摘要:

AbstractAnalytical flow models in the near sonic domain of compressible flow are discussed as a supplementary background to elliptic continuation and fictitious gas design methods, to extend shock‐free design into choked flow design, shock‐wave construction, with the aim of developing new analysis programs and of developing experience for three‐dimensional configuration d

ISSN:0029-5981    

DOI:10.1002/nme.1620220203

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractAn engineering method for the design of aerofoils having a prescribed pressure distribution in subsonic or transonic flow is described. The method is based on an iterative procedure of ‘residual‐correction’ type. In each iteration step, the difference between a current and a target pressure distribution (residual) is determined by a fast (multi‐grid) finite‐volume full‐potential code. Corrections to the geometry driving the pressure residual to zero are determined by a global, inverse, thin‐aerofoil theory based method for the subsonic part of the flow field, and by means of a local, inverse, wavy‐wall theory based formula for the supersonic part of the flow field. The determination of the geometry correction has been formulated as a minimization problem in the sense that pressure distribution and geometry requirements may be balanced in a weighted least squares sense. The method is described briefly, including the basic mathematical/physical formulation and the main computational aspects. The capabilities of the method are illustrated by means of examples of a

ISSN:0029-5981    

DOI:10.1002/nme.1620220204

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThis paper describes a numerical method for designing closed aerofoils that correspond to given surface speed distributions including flows with shock waves. The prescribed surface speed distribution in general contains three parameters whose values are found as part of the solution. The inverse aerofoil design problem is not well posed unless the prescribed speed satisfies three constraints that can be used to fix the value of the three adjustable parameters. The computational method is based on the numerical solution of the full potential equation in conservation form by an approximate factorization–multigrid scheme. The nature of the constraints and several strategies for introducing the necessary freedom in the prescribed speed are discussed along with typical solutions illustrating the metho

ISSN:0029-5981    

DOI:10.1002/nme.1620220205

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractA methodology is described for the inverse design and/or analysis of coolant flow passage shapes in multiholed internally cooled turbine blades. The user of this technique may specify the temperature (or heat flux) distribution along the aerofoil outer surface. In addition, the temperature on the surface of each of interior coolant flow passages (holes) may be specified. The numerical solution of the outer hot gas flow field determines the remaining unspecified aerofoil outer surface quantity—surface heat flux if temperature was originally specified or vice versa. The position and shape of each turbine blade coolant hole is then found iteratively by solving the heat conduction problem within the solid portions of the blade. This solution procedure involves satisfying the dual Dirichlet and Neumann specified boundary conditions of temperature and heat flux on the outer boundary of the aerofoil. The inner hole geometry is then modified using an optimization procedure in such a way as to minimize the error in satisfying the specified Dirichlet temperature boundary condition on the surface of each of the evolving interior holes. Results are shown for single‐hole and double‐hole configurations that have analytic solutions and for a realistic turbine blade design pr

ISSN:0029-5981    

DOI:10.1002/nme.1620220206

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractAn inverse inviscid–boundary‐layer interaction scheme is presented for the optimal design of axisymmetric ducts for subsonic, rotational flows. Distribution of the shape factorHon the duct wall, giving minimum total pressure loss and maximum static pressure rise, is used as boundary condition for the inverse integral boundary‐layer solution, to obtain the velocity and displacement thickness distributions on the wall. Vector addition of the inviscid core radius, derived from the solution of the inverse inviscid flow equations, and the displacement thickness produces the desired duct

ISSN:0029-5981    

DOI:10.1002/nme.1620220207

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractWith the aid of the elliptic continuation method, transonic aerofoils for two different purposes have been optimized. The design process is described and it is shown that the optimization is more difficult for higher design Mach numbers. The results of experimental investigations confirmed the good aerodynamic performances of the designed aerofoils, although no real shock‐free pressure distributions could be achieved in the experiments and the highest aerodynamic efficiencies occurred always at higher lift coefficients, with pressure distributions already having shock wave

ISSN:0029-5981    

DOI:10.1002/nme.1620220208

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractA computation method for the inverse design of supercritical cascades is described. It yields the flow field and the cascade geometry for a prescribed velocity distribution, which may be optimized by boundary‐layer calculation. Some developments of the method for convenient application and high accuracy—automatic tuning of the upstream boundary distributions, local mesh refinement with emboxed regions for high resolution of steep gradients—are shown. Comparison between calculation and experiment of the complete flow field is made for a supercritical nozzle flow, and comparison with another method for a turbine cascade. A supercritical compressor cascade and blades for a three‐stage axial compressor have been designed. They produced lower losses and higher efficiency in comparison with conventional NACA

ISSN:0029-5981    

DOI:10.1002/nme.1620220209

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe purpose of this paper is to outline the optimization‐system development at NLR. The paper starts with a discussion of the potential of mathematical optimization techniques in aeronautical engineering. Subsequently, the main requirements to be met by a general‐purpose optimization system are given. Following this, the implementation at NLR is described, and some examples of applications are presented to illustrate the optimization capabilit

ISSN:0029-5981    

DOI:10.1002/nme.1620220210

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

ISSN:0029-5981    

DOI:10.1002/nme.1620220211

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractA new method is developed in this paper for solving an aerodynamic hybrid problem of profile cascade on theS1stream surface of revolution by employing a stream‐function equation on the non‐orthogonal co‐ordinate system. For this kind of problem, the shape of a portion of the blade profile is unknown. The remainder is determined by a given prescribed velocity distribution. Three examples, including two turbine cascades and a compressor cascade, have been carried out to examine this method. It is shown that the calculation method presented herein can be used as a powerful tool, together with the aerodynamic optimization method, for blade cascade d

ISSN:0029-5981    

DOI:10.1002/nme.1620220212

出版商:John Wiley&Sons, Ltd    

年代:1986

数据来源: WILEY