Redesign of a Two and a Half Stage Subsonic Turbine Using a New Viscous Inverse Design Method

2008 ◽  
Author(s):  
Benedikt Roidl ◽  
Wahid Ghaly
Keyword(s):  
Stokes Equations ◽  
Design Method ◽  
Thickness Distribution ◽  
Suction Side ◽  
Accurate Solution ◽  
Arbitrary Lagrangian Eulerian ◽  
Pressure Loading ◽  
Multi Stage ◽  
Design Variables ◽  
Target Pressure

The midspan section of a multi-stage subsonic turbine that is built and tested at the University of Hannover is redesigned using a new inverse blade design method where the blade walls move with a virtual velocity distribution derived from the difference between the current and the target pressure loading on the blade surfaces. The prescribed design variables are the blade loading and thickness distribution. This new inverse method is fully consistent with the viscous flow assumption and is implemented into the time accurate solution of the Reynolds-Averaged Navier-Stokes equations that are expressed in an arbitrary Lagrangian-Eulerian (ALE) form to account for mesh movement. A cell-vertex finite volume method of the Jameson type is used to discretize the equations in space; time accurate integration is obtained using dual time stepping. An algebraic Baldwin-Lomax turbulence model is used for turbulence closure. The mixing plane approach is used to couple the blade row regions of the multistage. The CFD analysis formulation is first assessed against the multi-stage turbine experimental data. The method is then used to redesign the second and third stators of the 2.5 stage turbine so as to reduce the blade suction side diffusion. The results show that by carefully tailoring the target pressure loading, some improvement can be achieved in the turbine performance.

Redesign of a Low Speed Turbine Stage Using a New Viscous Inverse Design Method

2010 ◽  
Vol 133 (1) ◽  
Author(s):  
Benedikt Roidl ◽  
Wahid Ghaly
Keyword(s):  
Stokes Equations ◽  
Design Method ◽  
Accurate Solution ◽  
Inverse Design ◽  
Pressure Loading ◽  
Turbine Stage ◽  
Low Speed ◽  
Target Pressure ◽  
Stage Performance ◽  
Inverse Design Method

The midspan section of a low speed subsonic turbine stage that is built and tested at DFVLR, Cologne, is redesigned using a new inverse blade design method, where the blade walls move with a virtual velocity distribution derived from the difference between the current and target pressure distributions on the blade surfaces. This new inverse method is fully consistent with the viscous flow assumption and is implemented into the time-accurate solution of the Reynolds-averaged Navier–Stokes equations. An algebraic Baldwin–Lomax turbulence model is used for turbulence closure. The mixing plane approach is used to couple the stator and rotor regions. The computational fluid dynamics (CFD) analysis formulation is first assessed against the turbine stage experimental data. The inverse formulation that is implemented in the same CFD code is assessed for its robustness and merits. The inverse design method is then used to study the effect of the rotor pressure loading on the blade shape and stage performance. It is also used to simultaneously redesign both stator and rotor blades for improved stage performance. The results show that by carefully tailoring the target pressure loading on both blade rows, improvement can be achieved in the stage performance.

Redesign of a Low Speed Turbine Stage Using a New Viscous Inverse Design Method

2008 ◽  
Author(s):  
Benedikt Roidl ◽  
Wahid Ghaly
Keyword(s):  
Stokes Equations ◽  
Design Method ◽  
Accurate Solution ◽  
Inverse Design ◽  
Pressure Loading ◽  
Turbine Stage ◽  
Low Speed ◽  
Target Pressure ◽  
Stage Performance ◽  
Inverse Design Method

The midspan section of a low speed subsonic turbine stage that is built and tested at DFVLR, Cologne, is redesigned using a new inverse blade design method where the blade walls move with a virtual velocity distribution derived from the difference between the current and the target pressure distributions on the blade surfaces. This new inverse method is fully consistent with the viscous flow assumption and is implemented into the time accurate solution of the Reynolds-Averaged Navier-Stokes equations. An algebraic Baldwin-Lomax turbulence model is used for turbulence closure. The mixing plane approach is used to couple the stator and the rotor regions. The CFD analysis formulation is first assessed against the turbine stage experimental data. The inverse formulation that is implemented in the same CFD code is also assessed for its robustness and merits. The inverse design method is then used to study the effect of the rotor pressure loading on the blade shape and stage performance. It is also used to simultaneously redesign both stator and rotor blades for improved stage performance. The results show that by carefully tailoring the target pressure loading on both blade rows, improvement can be achieved in the stage performance.

Dual Point Redesign of Axial Turbines Using a Viscous Inverse Design Method

2009 ◽  
Author(s):  
Benedikt Roidl ◽  
Wahid Ghaly
Keyword(s):  
Inverse Method ◽  
Stokes Equations ◽  
Design Method ◽  
Single Point ◽  
Accurate Solution ◽  
Inverse Design ◽  
Suction Surface ◽  
Pressure Distributions ◽  
Wide Range ◽  
Inverse Design Method

A new dual-point inverse blade design method was developed and applied to the redesign of a highly loaded transonic vane, the VKI-LS89, and the first 2.5 stages of a low speed subsonic turbine, the E/TU-4 4-stage turbine that is built and tested at the university of Hannover, Germany. In this inverse method, the blade walls move with a virtual velocity distribution derived from the difference between the current and the target pressure distributions on the blade surfaces at both operating points. This new inverse method is fully consistent with the viscous flow assumption and is implemented into the time accurate solution of the Reynolds-Averaged Navier-Stokes equations. An algebraic Baldwin-Lomax turbulence model is used for turbulence closure. The mixing plane approach is used to couple the stator and rotor regions. The dual-point inverse design method is then used to explore the effect of different choices of the pressure distributions on the suction surface of one or more rotor/stator on the blade/stage performance. The results show that single point inverse design resulted in a local performance improvement whereas the dual point design method allowed for improving the performance of both VKI-LS89 vane and E/TU-4 2.5 stage turbines over a wide range of operation.

Redesign of a Highly Loaded Transonic Turbine Nozzle Blade Using a New Viscous Inverse Design Method

2007 ◽  
Author(s):  
Kasra Daneshkhah ◽  
Wahid Ghaly
Keyword(s):  
Inverse Method ◽  
Design Method ◽  
Guide Vane ◽  
Accurate Solution ◽  
Inverse Design ◽  
Arbitrary Lagrangian Eulerian ◽  
Pressure Distributions ◽  
Transonic Turbine ◽  
Inverse Design Method ◽  
Highly Loaded

The redesign of VKI-LS89 turbine vane, which is typical of a highly loaded transonic turbine guide vane is presented. The redesign is accomplished using a new inverse design method where the blade walls move with a virtual velocity distribution derived from the difference between the current and the target pressure distributions on the blade surfaces. This new inverse method is fully consistent with the viscous flow assumption and is implemented into the time accurate solution of the Reynolds-Averaged Navier-Stokes (RANS) equations that are expressed in an arbitrary Lagrangian-Eulerian (ALE) form to account for mesh movement. A cell-vertex finite volume method is used to discretize the equations in space; time accurate integration is obtained using dual time stepping. An algebraic Baldwin-Lomax model is used for turbulence closure. The flow analysis formulation is first assessed against the LS89 experimental data. The inverse formulation that is implemented in the same code, is also assessed for its robustness and accuracy, by inverse designing the LS89 original geometry through running the inverse method with the original LS89 pressure distributions as target distributions but starting from an arbitrary geometry. The inverse design method is then used to redesign the LS89 using an arbitrary pressure distributions at a subsonic and a transonic outflow condition and the results are interpreted in terms of the blade overall aerodynamic performance.

Squealer Tip Treatment Design for Axial Compressors

2020 ◽  
Author(s):  
Giuseppe Bruni ◽  
James Taylor ◽  
Senthil Krishnababu ◽  
Robert Miller ◽  
Roger Wells
Keyword(s):  
Thickness Distribution ◽  
Axial Compressor ◽  
Leading Edge ◽  
Experimental Tests ◽  
Suction Side ◽  
Rotor Blades ◽  
Superior Performance ◽  
Stall Margin ◽  
Wall Flows ◽  
Multi Stage

Abstract End-wall flows are amongst the main sources of losses in the rear stages of a typical multi-stage axial compressor. Reducing the tip leakage losses in the rotor blades and vanes can provide an increased efficiency and stall margin of a given axial compressor stage. One approach is to use squealer tips, which are traditionally designed to minimize the effect of tip rubbing. However, squealers can also provide a significant performance benefit, when designed considering aerodynamics from the beginning, as shown in this paper. A CFD based methodology, in which the blade or vane thickness distribution is varied in a controlled manner was developed. This design methodology was used to create different types of squealer tip geometry for a representative stage in a low speed compressor rig. Three different tip concepts were designed, based on a Suction Side Squealer, on a Pressure Side Squealer and on the combination of the two being merged between the leading edge and trailing edge, this new design is called the SuPr Tip. Subsequent experimental tests carried out agreed with the predicted relative ranking of the different squealer designs and on the superior performance of the SuPr tip design over the others, thus validating the methodology and the design process.

Dual Point Redesign of an Axial Compressor Airfoil Using a Viscous Inverse Design Method

2010 ◽  
Author(s):  
Raja Ramamurthy ◽  
Wahid Ghaly
Keyword(s):  
Performance Improvement ◽  
Stokes Equations ◽  
Design Method ◽  
Weighted Average ◽  
Inverse Design ◽  
Pressure Distributions ◽  
Target Pressure ◽  
The Difference ◽  
Inverse Design Method ◽  
Operating Points

The midspan section of Rotor 67 is redesigned simultaneously at two different design points using a new inverse blade design method where the blade walls move with a virtual velocity distribution derived from the difference between the current and the target pressure distributions on the blade surfaces. This inverse method is fully consistent with the viscous flow assumption and is implemented into the time accurate solution of the Reynolds-Averaged Navier-Stokes equations that are expressed in an arbitrary Lagrangian-Eulerian (ALE) form to account for mesh movement. A cell-vertex finite volume method of the Jameson type is used to discretize the equations in space; time accurate integration is obtained using dual time stepping. An algebraic Baldwin-Lomax turbulence model is used for turbulence closure. The CFD analysis provides the initial blade pressure distributions at both operating points, e.g. at two different back pressures and/or blade speeds. At each operating point, a target pressure distribution that results in a performance improvement, is prescribed. The inverse design method is then used to reach the prescribed target pressure distributions at both operating points, simultaneously. This is done by using a weighted average of the difference between the target and current pressure distributions at the two operating points, to modify the airfoil profile. The results show that by carefully tailoring the target pressure loadings at the two design points, some performance improvement can be achieved over the entire range between the two operating points.

scholarly journals Vibrations of Nonlinear Elastic Structure Excited by Compressible Flow

2021 ◽  
Vol 11 (11) ◽  
pp. 4748
Author(s):  
Monika Balázsová ◽  
Miloslav Feistauer ◽  
Jaromír Horáček ◽  
Adam Kosík
Keyword(s):  
Compressible Flow ◽  
Nonlinear Elasticity ◽  
Vocal Tract ◽  
Stokes Equations ◽  
Vocal Folds ◽  
Nonlinear Material ◽  
Navier Stokes ◽  
Arbitrary Lagrangian Eulerian ◽  
Navier Stokes Equations ◽  
Reliable Solution

This study deals with the development of an accurate, efficient and robust method for the numerical solution of the interaction of compressible flow and nonlinear dynamic elasticity. This problem requires the reliable solution of flow in time-dependent domains and the solution of deformations of elastic bodies formed by several materials with complicated geometry depending on time. In this paper, the fluid–structure interaction (FSI) problem is solved numerically by the space-time discontinuous Galerkin method (STDGM). In the case of compressible flow, we use the compressible Navier–Stokes equations formulated by the arbitrary Lagrangian–Eulerian (ALE) method. The elasticity problem uses the non-stationary formulation of the dynamic system using the St. Venant–Kirchhoff and neo-Hookean models. The STDGM for the nonlinear elasticity is tested on the Hron–Turek benchmark. The main novelty of the study is the numerical simulation of the nonlinear vocal fold vibrations excited by the compressible airflow coming from the trachea to the simplified model of the vocal tract. The computations show that the nonlinear elasticity model of the vocal folds is needed in order to obtain substantially higher accuracy of the computed vocal folds deformation than for the linear elasticity model. Moreover, the numerical simulations showed that the differences between the two considered nonlinear material models are very small.

scholarly journals Proposal of a stage-by-stage design method and its application on a multi-stage multiphase pump based on numerical simulations

2021 ◽  
Vol 13 (1) ◽  
pp. 168781402098731
Author(s):  
Yi Shi ◽  
Hongwu Zhu
Keyword(s):  
Volume Fraction ◽  
Design Method ◽  
Oil Field ◽  
Stage Design ◽  
Multiphase Pump ◽  
Flow Parameters ◽  
Multi Stage ◽  
Comparison Results ◽  
Third Stage ◽  
Gas Volume

Rotodynamic multiphase pumps are usually equipped with many compression units to provide sufficient boosting pressure for the transportation of production fluid in gas oil field. It is a challenge to maintain pump performance while flow parameters in each stage vary due to the compressibility of gas-liquid phase. In this article, a stage-by-stage design method is proposed to improve the boosting capability of a multiphase pump. Variations of flow parameters in each stage are investigated based on computational fluid dynamics (CFD) numerical simulation. Available methods to determinate main impeller geometry parameters of impeller are discussed. The stage-by-stage design method is applied on a five-stage multiphase pump when the inlet gas volume fraction (GVF) are 30% and 50% separately. The second stage is modified base on its corresponding inlet flow parameters when inlet GVF is 30% while the second and third stage are modified when inlet GVF is 50%. Flow parameters, pressure distribution and velocity distribution are compared between the original pump and modified pump. Differential pressure of the modified pump increases by 53.72 kPa and 58.57 kPa respectively when inlet GVFs are 30% and 50%. The feasibility of the stage-by-stage design method is verified through the comparison results.

Optimization Research on Dynamic Balance of Spatial Engine under Limiting Shaking Moment

2009 ◽  
Vol 626-627 ◽  
pp. 693-698
Author(s):  
Yong Yong Zhu ◽  
S.Y. Gao
Keyword(s):  
Mathematical Model ◽  
Objective Function ◽  
Kinetic Analysis ◽  
Optimization Design ◽  
Design Method ◽  
Dynamic Balance ◽  
Optimized Design ◽  
Design Variables ◽  
The Mathematical Model ◽  
Shaking Moment

Dynamic balance of the spatial engine is researched. By considering the special wobble-plate engine as the model of spatial RRSSC linkages, design variables on the engine structure are confirmed based on the configuration characters and kinetic analysis of wobble-plate engine. In order to control the vibration of the engine frame and to decrease noise caused by the spatial engine, objective function is choosed as the dimensionless combinations of the various shaking forces and moments, the restriction condition of which presents limiting the percent of shaking moment. Then the optimization design is investigated by the mathematical model for dynamic balance. By use of the optimization design method to a type of wobble-plate engine, the optimization process as an example is demonstrated, it shows that the optimized design method benefits to control vibration and noise on the engines and improve the performance practically and theoretically.

Shape Optimization of Forward-Curved-Blade Centrifugal Fan with Navier-Stokes Analysis

2004 ◽  
Vol 126 (5) ◽  
pp. 735-742 ◽  
Author(s):  
Kwang-Yong Kim ◽  
Seoung-Jin Seo
Keyword(s):  
Response Surface ◽  
Stokes Equations ◽  
Computing Time ◽  
Relative Size ◽  
Three Dimensional ◽  
Navier Stokes ◽  
Centrifugal Fan ◽  
Navier Stokes Equations ◽  
Design Variables ◽  
Curved Blade

In this paper, the response surface method using a three-dimensional Navier-Stokes analysis to optimize the shape of a forward-curved-blade centrifugal fan is described. For the numerical analysis, Reynolds-averaged Navier-Stokes equations with the standard k-ε turbulence model are discretized with finite volume approximations. The SIMPLEC algorithm is used as a velocity–pressure correction procedure. In order to reduce the huge computing time due to a large number of blades in forward-curved-blade centrifugal fan, the flow inside of the fan is regarded as steady flow by introducing the impeller force models. Four design variables, i.e., location of cutoff, radius of cutoff, expansion angle of scroll, and width of impeller, were selected to optimize the shapes of scroll and blades. Data points for response evaluations were selected by D-optimal design, and a linear programming method was used for the optimization on the response surface. As a main result of the optimization, the efficiency was successfully improved. Effects of the relative size of the inactive zone at the exit of impeller and momentum fluxes of the flow in scroll on efficiency were further discussed. It was found that the optimization process provides a reliable design of this kind of fan with reasonable computing time.

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