This paper discusses the influence of various volute designs on volute overall performance for a certain centrifu- gal compressor with both vaned and vaneless diffuser. Firstly, based on a free vortex flow pattern and...This paper discusses the influence of various volute designs on volute overall performance for a certain centrifu- gal compressor with both vaned and vaneless diffuser. Firstly, based on a free vortex flow pattern and the assumption of a circumferentially uniform flow at the design condition, a corrected method for volute design is adopted. By means of this method, corresponding to five geometric parameters affecting the volute overall performance, ten volute cases are designed. Secondly, the numerical simulation is employed and the detailed flow field and losses in different volutes with different geometric parameters are analyzed. The numerical investigation reveals that in all of the five geometric parameters, the radial location of the cross-section has the strongest influence on the performance of the volute. The non-uniform volute inlet formed by the upward vaned diffuser outlet flow is another important factor. Finally a relatively better value of D1/D2 is concluded.展开更多
The developable surface is an important surface in computer aided design, geometric modeling and industrial manufactory. It is often given in the standard parametric form, but it can also be in the implicit form which...The developable surface is an important surface in computer aided design, geometric modeling and industrial manufactory. It is often given in the standard parametric form, but it can also be in the implicit form which is commonly used in algebraic geometry. Not all algebraic developable surfaces have rational parametrizations. In this paper, the authors focus on the rational developable surfaces. For a given algebraic surface, the authors first determine whether it is developable by geometric inspection, and then give a rational proper parametrization in the affrmative case. For a rational parametric surface, the authors also determine the developability and give a proper reparametrization for the developable surface.展开更多
文摘This paper discusses the influence of various volute designs on volute overall performance for a certain centrifu- gal compressor with both vaned and vaneless diffuser. Firstly, based on a free vortex flow pattern and the assumption of a circumferentially uniform flow at the design condition, a corrected method for volute design is adopted. By means of this method, corresponding to five geometric parameters affecting the volute overall performance, ten volute cases are designed. Secondly, the numerical simulation is employed and the detailed flow field and losses in different volutes with different geometric parameters are analyzed. The numerical investigation reveals that in all of the five geometric parameters, the radial location of the cross-section has the strongest influence on the performance of the volute. The non-uniform volute inlet formed by the upward vaned diffuser outlet flow is another important factor. Finally a relatively better value of D1/D2 is concluded.
基金supported by Beijing Nova Program under Grant No.Z121104002512065The author PerezDíaz S is a member of the Research Group ASYNACS(Ref.CCEE2011/R34)
文摘The developable surface is an important surface in computer aided design, geometric modeling and industrial manufactory. It is often given in the standard parametric form, but it can also be in the implicit form which is commonly used in algebraic geometry. Not all algebraic developable surfaces have rational parametrizations. In this paper, the authors focus on the rational developable surfaces. For a given algebraic surface, the authors first determine whether it is developable by geometric inspection, and then give a rational proper parametrization in the affrmative case. For a rational parametric surface, the authors also determine the developability and give a proper reparametrization for the developable surface.
