The Problems of Measuring Profile and Roughness of Turbine Blades

2018 ◽  
Vol 876 ◽  
pp. 110-116
Author(s):  
Sergey Egorov ◽  
Alexey Kapitanov ◽  
Dmitriy Loktev ◽  
Sergey Fedorov ◽  
Tatiana Egorova
Keyword(s):  
Turbine Blade ◽  
Turbine Blades ◽  
Suction Side ◽  
Profile Measurement ◽  
Blade Profile ◽  
Complex Profile ◽  
Roughness Measurement ◽  
Pressure Surface ◽  
Side Pressure ◽  
Gland Packing

The article presents a study of a turbine blade profile and roughness measurement processes - the task facing any manufacturer of this part. The blade is one of the most complex regarding parts manufacture because of its complex profile. This profile should be measured in several sections on the feather on all profile elements - the suction side, pressure surface, leading and trailing edge of a blade. If the blade has a shroud platform, its profile should be also measured (and possibly the gland packing profile). It is also necessary to measure the feather end and base of blade profile. Finally, a separate independent task is the blade tang profile measurement.

Cooling Effectiveness on Film Cooled Turbine Blades

2001 ◽  
Author(s):  
M. Derrar ◽  
J. Nagler ◽  
W. W. Koschel
Keyword(s):  
Turbine Blade ◽  
Film Cooling ◽  
Separation Bubble ◽  
Turbine Blades ◽  
Suction Side ◽  
Experimental Simulation ◽  
Flow Conditions ◽  
Cooling Effectiveness ◽  
Boundary Interaction ◽  
Simultaneous Modeling

Abstract This paper presents experiments on the cooling effectiveness obtained for two different injection locations on the suction side of a turbine blade at transonic flow conditions. Previous results of a computational analysis and flow visualization indicated that a separation bubble is present on the suction side at a location x/L = 0.43 and the location x/L = 0.575 corresponds to a shock-boundary interaction zone [9]. The scientific interest is primarily focused on the realization of high film cooling efficiencies and its relevant parameters under these flow conditions. Streamwise aligned as well as inclined angled film coolant hole configurations have been investigated for each location. Due to the high number of interacting parameters the experimental simulation of turbine blade film cooling is extremely complex, which can only be solved by a simultaneous modeling using the experimentally measured results. Test rig, instrumentation and data analysis are described in detail. The goal of the investigations is to determine the optimum location of the film coolant injection.

Using CFD to Reduce Resonant Stresses on a Single-Stage, High-Pressure Turbine Blade

2002 ◽  
Author(s):  
J. P. Clark ◽  
A. S. Aggarwala ◽  
M. A. Velonis ◽  
R. E. Gacek ◽  
S. S. Magge ◽  
...  
Keyword(s):  
High Pressure ◽  
Turbine Blade ◽  
Guide Vane ◽  
Turbine Blades ◽  
Suction Side ◽  
Lessons Learned ◽  
Single Stage ◽  
Navier Stokes ◽  
High Pressure Turbine ◽  
Time Resolved

The ability to predict levels of unsteady forcing on high-pressure turbine blades is critical to avoid high-cycle fatigue failures. In this study, 3D time-resolved computational fluid dynamics is used within the design cycle to predict accurately the levels of unsteady forcing on a single-stage high-pressure turbine blade. Further, nozzle-guide-vane geometry changes including asymmetric circumferential spacing and suction-side modification are considered and rigorously analyzed to reduce levels of unsteady blade forcing. The latter is ultimately implemented in a development engine, and it is shown successfully to reduce resonant stresses on the blade. This investigation builds upon data that was recently obtained in a full-scale, transonic turbine rig to validate a Reynolds-Averaged Navier-Stokes (RANS) flow solver for the prediction of both the magnitude and phase of unsteady forcing in a single-stage HPT and the lessons learned in that study.

Film-Cooling on a Gas Turbine Blade Pressure Side or Suction Side With Compound Angle Shaped Holes

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Zhihong Gao ◽  
Diganta P. Narzary ◽  
Je-Chin Han
Keyword(s):  
Turbine Blade ◽  
Film Cooling ◽  
Pressure Ratio ◽  
Suction Side ◽  
Pressure Side ◽  
Blade Surface ◽  
Cooling Effectiveness ◽  
Film Cooling Effectiveness ◽  
Pressure Surface ◽  
Compound Angle

The film-cooling effectiveness on the surface of a high pressure turbine blade is measured using the pressure sensitive paint technique. Compound angle laidback fan-shaped holes are used to cool the blade surface with four rows on the pressure side and two rows on the suction side. The coolant injects to one side of the blade, either pressure side or suction side. The presence of wake due to the upstream vanes is simulated by placing a periodic set of rods upstream of the test blade. The wake rods can be clocked by changing their stationary positions to simulate progressing wakes. The effect of wakes is recorded at four phase locations along the pitchwise direction. The freestream Reynolds number, based on the axial chord length and the exit velocity, is 750,000. The inlet and exit Mach numbers are 0.27 and 0.44, respectively, resulting in a pressure ratio of 1.14. Five average blowing ratios ranging from 0.4 to 1.5 are tested. Results reveal that the tip-leakage vortices and endwall vortices sweep the coolant on the suction side to the midspan region. The compound angle laidback fan-shaped holes produce a good film coverage on the suction side except for the regions affected by the secondary vortices. Due to the concave surface, the coolant trace is short and the effectiveness level is low on the pressure surface. However, the pressure side acquires a relatively uniform film coverage with the multiple rows of cooling holes. The film-cooling effectiveness increases with the increasing average blowing ratio for either side of coolant ejection. The presence of stationary upstream wake results in lower film-cooling effectiveness on the blade surface. The compound angle shaped holes outperform the compound angle cylindrical holes by the elevated film-cooling effectiveness, particularly at higher blowing ratios.

Multi-Disciplinary Analyses for the Design of a High Pressure Turbine Blade Tip

2016 ◽  
Author(s):  
Stefano Caloni ◽  
Shahrokh Shahpar
Keyword(s):  
High Pressure ◽  
Turbine Blade ◽  
Turbine Blades ◽  
Suction Side ◽  
High Pressure Turbine ◽  
Cooling Flow ◽  
Barrier Coating ◽  
Flow Features ◽  
Internally Cooled ◽  
Blade Tip

The design of a high pressure turbine blade is a challenging task requiring multiple disciplines to be solved simultaneously. Most recently, conjugate analyses are being developed to tackle such a problem; they are able to resolve both the fluid dynamics in a turbine passage and the thermal distribution in the solid part of the component. In this paper, the in-house Hydra CFD solver is used to analyse a high pressure shroudless turbine blade for a modern jet engine. The turbine is internally cooled and a Thermal Barrier Coating (TBC) is applied on the aerofoil surface. The coupling technique used at the interface in the presence of the TBC is described. The flow features at the tip of the turbine blade are the main focus of this study. Four different tip configurations are analysed. A flat tip and a squealer tip are chosen as reference designs; however the effects of opening the Trailing Edge (TE) on the Suction Side (SS) and the Pressure Side (PS) are also investigated. Both a cooled and an uncooled configuration of the turbine blade are analysed and the effect of the cooling flow on the over tip leakage is studied. Finally, conjugate analyses for the cooled turbine blades are used to predict the temperature reached by the different tip designs. The design with an opened TE on the SS shows a significant aerodynamic improvement over the others without increasing the temperature the tip has to withstand in operation.

Investigation on the Reduction of Trailing Edge Shock Losses for a Highly Loaded Transonic Turbine

2016 ◽  
Author(s):  
Wei Zhao ◽  
Weiwei Luo ◽  
Qingjun Zhao ◽  
Jianzhong Xu
Keyword(s):  
Turbine Blades ◽  
Strong Shock ◽  
Suction Side ◽  
Loss Reduction ◽  
Blade Profile ◽  
Trailing Edge ◽  
Pressure Loss Coefficient ◽  
Reflected Shock ◽  
Transonic Turbine ◽  
Highly Loaded

A shock loss reduction method for highly loaded transonic turbine blades with convergent passages is presented. The method is illustrated with an improved blade profile that employs a negative curvature curve on its uncovered suction side. The improved profile and a conventional baseline profile are applied to two cascades with the same solidity, chord and aspect ratio respectively. The numerical simulation results for the two cascades show that a reduction of 4.58% in the total pressure loss coefficient is obtained for the improved profile at the design condition. The effects of back pressures on the performance of both cascades are also presented, and the improved blade profile shows a much better part-load performance. The paper compares the flow fields of the baseline and the improved blade profiles to understand loss reduction mechanism especially by analyzing the shock interactions downstream of the trailing edge. It is found that, for the improved profile, the reflected shock of pressure side leg of the trailing-edge shock rotates forward and the suction side leg of the trailing-edge shock rotates backward. Therefore, the two shocks delay their intersection points where they merge into a relatively strong shock, and consequently produce less shock losses than those of the baseline profile.

scholarly journals Investigation of Laminar-Turbulent Transition on a Rotating Wind Turbine Blade of Multi Megawatt Class with Thermography and a Microphone Array

2019 ◽  
Author(s):  
Torben Reichstein ◽  
Alois Peter Schaffarczyk ◽  
Christoph Dollinger ◽  
Nicolas Balaresque ◽  
Erich Schuelein ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Wind Turbine ◽  
Turbine Blade ◽  
Microphone Array ◽  
Turbine Blades ◽  
Suction Side ◽  
Wind Turbine Blade ◽  
Flow Transition ◽  
Turbulent Transition ◽  
Laminar Turbulent Transition

Knowledge about laminar-turbulent transition on operating multi-megawatt wind turbine blades needs sophisticated equipment like hot-films or microphone arrays. Contrarily thermographic pictures can easily be taken from the ground and temperature differences indicate different states of the boundary layer. The accuracy however, still is an open question, so that an aerodynamic glove known from experimental research on aero-planes was used to classify the boundary-layer state of a 2 megawatt wind turbine blade operating in the orthern part of Schleswig-Holstein, Germany. State-of-the-art equipment for measurering static surface pressure was used for monitoring the lift distribution. To distinguish laminar and turbulent parts of the boundary layer (suction side only) 48 microphones were applied together with ground-based thermographic cameras from two teams. Additionally, an optical camera mounted on the hub was used to survey vibrations. During start-up (from 0 to 9 rpm) extended, but irregularly shaped regions of a laminar boundary layer were observed which had the same extension measured both with microphones and Thermography. When an approximately constant rotor rotation (9 rpm corresponding to approximately 6 m/s wind-speed) was achieved, a flow transition was visible at the expected position of 40 % chord length on the rotor blade, which was fouled with dense turbulent wedges and an almost complete turbulent state on the glove was detected. In all observations, quantitative determination of the flow transition positions from thermography and microphones agree well within their accuracy.

Three-Tier Impingement Cooling Design for Gas Turbine Blade Trailing Edge

2018 ◽  
Author(s):  
Kishore Ranganath Ramakrishnan ◽  
Prashant Singh ◽  
Srinath V. Ekkad
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Turbine Blades ◽  
Jet Impingement ◽  
Suction Side ◽  
Internal Wall ◽  
Trailing Edge ◽  
Impingement Cooling ◽  
Cooling Design

Gas turbine blades are subjected to elevated heat loads due to highly turbulent hot gases exiting the combustor section. Several internal and external cooling techniques are used to protect the blades from such hostile environment. Trailing edge of a turbine blade is usually cooled with array of staggered cylindrical pins, which connects the pressure and suction side internal walls and hence provide improved structural integrity. However, the heat transfer enhancement levels for array of pin-fins is generally lower than jet impingement and ribbed channels. In this study, we present a three-tier impingement cooling design for blade trailing-edge and part of mid-chord region. In this design, pressure and suction side internal walls are subjected to oblique jet impingement. Three different configurations have been studied where we have systematically varied the jet diameters and number of jets in an array for different tiers. Numerical simulations have been carried out for different flow conditions, which corresponds to Reynolds numbers (based on 1st-passage jet diameter) ranging between 3000 and 46000. First two plenums had high levels of heat transfer due to oblique jet impingement, where the suction side internal wall representative surface, had higher heat transfer compared to the pressure side internal wall. Third tier had the lowest heat transfer due to triangle-like configuration where jets were almost parallel to pressure and suction side surfaces, and hence their effectiveness was lower than the oblique jet impingement in upstream two tiers.

scholarly journals Turbine Blade Three-Wavelength Radiation Temperature Measurement Method Based on Reflection Error Correction

2021 ◽  
Vol 11 (9) ◽  
pp. 3913
Author(s):  
Kaifeng Zheng ◽  
Jinguang Lü ◽  
Yingze Zhao ◽  
Jin Tao ◽  
Yuxin Qin ◽  
...  
Keyword(s):  
Temperature Measurement ◽  
Turbine Blade ◽  
Measurement Method ◽  
Turbine Blades ◽  
Target Surface ◽  
Maximum Error ◽  
Radiation Temperature ◽  
Average Error ◽  
Real Surface ◽  
Wavelength Radiation

The turbine blade is a key component in an aeroengine. Currently, measuring the turbine blade radiation temperature always requires obtaining the emissivity of the target surface in advance. However, changes in the emissivity and the reflected ambient radiation cause large errors in measurement results. In this paper, a three-wavelength radiation temperature measurement method was developed, without known emissivity, for reflection correction. Firstly, a three-dimensional dynamic reflection model of the turbine blade was established to describe the ambient radiation of the target blade based on the real surface of the engine turbine blade. Secondly, based on the reflection correction model, a three-wavelength radiation temperature measurement algorithm, independent of surface emissivity, was proposed to improve the measurement accuracy of the turbine blade radiation temperature in the engine. Finally, an experimental platform was built to verify the temperature measurement method. Compared with three conventional colorimetric methods, this method achieved an improved performance on blade temperature measurement, demonstrating a decline in the maximum error from 6.09% to 2.13% and in the average error from 2.82% to 1.20%. The proposed method would benefit the accuracy in the high-temperature measurement of turbine blades.

scholarly journals Low-pressure reversible axial fan with straight profile blades and relatively high efficiency

2012 ◽  
Vol 16 (suppl. 2) ◽  
pp. 593-603 ◽  
Author(s):  
Zivan Spasic ◽  
Sasa Milanovic ◽  
Vanja Sustersic ◽  
Boban Nikolic
Keyword(s):  
Numerical Simulations ◽  
High Efficiency ◽  
Suction Side ◽  
Standard Test ◽  
Maximum Efficiency ◽  
Specific Work ◽  
Blade Profile ◽  
Operating Characteristics ◽  
Axial Fan ◽  
Increase Energy Efficiency

The paper presents the design and operating characteristics of a model of reversible axial fan with only one impeller, whose reversibility is achieved by changing the direction of rotation. The fan is designed for the purpose of providing alternating air circulation in wood dryers in order to reduce the consumption of electricity for the fan and increase energy efficiency of the entire dryer. To satisfy the reversibility of flow, the shape of the blade profile is symmetrical along the longitudinal and transversal axes of the profile. The fan is designed with equal specific work of all elementary stages, using the method of lift forces. The impeller blades have straight mean line profiles. The shape of the blade profile was adopted after the numerical simulations were carried out and high efficiency was achieved. Based on the calculation and conducted numerical simulations, a physical model of the fan was created and tested on a standard test rig, with air loading at the suction side of the fan. The operating characteristics are shown for different blade angles. The obtained maximum efficiency was around 0.65, which represents a rather high value for axial fans with straight profile blades.

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