DDES Analysis of Wake Vortex Related Unsteadiness and Losses in the Environment of High-Pressure Turbine Stage

2017 ◽  
Author(s):  
Dun Lin ◽  
Xinrong Su ◽  
Xin Yuan
Keyword(s):  
High Pressure ◽  
Boundary Layer Transition ◽  
Wake Vortex ◽  
High Fidelity ◽  
Strong Impact ◽  
Detached Eddy Simulation ◽  
High Pressure Turbine ◽  
Layer Transition ◽  
Eddy Simulation ◽  
Delayed Detached Eddy Simulation

In this work, the flows inside the high pressure turbine (HPT) vane and stage are studied with the help of a high-fidelity delayed detached eddy simulation (DDES) code. This work intends to study the fundamental nozzle/blade interaction with special attention paid to the development and transportation of the vane wake vortex. There are two motivations for this work. On the one hand, the high pressure turbine operates at both transonic Mach numbers and high Reynolds numbers, which imposes a great challenge to modern computational fluid dynamics (CFD), especially for scale-resolved simulation methods. An accurate and efficient high-fidelity CFD solver is very important for a thorough understanding of the flow physics and the design of more efficient HPT. On the other hand, the periodic wake vortex shedding is an important origin of turbine losses and unsteadiness. The wake and vortex not only cause losses themselves, but also interact with the shock wave (under transonic working condition), pressure waves, and have a strong impact on the downstream blade surface (affecting boundary layer transition and heat transfer). Built on one of our previous DDES simulations of a HPT vane VKI LS89, this work further investigates the development and length characteristics of the wake vortex, provides explanations of the length characteristics and reveals the transportation of the wake vortex into the downstream rotor passage along with its impact on the downstream aero-thermal performance.

DDES Analysis of the Wake Vortex Related Unsteadiness and Losses in the Environment of a High-Pressure Turbine Stage

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
Dun Lin ◽  
Xinrong Su ◽  
Xin Yuan
Keyword(s):  
High Pressure ◽  
Boundary Layer Transition ◽  
Wake Vortex ◽  
Strong Impact ◽  
Detached Eddy Simulation ◽  
High Pressure Turbine ◽  
Layer Transition ◽  
Wake Vortices ◽  
Operation Conditions ◽  
Delayed Detached Eddy Simulation

In this work, the flows inside a high-pressure turbine (HPT) vane and stage are studied with a delayed detached eddy simulation (DDES) code. The fundamental nozzle/blade interaction is investigated with special attention paid to the development and transportation of the vane wake vortices. There are two motivations for this work. First, the extreme HPT operation conditions, including both transonic Mach numbers and high Reynolds numbers, impose a great challenge to modern computational fluid dynamics (CFD), especially for scale-resolved simulation methods. An accurate and efficient high-fidelity CFD solver is very important for a thorough understanding of the flow physics and the design of more efficient HPT. Second, the periodic wake vortex shedding is an important origin of turbine losses and unsteadiness. The wake and vortices not only cause losses themselves, but also interact with the shock wave (under transonic working condition), pressure waves, and have a strong impact on the downstream blade surface (affecting boundary layer transition and heat transfer). Based on one of our previous DDES simulations of a HPT vane, this work further investigates the development and length characteristics of the wake vortices, provides explanations for the length characteristics, and reveals the transportation of the wake vortices in the downstream rotor passages along with its impact on the downstream aero-thermal performance.

Delayed Detached Eddy Simulation of a Full 3-Dimensional High-Pressure Turbine Stage: Part I — Flow Topology

2018 ◽  
Author(s):  
Dun Lin ◽  
Xiutao Bian ◽  
Xin Yuan ◽  
Xinrong Su
Keyword(s):  
High Pressure ◽  
Horseshoe Vortex ◽  
Wake Vortex ◽  
High Fidelity ◽  
Detached Eddy Simulation ◽  
Tip Leakage Flow ◽  
High Pressure Turbine ◽  
Flow Topology ◽  
Eddy Simulation ◽  
Delayed Detached Eddy Simulation

In this work, the flow inside a high pressure turbine (HPT) stage is studied with the help of a high-fidelity delayed detached eddy simulation (DDES) code. This work intends to study the flow topology in the HPT stage. There are two motivations for this work: On the one hand, high pressure turbines operates at both transonic Mach numbers and high Reynolds numbers, which imposes a challenge to modern computational fluid dynamics (CFD), especially for scale-resolved simulation methods. An accurate and efficient high-fidelity CFD solver is very important for a thorough understanding of the flow physics and the design of higher-efficient HPT. On the other hand, the wake vortex shedding and tip-leakage flow are important origins of turbine losses and unsteadiness. Built on our previous DDES simulations of HPT vane and stage, this work further investigates the flow in a full 3-dimension HPT stage. The flow topology in the HPT stage is delineated by Q-criterion iso-surfaces. The development of the horseshoe vortex and its interaction with induced vortex and wake vortex is discussed. The wake vortex transportation especially its interaction with the rotor horseshoe vortex is investigated. The flow structures in the tip clearance region are also revealed.

High-fidelity fan-noise simulations based on improved delayed detached eddy simulation

2021 ◽  
Vol 150 (4) ◽  
pp. A131-A131
Author(s):  
Takao Suzuki ◽  
Michael L. Shur ◽  
Michael K. Strelets ◽  
Andrey K. Travin ◽  
Philippe R. Spalart
Keyword(s):  
High Fidelity ◽  
Detached Eddy Simulation ◽  
Fan Noise ◽  
Eddy Simulation ◽  
Delayed Detached Eddy Simulation

Steady State and Transient CFD Studies on Aerodynamic Performance Validation of a High Pressure Turbine

2012 ◽  
Author(s):  
Sridhar Murari ◽  
Sathish Sunnam ◽  
Jong S. Liu
Keyword(s):  
High Pressure ◽  
Total Pressure ◽  
Pressure Ratio ◽  
Aerodynamic Performance ◽  
Detached Eddy Simulation ◽  
High Pressure Turbine ◽  
Predictive Capacity ◽  
Flow Angle ◽  
Analysis And Design ◽  
Eddy Simulation

With the advent of fast computers and availability of less costly memory resources, computational fluid dynamics (CFD) has emerged as a powerful tool for the design and analysis of flow and heat transfer of high pressure turbine stages. CFD gives an insight in to flow patterns that are difficult, expensive or impossible to study using experimental techniques. However, the application of CFD depends on its accuracy and reliability. This requires the CFD code to be validated with laboratory measurements to ensure its predictive capacity. In the continual effort to improve analysis and design techniques, Honeywell has been investigating in the use of CFD to predict the aerodynamic performance of a high pressure turbine. Reynolds Averaged Navier Stokes (RANS), unsteady models like detached eddy simulation (DES), large eddy simulation (LES), and Scale Adaptive Simulation (SAS) are used to predict the aerodynamic performance of a high pressure turbine. Mixing plane approach is used to address the flow data transport across the stationary interface in RANS simulation. The film holes on blade surface and end walls for all the analysis are modeled by using actual film hole modeling technique. The validation is accomplished with the test results of a high pressure turbine, Energy Efficient Engine (E3). The aerodynamic performance data at design point, typical off-design points are taken as test cases for the validation study. One dimensional performance parameters such as corrected mass flow rate, total pressure ratio, cycle efficiency, and two dimensional spanwise distributions of total pressure, total temperature and flow angle that are obtained from CFD results are compared with test data. Streamlines and flow field results at different measurement planes are presented to understand the aerodynamic behavior.

scholarly journals Numerical Investigation of the Wake Vortex-Related Flow Mechanisms in Transonic Turbines

2020 ◽  
Vol 2020 ◽  
pp. 1-18
Author(s):  
Guoliang Wang ◽  
Ning Ge ◽  
Dongdong Zhong
Keyword(s):  
High Pressure ◽  
Great Influence ◽  
Flow Characteristics ◽  
Entropy Generation Rate ◽  
Wake Vortex ◽  
High Pressure Turbine ◽  
Local Loss ◽  
Eddy Simulation ◽  
Flow Mechanisms ◽  
Sas Model

As the core equipment of the power generation system, a gas turbine is an indispensable energy-converting device in the national industry. The flow inside a high-pressure turbine (HPT) is highly unsteady, which has a great influence on the aerothermal performance and structural strength. To better clarify the flow mechanism and guide the advanced design, the basic flow characteristics of transonic turbines are investigated in the paper by a modified scale-adaptive simulation (SAS) model based on the shear stress transport (SST) turbulence model. The numerical results reveal the formation and development of the secondary flow structures such as wake vortex, pressure wave, shock wave, and the interactions among them. The length and frequency characteristics of wake are in good agreement with the large eddy simulation (LES) and the experimental data. Based on the detailed flow information, the local loss analysis is performed using the entropy generation rate. In summary, the wake vortex-related flow is the main origin of unsteadiness and entropy loss in high-pressure turbine cascade.

Unsteady Boundary Layer Transition on a High Pressure Turbine Rotor Blade

1999 ◽  
Author(s):  
Maik Tiedemann ◽  
Friedrich Kost
Keyword(s):  
Boundary Layer ◽  
High Pressure ◽  
Rotor Blade ◽  
Suction Side ◽  
Turbine Rotor ◽  
Boundary Layer Transition ◽  
Unsteady Boundary Layer ◽  
High Pressure Turbine ◽  
Layer Transition ◽  
Turbine Rotor Blade

This investigation is aimed at the experimental determination of the location, the extent, and the modes of the laminar-to-turbulent transition processes in the boundary layers of a high pressure turbine rotor blade. The results are based on time-resolved, qualitative wall shear stress data which was derived from surface hotfilm measurements. The tests were conducted in the “Windtunnel for Rotating Cascades” of the DLR in Göttingen. For the evaluation of the influence of passing wakes and shocks on the unsteady boundary layer transition, a test with undisturbed rotor inlet flow was conducted in addition to full stage tests. Two different transition modes led to a periodic-unsteady, multi-moded transition on the suction side. In between two wakes, transition started in the bypass mode and terminated as separated-flow transition. Underneath the wakes, plain bypass transition occurred. The weak periodic boundary layer features on the pressure side indicate that this surface was not significantly affected by passing wakes or shocks. The acquired data reveals that the periodically disturbed suction side boundary layer is less susceptible to bubble bursting than the undisturbed flowfield. Thus, these blades may be subjected to higher aerodynamic loads. Accordingly, as in low pressure turbines, the unsteady effects in high pressure turbines may allow for a reduction of the number of rotor blades, with respect to the original design.

scholarly journals On the Influence of High Turbulence on the Convective Heat Flux on the High-Pressure Turbine Vane LS89

2019 ◽  
Vol 4 (4) ◽  
pp. 37
Author(s):  
Cação Ferreira ◽  
Arts ◽  
Croner
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
High Pressure ◽  
Temperature Distribution ◽  
Convective Heat ◽  
Boundary Layer Transition ◽  
Freestream Turbulence ◽  
High Pressure Turbine ◽  
Layer Transition ◽  
High Turbulence

High-pressure turbine vanes and blades are subjected to a turbulent combustor flow affecting the heat transfer and boundary layer transition, hence, the temperature distribution. The accurate prediction of the temperature distribution is crucial for a reliable design and cooling implementation. Engine-representative measurements are hence mandatory for improving design tools. Recently, convective heat transfer measurements were conducted on a high-pressure turbine inlet guide vane (VKI LS89 airfoil) in the Isentropic Compression Tube (CT-2) facility at the von Karman Institute. This contribution focuses on the effect of high freestream turbulence generated by a new turbulence grid allowing a range of turbulence intensities in excess of 10% with representative length scales of the order of 1–2 cm. Three cases with varying turbulence levels are discussed in this paper. The different flow conditions are exit isentropic Mach numbers of 0.70–0.97, Reynolds numbers of 0.53∙× 106 and 1.15∙× 106 and a constant temperature ratio equal to 1.36. The heat transfer distributions along the vane suction side indicate a clear link between boundary layer transition and the stream-wise pressure gradients even at high levels of freestream turbulence intensity. Differences are put in evidence in the dynamics of the transition development. Future developments will focus also on the contribution of the other flow parameters under high turbulence. Heat transfer predictions from the boundary layer code TEXSTAN and Reynolds-Averaged Navier–Stokes code elsA (ensemble logiciel pour la simulation en Aérodynamique) are additionally compared to the experiments. Inherent difficulties associated with high turbulence modelling are clear from this early numerical work.

Zonal Detached-Eddy Simulation Approach vs. URANS for the Prediction of the Flow Field Through a Low Pressure Vane Located Downstream of a Transonic High Pressure Turbine

2015 ◽  
Author(s):  
Pierre Gougeon ◽  
Ghislaine Ngo Boum
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
Computational Cost ◽  
Low Pressure ◽  
Good Alternative ◽  
Navier Stokes ◽  
Detached Eddy Simulation ◽  
High Pressure Turbine ◽  
Eddy Simulation ◽  
Numerical Predictions

The present work aims at studying the aerodynamic flow field within the first Low Pressure Vane (LPV) located downstream of a transonic High Pressure Turbine (HPT). A Zonal Detached-Eddy Simulation (ZDES) which is an hybrid URANS (Unsteady Reynolds Averaged Navier-Stokes)-DES approach, appears as a good alternative in terms of computational cost and quality of turbulent phenomena description when it comes to the capture of key parameters of losses generation in a LPV. ZDES is used on the LPV and the unsteady periodic flow field coming from the upstream HPT is modelled through a nonuniform rotating inlet boundary condition. The result is compared to a URANS simulation carried out with the same mesh and numerical parameters: this enables to quantify the differences and to state on the benefit of an advanced turbulent approach. Turbulent mechanisms are assessed with the computation of the power spectral density at different locations in the domain. To complete the analysis, the two numerical predictions are compared to experimental data. Wakes and vortices evolutions are studied in detail making it possible to put them into perspective with the aerodynamic losses generated in the LPV.

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