Air-Standard Aerothermodynamic Analysis of Gas Turbine Engines With Wave Rotor Combustion

2009 ◽  
Vol 131 (5) ◽  
Author(s):  
M. R. Nalim ◽  
H. Li ◽  
P. Akbari
Keyword(s):  
Gas Turbine ◽  
Gas Dynamics ◽  
Engine Performance ◽  
Algebraic Model ◽  
Operating Conditions ◽  
State Variables ◽  
Wave Rotor ◽  
Turbine Engine ◽  
Fill Fraction ◽  
Wave Compression

The wave rotor combustor can significantly improve gas turbine engine performance by implementing constant-volume combustion. The periodically open and closed combustor complicates thermodynamic analysis. Key cycle parameters depend on complex gas dynamics. In this study, a consistent air-standard aerothermodynamic model with variable specific heat is established. An algebraic model of the dominant gas dynamics estimates fill fraction and internal wave compression for typical port designs, using a relevant flow Mach number to represent wave amplitudes. Nonlinear equations for thermodynamic state variables are solved numerically by Newton–Raphson iteration. Performance measures and key operating conditions are predicted, and a quasi-one-dimensional computational model is used to evaluate the usefulness of the algebraic model.

Air-Standard Aerothermodynamic Analysis of Gas Turbine Engines With Wave Rotor Combustion

2009 ◽  
Author(s):  
Razi Nalim ◽  
Hongwei Li ◽  
Pezhman Akbari
Keyword(s):  
Gas Turbine ◽  
Gas Dynamics ◽  
Engine Performance ◽  
Algebraic Model ◽  
Operating Conditions ◽  
State Variables ◽  
Wave Rotor ◽  
Turbine Engine ◽  
Compression And Expansion ◽  
Wave Compression

The wave rotor combustor can significantly improve gas turbine engine performance by implementing constant-volume combustion. The periodically open and closed combustor complicates thermodynamic analysis, and key cycle parameters depend on complex gas dynamics. In this study, a consistent air-standard aerothermodynamic model with variable specific heat is established. An algebraic model of the dominant gas dynamics estimates fill fraction and internal wave compression for typical port designs, using a relevant flow Mach number to represent wave amplitudes of compression and expansion. Nonlinear equations for thermodynamic state variables are solved numerically by Newton-Raphson iteration. Performance measures and key operating conditions are predicted, and a quasi-one-dimensional computational model is used to evaluate the usefulness of the algebraic model.

scholarly journals Investigation of Micro Gas Turbine Systems for High Speed Long Loiter Tactical Unmanned Air Systems

Aerospace ◽  
2019 ◽  
Vol 6 (5) ◽  
pp. 55 ◽  
Author(s):  
James Large ◽  
Apostolos Pesyridis
Keyword(s):  
Gas Turbine ◽  
Fuel Consumption ◽  
High Speed ◽  
Engine Performance ◽  
Operating Conditions ◽  
Turbine Engine ◽  
Micro Gas Turbine ◽  
Fan Speed ◽  
Relative Design ◽  
Design Simplicity

In this study, the on-going research into the improvement of micro-gas turbine propulsion system performance and the suitability for its application as propulsion systems for small tactical UAVs (<600 kg) is investigated. The study is focused around the concept of converting existing micro turbojet engines into turbofans with the use of a continuously variable gearbox, thus maintaining a single spool configuration and relative design simplicity. This is an effort to reduce the initial engine development cost, whilst improving the propulsive performance. The BMT 120 KS micro turbojet engine is selected for the performance evaluation of the conversion process using the gas turbine performance software GasTurb13. The preliminary design of a matched low-pressure compressor (LPC) for the proposed engine is then performed using meanline calculation methods. According to the analysis that is carried out, an improvement in the converted micro gas turbine engine performance, in terms of thrust and specific fuel consumption is achieved. Furthermore, with the introduction of a CVT gearbox, the fan speed operation may be adjusted independently of the core, allowing an increased thrust generation or better fuel consumption. This therefore enables a wider gamut of operating conditions and enhances the performance and scope of the tactical UAV.

scholarly journals Wave-Rotor-Enhanced Gas Turbine Engines

1997 ◽  
Vol 119 (2) ◽  
pp. 469-477 ◽  
Author(s):  
G. E. Welch ◽  
S. M. Jones ◽  
D. E. Paxson
Keyword(s):  
Gas Turbine ◽  
Fuel Consumption ◽  
Engine Performance ◽  
Specific Fuel Consumption ◽  
Specific Power ◽  
Inlet Temperature ◽  
Wave Rotor ◽  
Performance Levels ◽  
Turbine Engine ◽  
The Impact

The benefits of wave rotor topping in small (300- to 500-kW [400- to 700-hp] class) and intermediate (2000- to 3000-kw [3000- to 4000-hp] class) turboshaft engines, and large (350- to 450-kN [80,000- to 100,000-lbf] class) high-bypass-ratio turbofan engines are evaluated. Wave rotor performance levels are calculated using a one-dimensional design/analysis code. Baseline and wave-rotor-enhanced engine performance levels are obtained from a cycle deck in which the wave rotor is represented as a burner with pressure gain. Wave rotor topping is shown to enhance the specific fuel consumption and specific power of small- and intermediate-sized turboshaft engines significantly. The specific fuel consumption of the wave-rotor-enhanced large turbofan engine can be reduced while it operates at a significantly reduced turbine inlet temperature. The wave-rotor-enhanced engine is shown to behave off-design like a conventional engine. Discussion concerning the impact of the wave rotor/gas turbine engine integration identifies technical challenges.

Gas-Dynamics Design of Reversible Turbine for Marine Gas Turbine Engine

2017 ◽  
Author(s):  
Xiying Niu ◽  
Feng Lin ◽  
Weishun Li ◽  
Chen Liang ◽  
Shunwang Yu ◽  
...  
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Gas Dynamics ◽  
Gas Turbine Engine ◽  
Operating Conditions ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Turbine Engine ◽  
Power Turbine ◽  
Full Speed

Gas turbine engines are widely used as the marine main power system. However, they can’t reverse like diesel engine. If the reversal is realized, other ways must be adopted, for example, controllable pitch propeller (CPP) and reversible gearing. Although CPP has widespread use, the actuator installation inside the hub of the propeller lead to the decrease in efficiency, and it takes one minute to switch “full speed ahead” to “full speed astern”. In addition, some devices need to be added for the reversible gearing, and it takes five minutes to switch from “full speed ahead” “to “full speed astern”. Based on the gas turbine engine itself, a reversible gas turbine engine is proposed, which can rotate positively or reversely. Most important of all, reversible gas turbine engine can realize operating states of “full speed ahead”, “full speed astern“ and “stop propeller”. And, it just takes half of one minute to switch “full speed ahead” to “full speed astern”. Since reversible gas turbine engines have compensating advantages, and especially in recent years computational fluid dynamics (CFD) technology and turbine gas-dynamics design level develop rapidly, reversible gas turbine engines will be a good direction for ship astern. In this paper, the power turbine of a marine gas turbine engine was redesigned by three dimensional shape modification, and the flow field is analyzed using CFD, in order to redesign into a reverse turbine. The last stage vanes and blades of this power turbine were changed to double-layer structure. That is, the outer one is reversible turbine, while the inner is the ahead one. Note that their rotational directions are opposite. In order to realize switching between rotation ahead and rotation astern, switching devices were designed, which locate in the duct between the low pressure turbine and power turbine. Moreover, In order to reduce the blade windage loss caused by the reversible turbine during working ahead, baffle plates were used before and after the reversible rotor blades. This paper mainly studied how to increase the efficiency of the reversible turbine stage, the torque change under different operating conditions, rotational speed and rotational directions, and flow field under typical operating conditions. A perfect profile is expected to provide for reversible power turbine, and it can decrease the blade windage loss, and increase the efficiency of the whole gas turbine engine. Overall, the efficiency of the newly designed reversible turbine is up to 85.7%, and the output power is more than 10 MW, which can meet requirements of no less than 30% power of rated condition. Most importantly, the shaft is not over torque under all ahead and astern conditions. Detailed results about these are presented and discussed in the paper.

Wave-Rotor Pressure-Gain Combustion Analysis for Power Generation and Gas Turbine Applications

2012 ◽  
Author(s):  
Manikanda Rajagopal ◽  
Abdullah Karimi ◽  
Razi Nalim
Keyword(s):  
Gas Turbine ◽  
Pressure Ratio ◽  
Turbulent Flame ◽  
Pressure Rise ◽  
Gas Turbine Engine ◽  
Operating Conditions ◽  
Specific Power ◽  
Inlet Temperature ◽  
Wave Rotor ◽  
Turbine Engine

A wave-rotor pressure-gain combustor (WRPGC) ideally provides constant-volume combustion and enables a gas turbine engine to operate on the Humphrey-Atkinson cycle. It exploits pressure (both compression and expansion) waves and confined propagating combustion to achieve pressure rise inside the combustor. This study first presents thermodynamic cycle analysis to illustrate the improvements of a gas turbine engine possible with a wave rotor combustor. Thereafter, non-steady reacting simulations are used to examine features and characteristics of a combustor rig that reproduces key features of a WRPGC. In the thermodynamic analysis, performance parameters such as thermal efficiency and specific power are estimated for different operating conditions (compressor pressure ratio and turbine inlet temperature). The performance of the WRPGC is compared with the conventional unrecuperated and recuperated engines that operates on the Brayton cycle. Fuel consumption may be reduced substantially with WRPGC introduction, while concomitantly boosting power. Simulations have been performed of the ignition of propane by a hot gas jet and subsequent turbulent flame propagation and shock-flame interaction.

scholarly journals Assessment of a Wave Rotor Topped Demonstrator Gas Turbine Engine Concept

1996 ◽  
Author(s):  
Philip H. Snyder ◽  
Raymond E. Fish
Keyword(s):  
Gas Turbine ◽  
Engine Performance ◽  
Gas Turbine Engine ◽  
Wave Rotor ◽  
Turbine Engine ◽  
Design Point ◽  
Engine Design ◽  
Engine Concept ◽  
Engine Cycle

A wave rotor topped gas turbine engine has been identified which incorporates five basic requirements of a successful demonstrator engine. Predicted performance maps of the wave rotor cycle have been used along with maps of existing gas turbine hardware in a design point study. The effects of wave rotor topping on the engine cycle and the subsequent need to rematch compressor and turbine sections in the topped engine are addressed. Comparison of performance of the resulting engine is made on the basis of wave rotor topped engine versus an appropriate baseline engine using common shaft compressor hardware. The topped engine design clearly demonstrates an improvement in shaft horsepower and SFC. Predicted off design part power engine performance for the wave rotor topped engine is presented including that at engine idle conditions. Operation of the engine at off design is closely examined with wave rotor operation at less than design burner outlet temperatures and rotor speeds. Challenges remaining in the development of a demonstrator engine are addressed.

scholarly journals Performance Benefits for Wave Rotor-Topped Gas Turbine Engines

1996 ◽  
Author(s):  
Scott M. Jones ◽  
Gerard E. Welch
Keyword(s):  
Steady State ◽  
Gas Turbine ◽  
Engine Performance ◽  
Thermodynamic Cycle ◽  
Cycle Performance ◽  
Specific Power ◽  
Inlet Temperature ◽  
Wave Rotor ◽  
Turbine Engine ◽  
One Dimensional

The benefits of wave rotor-topping in turboshaft engines, subsonic high-bypass turbofan engines, auxiliary power units, and ground power units are evaluated. The thermodynamic cycle performance is modeled using a one-dimensional steady-state code; wave rotor performance is modeled using one-dimensional design/analysis codes. Design and off-design engine performance is calculated for baseline engines and wave rotor-topped engines, where the wave rotor acts as a high pressure spool. The wave rotor-enhanced engines are shown to have benefits in specific power and specific fuel flow over the baseline engines without increasing turbine inlet temperature. The off-design steady-state behavior of a wave rotor-topped engine is shown to be similar to a conventional engine. Mission studies are performed to quantify aircraft performance benefits for various wave rotor cycle and weight parameters. Gas turbine engine cycles most likely to benefit from wave rotor-topping are identified. Issues of practical integration and the corresponding technical challenges with various engine types are discussed.

scholarly journals Investigation of Micro Gas Turbine Systems for High Speed Long Loiter Tactical Unmanned Air Systems

2018 ◽  
Author(s):  
James Large ◽  
Apostolos Pesyridis
Keyword(s):  
Gas Turbine ◽  
Fuel Consumption ◽  
High Speed ◽  
Engine Performance ◽  
Operating Conditions ◽  
Turbine Engine ◽  
Micro Gas Turbine ◽  
Fan Speed ◽  
Relative Design ◽  
Design Simplicity

In this study, the on-going research into the improvement of micro-gas turbine propulsion system performance and the suitability for application as propulsion systems for small tactical UAVs (&lt;600 kg) is investigated. The study is focused around the concept of converting existing micro turbojet engines to turbofan with the use of a continuously variable gearbox, thus maintaining a single spool configuration and relative design simplicity. This is an effort to reduce the initial engine development cost, whilst improving propulsive performance. The BMT 120 KS micro turbojet engine is selected for performance evaluation of the conversion process using gas turbine performance software, GasTurb13. The preliminary design of a matched low-pressure compressor (LPC) for the proposed engine is then performed using meanline calculation methods. According to the analysis carried out, an improvement in the converted micro gas turbine engine performance in terms of thrust and specific fuel consumption is achieved. Furthermore, with the introduction of a CVT gearbox, fan speed operation may be adjusted independently of the core, allowing increased thrust generation or better fuel consumption. Therefore, enabling a wider gamut of operating conditions and enhances the performance and scope of tactical UAV.

Design, Development and Application of Vehicle Gas Turbine Engines

1966 ◽  
Vol 181 (1) ◽  
pp. 149-172
Author(s):  
P. A. Phillips ◽  
Peter Spear
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Low Cost ◽  
Engine Performance ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Design Development ◽  
Turbine Engine ◽  
Wide Range ◽  
Cycle Temperature

After briefly summarizing worldwide automotive gas turbine activity, the paper analyses the power plant requirements of a wide range of vehicle applications in order to formulate the design criteria for acceptable vehicle gas turbines. Ample data are available on the thermodynamic merits of various gas turbine cycles; however, the low cost of its piston engine competitor tends to eliminate all but the simplest cycles from vehicle gas turbine considerations. In order to improve the part load fuel economy, some complexity is inevitable, but this is limited to the addition of a glass ceramic regenerator in the 150 b.h.p. engine which is described in some detail. The alternative further complications necessary to achieve satisfactory vehicle response at various power/weight ratios are examined. Further improvement in engine performance will come by increasing the maximum cycle temperature. This can be achieved at lower cost by the extension of the use of ceramics. The paper is intended to stimulate the design application of the gas turbine engine.

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