scholarly journals A Matching Problem between the Front Fan and Aft Fan Stages in Adaptive Cycle Engines with Convertible Fan Systems

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 840
Author(s):  
Xin Meng ◽  
Zhili Zhu ◽  
Min Chen ◽  
Yihao Xu
Keyword(s):  
Variable Geometry ◽  
Matching Problem ◽  
Adaptive Cycle ◽  
Numeric Simulation ◽  
Rate Adjustment ◽  
Component Matching ◽  
Matching Mechanism ◽  
Front Fan ◽  
Bypass Ratio ◽  
Steady State Performance

In the process of studying the steady-state performance and component matching of adaptive cycle engines with convertible fan system, it was found that the front fan and aft fan stage have a unique matching problem when the mode select valve is closed and engine is operating at higher Mach number conditions. The cause of this matching problem was studied with numeric simulation in this paper. Based on the features of adaptive cycle engines with convertible fan system, the possible methods and their feasibilities of solving this matching problem were also discussed. According to the results, the flow rate adjustment capacity of the aft fan stage directly determines the occurrence and severity of this matching problem. The matching problem can be ameliorated in some extent by either reducing the design second bypass ratio or adjusting the variable geometry mechanisms, but it cannot be completely solved at the aspect of component matching mechanism.

Preliminary Research on Future Smart Engine Architecture

2020 ◽  
Author(s):  
Yudong Liu ◽  
Min Chen ◽  
Hailong Tang
Keyword(s):  
Aerospace Industry ◽  
Research Projects ◽  
Engine Design ◽  
Engine Component ◽  
Aero Engine ◽  
The Future ◽  
Component Matching ◽  
Matching Mechanism ◽  
Preliminary Research ◽  
Aero Engines

Abstract Aero engines that fit the future have now increasingly attracted the attention of aerospace industry and academia. With this trend, many research projects have been carried out to explore future aero engine technologies. This paper focuses on engine design field, and aims to satisfy the future flight missions that may be unpredictably varying. However, the intrinsic strong coupling of engine component matching mechanism blocks acceleration of engine design. Under this condition, this paper comes up with the concept of smart engine architecture that via a series of engine decoupling strategies, the components can be decoupled to an extent that by properly selecting and assembling them, an engine that satisfies certain flight mission can be designed, this is named mission-oriented pluggable design mode in this paper. Following this idea, a multi-purpose engine design scheme is presented to demonstrate the potential of this engine design mode, and further value of smart engine architecture is discussed.

scholarly journals Matching mechanism analysis on an adaptive cycle engine

2017 ◽  
Vol 30 (2) ◽  
pp. 706-718 ◽  
Author(s):  
Junchao Zheng ◽  
Min Chen ◽  
Hailong Tang
Keyword(s):  
Mechanism Analysis ◽  
Adaptive Cycle ◽  
Matching Mechanism

Optimizing Separate Exhaust Turbofans for Cruise Specific Fuel Consumption

2017 ◽  
Vol 139 (12) ◽  
Author(s):  
Syed J. Khalid
Keyword(s):  
Fuel Consumption ◽  
Control Algorithm ◽  
Velocity Ratio ◽  
Transmission Efficiency ◽  
Specific Fuel Consumption ◽  
Variable Geometry ◽  
Nozzle Throat ◽  
Propulsive Efficiency ◽  
Turbofan Engines ◽  
Bypass Ratio

Cruise specific fuel consumption (SFC) of turbofan engines is a key metric for increasing airline profitability and for reducing CO2 emissions. Although increasing design bypass ratio (BPR) of separate exhaust turbofan configurations improves cruise SFC, further improvements can be obtained with online control actuated variable geometry modulations of bypass nozzle throat area, core nozzle throat area, and compressor variable vanes (CVV/CVG). The scope of this paper is to show only the benefits possible, and the process used in determining those benefits, and not to suggest any particular control algorithm for searching the best combination of the control effectors. A parametric cycle study indicated that the effector modulations could increase the cruise BPR, core efficiency, transmission efficiency, propulsive efficiency, and ideal velocity ratio resulting in a cruise SFC improvement of as much as 2.6% depending upon the engine configuration. The changes in these metrics with control effector variations will be presented. Scheduling of CVV is already possible in legacy digital controls; perturbation to this schedule and modulation of nozzle areas should be explored in light of the low bandwidth requirements at steady-state cruise conditions.

scholarly journals VATEMP: The Variable Area Turbine Engine Matching Program

1990 ◽  
Author(s):  
J. E. A. Roy-Aikins ◽  
J. R. Palmer
Keyword(s):  
Steady State ◽  
Gas Turbines ◽  
Variable Geometry ◽  
Aircraft Engines ◽  
Flow Temperature ◽  
Turbine Engine ◽  
Path Component ◽  
The Impact ◽  
Engine Cycle ◽  
Steady State Performance

Variable geometry in key gas turbine components offers the advantage of either improving the internal performance of a component or of re-matching the engine cycle to alter the flow-temperature-pressure relationships. Future gas turbines are expected to use variable geometry components extensively if they are to overcome some of the problems encountered by present day engines at off-design conditions in order to give much more advanced performance. Greater attention is also being paid to the impact of installation losses on the performance of aircraft engines. A computer program called VATEMP, herein described, has been developed capable of simulating the steady-state performance of arbitrary gas turbines with or without variable geometry in almost any gas path component. Results obtained from the program led to the conclusion that variable geometry components have the potential to improve significantly the off-design performance of gas turbines.

scholarly journals Two-Sided Matching with Endogenous Preferences

2015 ◽  
Vol 7 (3) ◽  
pp. 241-258 ◽  
Author(s):  
Yair Antler
Keyword(s):  
Stable Matching ◽  
The Other ◽  
Matching Theory ◽  
Endogenous Preferences ◽  
Matching Problem ◽  
Matching Mechanism

We modify the stable matching problem by allowing agents' preferences to depend on the endogenous actions of agents on the other side of the market. Conventional matching theory results break down in the modified setup. In particular, every game that is induced by a stable matching mechanism (e.g., the Gale-Shapley mechanism) may have equilibria that result in matchings that are not stable with respect to the agents' endogenous preferences. However, when the Gale-Shapley mechanism is slightly modified, every equilibrium of its induced game results in a pairwise stable matching with respect to the endogenous preferences as long as they satisfy a natural reciprocity property. (JEL C78, D82)

Research of the XF3-1 Turbofan Engine

1978 ◽  
Author(s):  
M. Kohzu ◽  
H. Chinone ◽  
M. Miyake ◽  
K. Murashima ◽  
K. Yamanaka ◽  
...  
Keyword(s):  
Research Program ◽  
Engine Performance ◽  
Bench Test ◽  
Turbofan Engine ◽  
The Status ◽  
Test Engine ◽  
Matching Performance ◽  
Basic Studies ◽  
Front Fan ◽  
Bypass Ratio

A research program of low bypass ratio small front fan engines has been in process at Third Research Center of Technical Research and Development Institute of Japan Defence Agency since 1975. The final target of this program is the development of the propulsion engine for the high subsonic small aircraft. As the first phase of this program, the bench test engine XF3-1 was manufactured and the basic studies of the overall engine matching performance and the effect of each component on the engine performance have been carried out. This paper describes the XF3-1 engine, reviews the status of the research and presents the major engineering progress attained through the research.

Optimizing Separate Exhaust Turbofans for Cruise Specific Fuel Consumption

2016 ◽  
Author(s):  
Syed Khalid
Keyword(s):  
Fuel Consumption ◽  
Control Algorithm ◽  
Velocity Ratio ◽  
Transmission Efficiency ◽  
Specific Fuel Consumption ◽  
Variable Geometry ◽  
Nozzle Throat ◽  
Propulsive Efficiency ◽  
Turbofan Engines ◽  
Bypass Ratio

Cruise specific fuel consumption (SFC) of turbofan engines is a key metric for increasing airline profitability and for reducing CO2 emissions. Although increasing design bypass ratio (BPR) of separate exhaust turbofan configurations improves cruise SFC, further improvements can be obtained with control actuated variable geometry modulations of core nozzle throat area, bypass nozzle throat area, and compressor variable vanes (CVV). The scope of this paper is to show only the benefits possible, and the process used in determining those benefits, and not to suggest any particular control algorithm for searching the best combination of the control effectors. A parametric cycle study indicated that the effector modulations could increase the cruise BPR, core efficiency, transmission efficiency, propulsive efficiency, and ideal velocity ratio resulting in a cruise SFC improvement of as much as 2.6% depending upon the engine configuration. The changes in these metrics with control effector variations will be presented. Modulation of CVV is already possible in legacy digital controls, and modulation of nozzle areas should be explored in light of the low bandwidth requirements at steady-state cruise conditions.

scholarly journals The Influence of a Variable Capacity Turbine in the Performance of a Variable Cycle Engine

1999 ◽  
Author(s):  
Martin Dodds ◽  
Pericles Pilidis
Keyword(s):  
Low Pressure ◽  
Variable Geometry ◽  
Variable Flow ◽  
Low Pressure Turbine ◽  
Extensive Variable ◽  
Variable Capacity ◽  
Lp Turbine ◽  
The Cost ◽  
Engine Components ◽  
Bypass Ratio

An investigation was conducted to examine the effects of a variable flow low pressure turbine on a variable cycle engine’s performance. One of the greatest challenges, during the design of a variable cycle engine is how to optimise the various cycles and then to match then to the capabilities of the engine components, the use of extensive variable geometry is required to achieve this. A method of matching variable cycle engines that was developed Cranfield University was adapted to cater for the use of a variable flow low pressure turbine. It was discovered that the implementation of variable geometry within the low pressure turbine could significantly reduce the requirements for variable geometry within the compressor system, at the cost of replacing well proven compressor variable geometry with high risk technology within the LP turbine. Utilising the variable flow turbine to expand the bypass ratio range of the engine was studied. Increasing the LPM bypass ratio to 1.1 and 1.2 yielded SFC reductions of 3% and 5% respectively, reducing the bypass ratio of the HPM to 0.1 gave a 20% increase in specific thrust. It was found that the performance benefits gained from expanding the bypass ratio are large enough to warrant further investigation into this concept.

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