An intuitive parameterization method with inherently high-order differentiability for compressor blade sections based on ellipse hierarchical deformation

Shape parameterization has a crucial influence on the optimal solution of aerodynamic optimization.This paper proposes a novel parameterization method for compressor blade sections based on the three-level deformation of the ellipse,which simultaneously satisfies the requirements of flexibility,smoothness,intuitiveness,and compactness.In proposed method,the first-level deformation directly controls nine key geometric parameters to construct the blade section profile,and then the second-and third-level deformations are performed respectively to coarsely and finely modify the profile while keeping the key geometric parameters unchanged.These three levels of deformation effectively decompose the design space without destroying the ellipse’s infinite differentiability,allowing designers to work only with intuitive shape-related parameters to design blade sections with inherently high-order continuity.To verify the effectiveness,six existing blade sections are first fitted and then one of them is selected for a three-level optimization.The results show that the geometry and aerodynamic performance of the fitted and the original blade sections are in good agreement,and the loss coefficient of the optimized blade section is reduced by a total of 36.41%,with 27.34%,8.45%,and 0.62%reductions for the first to the third level,respectively.Therefore,the proposed parameterization method facilitates the design of lower-loss and higher-load compressor blade sections.

On the Parametric Modeling of Turbine Blade Section Curve

Geometric parameters of the turbine blade are classified according to their destined functions, and the mathematical definition of those parameters in the section curve is introduced in detail. Some parts of the section curve shape can be adjusted freely, offering more flexibility to designers.

BLADE SECTION DESIGN OF MARINE PROPELLERS WITH MAXIMUM CAVITATION INCEPTION SPEED

Kuiper and Jessup（1993）developed a design method for propellers in a wake based on the Eppler foil design method.The optimized section is transformed into the three-dimensional propeller flow using the approach of the effective blade sections.Effective blade sections are two-dimensional sections in two-dimensional flow which have the same chordwise loading distribution as the three-dimensional blade sections of a propeller.However,the design procedure is laborious in two aspects：finding an optimum blade section using the Eppler program requires much skill of the designer,and transforming the two-dimensional blade section into a propeller blade section in three-dimensional flow is complex.In this work,these two problems were coped with.A blade section design procedure was presented using an optimization technique and an alternative procedure for the effective blade section is developed using a lifting surface design method.To validate the method a benchmark model of a naval ship was used.This benchmark model was extended by new appendices and a reference propeller,and designed using conventional design methods.This reference propeller was optimized using the new design procedure and model tests were carried out.Special attention was given to the data of the model and the reference propeller,to make the configuration suitable for the Reynolds-Averaged Navier-Stokes（RANS）calculations.

Investigation of the Compressible Flow through the Tip-Section Turbine Blade Cascade with Supersonic Inlet

The contribution deals with the experimental and numerical investigation of compressible flow through the tip-section turbine blade cascade with the blade 54″ long. Experimental investigations by means of optical(interferometry and schlieren method) and pneumatic measurements provide more information about the behaviour and nature of basic phenomena occurring in the profile cascade flow field. The numerical simulation was carried out by means of the EARSM turbulence model according to Hellsten [5] completed by the bypass transition model with the algebraic equation for the intermittency coefficient proposed by Straka and P?íhoda [6] and implemented into the in-house numerical code. The investigation was focused particularly on the effect of shock waves on the shear layer development including the laminar/turbulent transition. Interactions of shock waves with shear layers on both sides of the blade result usually in the transition in attached and/ or separated flow and so to the considerable impact to the flow structure and energy losses in the blade cascade.