Endwall Contouring Research Articles

Multi-Objective Optimization of Non-Axisymmetric Contoured Endwall for Axial Turbines

Multi-Objective Optimization of Non-Axisymmetric Contoured Endwall for Axial Turbines

Effects of varying non-axisymmetric contours of the turbine endwall on aerodynamics and heat transfer Aspects:A sensitivity analysis study

Non-axisymmetric endwall contouring of gas turbines has been widely employed as an effective way to improve the aerodynamic performance or heat transfer features. Though efforts have been exerted by previous investigators to generate improved contoured endwall designs, better understandings of the physics behind the phenomenon that non-axisymmetric contoured endwall configurations change the aerodynamic or heat transfer performances are still in demand. In this study, a global sensitivity analysis (GSA) methodology is used to determine shape changes at which locations on the endwall have the most significant impact on the aerodynamic or endwall heat transfer performances. Then, typical non-axisymmetric contoured endwall cases found by a multi-objective optimization approach are studied to understand further why shape changes in such locations impact the passage aero-thermal aspects so much. The results show that the most prominent areas for the passage aerodynamic performance are at the passage mid-pitch from the passage forepart to the aft part by impacting the stream-wise acceleration features. The locations at the passage's aft part influence the heat transfer features most due to high velocity, thus large heat transfer coefficient values there.

Numerical investigation and loss estimation of high-pressure turbine cascade flow with contoured endwall and incoming wakes

With the aim of suppressing the irreversible losses, the secondary flow at endwall and incoming vortices interactions are assumed to be the most concerned physics in gas turbine for modern aero-engine and military vehicles. However, the combining effect of contoured endwall and incoming periodic wakes were seldom discussed previously. In the present work, the research subject is the high-pressure turbine cascade with non-axisymmetric endwall and incoming wakes induced by moving bar fulfilled with periodic boundary conditions in pitchwise direction. Firstly, the aerodynamics and thermodynamics in the turbine cascade with secondary flow control technique, which denotes to non-axisymmetric endwall, were experimentally and numerically investigated. For what concerns the profile aerodynamic loadings, total pressure loss coefficients and vortices coefficient were surveyed to quantify the influence of interaction between incoming wakes and secondary flow at contoured endwall. The cumulative difference of entropy production rate associated with dissipation is then employed to evaluate the loss under different inflow condition. Combined with dynamic mode decomposition (DMD) method, the energy loss features associated with incoming wakes at different passing frequencies was captured. The results indicated that the flow separation at the suction wall with the axial position of 70%∼80% Cax upstream trailing edge was suppressed in the cases with incoming wakes for high pressure turbine cascade. And stronger incoming wakes tends show better suppression effect on the flow separation. However, when combined with contoured endwall, the negative influence of non-axisymmetric endwall at the middle passage was enlarged. And the general aerodynamics of the cascade flow may not be necessarily improved in term of energy loss characteristics with the increase of passing frequency of incoming wakes. The present work preserves guiding significance for the design and flow control of high pressure turbine cascade.

Effect of non-axisymmetric endwall and periodic upstream wakes on the aero-thermal dynamics in turbine cascade

The thermal management and heat transfer behavior considering both the contoured endwall and upstream wakes were seldom investigated. In the present work, the experimental measurements of aero-thermal characteristics regarding to a high-pressure turbine cascade with flat and non-axisymmetric endwall, which was optimized with the aim of minimum aerodynamic losses, were carried out. The numerical analysis of the cascade flow with and without upstream wakes and contoured endwall was performed. Then the field synergy theory and entropy production rate concerning heat transfer were introduced. Furthermore, the combining influence of incoming wakes and secondary flow at endwall on the heat transfer characteristics was investigated. Results show that the non-axisymmetric endwall suppresses the passage vortex by weakening the cross flow and surface vortex with concave profiling. And the underturning effect of yaw angle at the cascade exit is reduced due to lower spanwise positon of passage vortex and weaker secondary flow. The positive influence of contoured endwall on losses induced by temperature gradients is mainly localized at the passage downstream, and the leading edge area for contoured endwall, however, has the potential of overheating due to significantly strengthened horse shoe vortex at suction side. The periodic wakes scatter and suppress the negative influence of the contoured endwall on the heat transfer at the leading edge by mixing with the horse shoe vortex. And when wakes and passage vortex meet, the risk of overheating at the rear part of the cascade is reduced. The present work may guide shed now lights into the application of cooling technique on the high-pressure turbine cascade.

Full coverage film cooling on a non-axisymmetric contoured endwall and the baseline endwall

Full coverage film cooling arrangement is widely needed in nozzle guide vanes (NGVs) to keep the turbine surfaces from melting due to the unprecedented high turbine inlet temperature. Meanwhile, to reduce the passage aerodynamic losses, non-axisymmetric endwall contouring are widely applied. The employment of endwall contouring will impact the full coverage film cooling performance, thus changing the turbine durability. Thus, it is important to deeper know the effect of non-axisymmetric endwall contouring on endwall full coverage film cooling performance. In this study, Pressure Sensitivity Paint (PSP) technique is used to measure the full coverage film cooling effectiveness (η) distributions on a non-axisymmetric contoured endwall (CE) and the corresponding baseline endwall (BE) with several coolant mass flow ratios (MFRs). Meanwhile, cases with the corresponding experimental conditions by computational fluid dynamics (CFD) are done to calculate the blowing ratio (BR) and MFR distributions of the film cooling holes. The η distributions on the CE and the BE are compared, and the effect of MFR on the CE full coverage film cooling performance are documented. In addition, different turbulence models are evaluated on the ability to model the endwall film cooling problems by comparing the CFD results with the experimental results. With small MFR values, the film cooling performance are worse on the CE in the near-hole regions at the fore part of the passage but better on the CE in the far-hole regions and at the aft part of the passage than that on the BE. While with large MFRvalues, the CE perform better than the BE throughout the endwall surface.

Optimization of Non-axisymmetric Endwall Contours for the Rotor of a Low Speed, 112-Stage Research Turbine With Unshrouded Blades—Optimization and Experimental Validation

Abstract This paper presents the predicted, as well as final experimental results for the design of an automatically optimized non-axisymmetric endwall and as such, attempts to close the loop between design and practice, providing additional information to other groups involved in the design of endwall contours. The contours designed in this investigation were manufactured using the direct laser sintering rapid prototyping method and installed and tested in the low-speed, 112-stage turbine at the CSIR’s test turbine facility (TTF) in Pretoria, South Africa. Steady-state 5-hole pressure probe traverses were used to characterize the performance and flow profiles upstream, immediately downstream and in a quasi-“mixed-out” sense downstream of the rotor. In addition to the datum (annular) case, both the computed as well as experimental results were compared to the corresponding results generated for a “generically” contoured rotor which was originally designed for a linear cascade test case, but one which used the same blade profile to the current case. The results show that in general both sets of contours performed well, although the added emphasis on flow correction for the contours produced in this investigation resulted in slightly worse performance in terms of loss at the rotor exit (X3) but greatly improved performance in terms of the efficiency and flow angles at the “mixed-out” (X4) measurement plane.

Development of an automated non-axisymmetric endwall contour design system for the rotor of a 1-stage research turbine – Part 2 computed and experimental results

In this paper, we present the computed flow results for those endwall designs produced using the automated non-axisymmetric endwall design procedure and target objective functions detailed in Part 1 of this paper, and where available, compare these with experimental measurements made using the CSIR low-speed research turbine used as the test case for the designs. Experimental measurements were taken immediately aft (X3) as well as downstream (X4) of the rotor row using a drilled 5-hole elbow probe, and both the computed as well as physical results were processed identically to ensure as high a degree of comparability between the computed and physical datasets. For the two initial cases (the η tt- and C ske-based designs), the results of the experiments confirmed the predictions of the simulations, although unexpected flow separations which were not predicted by the computational fluid dynamics (CFD) resulted in poorer agreement for the two remaining contoured cases. In general, the results of the CFD, as confirmed by the experiment, showed that the best metric for the design of the endwall contours for this rig was that based on the rotor total–total efficiency although importantly, the well-known coefficient of secondary kinetic energy ( C ske), even when formulated using a reasonably simple approach, was able to produce closely competitive results to the efficiency-based metric. These findings are significant firstly because, to date, the use of efficiency is not widespread for the design of non-axisymmetric endwall contours, and secondly, because in cases where the efficiency might be difficult to measure and/or predict, the C ske may form a robust if only slightly less effective alternative.

Study of effects of axisymmetric endwall contouring on film cooling/heat transfer and secondary losses in a cascade of first stage nozzle guide vane

The film cooling and heat transfer on the endwall especially in the junction region of a vane/blade which encounters strong vortical flow is of great significance in turbomachinery. Achievement of excellent film cooling and aerodynamic performance by controlling the secondary flow in that region can lead to increased gas turbine efficiency. This study investigates axisymmetric endwall contouring promising to design the assembly of combustor and gas turbine part (first nozzle guide vane) with film cooling in the upstream junction region of nozzle guide vane (NGV). Moreover, being first stage NGV, a slot between them was also modeled with a leakage flow. The study investigated the effect of contouring on the film cooling, heat transfer and secondary flow. Moreover, two contouring angles were studied along with a flat endwall for comparison. The results showed that the film cooling effectiveness from discrete holes provided more coolant coverage in the stagnation region with the large contouring angle. Similarly, cooling flow from the slot was improved significantly with contoured endwall, particularly in the middle section of the passage at higher endwall contouring. Moreover, coolant coverage on the pressure side of the NGV was improved significantly in the passage region. The heat transfer study showed that the contouring angle of 25° reduced Nusselt number in the junction region compared to 15° contoured endwall and planner endwall both with and without film cooling.The heat transfer raised with the presence of flow from the film cooling holes and slot compared to the case without film cooling also suppressed with the contoured endwall with large contouring angle being more effective. The secondary flow generated in the stagnation plane was reduced substantially with the contoured endwall illustrated the phenomenon of improved film cooling effectiveness. The size of the horseshoe vortex was suppressed and stepped up to the stagnation point. The mitigated strength of the secondary flow, improved film cooling effectiveness and reduction of heat transfer greatly depended on the endwall contouring angle.

A Geometry Generation Framework for Contoured Endwalls

Abstract The mainstream, or primary, flow in a gas turbine annulus is characteristically two-dimensional over the midspan region of the blading, where the radial flow is almost negligible. Contrastingly, the flow in the endwall and tip regions of the blading is highly three-dimensional (3D), characterized by boundary layer effects, secondary flow features, and interaction with cooling flows. Engine designers employ geometric contouring of the endwall region in order to reduce secondary flow effects and subsequently minimize their contribution to aerodynamic loss. Such is the geometric variation of vane and blade profiles—which has become a proprietary art form—the specification of an effective endwall geometry is equally unique to each blade row. Endwall design methods, which are often directly coupled to aerodynamic optimizers, are widely developed to assist with the generation of contoured surfaces. Most of these construction methods are limited to the blade row under investigation, while few demonstrate the controllability required to offer a universal platform for endwall design. This paper presents a geometry generation framework (GGF) for the generation of contoured endwalls. The framework employs an adaptable meshing strategy, capable of being applied to any vane or blade, and a versatile function-based approach to defining the endwall shape. The flexibility of this novel approach is demonstrated by recreating a selection of endwalls from the literature, which were selected for their wide range of contouring approaches.

Effect of axial turbine non-axisymmetric endwall contouring on film cooling at different locations

Non-axisymmetric endwall contouring in axial turbines are becoming popular to improve the passage aerodynamic performance or the endwall heat transfer characteristics. Meanwhile, endwall contouring changes the film cooling performance on the endwall surface by modifying the secondary flow fields and the endwall surface shapes, thus impacting the turbine efficiency and durability. Better understandings of the non-axisymmetric contoured endwall film cooling performances are in great need. In this study, adiabatic film cooling effectiveness (η) of discrete film cooling hole injections at different axial locations on an non-axisymmetric contoured endwall and a baseline endwall with different density ratios and matched averaged blowing ratios to the engine conditions are studied experimentally using Pressure Sensitivity Paint (PSP) technique. Computational fluid dynamics (CFD) simulations are also carried out to look into the local flow fields. The results show that the differences in endwall η distributions between the contoured endwall and the baseline endwall are dominated by the streamwise pressure gradients, i.e. at locations with smaller streamwise pressure gradient values on the contoured endwall than those on the flat endwall, the local η values on the contoured endwall are smaller than those on the flat endwall, and vice versa.

An Advanced Single-Stage Turbine Facility for Investigating Nonaxisymmetric Contoured Endwalls in the Presence of Purge Flow

AbstractIn modern gas turbines, endwall contouring (EWC) is employed to modify the static pressure field downstream of the vanes and minimize the growth of secondary flow structures developed in the blade passage. Purge flow (or egress) from the upstream rim-seal interferes with the mainstream flow, adding to the loss generated in the rotor. Despite this, EWC is typically designed without consideration of mainstream–egress interactions. The performance gains offered by EWC can be reduced, or in the limit eliminated, when purge air is considered. In addition, EWC can result in a reduction in sealing effectiveness across the rim seal. Consequently, industry is pursuing a combined design approach that encompasses the rim-seal, seal-clearance profile, and EWC on the rotor endwall. This paper presents the design of and preliminary results from a new single-stage axial turbine facility developed to investigate the fundamental fluid dynamics of egress–mainstream flow interactions. To the authors' knowledge, this is the only test facility in the world capable of investigating the interaction effects between cavity flows, rim seals, and EWC. The design of optical measurement capabilities for future studies, employing volumetric velocimetry (VV) and planar laser-induced fluorescence (PLIF), is also presented. The fluid-dynamically scaled rig operates at benign pressures and temperatures suited to these techniques and is modular. The facility enables expedient interchange of EWC (integrated into the rotor bling), blade-fillet and rim-seal geometries. The measurements presented in this paper include: gas concentration effectiveness and swirl measurements on the stator wall and in the wheel-space core; pressure distributions around the nozzle guide vanes (NGV) at three different spanwise locations; pitchwise static pressure distributions downstream of the NGV at four axial locations on the stator platform.

Secondary Flow and Endwall Optimization of a Transonic Turbine

A detailed numerical analysis of secondary flows in a transonic turbine is presented in this paper. The turbine stage is optimized by mitigating secondary flow through the method of non-axisymmetric endwall design. An automated optimization platform of NUMECA/Design3D was coupled with Euranus as a flow solver for the numerical investigation. The contoured endwalls of the stator and the rotor hub were designed based on equidistant Bézier curves along the camber line in the blade channel. The initial design samples were ten times the number of the design variables, and were generated through the LHS method for database generation. The optimization of the endwalls was achieved by using a state-of-the-art multi-objective optimization algorithm, NSGA-II, connected with the BPNN to increase the isentropic efficiency and decrease the secondary kinetic energy, while the mass flow and the degree of reaction were constrained to remain on the datum value as in the original geometry. The individual optimization of the hub endwalls of the stator and the rotor produced an increase in the efficiency of 0.27% and 0.25%, respectively, resulting in a cumulative improvement of 0.46% in the efficiency. The increase in the performance was analyzed at part-load conditions, and it was further confirmed through unsteady simulations.

Development of an automated non-axisymmetric endwall contour design system for the rotor of a 1-stage research turbine – part 1: System design

Secondary flows are a well-known source of loss in turbomachinery flows, contributing up to 30% of the total aerodynamic blade row loss. With the increase in pressure on aero-engine manufacturers to produce lighter, more powerful and increasingly more efficient engines, the mitigation of the losses associated with secondary flow has become significantly more important than in the past. This is because the production of secondary flow is closely related to the amount of loading and hence the work output of a blade row, which then allows part counts and overall engine weight to be reduced. Similarly, higher efficiency engines demand larger engine pressure ratios which in turn lead to reduced blade passage heights in which secondary flows then dominate. This article discusses the design and application of an automated turbine non-axisymmetric endwall contour optimization procedure for the rotor of a low speed, 1-stage research turbine, which was used as part of a research program to determine the most effective objective functions for reducing turbine secondary flows. In order to produce as effective as possible designs, the optimization procedure was coupled to a computational fluid dynamics routine with as high a degree of fidelity as possible and an efficient global optimization scheme based on the so-called efficient global optimization algorithm. In order to compliment the requirements of the efficient global optimization approach, as well as offset some of the computational requirements of the computational fluid dynamics, the DACE metamodel was used as an underlying surrogate model.

Effect of periodic wakes and a contoured endwall on secondary flow in a high-lift low-pressure turbine cascade at low Reynolds numbers

The use of a contoured endwall has the potential to suppress endwall secondary flow. Unsteady wakes affect not only the boundary layer characteristics of blade suction surface at blade midspan but also the endwall flow structures. The lack of understanding of the flow mechanism of the combined effects of periodic wakes and contoured endwall on secondary flow limits their roles. This paper presents a experimental and numerical investigation of the endwall secondary flow in a typical high-lift low-pressure turbine cascade. Wakes were produced by moving rods upstream of cascade, and the flow fields at the exit of cascade were measured using a seven-hole pressure probe. The study focused on the combined effect of the upstream wakes and the contoured endwall on the secondary flow as well as the underlying physical mechanisms. The influences of the Reynolds numbers and the contoured endwall on the performance of high-lift low-pressure turbine endwall regions were also discussed. At steady conditions without wakes, the total losses in the turbine cascade increased with decreasing Reynolds number; the most intense passage vortex, counter vortex and corner vortex were observed at a low Reynolds number of 25,000 (based on the axial chord and the inlet velocity). The contoured endwall decreased the cross-passage pressure gradient, and suppressed the passage vortex. Under unsteady conditions, the interaction between upstream wakes and the passage vortex results in reduction of the passage vortex. The combined effect of the contoured endwall and periodic wakes redistributed the endwall pressure and further decreased the cross-passage pressure gradient. Consequently, the intensities of the passage vortex and counter vortex decreased by 17% and 11% respectively, compared with the flat endwall cascade with wakes. Contoured endwall with wakes reduced secondary kinetic energy of cascade exit by 53.8% than the result of the flat endwall no wake. Which is beneficial to improve the aerodynamic performance of the high-lift low-pressure turbine.

Purge flow effects on rotor hub endwall heat transfer with extended endwall contouring into the disk cavity

Efficiency improvements for gas turbines are strongly coupled with increasing turbine inlet temperatures. This imposes new challenges for designers for efficient and adequate cooling of turbine components. Modern gas turbines inject bleed air from the compressor into the stator/rotor rim seal cavity to prevent hot gas ingestion from the main flow, while cooling the rotor disk. The purge flow interacts with the main flow field and static pressure field imposed by the turbine blades. This complex interaction causes non-uniform and jet-like penetration of the purge flow into the main flow field, hence affecting the endwall heat transfer on the rotor. To improve the understanding of purge flow effects on rotor hub endwall heat transfer, an unshrouded, high-pressure representative turbine design with 3D blading and extended endwall contouring of the rotor into the cavity seal was tested. The measurements were conducted in the 1.5-stage axial turbine facility LISA at ETH Zurich, where a state-of-the-art measurement setup with a high-speed infrared camera and thermally managed rotor insert was used to perform high-resolution heat transfer measurements on the rotor. Three different purge flow rates were investigated with regard to hub endwall heat transfer. Additionally, steady-state computational fluid dynamics simulations were performed to complement the experiments. It was found that the local heat transfer rate changes up to ±20% depending on the purge flow rate. The main part of the purged air is ejected at the endwall trough location and swept towards the rotor suction side, which is caused by the interaction of main flow and the cavity extended endwall design. The presence of low momentum purge flow locally reduces the heat transfer rate. Changes in adiabatic wall temperature and heat transfer (depending on purge rate) are observed from the platform start up to the cross passage migration of the secondary flow structures.

Influence of endwall 2D contouring on endwall adiabatic cooling effectiveness and aerodynamic performance

Endwall 2D contouring is a presently-employed design method for reducing the strength of secondary flows within gas turbine airfoil passages. Such contouring can lead to significant changes of passage flow. Also affecting passage flow is flow through an interface, or leakage slot, between the combustor and the turbine. Though introduced for eliminating ingression of passage gas into the cavity, leakage flow through the leakage slot, which has bypassed the combustor, can be used to cool the endwall and vane surfaces. Moreover, the leakage flow interacts with the main flow resulting in a change of aerodynamic losses. In this study, a 3D numerical method was used to compare endwall adiabatic cooling effectiveness values, η, and passage Total Pressure Loss Coefficients (TPLC) between a 2D contoured-endwall passage and a flat-endwall passage in a Nozzle Guide Vane (NGV) cascade using several Mass Flow Rate (MFR) values and several momentum flux ratios, I, of slot leakage flow. The numerical method was validated by comparing its computed results with experimental data, then the shape of endwall contouring was designed using an aerodynamic optimization system. The results indicate that with endwall contouring, adiabatic cooling effectiveness values on the endwall are higher than with the flat endwall for all MFR values investigated. Moreover, with the same average momentum flux ratio, I, value of leakage flow, contoured endwall and flat endwall passages show similar adiabatic cooling effectiveness distributions, especially at the regions over the upstream part of the passage, which means that η scales well with I. Over the downstream part of the passage, the contoured endwall cases show higher adiabatic cooling effectiveness values on the contoured endwall with the same average I value as used with the flat endwall passage. Over the MFR range of this study, the contoured-endwall passage shows better aerodynamic performance than that of the flat-endwall passage.

Secondary Flow Loss Reduction by Endwall Contouring in Gas Turbine Cascade Using Optimization Technique

Secondary Flow Loss Reduction by Endwall Contouring in Gas Turbine Cascade Using Optimization Technique

Application of endwall contouring in a high-subsonic tandem cascade with endwall boundary layer suction

A proper combination of active and passive flow control methods would be a promising way to further enhance the compressor performance. This numerical investigation presents a new attempt of application of endwall contouring in a high subsonic tandem cascade with the endwall boundary layer suction implemented in the forward blade. The study aims to further improve the corner flow in the rear blade at design and lower incidences. The planar endwall is redesigned using the optimization method. Nonuniform rational B-spline surface is employed to parameterize the endwall surface. A multi-points optimization strategy is selected to minimize the aerodynamic loss generated in the cascade. In the optimization, the suction strategy remains unchanged. To clarify the impacts of endwall contouring on the cascade performance, flow details in both mainflow passage and suction flow path at design and off-design incidences are analyzed.As a result, the total loss decreases by 8.4% at the design incidence via the endwall contouring. Furthermore, a more prominent loss reduction can be achieved at lower incidences. However, the control effects of endwall contouring is weakened towards higher positive incidences. Worse still, even a deterioration in the cascade performance can be detected at I=5° due to the presence of a small-scale corner stall in the forward blade. The results indicate that, as the gap flow is not strong enough to counteract the endwall secondary flow, the endwall contouring could be employed to further enhance the flow control ability of the previous proposed compound flow control method, while its negative impact on the cascade performance at higher positive incidences still remains to be addressed.

Thermal Management of a Transonic Turbine: Leakage Flow and Endwall Contouring Effects

Comparison of heat transfer performance of a nonaxisymmetric contoured endwall to a planar baseline endwall in the presence of leakage flow through a stator-rotor rim seal interface is reported in this paper. Heat transfer experiments were performed on a high turning turbine airfoil passage at a transonic exit Mach number at different leakages to mainstream mass flow ratios. The contoured endwall geometry was optimized for secondary flow aerodynamic losses. Transient infrared thermography was used to measure the endwall surface temperature. Simultaneous calculation of the heat transfer coefficient (HTC) and adiabatic cooling effectiveness (ETA) was performed assuming one-dimensional semi-infinite transient conduction. Results show nominal reduction in the area-averaged HTC but significantly higher coolant film coverage using the contoured endwall compared to baseline endwall at different levels of coolant MFR. Interestingly, significant reduction in the area-averaged heat transfer coefficient was observed for cases without coolant flow in the presence of a purge slot when compared with a solid cascade without any cooling features. The backward-facing step seemed to have a first-order impact on endwall heat transfer coefficient distribution compared to coolant blowing cases. The contoured endwall also showed major improvement in net heat flux reduction (combining the effects of the HTC and ETA) especially near the suction side of the platform.

On- and off-design performance of a model rotating turbine with non-axisymmetric endwall contouring and a comparison to cascade data

ABSTRACTNon-axisymmetric endwalls in turbine stages have shown to be a robust method to improve the performance of turbines in both power generation and aero-derivative applications. Non-axisymmetric endwalls target the control of secondary flows and are designed using detailed computational fluid dynamics coupled with a variety of optimisation algorithms and utilising a number of objective functions according to the engine company or researcher's preference. These numerical predictions are often backed up by detailed measurements in linear and annular cascades and later proven in full-scale engine tests. Relatively little literature is available describing their performance in rotating test rigs or at conditions other than design, apart from that of the authors. This study comprehensively revisits the low-speed, model turbines used in the earlier study, replacing all of the 5-hole probe data with more accurate results and additional hot-film measurements. These results together with computational fluid dynamics solutions are used to show the success of the method across a large incidence range and to compare to earlier cascade results for a similar endwall and blade profile to establish the usefulness of cascade testing in this application. In addition, a comparison to two other off-design studies is made. Results indicate that the endwalls successfully improve the rotor total isentropic efficiency at all test conditions and that the improvement increases with increased turning in the blade row, from 0.5% to 1.8% across the incidence range. The results also compare well to the estimation of isentropic efficiency improvement that can be drawn from the cascade testing which stands at 1.55%.