Vane Row Research Articles

SCOUR IN FRONT OF THE LATERAL INTAKES DUE TO USING SINGLE ROW OF SUBMERGED VANES

Submerged vanes can be used to create sufficient depth for navigation, to mitigate bank erosion or to divert sediment away of lateral intakes. Besides these intended effects, submerged vanes also produce local scour, which may interfere with the intended morphological correction and which is relevant to the structural stability of the vanes. The present paper shows an experimental study that was executed in order to investigate the local scour that induced in front of the lateral intakes due to using a single row of submerged vanes to minimize the sediment that entered the intake channel. Sixty experiments were carried out using a single row of vanes, considering various vane heights, angles, and positions under different flow conditions. A case of flat floor without vanes was included to estimate the influence of the submerged vanes on the scour in front of the diversions. Obtained results were analyzed and graphically presented, and also provide simple formulas to compute the maximum scour depth in vicinity of the single submerged vanes at different flows entering the lateral intake.

Investigation of Flow Physics of Vane Clocking Effects on Rotor Resonant Response

Vane clocking is the circumferential indexing of adjacent vane rows with identical vane counts. Vane clocking affects tone noise propagation, performance, and forced response characteristics in compressors. Recent vane clocking experiments performed in the embedded stage of the Purdue 3-Stage Research Compressor showed significant differences in the rotor 2 resonant response depending on the clocking configuration of stator 1 and stator 2, as measured by a nonintrusive stress measurement system. This research is focused on computing the fluidstructure interaction observed in this experiment to gain further insight into the flow physics associated with vane clocking. AU3D, an implicit, unsteady, unstructured, compressible flow solver is used to compute the vane clocking effects on rotor 2 resonant response, and the results are compared with experimental data. While many have investigated vane clocking effects on unsteady blade loading, this is one of the few investigations focused on rotor resonance.

Fully Cooled Single Stage HP Transonic Turbine—Part II: Influence of Cooling Mass Flow Changes and Inlet Temperature Profiles on Blade and Shroud Heat-Transfer

Abstract A fully cooled transonic high-pressure turbine stage is utilized to investigate the combined effects of turbine stage cooling variation and vane inlet temperature profile on heat transfer to the blades with the stage operating at the proper design corrected conditions. For this series of experiments, both the vane row and the blade row were fully cooled. The matrix of experimental conditions included varying the cooling flow rates and the vane inlet temperature profiles to observe the overall effect on airfoil heat-transfer. The data presented in Part I focused on the aerodynamics of the fully cooled turbine for a subset of the cases investigating two vane inlet temperature profiles (uniform and radial) and three different cooling levels (none, nominal, and high) for the high Reynolds number condition. This part of the paper focuses on the time-average heat-flux measurements on the blade and shroud region for the same cooling mass flow rates and vane inlet temperature profiles. The cooling effects are shown to be small and are centered primarily on the suction side of the airfoil. This relatively small influence is due to the ratio of the cooling gas to metal temperature being closer to 1 than the design value would dictate. The vane inlet temperature profile effects are more dominant, and using a net Stanton number reduction factor to compare the cases, an effect on the order of about 0.25 is demonstrated. This effect is due primarily to the change in the reference temperature used for the Stanton number calculation. The differences due to profile effects are small but observable toward the trailing edge of both the blade and rotor shroud. This data set forms an excellent baseline for heat-flux calculations, as the variation in the main input conditions are well documented and do not produce large changes in the heat-flux. It provides insight into the flow physics of an actual engine and guidelines about proper normalization of variables for a cooled turbine stage, supporting further development of computational heat-flux modeling techniques.

The Application of Flow Control to an Aft-Loaded Low Pressure Turbine Cascade With Unsteady Wakes

The synchronous application of flow control in the presence of unsteady wakes was studied on a highly loaded low pressure turbine blade. At low Reynolds numbers, the blade exhibits a nonreattaching separation bubble under steady flow conditions without upstream wakes. Unsteady wakes from an upstream vane row are simulated with a moving row of bars. The separation zone is modified substantially by the presence of unsteady wakes, producing a smaller separation zone and reducing the area-averaged wake total pressure loss by more than 50%. The wake disturbance accelerates transition in the separated shear layer but stops short of reattaching the flow. Rather, a new time-averaged equilibrium location is established for the separated shear layer. The focus of this study was the application of pulsed flow control using two spanwise rows of discrete vortex generator jets. The jets were located at 59% Cx, approximately the peak cp location, and at 72% Cx. The most effective separation control was achieved at the upstream location. The wake total pressure loss decreased 60% from the wake-only level and the cp distribution fully recovered its high Reynolds number shape. The jet disturbance dominates the dynamics of the separated shear layer, with the wake disturbance assuming a secondary role only. When the pulsed jet actuation was initiated at the downstream location, synchronizing the jet to actuate between wake events was key to producing the most effective separation control. Evidence suggests that flow control using vortex generator jets (VGJs) will be effective in the highly unsteady low pressure turbine environment of an operating gas turbine, provided the VGJ location and amplitude are adapted for the specific blade profile.

Aerodynamics and Heat Transfer for a Cooled One and One-Half Stage High-Pressure Turbine–Part II: Influence of Inlet Temperature Profile on Blade Row and Shroud

Heat flux measurements are presented for the uncooled blades of a one and one-half stage turbine operating at design corrected conditions with a fully cooled upstream vane row and with rotor disk cavity purge flow. This paper highlights the differences in blade heat flux and temperature caused by uniform, radial, and hot streak inlet temperature profiles. A general discussion of temperature profile migration is provided in Part I, and Part III presents data for hot streak magnitudes and alignments. The heat flux and fluid temperature measurements for the blade airfoil, platform, angel wing (near the root), and tip as well as for the stationary outer shroud are influenced by the vane inlet temperature profile. The inlet temperature profile shape can be clearly observed in the blade Stanton number measurements, with the radial and hot streak profiles showing a greater redistribution of energy than the uniform case due to secondary flows. Hot-gas segregation is observed to increase with the strength of the temperature distortion. Measurements for the hot streak profile show a segregation of higher temperature fluid to the pressure surface when compared with a uniform profile. The introduction of vane and purge cooling is found to further accentuate the flow segregation due to coolant migration to the suction surface.

Vane Clocking Effects on the Resonant Response of an Embedded Rotor

st torsion mode resonant response of IBR-2 generated by the wakes from the upstream stators is quantified non-intrusively utilizing an Agilis NSMS for six vane clocking configurations at the design and high loading conditions. The forcing function to IBR-2 consists of the Stator1 wakes and the potential fields from Stators-1 and Stator-2, and their aerodynamic interactions. Thus, the IBR-2 resonant response experiments involve classic vane clocking, with the IGV, Stator-1 and Stator-2 each having identical vane counts. I. Introduction IGH Cycle Fatigue (HCF) and resonant response of turbomachine blading resulting from flow-induced vibrations continues to be a significant problem throughout the gas turbine industry. Design resonant response analyses consider a tuned blade row, i.e. a rotor with all blades having the same structural properties and thus, identical natural frequencies. In fact, there are small blade-to-blade structural property variations, termed mistuning, which are known to lead to significant increases in blade resonant response amplitude as compared to that of the tuned blade row, with mistuning often cited as an HCF source. Turbomachinery rotors have typically been bladed-disks, with individual blades inserted into a slotted disk and retained by means of a dove-tail or fir-tree attachment. Advances in manufacturing techniques have resulted in bladed-disks with increased uniformity, i.e. small mistuning. Unfortunately, smaller mistuning does not translate into lower amplitude blade vibrations. In addition, new manufacturing techniques have enabled integrally bladed rotors (IBRs) wherein the blades and disk are machined from a single piece of material. However, as compared to bladed-disks, IBRs have both much smaller mistuning and mechanical damping. As compared to bladed-disks, IBRs exacerbate the potential for large amplitude resonant response and HCF because of reduced mechanical damping and mistuning. The implementation of IBRs into engine designs also affects the development of acceptable rotors. When bladed-disks are found to have unacceptably high vibration amplitudes and vibratory stress during development or in the field, a traditional approach is to incorporate friction dampers. However, resonant response problems in IBRs may not be able to be solved with friction dampers because they cannot be easily implemented. Hence, new solutions are required to address IBR resonant response problems. In this regard, vane clocking is a potential technique for the control of the resonant response of embedded rotors. A particular embedded rotor is subjected to the periodic passing of the wakes from the upstream airfoil row and the potential disturbances from both the upstream and the downstream airfoils rows, i.e. an embedded rotor is subjected to three forcing functions, Figure 1. With airfoil rows having similar vane counts, the stationary vane rows can be indexed relative to one another to affect the airfoil row unsteady aerodynamic interactions. This circumferential indexing of vanes in adjacent rows with similar vane counts is termed vane clocking. Experimental research has shown that vane clocking can be an effective tool to increase turbine performance 1-4 , increase compressor

Particle Image Velocimetry Characterization of High-Speed Centrifugal Compressor Impeller-Diffuser Interaction

High-density instantaneous and rotor phase-locked velocity field measurements are made in the centrifugal compressor diffuser vaneless space by means of the particle image velocimetry technique. The technique is challenged in this application by a small length scale and large velocities yielding very small flow time scales and demanding the use of extremely small flow tracking particles. The experiments reveal a detailed picture of the rotor phase-lockedaverageimpellerexitanddiffuserinlet flowfieldasisusefulforunsteady flowmodeling.Strongpassage velocity gradients exist across the vaneless space up to the diffuser vanes, showing that the phase-locked averaged impeller exit flow presents a highly unsteady non-mixed-out velocity field for the downstream vane row. This unsteady vane intake is thus characterized by a strong fluctuation in incidence angle with the passing blade event. Measured time variation in the velocity field indicates a significant time-varying potential field due to incidence fluctuations. Nomenclature Rduct = inlet duct radius r = radius � = radius ratio (diffuser leading-edge radius/impeller tip radius) � = 1 standard deviation

Design and experimental validation of the inlet guide vane system of a mini hydraulic bulb-turbine

The paper presents a fast design method for the inlet guide vanes of low-cost mini hydraulic bulb turbines. The guide vanes are positioned between two conical surfaces with a common vertex and have constant thickness distribution, except close to the leading and the trailing edges. The conical-walled inlet guide vane row is designed using a quasi-three-dimensional calculation method, by prescribing the angular-momentum distribution along the span at the outlet section of the guide vanes. The meridional through-flow is computed by a streamline curvature method and the blade-to-blade flow by a singularity surface method. The stagger angle and the vane camber are computed to fulfil the required design circulation and zero-incidence flow at the leading edge. The final vane shape is a single-curvature surface with straight leading and trailing edges. To validate the design method, a conical-walled inlet guide vane row nozzle-model with six fixed vanes was designed, manufactured and tested in an airflow rig. Traversing measurements along the circumferential and radial directions were made with a five-hole probe. The experimental results are compared with the prescribed design conditions and with numerical results from the three-dimensional inviscid and viscous flow computed with the FLUENT code.

Rotor Wake Variability in a Multistage Compressor

Rotorwakevariability isnot typically accountedforin computational fluid dynamics models,yet small deviations from the modeled average wake could have impacts on performance and forced vibratory response of airfoils. This paper quantifies rotor wake variability, in terms of wake depth and width, for each stage in a three-stage research compressor. Time-resolved flow angle data are acquired with a cross-film sensor at midspan for all three rotor exits for 50 circumferential positions spanning a vane passage. This research focuses on rotor wake variability driven by blade row interactions. The scope of the study includes wake variations caused by blade-to-blade differences, interactions with upstream rotor wakes, and interactions with the potential field of the downstream vane row. The lowest levels of variability are associated with rotor 1. In the downstream rotors, ensemble-averaged revolutions of data show an amplitude modulation caused by interactions with the rotor wakes from the upstream blade rows and, thus, increased levels of blade-to-blade wake variability. The main effect of the downstream vane row is to shift the mean levels of the wake without significantly influencing the wake shape. Nomenclature mc = corrected mass flow rate Nc = corrected rotational speed R = rotor Rec = Reynolds number based on chord length S = stator t = time U = wheel speed V = flow velocity in the absolute reference frame W = flow velocity in the rotating reference frame � = absolute flow angle � = relative flow angle � = adiabatic efficiency � = standard deviation

1308 可動式案内羽根翼列を有する直線翼垂直軸風車のフィールド試験(流体力学II)

1308 可動式案内羽根翼列を有する直線翼垂直軸風車のフィールド試験(流体力学II)

1421 可動式案内羽根翼列を有する直線翼垂直軸風車の実証試験(OS14-4 再生可能流体エネルギー,オーガナイズドセッション)

1421 可動式案内羽根翼列を有する直線翼垂直軸風車の実証試験(OS14-4 再生可能流体エネルギー,オーガナイズドセッション)

An Experimental Study of Vane Clocking Effects on Embedded Compressor Stage Performance

Previous research has shown that vane clocking, the circumferential indexing of adjacent vane rows with similar vane counts, can be an effective means to increase stage performance, reduce discrete frequency noise, and/or reduce the unsteady blade forces that can lead to high cycle fatigue. The objective of this research was to experimentally investigate the effects of vane clocking in an embedded compressor stage, focusing on stage performance. Experiments were performed in the intermediate-speed Purdue three-stage compressor, which consists of an IGV followed by three stages. The IGV, Stator 1, and Stator 2 vane rows have identical vane counts, and the effects of vane clocking were studied on Stage 2. Much effort went into refining performance measurements to enable the detection of small changes in stage efficiency associated with vane clocking. At design loading, the change in stage efficiency between the maximum and minimum efficiency clocking configurations was 0.27 points. The maximum efficiency clocking configuration positioned the Stator 1 wake at the Stator 2 leading edge. This condition produced a shallower and thinner Stator 2 wake compared with the clocking configuration that located the wake in the middle of the Stator 2 passage. At high loading, the change in Stage 2 efficiency associated with vane clocking effects increased to 1.07 points; however, the maximum efficiency clocking configuration was the case where the Stator 1 wake passed through the middle of the downstream vane passage. Thus, impingement of the upstream vane wake on the downstream vane leading edge resulted in the best performance at design point but provided the lowest efficiency at an off-design condition.

Three Dimensional Clocking Effects in a One and a Half Stage Transonic Turbine

This paper presents an experimental investigation of the flow field in a high-pressure transonic turbine with a downstream vane row (1.5 stage machine) concerning the airfoil indexing. The objective is a detailed analysis of the three-dimensional aerodynamics of the second vane for different clocking positions. To give an overview of the time-averaged flow field, five-hole probe measurements were performed upstream and downstream of the second stator. Furthermore in these planes additional unsteady measurements were carried out with laser Doppler velocimetry in order to record rotor phase-resolved velocity, flow angle, and turbulence distributions at two different clocking positions. In the planes upstream of the second vane, the time-resolved pressure field has been measured by means of a fast response aerodynamic pressure probe. This paper shows that the secondary flows of the second vane are significantly modified by the different clocking positions, in connection with the first vane modulation of the rotor secondary flows. An analysis of the performance of the second vane is also carried out, and a 0.6% variation in the second vane loss coefficient has been recorded among the different clocking positions.

A straight-bladed vertical axis wind turbine with a directed guide vane row — Effect of guide vane geometry on the performance —

The objective of this study is to show the effect of guide vane geometry on the performance. In order to overcome the disadvantages of vertical axis wind turbine, a straight-bladed vertical axis wind turbine (S-VAWT) with a directed guide vane row has been proposed and tested by the authors. According to previous studies, it was clarified that the performance of the turbine can be improved by means of the directed guide vane row. However, the guide vane geometry of S-VAWT has not been optimized so far. In order to clarify the effect of guide vane geometry, the effects of setting angle and gap between rotor blade and guide vane on power coefficient and starting characteristic were investigated in the experiments. The experimental study of the proposed wind turbine was carried out by a wind tunnel. The wind tunnel with a diameter of 1.8m is open jet type. The wind velocity is 8 m/s in the experiments. The rotor has three straight blades with a profile of NACA0018 and a chord length of 100 mm, a diameter of 0.6 m and a blade height of 0.7 m. The guide vane row consists of 3 arc plates.

1209 可動式案内羽根翼列を有する直線翼垂直軸風車 : 風車性能に及ぼす案内羽根弦節比の影響(OS12-2 再生可能流体エネルギー,オーガナイズドセッション)

1209 可動式案内羽根翼列を有する直線翼垂直軸風車 : 風車性能に及ぼす案内羽根弦節比の影響(OS12-2 再生可能流体エネルギー,オーガナイズドセッション)

Electrostatic filter efficiency improvement based on velocity and pressure field numerical simulation

This paper deals with the numerical simulation of exhaust gas flow through the electrostatic filter (EF) in block IV of the Šoštanj thermal power plant. Four different variants of the geometry were analysed. The exhaust gas flow was modelled as a turbulent incompressible viscous fluid flow. The commercial computational fluid dynamics package CFX-4.4 from ANSYS was used for flow analysis. The discrete models were very complex due to the internal objects such as guide vane rows, perforated screens, and electrodes. The turbulence model was the standard k—ɛ model with wall functions. Perforated screens were considered by an additional source term in momentum conservation equations. Velocity boundary conditions were obtained by interpolating the measured values on the discrete model nodes. The results of numerical simulation show that the most efficient is the variant where an additional screen is inserted between the second and the third EF volume. The maximum velocity is decreased and the distribution of velocity over the cross-section is more uniform. The increase in pressure drop was acceptable. The measurements of the velocity field after EF modification confirmed the prediction of the numerical simulation.

The Effect of Vane Clocking on the Unsteady Flow Field in a One-and-a-Half Stage Transonic Turbine

The current paper presents the results of numerical and experimental clocking investigations performed in a high-pressure transonic turbine with a downstream vane row. The objective was a detailed analysis of shock and wake interactions in such a 1.5-stage machine while clocking the vanes. Therefore, a transient 3D Navier–Stokes calculation was done for two clocking positions, and the three-dimensional results are compared with laser-Doppler-velocimetry measurements at midspan. Additionally, the second vane was equipped with fast response pressure transducers to record the instantaneous surface pressure for 20 different clocking positions at midspan.

A Straight-bladed Vertical Axis Wind Turbine with a Directed Guide Vane Row

A straight-bladed vertical axis wind turbine with a directed guide vane row has been proposed in order to enhance its torque. The experimental study of the proposed wind turbine was carried out by a wind tunnel with an outlet diameter of 1.8m. The tested rotor has some straight rotor blades with a profile of NACA0015, a diameter of 0.6 m and a height of 0.7 m. The guide vane row having 3 arc plates rotates around the rotor and is directed to the wind by aerodynamic force generated by tail vanes, so as to put the guide vane row in upstream of the rotor. As a result, the performance of the straight-bladed vertical axis turbine was improved by means of the directed guide vane row. Further, by the use of the guide vane row adopted in the study, the power coefficient of the proposed wind turbine was approximately 1.5 times higher than that of the original wind turbine which has no guide vane.

E19 可動式案内羽根翼列を有する直線翼垂直軸風車 : 性能に及ぼす案内羽根位置の影響(流体工学II)

E19 可動式案内羽根翼列を有する直線翼垂直軸風車 : 性能に及ぼす案内羽根位置の影響(流体工学II)

OS2-9 可動式案内羽根翼列を有する直線翼垂直軸風車(OS2 自然エネルギー,循環型社会における動力エネルギー技術)

A straight-bladed vertical axis wind turbine with a directed guide vane row has been proposed in order to enhance its torque. The experimental study on the proposed wind turbine was carried out by a wind tunnel with an outlet diameter of 1.8m. The tested rotor has 3 straight blades with a profile of NACA0015, a diameter of 0.6m and a blade height of 0.7m. The guide vane row having 3 arc plates rotates around the rotor and is directed to the wind by aerodynamic force generated by a tail vane, so as to put the guide vane row upstream of the rotor. As a result, the performance of the straight-bladed vertical axis turbine was improved by means of the directed guide vane row. Further, by the use of the guide vane row adopted in the study, the power coefficient of the proposed wind turbine was approximately 1.5 times higher than that of the original wind turbine which has no guide vane.