Off-Design Performance of an Interstage Turbine Burner Turbofan Engine

2017 ◽  
Vol 139 (8) ◽  
Author(s):  
Feijia Yin ◽  
Arvind G. Rao
Keyword(s):  
Fuel Efficiency ◽  
Cycle Performance ◽  
Inlet Temperature ◽  
Engine Operation ◽  
Turbofan Engine ◽  
Design Performance ◽  
Low Pressure Turbine ◽  
Performance Requirements ◽  
Engine Design ◽  
Operating Points

This paper focuses on the off-design performance of a turbofan engine with an interstage turbine burner (ITB). The ITB is an additional combustion chamber located between the high-pressure turbine (HPT) and the low-pressure turbine (LPT). The incorporation of ITB in an engine can provide several advantages, especially due to the reduction in the HPT inlet temperature and the associated NOx emission reduction. The objective is to evaluate the effects of the ITB on the off-design performance of a turbofan engine. The baseline engine is a contemporary classical turbofan. The effects of the ITB are evaluated on two aspects: first, the influences of an ITB on the engine cycle performance; second, the influences of an ITB on the component characteristics. The dual combustors of an ITB engine provide an extra degree-of-freedom for the engine operation. The analysis shows that a conventional engine has to be oversized to satisfy off-design performance requirement, like the flat rating temperature. However, the application of an ITB eases the restrictions imposed by the off-design performance requirements on the engine design, implying that the off-design performance of an ITB engine can be satisfied without sacrificing the fuel efficiency. Eventually, the performance of the ITB engine exhibits superior characteristics over the baseline engine at the studied operating points over a flight mission.

Exploring GasTurb 12 for Supplementary Use on an Introductory Propulsion Design Project

2017 ◽  
Author(s):  
Aaron R. Byerley ◽  
Kurt P. Rouser ◽  
Devin O. O’Dowd
Keyword(s):  
System Analysis ◽  
Pressure Ratio ◽  
Supplementary Information ◽  
Design System ◽  
Inlet Temperature ◽  
Turbofan Engine ◽  
Design Project ◽  
Engine Design ◽  
Aeronautical Engineering ◽  
Engine Cycle

The purpose of this paper is to explore GasTurb 12, a commercial gas turbine engine performance simulation program, for supplementary use on an introductory propulsion design project in an undergraduate course. This paper will describe several possible opportunities for supplementing AEDsys (Aircraft Engine Design System Analysis) version 4.012, the engine design software tool currently in use. The project is assigned to juniors taking their first propulsion course in the aeronautical engineering major at the USAF Academy. This course, Aeronautical Engineering 361, which focuses on cycle analysis and selection, is required of all aero majors and is used to satisfy the ABET Program Criterion requiring knowledge of propulsion fundamentals. This paper describes the most recent design project that required the students to re-engine the USAF T-38 with the aim of competing for the Advanced Pilot Training Program (T-X) program. The goal of the T-X program is to replace the T-38 aircraft that entered service in 1961 with an aircraft capable of sustained high-G operations that is also more fuel efficient. The design project required the students to select an engine-cycle for a single, non-afterburning, mixed stream, low bypass turbofan engine to replace the two J85 turbojets currently in the T-38. It was anticipated that the high specific thrust requirements might possibly be met through the use of modern component measures of merit to include a much higher turbine inlet temperature. Additionally, it was anticipated that the required 10% reduction in thrust specific fuel consumption might possibly be achieved by using a turbofan engine cycle with a higher overall pressure ratio. This paper will describe the use of GasTurb 12 to perform the same design analysis that was described above using AEDsys as well as additional features such as numerical optimization, temperature-entropy diagrams, and the generation of scaled, two-dimensional engine geometry drawings. The paper will illustrate how GasTurb 12 offers important supplementary information that will deepen student understanding of engine cycle design and analysis.

Optimisation of Diesel Engine for Hybrid Military Tracked Vehicles using Matlab-Simulink

2017 ◽  
Vol 67 (4) ◽  
pp. 360
Author(s):  
Hari Viswanath ◽  
A. Kumaraswamy ◽  
P. Sivakumar
Keyword(s):  
Diesel Engine ◽  
Dynamic Performance ◽  
Fuel Efficiency ◽  
Negative Power ◽  
Matlab Simulink ◽  
Performance Requirements ◽  
In Series ◽  
And Performance ◽  
High Power Batteries ◽  
Operating Points

<p class="Abstract">The demand in the technology requirements for diesel engines is growing keeping hybrid vehicles in mind. In future the diesel engine no longer drives the wheels directly; as a result the engine can be engaged at a limited number of operating points, thus, offering an opportunity to optimise the fuel efficiency and performance at those operating points. The extent to which this optimisation is possible is limited by practical considerations. Also if the positive and negative power peaks in vehicle during mobility (e.g. acceleration and regenerative braking respectively) can be accommodated by high-power batteries, then the size of the engine can be considerably reduced. The engine’s operating points depend on the power-control strategy. The consequences of modifications to these operating points will have an effect on performance and efficiency. As in series hybrid only a limited number of operating points are involved and dynamic performance requirements are not imposed on the diesel engine, significant improvements can be achieved by the optimisation of the diesel engine at these operating points. The feasibility of optimisation of the engine at these operating points can be done by modification on the injection systems, the valve timings and other such parameters. This kind of approach requires the use of complex and repeated experimental analysis of the engine which is costly, cumbersome and time consuming. An alternative to this kind of experimental approach is to develop a simulation model of the engine with the generator in Matlab- Simulink.</p>

Parametric Study for Adoption of Variable Cycle Engine Concept for Low Bypass Ratio Turbofan Engine

2019 ◽  
Author(s):  
Kaviya Swaminathan ◽  
Chetan S. Mistry
Keyword(s):  
Fuel Consumption ◽  
Mass Flow ◽  
Parametric Study ◽  
High Efficiency ◽  
Turbofan Engine ◽  
Engine Design ◽  
Flow Through ◽  
Operating Points ◽  
Bypass Ratio ◽  
Multiple Operating Points

Abstract Turbojet and turbofan engine propulsion system are extensively used in aircraft. Turbojets have simple engine design and extensively used for supersonic flights. Turbofan engine has high mass flow rate and efficient for subsonic application. Variable Cycle Engines, unlike the traditional engines, can vary between high thrust mode for supersonic operations and high efficiency mode for subsonic operations hence are potentially attractive for supersonic transport and advanced tactical fighter aircraft. Variable Cycle Engine can be described as the one that operates with two or more cycles, could serve as a possible solution to reconciling the necessary performance at different operating conditions. The aim of the engine is to combine the best traits of turbojet (high specific thrust) and turbofan (low specific fuel consumption, low noise). Traditional engines have fixed mass flow but VCE can alter the mass flow and function as high bypass engine for the subsonic case and low bypass engine at the supersonic case. Different variable cycle engine design philosophies were studied and the engine architecture used in F120 was incorporated into the base design of a low bypass ratio Turbofan Engine. Cycle analysis of VCE was primarily done based on theoretical calculation and parametric study performed with the use of Gasturb software. Two Variable Area Bypass Injectors (VABI) were used to vary the mass flow through the core and the bypass stream. We aspire to achieve enhanced performance at subsonic and supersonic mission segments. Subsonic, supersonic and take off conditions were decided and the base engine was modified to have multiple operating points. The VCE combines two cycles (subsonic, supersonic) in same engine body and it is crucial for the engine components to deliver the required performance at both the design points. The engine design procedure consists of the matching of components like turbine, compressor, exhaust nozzle and the exhaust mixing area. Systematic study of turbine matching for such engine configuration with multiple operating points was carried out to understand the utility of variable geometry in a VCE. For turbine matching, the mass flow through turbine was held constant by adjusting the VABIs and this was repeated for different takeoff conditions to analyses the output in detail. The non dimensional mass flow through the turbine was fixed for both the design points and hence the turbine could be designed to provide high efficiency. The fuel consumption was found to have decreased compared to the baseline condition which in turn leads to low SFC and higher endurance.

scholarly journals Rapid Calculation of Engine Performance

1985 ◽  
Author(s):  
Zhang Jin ◽  
Zhu Xinjian
Keyword(s):  
Working Conditions ◽  
Statistical Data ◽  
Engine Performance ◽  
Calculation Procedure ◽  
Turbofan Engine ◽  
Design Performance ◽  
Engine Design ◽  
Rapid Calculation ◽  
Performance Calculation ◽  
Preliminary Phase

A rapid calculation procedure for design and off-design performance of turbojet and turbofan engine is developed. It peculiarity is that the general characteristics of components are established based on statistical data and the engine working conditions are searched according to matching of these general characteristics. This method can be used to select cycle parameters in engine design, and has been employed in engine performance calculation program used in the preliminary phase of engine design or airframe/engine integration design.

Assessment of Solar Steam Injection in Gas Turbines

2016 ◽  
Author(s):  
C. Kalathakis ◽  
N. Aretakis ◽  
I. Roumeliotis ◽  
A. Alexiou ◽  
K. Mathioudakis
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Fuel Efficiency ◽  
Thermal Power ◽  
Steam Injection ◽  
Power Production ◽  
Engine Operation ◽  
Efficiency Increase ◽  
Solar Receiver ◽  
Steam Production

The concept of solar steam production for injection in a gas turbine combustion chamber is studied for both nominal and part load engine operation. First, a 5MW single shaft engine is considered which is then retrofitted for solar steam injection using either a tower receiver or a parabolic troughs scheme. Next, solar thermal power is used to augment steam production of an already steam injected single shaft engine without any modification of the existing HRSG by placing the solar receiver/evaporator in parallel with the conventional one. For the case examined in this paper, solar steam injection results to an increase of annual power production (∼15%) and annual fuel efficiency (∼6%) compared to the fuel-only engine. It is also shown that the tower receiver scheme has a more stable behavior throughout the year compared to the troughs scheme that has better performance at summer than at winter. In the case of doubling the steam-to-air ratio of an already steam injected gas turbine through the use of a solar evaporator, annual power production and fuel efficiency increase by 5% and 2% respectively.

In-Service Reliability Assessment of Turbine Blade Thermal Barrier Coatings Based on a Novel Cumulative Damage Index Model

2021 ◽  
Author(s):  
He Liu ◽  
Jianzhong Sun ◽  
Shiying Lei
Keyword(s):  
Damage Index ◽  
Cumulative Damage ◽  
Life Assessment ◽  
Thermal Barrier ◽  
Inlet Temperature ◽  
Service Reliability ◽  
Engine Operation ◽  
Premature Failure ◽  
Covariate Data ◽  
Index Model

Abstract Thermal barrier coating (TBC) has been used widely on turbine blades to provide temperature and oxidation protection. With the turbine inlet temperature continuously increasing, TBCs have become more likely to oxide spallation, leading to premature failure of blade metal substrates. Thus, It is necessary to accurately evaluate the in-service reliability of TBCs for blade life assessment and engine operation safety. Nowadays, it is common to dynamically record aero-engine operating and performance data, called dynamic covariate data, which provides periodic snapshots for obtaining reliability information of engine components. Nevertheless, existing TBC life prediction models that pay adequate attention to dynamic covariate information are rare. This paper focuses on using limited failure samples with associated dynamic covariate data to make in-service reliability assessments of TBCs through a proposed cumulative damage index model. For the demonstration of the proposed approach, an integrated TBC life simulation approach has been introduced, which comprises engine performance, blade thermal, TBC damage, and damage accumulation models. The case study shows that the proposed cumulative damage index model based method provides more stable and accurate results than the traditional statistical method based on failure-time data.

Investigation of a Rotor Blade With Tip Cooling Subject to a Nonuniform Temperature Profile

2021 ◽  
Vol 143 (7) ◽  
Author(s):  
Harika S. Kahveci
Keyword(s):  
Temperature Profile ◽  
Turbine Blade ◽  
Numerical Study ◽  
Turbine Rotor ◽  
Inlet Temperature ◽  
Pressure Side ◽  
Engine Operation ◽  
Pressure Losses ◽  
Blade Tip ◽  
Temperature Levels

Abstract One of the challenges in the design of a high-pressure turbine blade is that a considerable amount of cooling is required so that the blade can survive high temperature levels during engine operation. Another challenge is that the addition of cooling should not adversely affect blade aerodynamic performance. The typical flat tips used in designs have evolved into squealer form that implements rims on the tip, which has been reported in several studies to achieve better heat transfer characteristics as well as to decrease pressure losses at the tip. This paper demonstrates a numerical study focusing on a squealer turbine blade tip that is operating in a turbine environment matching the typical design ratios of pressure, temperature, and coolant blowing. The blades rotate at a realistic rpm and are subjected to a turbine rotor inlet temperature profile that has a nonuniform shape. For comparison, a uniform profile is also considered as it is typically used in computational studies for simplicity. The effect of tip cooling is investigated by implementing seven holes on the tip near the blade pressure side. Results confirm that the temperature profile nonuniformity and the addition of cooling are the drivers for loss generation, and they further increase losses when combined. Temperature profile migration is not pronounced with a uniform profile but shows distinct features with a nonuniform profile for which hot gas migration toward the blade pressure side is observed. The blade tip also receives higher coolant coverage when subject to the nonuniform profile.

Model Based Design and Optimization for Large Bore Engines: Some Industrial Case Studies

2017 ◽  
Author(s):  
Prashant Srinivasan ◽  
Sanketh Bhat ◽  
Manthram Sivasubramaniam ◽  
Ravi Methekar ◽  
Maruthi Devarakonda ◽  
...  
Keyword(s):  
System Design ◽  
Case Studies ◽  
Control Strategy ◽  
Internal Combustion Engines ◽  
Cost Optimization ◽  
Engine Performance ◽  
Design And Optimization ◽  
Model Based ◽  
Performance Requirements ◽  
Engine Design

Large bore reciprocating internal combustion engines are used in a wide variety of applications such as power generation, transportation, gas compression, mechanical drives, and mining. Each application has its own unique requirements that influence the engine design & control strategy. The system architecture & control strategy play a key role in meeting the requirements. Traditionally, control design has come in at a later stage of the development process, when the system design is almost frozen. Furthermore, transient performance requirements have not always been considered adequately at early design stages for large engines, thus limiting achievable controller performance. With rapid advances in engine modeling capability, it has now become possible to accurately simulate engine behavior in steady-states and transients. In this paper, we propose an integrated model-based approach to system design & control of reciprocating engines and outline ideas, processes and real-world case studies for the same. Key benefits of this approach include optimized engine performance in terms of efficiency, transient response, emissions, system and cost optimization, tools to evaluate various concepts before engine build thus leading to significant reduction in development time & cost.

Matching and Optimisation of Turbochargers for Upgradation of High Horse Power Diesel Electric Locomotives for Indian Railways

2005 ◽  
Author(s):  
Anirudh Gautam ◽  
Avinash Kumar Agarwal
Keyword(s):  
Engine Speed ◽  
Thermal Loading ◽  
Fuel Efficiency ◽  
Operating Point ◽  
Inlet Temperature ◽  
Test Bed ◽  
Optimum Configuration ◽  
Air Inlet ◽  
First Case ◽  
Brake Mean Effective Pressure

As a part of the upgradation program of its fleet of 1940 kW diesel electric locomotives, Indian Railways undertook evaluation, matching and optimization of different turbochargers. The objective was to increase engine output, improve fuel efficiency and limit thermal loading. Trials with different makes of turbochargers using different combinations of diffuser, nozzle rings and compressors were carried out for identifying the optimum configuration for an uprated engine rating of 2310 kW. Test bed evaluations have been carried out on Research Design & Standards Organization (RDSO) test beds for four different designs of turbochargers with different configurations. Two types of surge tests were carried out at each operating point i.e. constant brake mean effective pressure (BMEP) and constant power. In the first case, BMEP was kept constant and engine speed varied and in the second case, power was kept constant and engine speed was varied. The tests consisted of recording the parameters at various combinations of engine speed and power. With different combinations, the highest operating point for a test was governed by peak firing pressures. Some of the parameters, which were monitored, were the compressor air inlet temperature, representative peak firing pressures, turbine inlet temperature, average cylinder head temperature, brake specific fuel consumption (BSFC) and air manifold temperature. This paper discusses the methods adopted in carrying out these evaluations and optimizations and the results obtained thereof along with the decision criteria for making final selections.

Application of Digital Twin Concept for Supercritical CO2 Off-Design Performance and Operation Analyses

2020 ◽  
Author(s):  
Leonid Moroz ◽  
Maksym Burlaka ◽  
Tishun Zhang ◽  
Olga Altukhova
Keyword(s):  
Supercritical Co2 ◽  
Control Strategies ◽  
System Modeling ◽  
Performance Estimation ◽  
Cycle Performance ◽  
Small Scale ◽  
Part Load ◽  
Digital Twin ◽  
Design Performance ◽  
Cycle Simulation

Abstract To date variety of supercritical CO2 cycles were proposed by numerous authors. Multiple small-scale tests performed, and a lot of supercritical CO cycle aspects studied. Currently, 3-10 MW-scale test facilities are being built. However, there are still several pieces of SCO2 technology with the Technology Readiness Level (TRL) 3-5 and system modeling is one of them. The system modeling approach shall be sufficiently accurate and flexible, to be able to precisely predict the off-design and part-load operation of the cycle at both supercritical and condensing modes with diverse control strategies. System modeling itself implies the utilization of component models which are often idealized and may not provide a sufficient level of fidelity. Especially for prediction of off-design and part load supercritical CO2 cycle performance with near-critical compressor and transition to condensing modes with lower ambient temperatures, and other aspects of cycle operation under alternating grid demands and ambient conditions. In this study, the concept of a digital twin to predict off-design supercritical CO2 cycle performance is utilized. In particular, with the intent to have sufficient cycle simulation accuracy and flexibility the cycle simulation system with physics-based methods/modules were created for the bottoming 15.5 MW Power Generation Unit (PGU). The heat source for PGU is GE LM6000-PH DLE gas turbine. The PGU is a composite (merged) supercritical CO2 cycle with a high heat recovery rate, its design and the overall scheme are described in detail. The calculation methods utilized at cycle level and components’ level, including loss models with an indication of prediction accuracy, are described. The flowchart of the process of off-design performance estimation and data transfer between the modules as well. The comparison of the results obtained utilizing PGU digital twin with other simplified approaches is performed. The results of the developed digital twin utilization to optimize cycle control strategies and parameters to improve off-design cycle performance are discussed in detail.

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