A Parametric Impact Study of the Geometry, Air System and Thermal Boundary Conditions on the Life of a Two-Stage High Pressure Turbine

2012 ◽  
Author(s):  
Thomas Weiss ◽  
Jose Maria Rey Villazón ◽  
Arnold Kühhorn
Keyword(s):  
High Pressure ◽  
Boundary Conditions ◽  
Mechanical Analysis ◽  
High Pressure Turbine ◽  
Two Stage ◽  
Thermal Boundary Conditions ◽  
Air System ◽  
Micro Turbine ◽  
Aero Engines ◽  
A Chain

High Pressure Turbine Discs of Aero Engines are classified as Critical Parts. Critical Parts are those whose failure is classified as likely to have hazardous or even catastrophic effects (e.g. damage to or loss of aircraft structure, injury/loss of the crew/passengers) and therefore require special control in order to achieve an acceptably low probability of individual failure. Even though special care is taken during the design and manufacturing process of these parts, there are still tolerances within their manufacturing route and during operation. Historically, Aero Engine parts were designed and laid out not to fail by using large safety factors to allow for scatter in different parameters. With the advent of high power computing, the time to conduct detailed thermo-mechanical assessments has drastically reduced and is therefore now open for Probabilistic Analytical Methods to determine the influence of parameter scatter on life and integrity. This paper presents a parametric study of a typical two stage High Pressure Turbine (HPT) disc arrangement with a micro-turbine system, which feeds cooling air into the interstage cavity [1]. A series of automated studies were performed to determine the relevance of parameters, assess their sensitivity and evaluate their combined impact on the targets of the disc design process. The automated workflow couples a chain of programs that perform geometry manipulation, Finite-Element Thermo-Mechanical analysis simulation and life prediction. This process was used to assess parameter variations in the air system, thermal boundary conditions and the geometry of several turbine disc features. The resulting outputs of this study are the percentile impacts and correlations of each parameter on the life expectancy of the turbine discs. This provides a qualitative understanding of the relevance of each parameter when approaching the design of turbine discs.

Disc Design and Air System Comparison Between a Single and a Two Stage High Pressure Turbine Aero Engine

2000 ◽  
Author(s):  
Fathi Ahmad ◽  
Alexander V. Mirzamoghadam
Keyword(s):  
High Pressure ◽  
Boundary Conditions ◽  
Cover Plate ◽  
High Pressure Turbine ◽  
Two Stage ◽  
Know How ◽  
Aero Engine ◽  
Structural Tests ◽  
Cooling Air ◽  
Effective Design

The design of the high pressure turbine (HPT) module of an aero engine and the method used to predict disc life and burst margin are different among the manufactures. In this paper, two different disc design methods are presented and compared, namely, the strain instability and the Chambers methods. The results of the disc study show that the strain instability method introduces low disc weight compared to the Chambers method. Both methods satisfy the burst speed requirement of 125% of the red line limit speed. The strain instability method was applied to design the disc of a single stage (SS) and of a two stage (TS) HPT configuration. The design philosophy of the SS is to run the HPT with a high rpm and a low SOT, whereas the TS design is based on low rpm and high SOT. The disc preliminary design considered the mechanical boundary conditions only without a temperature gradient. The total boundary conditions (thermal and mechanical) were then applied to the detailed disc design. A comparison between the two applied air systems of the SS and the TS design configuration was also performed. In comparing the two, the SS presents a design with low cooling air consumption, and it is also found that a cover plate is necessary for the front side of the SS configuration. The results of this study could be useful for the design engineer to know how and what is needed to accomplish a safe and effective design. Complementary thermal and structural tests should be performed to identify the limits and benefits of each approach.

Large-Scale Simulation of the Clocking Impact of 2D Combustor Profile on a Two Stage High Pressure Turbine

2014 ◽  
Author(s):  
Thomas E. Dyson ◽  
David B. Helmer ◽  
James A. Tallman
Keyword(s):  
High Pressure ◽  
Large Scale ◽  
High Pressure Turbine ◽  
Cfd Simulations ◽  
Two Stage ◽  
Substantial Impact ◽  
Sliding Mesh ◽  
Wall Flow ◽  
End Wall ◽  
Film Flows

This paper presents sliding-mesh unsteady CFD simulations of high-pressure turbine sections of a modern aviation engine in an extension of previously presented work [1]. The simulation included both the first and second stages of a two-stage high-pressure turbine. Half-wheel domains were used, with source terms representing purge and film flows. The end-wall flow-path cavities were incorporated in the domain to a limited extent. The passage-to-passage variation in thermal predictions was compared for a 1D and 2D turbine inlet boundary condition. Substantial impact was observed on both first and second stage vanes despite the mixing from the first stage blade. Qualitative and quantitative differences in surface temperature distributions were observed due to different ratios between airfoil counts in the two domains.

Modeling of the Cavity Response to Rapid Transient Considering the Effect of Heat Transfer

2018 ◽  
Author(s):  
Shuiting Ding ◽  
Hang Yu ◽  
Tian Qiu ◽  
Chuankai Liu
Keyword(s):  
Heat Transfer ◽  
Boundary Conditions ◽  
Heat Transfer Characteristics ◽  
Transient Responses ◽  
Transfer Characteristics ◽  
Thermal Boundary Conditions ◽  
Air System ◽  
Relative Errors ◽  
Low Dimensional ◽  
Rapid Transients

The internal air system, as one of the important subsystems of the aeroengine, is used to cooling and sealing, and plays a vital role in the safe operation of the engine. Especially in rapid transients, the complex dynamic response in air system may impose hazardous transition state loads on engine. Cavity is a component with pretty evident characteristics of transient in the air system due to the storage and release effects on the air. The flow and heat transfer characteristics of cavity should be made clear to precisely quantify the performance of the air system. The traditional study on cavity is based on the adiabatic assumption. However, the assumption is applicable to the transient of millisecond time scales physical phenomena in the air system, which is not usually common. Generally, the actual transition process is not instantaneous. Great discrepancies exist in the process of transition predicted by the adiabatic hypothesis compared with the practical process. The objective of this work is to propose a feasible method to solve the heat transfer issue throughout the transient process, which has not been settled by a proper method before, and develop a model for simulating the transient responses of the cavity with consideration of the heat transfer effect on the basis of the method. The model can predict transient responses under different thermal boundary conditions. Experiments have been developed for investigation of the charging process of the cavity. The thermal boundary can be controlled in the experiment, and the pressure and temperature responses of the cavity under different thermal boundary conditions have been analyzed. The non-dimensional numbers related to heat transfer characteristics were deduced by dimensional analysis, and the empirical formula of characteristics was proposed based on the experimental results. The non-adiabatic low-dimensional transient model of the cavity was established based on the heat transfer characteristics correlation. Results of transient responses calculated by non-adiabatic model were compared with the experimental data. It is found that both the transient responses of pressure and temperature agree well, with the maximum relative errors less than 2%. By comparison, the relative errors of pressure and temperature calculated by adiabatic model are about 8% and 12%, respectively. Meanwhile, the tendency of temperature response deviates from the actual process. Thus, the modeling method proposed is feasible and high-precision. The present work provides a technical method for establishing a low-dimensional model to describe the transient responses of the cavity with high accuracy, and supports the component-level modeling of the transient air system.

Emission characteristics of turbulent non-premixed ammonia/air and methane/air swirl flames through a rich-lean combustor under various wall thermal boundary conditions at high pressure

2019 ◽  
Vol 210 ◽  
pp. 247-261 ◽  
Author(s):  
Kapuruge Don Kunkuma Amila Somarathne ◽  
Ekenechukwu C. Okafor ◽  
Akihiro Hayakawa ◽  
Taku Kudo ◽  
Osamu Kurata ◽  
...  
Keyword(s):  
High Pressure ◽  
Boundary Conditions ◽  
Emission Characteristics ◽  
Thermal Boundary Conditions

Weibull Distributions Applied to Cost and Risk Analysis for Aero Engines

2008 ◽  
Author(s):  
D. S. Pascovici ◽  
K. G. Kyprianidis ◽  
F. Colmenares ◽  
S. O. T. Ogaji ◽  
P. Pilidis
Keyword(s):  
High Pressure ◽  
Risk Analysis ◽  
Economic Model ◽  
Spare Parts ◽  
Weibull Distributions ◽  
High Pressure Turbine ◽  
Aero Engines ◽  
The Cost ◽  
The Impact ◽  
Different Parts

This paper presents the use of Weibull formulation to the life analysis of different parts of the engine in order to estimate the cost of maintenance, the direct operating costs (DOC) and net present cost (NPC) of future type turbofan engines. The Weibull distribution is often used in the field of life data analysis due to its flexibility—it can mimic the behavior of other statistical distributions such as the normal and the exponential. The developed economic model is composed of three modules: a lifing module, an economic module and a risk module. The lifing module estimates the life of the high pressure turbine blades through the analysis of creep and fatigue over a full working cycle of the engine. The value of life calculated by the lifing is then taken as the baseline distribution to calculate the life of other important modules of the engine using the Weibull approach. Then the lower of the values of life of all the distributions is taken as time between overhaul (TBO), and used into the economic module calculations. The economic module uses the TBO together with the cost of labour and the cost of the engine (needed to determine the cost of spare parts) to estimate the cost of maintenance and DOC of the engine. In the present work five Weibull distributions are used for five important sources of interruption of the working life of the engine: Combustor, Life Limited Parts (LLP), High Pressure Compressor (HPC), General breakdowns and High Pressure Turbine (HPT). The risk analysis done in this work shows the impact of the breakdown of different parts of the engine on the NPC and DOC, the importance that each module of the engine has in its life, and how the application of the Weibull theory can help us in the risk assessment of future aero engines. A detailed explanation of the economic model is done in two other works (Pascovici et. al. [6] and Pascovici et. al. [7]), so in this paper only a general overview is done.

150 kW Class Two-Stage Radial Inflow Condensing Steam Turbine System

2011 ◽  
Author(s):  
Kazutaka Hayashi ◽  
Hiroyuki Shiraiwa ◽  
Hiroyuki Yamada ◽  
Susumu Nakano ◽  
Kuniyoshi Tsubouchi
Keyword(s):  
High Pressure ◽  
Steam Turbine ◽  
Output Power ◽  
Power Output ◽  
Thermal Efficiency ◽  
Rotational Speed ◽  
High Pressure Turbine ◽  
Two Stage ◽  
Electrical Efficiency ◽  
Design Value

A prototype machine for a 150 kW class two-stage radial inflow condensing steam turbine system has been constructed. This turbine system was proposed for use in the bottoming cycle for 2.4 MW class gas engine systems, increasing the total electrical efficiency of the system by more than 2%. The gross power output of the prototype machine on the generator end was 150kW, and the net power output on the grid end which includes electrical consumption of the auxiliaries was 135kW. Then, the total electrical efficiency of the system was increased from 41.6% to 43.9%. The two-stage inflow condensing turbine system was applied to increase output power under the supplied steam conditions from the exhaust heat of the gas engines. This is the first application of the two-stage condensing turbine system for radial inflow steam turbines. The blade profiles of both high- and low-pressure turbines were designed with the consideration that the thrust does not exceed 300 N at the rated rotational speed. Load tests were carried out to demonstrate the performance of the prototype machine and stable output of 150 kW on the generator end was obtained at the rated rotational speed of 51,000 rpm. Measurement results showed that adiabatic efficiency of the high-pressure turbine was less than the design value, and that of the low-pressure turbine was about 80% which was almost the same as the design value. Thrust acting on the generator rotor at the rated output power was lower than 300 N. Despite a lack of high-pressure turbine efficiency, total thermal efficiency was 10.5% and this value would be enough to improve the total thermal efficiency of a distributed power system combined with this turbine system.

Prediction of Main/Secondary-Air System Flow Interaction in a High-Pressure Turbine

2005 ◽  
Vol 21 (1) ◽  
pp. 158-166
Author(s):  
Roger L. Davis ◽  
Juan J. Alonso ◽  
Jixian Yao ◽  
Roger Paolillo ◽  
Om P. Sharma
Keyword(s):  
High Pressure ◽  
High Pressure Turbine ◽  
Flow Interaction ◽  
System Flow ◽  
Air System ◽  
Secondary Air

Aerodynamic Optimization of High Pressure Turbine and Interstage Duct in a Two-Stage Air System for a Heavy-Duty Diesel Engine

2017 ◽  
Author(s):  
Uswah Khairuddin ◽  
Aaron W. Costall
Keyword(s):  
High Pressure ◽  
Diesel Engine ◽  
Operating Point ◽  
Heavy Duty ◽  
Aerodynamic Optimization ◽  
High Pressure Turbine ◽  
Two Stage ◽  
Turbine Wheel ◽  
Heavy Duty Diesel Engine ◽  
Heavy Duty Diesel

Turbochargers are a key technology for reducing the fuel consumption and CO2 emissions of heavy-duty internal combustion engines by enabling greater power density, which is essential for engine downsizing and downspeeding. This in turn raises turbine expansion ratio levels and drives the shift to air systems with multiple stages, which also implies the need for interconnecting ducting, all of which is subject to tight packaging constraints. This paper considers the challenges in the aerodynamic optimization of the exhaust side of a two-stage air system for a Caterpillar 4.4-litre heavy-duty diesel engine, focusing on the high pressure turbine wheel and interstage duct. Using the current production designs as a baseline, a genetic algorithm-based aerodynamic optimization process was carried out separately for the wheel and duct components in order to minimize the computational effort required to evaluate seven key operating points. While efficiency was a clear choice for the cost function for turbine wheel optimization, the most appropriate objective for interstage duct optimization was less certain, and so this paper also explores the resulting effect of optimizing the duct design for different objectives. Results of the optimization generated differing turbine wheel and interstage duct designs depending on the corresponding operating point, thus it was important to check the performance of these components at every other operating point, in order to determine the most appropriate designs to carry forward. Once the best compromise high pressure turbine wheel and interstage duct designs were chosen, prototypes of both were manufactured and then tested together against the baseline designs to validate the CFD predictions. The best performing high pressure turbine design, wheel A, was predicted to show an efficiency improvement of 2.15 percentage points, for on-design operation. Meanwhile, the optimized interstage duct contributed a 0.2 and 0.5 percentage-point efficiency increase for the high and low pressure turbines, respectively.

Experimental and Numerical Studies on Highly Loaded Supersonic Axial Turbine Cascades

2010 ◽  
Author(s):  
T. Wolf ◽  
F. Kost ◽  
E. Janke ◽  
F. Haselbach ◽  
L. Willer
Keyword(s):  
High Pressure ◽  
Mach Number ◽  
Attractive Alternative ◽  
High Pressure Turbine ◽  
Number Range ◽  
Potential Benefits ◽  
High Mach ◽  
Aero Engines ◽  
Turbine Airfoils ◽  
Highly Loaded

For the small to medium thrust range of modern aero engines, highly loaded single stage HP turbines facilitate an attractive alternative to a more conventional 2-stage HPT architecture. Whereas the potential benefits of reductions in component length and part count, hence, in weight and cost do motivate their application, the related risks are in maintaining associated losses of supersonic flows at low values as well as managing the interaction losses between HPT and the downstream sub-component to arrive at competitive levels of component efficiencies. This paper focuses on fundamental aerodynamic concept studies and related cascade experiments in support of a future highly loaded high-pressure turbine architecture. Starting with some general remarks on low-loss supersonic aerodynamic concepts for high-pressure turbines, results from development efforts towards 2D airfoil concepts viable for high-pressure turbine airfoils are shown. In particular, CFD based design approaches are compared against experimental data taken at DLR Go¨ttingen in un-cooled cascade tests and at engine representative levels of Mach and Reynolds numbers. For the airfoils investigated, it turns out that there is indeed a supersonic Mach number range were loss levels are comparable to high Mach number subsonic values, thereby enabling a competitive aerodynamic design concept for a 3D high-pressure turbine stage.

Unsteady Simulation of a Two-Stage Cooled High Pressure Turbine Using an Efficient Non-Linear Harmonic Balance Method

2013 ◽  
Author(s):  
Venkataramanan Subramanian ◽  
Chad H. Custer ◽  
Jonathan M. Weiss ◽  
Kenneth C. Hall
Keyword(s):  
High Pressure ◽  
Harmonic Balance ◽  
Nearest Neighbor ◽  
Harmonic Balance Method ◽  
Balance Method ◽  
High Pressure Turbine ◽  
Two Stage ◽  
Nearest Neighbor Algorithm ◽  
Blade Row ◽  
Unsteady Simulation

The harmonic balance method is a mixed time domain and frequency domain approach for efficiently solving periodic unsteady flows. The implementation described in this paper is designed to efficiently handle the multiple frequencies that arise within a multistage turbomachine due to differing blade counts in each blade row. We present two alternative algorithms that can be used to determine which unique set of frequencies to consider in each blade row. The first, an all blade row algorithm, retains the complete set of frequencies produced by a given blade row’s interaction with all other blade rows. The second, a nearest neighbor algorithm, retains only the dominant frequencies in a given blade row that arise from direct interaction with the adjacent rows. A comparison of results from a multiple blade row simulation based on these two approaches is presented. We will demonstrate that unsteady blade row interactions are accurately captured with the reduced frequency set of the nearest neighbor algorithm, and at a lower computational cost compared to the all blade row algorithm. An unsteady simulation of a two-stage, cooled, high pressure turbine cascade is achieved using the present harmonic balance method and the nearest neighbor algorithm. The unsteady results obtained are compared to steady simulation results to demonstrate the value of performing an unsteady analysis. Considering an unsteady flow through a single blade row turbine blade passage, it is further shown that unsteady effects are important even if the objective is to obtain accurate time-averaged integrated values, such as efficiency.

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