Application of Pulse Detonation Combustion to Turbofan Engines

2002 ◽  
Vol 125 (1) ◽  
pp. 270-283 ◽  
Author(s):  
M. A. Mawid ◽  
T. W. Park ◽  
B. Sekar ◽  
C. Arana
Keyword(s):  
Cfd Analysis ◽  
Turbofan Engine ◽  
Turbofan Engines ◽  
Pulse Detonation ◽  
Detonation Combustion ◽  
Partial Filling ◽  
Significant Performance ◽  
Specific Thrust ◽  
Performance Gains ◽  
Engine Concept

The potential performance gain of utilizing pulse detonation combustion in the bypass duct of a turbofan engine for possible elimination of the traditional afterburner was investigated in this study. A pulse detonation turbofan engine concept without an afterburner was studied and its performance was assessed. The thrust, specific fuel consumption (SFC), and specific thrust of a conventional turbofan with an afterburner and the new pulse detonation turbofan engine concept were calculated and compared. The pulse detonation device performance in the bypass duct was obtained by using multidimensional CFD analysis. The results showed that significant performance gains can be obtained by using the pulse detonation turbofan engine concept as compared to the conventional afterburning turbofan engine. In particular, it was demonstrated that for a pulse detonation bypass duct operating at a frequency of 100 Hz and higher, the thrust and specific thrust of a pulse-detonation turbofan engine can nearly be twice as much as those of the conventional afterburning turbofan engine. SFC was also shown to be reduced. The effects of fuel-air mixture equivalence ratio and partial filling on performance were also predicted. However, the interaction between pulse detonation combustion in the bypass duct and the engine fan, for potential fan stall, and engine nozzle have not been investigated in this study.

Application of Pulse Detonation Combustion to Turbofan Engines

2001 ◽  
Author(s):  
M. A. Mawid ◽  
T. W. Park ◽  
B. Sekar ◽  
C. Arana
Keyword(s):  
Cfd Analysis ◽  
Turbofan Engine ◽  
Turbofan Engines ◽  
Pulse Detonation ◽  
Detonation Combustion ◽  
Partial Filling ◽  
Significant Performance ◽  
Specific Thrust ◽  
Performance Gains ◽  
Engine Concept

The potential performance gain of utilizing pulse detonation combustion in the bypass duct of a turbofan engine for possible elimination of the traditional afterburner was investigated in this study. A pulse detonation turbofan engine concept without an afterburner was studied and its performance was assessed. The thrust, SFC and specific thrust of a conventional turbofan with an afterburner and the new pulse detonation turbofan engine concept were calculated and compared. The pulse detonation device performance in the bypass duct was obtained by using multidimensional CFD analysis. The results showed that significant performance gains can be obtained by using the pulse detonation turbofan engine concept as compared to the conventional afterburning turbofan engine. In particular, it was demonstrated that for a pulse detonation bypass duct operating at a frequency of 100 Hz and higher, the thrust and specific thrust of a pulse-detonation turbofan engine can nearly be twice as much as those of the conventional afterburning turbofan engine. SFC was also shown to be reduced. The effects of fuel-air mixture equivalence ratio and partial filling on performance were also predicted. However, the interaction between pulse detonation combustion in the bypass duct and the engine fan, for potential fan stall, and engine nozzle have not been investigated in this study.

scholarly journals Variable Flow Turbofan Engine for an HSCT Application

1997 ◽  
Author(s):  
George L. Converse ◽  
Donald K. Dunbar ◽  
Marlen L. Miller ◽  
Paul D. Hoskins ◽  
Scott M. Jones
Keyword(s):  
Mach Number ◽  
Pressure Ratio ◽  
High Flow ◽  
Turbofan Engine ◽  
Variable Flow ◽  
Guide Vanes ◽  
Turbofan Engines ◽  
Inlet Guide Vanes ◽  
Specific Thrust ◽  
Aircraft Propulsion System

A variable flow fan aircraft propulsion system offers the potential for achieving a low specific thrust with high flow and low jet velocity requirement as specified for takeoff, side-line noise, initial climb, and a high specific thrust requirement for climb and acceleration to supersonic cruise. These requirements are conflicting. To achieve this, the operating envelope of a variable flow fan has to be expanded over existing turbofan engines. The variable flow fan concept (i.e., the Variable Fan Exit or “VFX”) can efficiently operate beyond the usual fan (or compressor) stall operating line using novel methods of designing and scheduling the fan geometry as a function of flight Mach Number, fan pressure ratio and corrected speed. Fan geometry is altered by using variable inlet guide vanes (IGV’s), variable stators, and variable outlet guide vanes (OGV’s).

scholarly journals Study of Bypass Ratio Increasing Possibility for Turbofan Engine and Turbofan with Inter Turbine Burner

2019 ◽  
Vol 26 (2) ◽  
pp. 61-68
Author(s):  
Robert Jakubowski
Keyword(s):  
Fuel Consumption ◽  
Energy Input ◽  
Pressure Ratio ◽  
Specific Fuel Consumption ◽  
Additional Energy ◽  
Fast Analysis ◽  
Turbofan Engine ◽  
Turbofan Engines ◽  
Specific Thrust ◽  
Bypass Ratio

Abstract Current trends in the high bypass ratio turbofan engines development are discussed in the beginning of the paper. Based on this, the state of the art in the contemporary turbofan engines is presented and their change in the last decade is briefly summarized. The main scope of the work is the bypass ratio growth analysis. It is discussed for classical turbofan engine scheme. The next step is presentation of reach this goal by application of an additional combustor located between high and low pressure turbines. The numerical model for fast analysis of bypass ratio grows for both engine kinds are presented. Based on it, the numerical simulation of bypass engine increasing is studied. The assumption to carry out this study is a common core engine. For classical turbofan engine bypass ratio grow is compensated by fan pressure ratio reduction. For inter turbine burner turbofan, bypass grown is compensated by additional energy input into the additional combustor. Presented results are plotted and discussed. The main conclusion is drawing that energy input in to the turbofan aero engine should grow when bypass ratio is growing otherwise the energy should be saved by other engine elements (here fan pressure ratio is decreasing). Presented solution of additional energy input in inter turbine burner allow to eliminate this problem. In studied aspect, this solution not allows to improve engine performance. Specific thrust of such engine grows with bypass ratio rise – this is positive, but specific fuel consumption rise too. Classical turbofan reaches lower specific thrust for higher bypass ratio but its specific fuel consumption is lower too. Specific fuel consumption decreasing is one of the goal set for future aero-engines improvements.

An Evaluation of the Geometry and Weight of a Mixed Flow Low Bypass Ratio Turbofan Engine With an Intermediate Turbine Burner

2005 ◽  
Author(s):  
Chorng-Yow Chen ◽  
Mark H. Waters ◽  
Dimitri Mavris
Keyword(s):  
Mechanical Design ◽  
Pressure Ratio ◽  
Flow Path ◽  
Mixed Flow ◽  
Turbofan Engine ◽  
Turbofan Engines ◽  
Low Pressure Turbine ◽  
The Subject ◽  
Specific Thrust ◽  
Bypass Ratio

Turbofan engines are designed with two or even three spools of fan- compressor and turbine combinations. This arrangement allows the possibility of increased power output by placing a second combustor between turbine spools. Such a combustor is called an “Intermediate Turbine Burner, ITB,” and in a twin spool turbofan engine the combustor would be placed between the discharge of the high pressure turbine and the entrance of the low pressure turbine. An evaluation of the mechanical design of an ITB integrated into a low bypass ratio mixed flow turbofan is the subject of this paper. It is well known that an engine with an ITB has increased specific thrust but at the expense of increased specific fuel consumption. To take advantage of the ITB potential, the choice of cycle parameters — fan pressure ratio, overall pressure ratio and bypass ratio must be evaluated, and recent studies have demonstrated that the turbofan cycle with an ITB should have increased fan and overall pressure ratios to maximize performance. However, little has been done to estimate the weight and dimensions of an ITB integrated engine including the weight, flow path area and length of the ITB. Of particular concern are the volume and resulting flow path area and length required for the ITB.

Active fault tolerant control of turbofan engines with actuator faults under disturbances

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Yan-Hua Ma ◽  
Xian Du ◽  
Lin-Feng Gou ◽  
Si-Xin Wen
Keyword(s):  
Active Fault ◽  
Fault Tolerant ◽  
Fault Tolerant Control ◽  
Feedback Controller ◽  
Actuator Faults ◽  
Error Feedback ◽  
Turbofan Engine ◽  
Turbofan Engines ◽  
Interval Observer ◽  
State Error

AbstractIn this paper, an active fault-tolerant control (FTC) scheme for turbofan engines subject to simultaneous multiplicative and additive actuator faults under disturbances is proposed. First, a state error feedback controller is designed based on interval observer as the nominal controller in order to achieve the model reference rotary speed tracking control for the fault-free turbofan engine under disturbances. Subsequently, a virtual actuator based reconfiguration block is developed aiming at preserving the consistent performance in spite of the occurrence of the simultaneous multiplicative and additive actuator faults. Moreover, to improve the performance of the FTC system, the interval observer is slightly modified without reconstruction of the state error feedback controller. And a theoretical sufficiency criterion is provided to ensure the stability of the proposed active FTC system. Simulation results on a turbofan engine indicate that the proposed active FCT scheme is effective despite of the existence of actuator faults and disturbances.

scholarly journals DDxNet: a deep learning model for automatic interpretation of electronic health records, electrocardiograms and electroencephalograms

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jayaraman J. Thiagarajan ◽  
Deepta Rajan ◽  
Sameeksha Katoch ◽  
Andreas Spanias
Keyword(s):  
Electronic Health Records ◽  
Rapid Development ◽  
Benchmark Problems ◽  
Health Records ◽  
Automatic Interpretation ◽  
Deep Architecture ◽  
Significant Performance ◽  
Electronic Health ◽  
Improving Accuracy ◽  
Performance Gains

Abstract Effective patient care mandates rapid, yet accurate, diagnosis. With the abundance of non-invasive diagnostic measurements and electronic health records (EHR), manual interpretation for differential diagnosis has become time-consuming and challenging. This has led to wide-spread adoption of AI-powered tools, in pursuit of improving accuracy and efficiency of this process. While the unique challenges presented by each modality and clinical task demand customized tools, the cumbersome process of making problem-specific choices has triggered the critical need for a generic solution to enable rapid development of models in practice. In this spirit, we develop DDxNet, a deep architecture for time-varying clinical data, which we demonstrate to be well-suited for diagnostic tasks involving different modalities (ECG/EEG/EHR), required level of characterization (abnormality detection/phenotyping) and data fidelity (single-lead ECG/22-channel EEG). Using multiple benchmark problems, we show that DDxNet produces high-fidelity predictive models, and sometimes even provides significant performance gains over problem-specific solutions.

First and Second Law Analysis of Intercooled Turbofan Engine

2015 ◽  
Vol 138 (2) ◽  
Author(s):  
Xin Zhao ◽  
Oskar Thulin ◽  
Tomas Grönstedt
Keyword(s):  
High Pressure ◽  
Conceptual Design ◽  
Exergy Analysis ◽  
Second Law ◽  
Turbofan Engine ◽  
Blade Height ◽  
Turbofan Engines ◽  
Fuel Burn ◽  
Aero Engine ◽  
Last Stage

Although the benefits of intercooling for aero-engine applications have been realized and discussed in many publications, quantitative details are still relatively limited. In order to strengthen the understanding of aero-engine intercooling, detailed performance data on optimized intercooled (IC) turbofan engines are provided. Analysis is conducted using an exergy breakdown, i.e., quantifying the losses into a common currency by applying a combined use of the first and second law of thermodynamics. Optimal IC geared turbofan engines for a long range mission are established with computational fluid dynamics (CFD) based two-pass cross flow tubular intercooler correlations. By means of a separate variable nozzle, the amount of intercooler coolant air can be optimized to different flight conditions. Exergy analysis is used to assess how irreversibility is varying over the flight mission, allowing for a more clear explanation and interpretation of the benefits. The optimal IC geared turbofan engine provides a 4.5% fuel burn benefit over a non-IC geared reference engine. The optimum is constrained by the last stage compressor blade height. To further explore the potential of intercooling the constraint limiting the axial compressor last stage blade height is relaxed by introducing an axial radial high pressure compressor (HPC). The axial–radial high pressure ratio (PR) configuration allows for an ultrahigh overall PR (OPR). With an optimal top-of-climb (TOC) OPR of 140, the configuration provides a 5.3% fuel burn benefit over the geared reference engine. The irreversibilities of the intercooler are broken down into its components to analyze the difference between the ultrahigh OPR axial–radial configuration and the purely axial configuration. An intercooler conceptual design method is used to predict pressure loss heat transfer and weight for the different OPRs. Exergy analysis combined with results from the intercooler and engine conceptual design are used to support the conclusion that the optimal PR split exponent stays relatively independent of the overall engine PR.

Advanced Turbofan Engines for Low Fuel Consumption

1978 ◽  
Author(s):  
William Sens
Keyword(s):  
Fuel Consumption ◽  
Advanced Technology ◽  
Commercial Aircraft ◽  
New Production ◽  
Turbofan Engine ◽  
Fuel Savings ◽  
Turbofan Engines ◽  
Aircraft Fuel ◽  
Design Characteristics ◽  
Year 2000

The anticipated commercial aircraft fuel usage through the year 2000 is divided into three categories: that which will be consumed by existing engines, new production of current type engines, and new turbofan engines with advanced technology. Means of improving fuel consumption of each of these engine categories will be reviewed and the potential fuel savings identified. The cycle selection and design characteristics of an advanced turbofan engine configuration will be discussed and the potential improvements in fuel consumption and economics identified.

Simulation of a Floating Offshore Wind Turbine With an Integrated Response Mitigation Technology

2018 ◽  
Author(s):  
Christopher K. Allen ◽  
Andrew J. Goupee ◽  
Jeffrey Lindner ◽  
Robert Berry
Keyword(s):  
Offshore Wind ◽  
Offshore Wind Turbine ◽  
The Novel ◽  
Mass Reduction ◽  
Turbine Performance ◽  
Additional Equipment ◽  
Significant Performance ◽  
Integrated Response ◽  
The University ◽  
Performance Gains

This work investigates the implementation of a novel, NASA-developed Fluid Harmonic Absorber (FHA) technology to mitigate platform motions and structural loads that can lead to lighter platforms, increased turbine performance, and ultimately, a lower LCOE. The novel damping strategy takes advantage of existing water ballast in the VolturnUS semi-submersible platform to achieve significant performance gains with minimal additional equipment and complexity. NREL’s FOWT software FAST is modified to include the primary features of the FHA technology. A study of the University of Maine-developed VolturnUS semi-submersible FOWT augmented with FHA technology is undertaken to quantify global performance of the system. When compared to the baseline technology, numerical simulations of a redesigned platform utilizing the FHA dampers indicate a reduction of 15.8% in hull structural material. Finally, the improvements in LCOE resulting from this mass reduction are assessed to demonstrate the advantages of NASA’s FHA technology for FOWT applications.

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