinate system is formulated under the irrotationality and isentropic assumptions. The emphasis is placed on supercritical flow, in which the treatment of embedded shock waves is crucial to get convergent solutions. Shock jump conditions are employed and shock point operators (SPOs) are constructed in the body‐fitting streamline co‐ordinate system. SPOs and a type‐dependent difference scheme are applied to solve the ‘main’ equation for the ‘main’ variable, the streamline ordinatey. A number of ‘secondary’ equations are deduced for the corresponding ‘secondary’ variables. An optimal combination for the ‘secondary’ variable, its equation and related difference scheme is selected to be the generalized densityR, its linear equation and the Crank‐Nicolson scheme. Numerical results show that the present approach gives good agreement with experimental data and other computational work for NACA0012 and biconvex aerofoils in both sub

ISSN:0271-2091    

DOI:10.1002/fld.1650150806

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650150807

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650150808

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY

ISSN:0271-2091    

DOI:10.1002/fld.1650150801

出版商:John Wiley&Sons, Ltd    

年代:1992

数据来源: WILEY