Studies on Flow Field near Trailing Edge and Base Pressure of LP Turbine Blade for Aero Engines

2017 ◽  
Vol 2017.52 (0) ◽  
pp. 172
Author(s):  
Katsunori SATO ◽  
Ken-ichi FUNAZAKI ◽  
Hideo TANIGUCHI ◽  
Ryo FUNAKOSHI
Keyword(s):  
Flow Field ◽  
Turbine Blade ◽  
Base Pressure ◽  
Trailing Edge ◽  
Aero Engines ◽  
Lp Turbine

Unsteady Secondary Flow in a Low Pressure Turbine With Integrated 3D Design

2013 ◽  
Author(s):  
D. Schrack ◽  
C. M. Schneider ◽  
M. Fraas ◽  
M. G. Rose ◽  
S. Staudacher ◽  
...  
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Mean Flow ◽  
3D Design ◽  
Low Pressure Turbine ◽  
Turbine Efficiency ◽  
Flow Features ◽  
Aero Engines ◽  
Lp Turbine ◽  
Secondary Flow Field

The LP turbine research rig “ATRD” allows the study of detailed aerodynamics at low Reynolds numbers. The two-stage LP turbines are designed by MTU Aero Engines GmbH and tested in cooperation with the Institute of Aircraft Propulsion Systems (ILA) at Stuttgart University. This paper focuses on the development of the unsteady secondary flow field in two turbine geometries. The flow structures and vortex behaviour of a turbine with integrated 3D design (I3D) is compared to those of a datum case with axisymmetric endwalls. The unsteady flow and its effect on the time mean flow is analysed with five hole probe area traverse data and multistage URANS CFD calculations. The improvement through design optimisation is assessed by analysing secondary flow features as well as loss generation in the first rotor and the second vane. The RANS and URANS predicted improvements in turbine efficiency agree well with the measurement within wide uncertainty bounds. The structure of the secondary flow field is substantially unaltered by the I3D design, but loss coefficients show row loss reductions. The secondary flow structure of the first rotor is dominated by the first NGV which was not redesigned. Therefore an opportunity exists for further performance improvement with its redesign.

An LP Turbine at Extreme Off-Design Operation

2013 ◽  
Author(s):  
Martin Lipfert ◽  
Martin Marx ◽  
Martin G. Rose ◽  
Stephan Staudacher ◽  
Inga Mahle ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Flow Field ◽  
Three Dimensional ◽  
Leading Edge ◽  
Test Facility ◽  
Second Stage ◽  
Wide Range ◽  
High Incidence ◽  
Aero Engines ◽  
Lp Turbine

In a cooperative project between the Institute of Aircraft Propulsion Systems (ILA) and MTU Aero Engines GmbH a two-stage low pressure turbine with integrated 3D airfoil and endwall contouring is tested. The experimental data taken in the altitude test-facility study the effect of high incidence in off-design operation. Steady measurements are covering a wide range of Reynolds numbers between 40,000 and 180,000. The results are compared with steady multistage CFD predictions with a focus on the stator rows. A first unsteady simulation is taken into account as well. The CFD simulations include leakage flow paths with disc cavities modeled. Compared to design operation the extreme off-design high-incidence conditions lead to a different flow-field Reynolds number sensitivity. Airfoil lift data reveals changing incidence with Reynolds number of the second stage. Increased leading edge loading of the second vane indicates a strong cross channel pressure gradient in the second stage leading to larger secondary flow regions and a more three-dimensional flow field. Global characteristics and area traverse data of the second vane are discussed. The unsteady CFD approach indicates improvement in the numerical prediction of the predominating flow field.

scholarly journals Mitigation of Turbine Vane Shock Waves Through Trailing Edge Cooling

2018 ◽  
Vol 188 ◽  
pp. 04014
Author(s):  
Bora O. Cakir ◽  
Bayindir H. Saracoglu
Keyword(s):  
Supersonic Flow ◽  
Shock Waves ◽  
Flow Field ◽  
Shock Intensity ◽  
High Efficiency ◽  
Turbine Rotor ◽  
Frequency Domain Analysis ◽  
Market Demand ◽  
Trailing Edge ◽  
Aero Engines

The immense market demand on the high efficiency and lightweight aero-engines results in designs with compact high-pressure turbine stages experiencing supersonic flow field. In supersonic turbines, shocks appear at the vane trailing edges. The interaction of these shock with the neighbouring airfoils and blades on the adjacent rotor row and consequently create considerable amount of losses on the aerodynamic performance of the turbine. Moreover, periodic excitation created by the interaction of the shock waves and the motion of the turbine rotor causes fatigue problems and reduces the lifetime of the engine. Current study aims to alter the vane shock waves through blowing at the trailing edge. In order to characterize the effect of active blowing on the trailing edge flow field, a series of URANS simulations were conducted on OpenFOAM solver platform. Various blowing schemes were simulated over a simplified trailing edge geometry exposed in supersonic flow. The computations were compared in terms of shock intensity, oscillation frequency and exerted pressure forcing over the downstream components. The results showed that unsteady trailing edge blowing were able to modify the fluctuations observed on the shocks by altering the shock intensity, angle and frequency of oscillations. The classification of the wake unsteadiness, i.e. vortex shedding, in terms of trailing edge characteristics were also accomplished through frequency domain analysis of simulations.

Heat Transfer Analysis of a Wedge Shaped Duct With Pin Fin and Pedestal Arrays: A Comparison Between Numerical and Experimental Results

2004 ◽  
Author(s):  
Antonio Andreini ◽  
Carlo Carcasci ◽  
Andrea Magi
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Gas Turbine ◽  
Turbine Blade ◽  
Experimental Results ◽  
Heat Transfer Analysis ◽  
Bottom Surface ◽  
Mean Flow ◽  
Trailing Edge ◽  
Pin Fin

The use of pin fin arrays in channels is one of the best choices to enhance overall heat transfer in gas turbine trailing edge blade cooling. Furthermore, in this particular application, the use of cross-pins in the trailing edge section of a turbine blade is a good way for supplying structural integrity to the blade itself. In this paper, results of several 3D RANS calculations performed in channels with cross-pins disposition such as in a typical trailing edge of a gas turbine blade are shown. Numerical calculations were compared with experimental results obtained on the same geometries using a transient Thermochromic Liquid Crystals (TLC) based technique. Goals of this comparison are both the evaluation of the accuracy of CFD packages with standard two equation turbulence models in heat transfer problems with complex geometries and the analysis of flow details to complete and support experimental activity. Two computational domains have been considered: they both consist in a wedge shaped channel with a stream-wise normal pin fin or pedestal arrays. The aim of the numerical analysis is the evaluation of convective Heat Transfer Coefficient (HTC) on the planar bottom surface of the wedge-shaped duct: this surface is commonly named “endwall” surface. Detailed analysis of the flow field points out the coexistence of an horse-shoe vortex, a stagnant wake behind the pin and a mean flow acceleration due to convergent shape of the channel. Calculations reveal the presence of a weak jet-like flow field toward endwall surfaces caused by the strong recirculation behind each pin.

The Influence of the Capacity-Increasing in the Trailing-Edge Cutting of HL240 Turbine Blade

2013 ◽  
Vol 655-657 ◽  
pp. 127-132
Author(s):  
Yu Lin ◽  
Shu Ren Han ◽  
Min Sheng
Keyword(s):  
Flow Field ◽  
Turbine Blade ◽  
Hydraulic Characteristic ◽  
Mixed Flow ◽  
Hydraulic Power ◽  
Trailing Edge ◽  
Singular Distribution ◽  
Water Turbine ◽  
Electric Station

In the precondition of calculating the flow field around the blade with the singular distribution way, the hydraulic characteristic after cutting the mixed-flow blade is calculated by CFD software , the optimum value of output in HL240-WJ50 water turbine and the influence of the flow field are found out by using that way: when the cutting measure of the cutting tip is 9.4mm, the output of the rotating wheel is increased 5.7% and the characteristic of cavitations isn’t clearly worsened. The improved water turbine blade is applied to the capacity-increasing rebuild of the small electric station. The cutting measure is 5 percent of the average of the blade’s upper canopy and lower rim. The power of the rotating wheel is improved from 232KW to 253KW after cutting, and the output can reach the requirement of the electric station. So the lesser economy to the trailing-edge can get into the better goal of rebuilding, that is suitable to rebuild the small hydraulic power station’s wheel.

Numerical study on the airfoil self-noise of three owl-based wings with the trailing-edge serrations

2021 ◽  
pp. 095441002098822
Author(s):  
Dian Li ◽  
Xiaomin Liu ◽  
Lei Wang ◽  
Fujia Hu ◽  
Guang Xi
Keyword(s):  
Flow Field ◽  
Noise Reduction ◽  
Numerical Study ◽  
Barn Owl ◽  
Aerodynamic Noise ◽  
Frequency Noise ◽  
Trailing Edge ◽  
Reduction Mechanisms ◽  
Trailing Edge Serrations ◽  
Bionic Airfoil

Previous publications have summarized that three special morphological structures of owl wing could reduce aerodynamic noise under low Reynolds number flows effectively. However, the coupling noise-reduction mechanism of bionic airfoil with trailing-edge serrations is poorly understood. Furthermore, while the bionic airfoil extracted from natural owl wing shows remarkable noise-reduction characteristics, the shape of the owl-based airfoils reconstructed by different researchers has some differences, which leads to diversity in the potential noise-reduction mechanisms. In this article, three kinds of owl-based airfoils with trailing-edge serrations are investigated to reveal the potential noise-reduction mechanisms, and a clean airfoil based on barn owl is utilized as a reference to make a comparison. The instantaneous flow field and sound field around the three-dimensional serrated airfoils are simulated by using incompressible large eddy simulation coupled with the FW-H equation. The results of unsteady flow field show that the flow field of Owl B exhibits stronger and wider-scale turbulent velocity fluctuation than that of other airfoils, which may be the potential reason for the greater noise generation of Owl B. The scale and magnitude of alternating mean convective velocity distribution dominates the noise-reduction effect of trailing-edge serrations. The noise-reduction characteristic of Owl C outperforms that of Barn owl, which suggests that the trailing-edge serrations can suppress vortex shedding noise of flow field effectively. The trailing-edge serrations mainly suppress the low-frequency noise of the airfoil. The trailing-edge serration can suppress turbulent noise by weakening pressure fluctuation.

Experimental study of a cooling scheme for a turbine blade trailing edge

2015 ◽  
Vol 229 (8) ◽  
pp. 832-848 ◽  
Author(s):  
Ahmed Beniaiche ◽  
Adel Ghenaiet ◽  
Carlo Carcasci ◽  
Marco Pievarolli ◽  
Bruno Facchini
Keyword(s):  
Experimental Study ◽  
Turbine Blade ◽  
Trailing Edge

Three-Dimensional and Rotational Aerodynamics on the NREL Phase VI Wind Turbine Blade

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Alvaro Gonzalez ◽  
Xabier Munduate
Keyword(s):  
Wind Turbine ◽  
Turbine Blade ◽  
Three Dimensional ◽  
Separated Flow ◽  
Leading Edge ◽  
Wind Turbine Blade ◽  
Trailing Edge ◽  
Rotating Blade ◽  
Nrel Phase Vi ◽  
Edge Separation

This work undertakes an aerodynamic analysis over the parked and the rotating NREL Phase VI wind turbine blade. The experimental sequences from NASA Ames wind tunnel selected for this study respond to the parked blade and the rotating configuration, both for the upwind, two-bladed wind turbine operating at nonyawed conditions. The objective is to bring some light into the nature of the flow field and especially the type of stall behavior observed when 2D aerofoil steady measurements are compared to the parked blade and the latter to the rotating one. From averaged pressure coefficients together with their standard deviation values, trailing and leading edge separated flow regions have been found, with the limitations of the repeatability of the flow encountered on the blade. Results for the parked blade show the progressive delay from tip to root of the trailing edge separation process, with respect to the 2D profile, and also reveal a local region of leading edge separated flow or bubble at the inner, 30% and 47% of the blade. For the rotating blade, results at inboard 30% and 47% stations show a dramatic suppression of the trailing edge separation, and the development of a leading edge separation structure connected with the extra lift.

Experimental Investigation of Effect of Tip Coolant Ejection on Internal Flow Characteristics Within a Realistic Blade Coolant Channel

2013 ◽  
Author(s):  
Jian Pu ◽  
Zhaoqing Ke ◽  
Jianhua Wang ◽  
Lei Wang ◽  
Hongde You
Keyword(s):  
Experimental Investigation ◽  
Reynolds Number ◽  
Pressure Drop ◽  
Turbine Blade ◽  
Flow Rate ◽  
Flow Characteristics ◽  
Reynolds Numbers ◽  
Flow Ratio ◽  
Lp Turbine ◽  
Mass Flow Ratio

This paper presents an experimental investigation on the characteristics of the fluid flow within an entire coolant channel of a low pressure (LP) turbine blade. The serpentine channel, which keeps realistic blade geometry, consists of three passes connected by a 180° sharp bend and a semi-round bend, 2 tip exits and 25 trailing edge exits. The mean velocity fields within several typical cross sections were captured using a particle image velocimetry (PIV) system. Pressure and flow rate at each exit were determined through the measurements of local static pressure and volume flow rate. To optimize the design of LP turbine blade coolant channels, the effect of tip ejection ratio (ER) from 180° sharp bend on the flow characteristics in the coolant channel were experimentally investigated at a series of inlet Reynolds numbers from 25,000 to 50,000. A complex flow pattern, which is different from the previous investigations conducted by a simplified square or rectangular two-pass U-channel, is exhibited from the PIV results. This experimental investigation indicated that: a) in the main flow direction, the regions of separation bubble and flow impingement increase in size with a decrease of the ER; b) the shape, intensity and position of the secondary vortices are changed by the ER; c) the mass flow ratio of each exit to inlet is not sensitive to the inlet Reynolds number; d) the increase of the ER reduces the mass flow ratio through each trailing edge exit to the extent of about 23–28% of the ER = 0 reference under the condition that the tip exit located at 180° bend is full open; e) the pressure drop through the entire coolant channel decreases with an increase in the ER and inlet Reynolds number, and a reduction about 35–40% of the non-dimensional pressure drop is observed at different inlet Reynolds numbers, under the condition that the tip exit located at 180° bend is full open.

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