Plausibility Study of Hecto Pressure Ratio Concepts in Large Civil Aero-Engines

2017 ◽  
Vol 140 (5) ◽  
Author(s):  
Felix Klein ◽  
Stephan Staudacher
Keyword(s):  
Gas Turbine ◽  
Lightweight Design ◽  
Pressure Ratio ◽  
Maximum Efficiency ◽  
Wave Rotor ◽  
Piston Engine ◽  
Chamber Volume ◽  
Efficiency Increase ◽  
Component Efficiency ◽  
Aero Engines

Enabling high overall pressure ratios (OPR), wave rotors, and piston concepts (PCs) seem to be solutions surpassing gas turbine efficiency. Therefore, a comparison of a wave rotor and three PCs relative to a reference gas turbine is offered. The PPCs include a Wankel, a two-stroke reciprocating engine, and a free piston. All concepts are investigated with and without intercooling. An additional combustion chamber (CC) downstream the piston engine is investigated, too. The shaft power chosen corresponds to large civil turbofans. Relative to the reference gas turbine, a maximum efficiency increase of 11.2% for the PCs and 9.8% for the intercooled wave rotor is demonstrated. These improvements are contrasted by a 5.8% increase in the intercooled reference gas turbine and a 4.2% increase due to improved gas turbine component efficiencies. Intercooling the higher component efficiency gas turbine leads to a 9.8% efficiency increase. Furthermore, the study demonstrates the high difference between intercooler and piston engine weight and a conflict between PC efficiency and chamber volume, highlighting the need for extreme lightweight design in any piston engine solution. Improving piston engine technology parameters is demonstrated to lead to higher efficiency, but not to a chamber volume reduction. Heat loss in the piston engines is identified as the major efficiency limiter.

Plausibility Study of Hecto Pressure Ratio Concepts in Large Civil Aero Engines

2017 ◽  
Author(s):  
Felix Klein ◽  
Stephan Staudacher
Keyword(s):  
Gas Turbine ◽  
Lightweight Design ◽  
Pressure Ratio ◽  
Maximum Efficiency ◽  
Wave Rotor ◽  
Piston Engine ◽  
Chamber Volume ◽  
Percent Increase ◽  
Efficiency Increase ◽  
Component Efficiency

Enabling high overall pressure ratios, wave rotors and piston concepts seem to be solutions surpassing gas turbine efficiency. Therefore, a comparison of a wave rotor and three piston concepts relative to a reference gas turbine is offered. The piston concepts include a Wankel, a 2-stroke reciprocating engine and a free-piston. All concepts are investigated with and without intercooling. An additional combustion chamber downstream the piston engine is investigated, too. The shaft power chosen corresponds to large civil turbofans. Relative to the reference gas turbine a maximum efficiency increase of 11.2 percent for the piston concepts and 9.8 percent for the intercooled wave rotor is demonstrated. These improvements are contrasted by a 5.8 percent increase in the intercooled reference gas turbine and a 4.2 percent increase due to improved gas turbine component efficiencies. Intercooling the higher component efficiency gas turbine leads to a 9.8 percent efficiency increase. Furthermore, the study demonstrates the high difference between intercooler and piston engine weight and a conflict between piston concept efficiency and chamber volume, highlighting the need for extreme lightweight design in any piston engine solution. Improving piston engine technology parameters is demonstrated to lead to higher efficiency, but not to a chamber volume reduction. Heat loss in the piston engines is identified as the major efficiency limiter.

Cycle Optimization Potential of Composite Cycle and Turbocompound Aero-Engines

2020 ◽  
Vol 142 (6) ◽  
Author(s):  
Felix Klein ◽  
Stephan Staudacher
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Exchange Process ◽  
Aircraft Engine ◽  
Time Frame ◽  
Fuel Burn ◽  
Component Efficiency ◽  
Low Efficiency ◽  
Aero Engines

Abstract Fair comparison of future aircraft engine concepts requires the assumption of similar technological risk and a transparent book keeping of losses. A 1000 km and a 7000 km flight mission of a single-aisle airplane similar to the Aribus A321neo LR have been used to compare composite cycle engines, turbocompound engines and advanced gas turbines as potential options for an entry-into-service time frame of 2050+. A 2035 technology gas turbine serves as reference. The cycle optimization has been carried out with a peak pressure ratio of 250 and a maximum cycle temperature of 2200 K at cruise as boundary conditions. With the associated heat loss and the low efficiency of the gas exchange process limiting piston component efficiency, the cycle optimization filtered out composite cycle concepts. Taking mission fuel burn (MFB) as the most relevant criterion, the highest MFB reduction of 13.7% compared to the 2035 reference gas turbine is demonstrated for an air-cooled turbocompound concept with additional combustion chamber. An intercooled, hectopressure gas turbine with pressure gain combustion achieves 20.6% reduction in MFB relative to the 2035 reference gas turbine.

scholarly journals Further Studies of the Influence of Thermal Effects on the Predicted Acceleration of Gas Turbines

1981 ◽  
Author(s):  
N. R. L. MacCallum
Keyword(s):  
Gas Turbine ◽  
Thermal Effects ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Lower Pressure ◽  
Characteristic Change ◽  
Heat Absorption ◽  
Component Efficiency ◽  
Heat Transfers

A previous study has investigated the effect of changes in compressor characteristics, due to transient heat transfers, on the predicted accelerations of a singles-pool aero gas turbine of pressure ratio 9.5. In the present paper the analysis is extended to a two-spool bypass engine of pressure ratio 21. The increases in the predicted acceleration times of this engine, due to the inclusion of heat absorption and compressor characteristic change, are more marked than with the lower pressure ratio engine, depending on the fuel schedule used. The effects of changes in component efficiencies on predicted acceleration have also been studied. Again, the higher pressure ratio engine shows the greater influence. Compared with thermal absorptions, it is likely that component efficiency changes have as much, if not more effect on predicted accelerations.

Parametric analysis of a gas turbine cycle coupled to a Brayton refrigeration cycle

2009 ◽  
Vol 223 (5) ◽  
pp. 497-503 ◽  
Author(s):  
L Chen ◽  
W Zhang ◽  
F Sun
Keyword(s):  
Gas Turbine ◽  
Power Efficiency ◽  
Pressure Ratio ◽  
Maximum Efficiency ◽  
Working Fluid ◽  
Inlet Temperature ◽  
Refrigeration Cycle ◽  
Fluid Temperature ◽  
Optimal Power ◽  
Brayton Refrigeration Cycle

Performance analysis and optimization of an endoreversible Brayton cycle coupled to a Brayton refrigeration cycle has been performed using finite-time thermodynamics. The analy-tical formulae are derived with respect to power, efficiency, optimal extracted pressure ratio of air refrigeration cycle corresponding to optimal power, optimal power and the corresponding efficiency. The influences of various parameters on the cycle performances are analysed by numerical examples. The results show that there exists one optimal pressure ratio of the compressor corresponding to maximum power and another optimal pressure ratio of the compressor corresponding to maximum efficiency; the compressor inlet temperature is reduced by mixing the chilled working fluid from the Brayton refrigeration cycle and the main intake working fluid streams; the intake working fluid temperature could be controlled even below the temperature of the heat sink and the gas turbine performance can be improved.

scholarly journals Comparing combined gas tubrine/steam turbine and marine low speed piston engine/steam turbine systems in naval applications

2011 ◽  
Vol 18 (4) ◽  
pp. 43-48 ◽  
Author(s):  
Marek Dzida ◽  
Wojciech Olszewski
Keyword(s):  
Diesel Engine ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Exhaust Gas ◽  
Piston Engine ◽  
Large Power ◽  
Low Speed ◽  
Efficiency Increase ◽  
Main Engine

Comparing combined gas tubrine/steam turbine and marine low speed piston engine/steam turbine systems in naval applications The article compares combined systems in naval applications. The object of the analysis is the combined gas turbine/steam turbine system which is compared to the combined marine low-speed Diesel engine/steam turbine system. The comparison refers to the additional power and efficiency increase resulting from the use of the heat in the exhaust gas leaving the piston engine or the gas turbine. In the analysis a number of types of gas turbines with different exhaust gas temperatures and two large-power low-speed piston engines have been taken into account. The comparison bases on the assumption about comparable power ranges of the main engine.

Turbines and Structures for Ultra-High Pressure Ratio Aero-Engines

2016 ◽  
Author(s):  
Anders Lundbladh ◽  
Ralf von der Bank ◽  
Richard Avellán ◽  
Stefan Forsman ◽  
Stefan Donnerhack ◽  
...  
Keyword(s):  
High Pressure ◽  
Direct Reduction ◽  
Pressure Ratio ◽  
Weight Ratio ◽  
Performance Improvements ◽  
High Pressure Ratio ◽  
Ultra High Pressure ◽  
Component Efficiency ◽  
Aero Engines ◽  
Emission Core

This paper describes the research carried out in the European Commission co-funded project LEMCOTEC (Low Emission Core Engine Technology) on aerodynamics for turbines and structures for compressors, combustors and turbines. The aim is to significantly contribute to the reduction of the environmental footprint of aviation with regard to emissions from aero engines. The LEMCOTEC turbine and structure technologies are directed primarily to act as enablers for higher thermal efficiency arising from increased overall pressure ratio. Thus the work is supporting increased operating temperatures, reduced core deformation, reduced cooling flows and increased performance to weight ratio, in addition to direct reduction of flow losses and associated component efficiency increases. The article details the targets for performance improvements, the validation of the technologies and how they, together with LEMCOTEC’s improved technologies on compressors and combustors, relate to the goal of building ultra-high pressure ratio engines.

The Optimum Pressure Ratio for a Combined Cycle Gas Turbine Plant

1995 ◽  
Vol 209 (4) ◽  
pp. 259-264 ◽  
Author(s):  
J H Horlock
Keyword(s):  
Gas Turbine ◽  
Pressure Ratio ◽  
Combined Cycle ◽  
Maximum Efficiency ◽  
Specific Work ◽  
Optimum Pressure ◽  
Turbine Plant ◽  
Gas Turbine Plant ◽  
Overall Efficiency ◽  
Gas Turbine Cycle

A graphical method of calculating the performance of gas turbine cycles, developed by Hawthorne and Davis (1), is adapted to determine the pressure ratio of a combined cycle gas turbine (CCGT) plant which will give maximum overall efficiency. The results of this approximate analysis show that the optimum pressure ratio is less than that for maximum efficiency in the higher level (gas turbine) cycle but greater than that for maximum specific work in that cycle. Introduction of reheat into the higher cycle increases the pressure ratio required for maximum overall efficiency.

Performance Enhancement of Advanced Combined Cycles

2003 ◽  
Author(s):  
Sanjay ◽  
Onkar Singh ◽  
B. N. Prasad
Keyword(s):  
Gas Turbine ◽  
Steam Generator ◽  
Heat Recovery ◽  
Performance Enhancement ◽  
Pressure Ratio ◽  
Combined Cycle ◽  
Inlet Temperature ◽  
Heat Recovery Steam Generator ◽  
Component Efficiency ◽  
Plant Efficiency

This paper reports on the development requirements of gas/steam combined cycle with an aim to achieve plant efficiency greater than 62% through various development possibilities in gas turbine and steam turbine cycle by taking a reference combined cycle configuration (MS9001H gas turbine and three pressure heat recovery steam generator with reheat). The innovative development possibilities include the advanced inlet design to reduce pressure loss, the increase in turbine inlet temperature, use of advanced turbine blade material, increased component efficiency, improved turbine cooling technologies along with better cooling medium, incorporating intercooling, reheat and regeneration either separately or in combination with simple gas turbine cycle using higher compressor pressure ratio, better utilization of heat recovery steam generator, minimum stack temperature, single shaft system configuration, etc. Based on the quantification of each development item, if incorporated in reference cycle, it has been estimated that the combined cycle as the potential to achieve the plant efficiency in excess of 63%.

Development of a New Simulation Program for Combined Cycle System

2002 ◽  
Author(s):  
Sepehr Sanaye ◽  
Arash Moradi
Keyword(s):  
Gas Turbine ◽  
Pressure Ratio ◽  
Combined Cycle ◽  
Simulation Program ◽  
Specific Power ◽  
Maximum Efficiency ◽  
Gas Temperature ◽  
Cycle System ◽  
Compressor Inlet ◽  
And Performance

The turbine inlet gas temperature ( Toso ) is an important parameter in design and performance analysis of gas turbine cycles. By increasing Toso, air bleeding for blade cooling increases and it can be about 25 percent of compressor inlet air mass flow rate for Toso equal to 1600 K. Therefore air bleeding has an important impact on thermal efficiency, specific power output and the optimum compressor pressure ratio at which maximum efficiency occurs. For the gas turbine part of a combined cycle, these performance curves are obtained and shown using a developed simulation program (GTE). Also for heat recovery steam generator (HRSG) part of a combined cycle plant, HRSG simulates the transient and steady state temperature distribution of hot gases, steam and tube metal at different parts of HRSG. Any number of pressure levels (high, intermediate and low) and heating elements (superheater, evaporator and economizer) including desuperheater and deaerator can be included. GTE outputs show less than two percent difference from reported measured values. This difference was less than six percent for HRSG model.

scholarly journals Technical Approach for a MultiPurpose Small Power Unit

1988 ◽  
Author(s):  
Robert G. Thompson ◽  
Sidney D. Parker
Keyword(s):  
Gas Turbine ◽  
Power Unit ◽  
Pressure Ratio ◽  
Technical Approach ◽  
Program Goal ◽  
Small Power ◽  
Turbine Engine ◽  
Component Efficiency ◽  
And Performance ◽  
Engine Components

This paper describes the technical approach used to select the engine configuration and performance cycle for a small gas turbine engine. The work was done during the preparation of a proposal to the U.S. Army for an advanced gas-turbine-based MultiPurpose Small Power Unit (MPSPU) in the 50–75 SHP class. Uprating to 100 hp (74.6 kw) with the fewest possible component changes was also desired and will be demonstrated. The proposal was successful, and the resultant engine offering, the T-100 MPSPU, is currently under development. The performance analyses used to quantify the T-100 MPSPU cycle were unique in that component efficiency correlations were used interactively when estimating performance at high levels of work (or pressure ratio per stage) with relatively small size components. The MPSPU program goal is to verify gas turbine technology advancements in small engine components, materials and design techniques that will lead to significant reductions in fuel consumption for this size class engine. Successful incorporation of these technologies will lead to significant savings in fuel usage and logistic requirements.

Sign in / Sign up

Export Citation Format

Share Document