A Numerical Simulation Capability for Analysis of Aircraft Inlet-Engine Compatibility

2004 ◽  
Vol 128 (3) ◽  
pp. 473-481 ◽  
Author(s):  
Alan Hale ◽  
Milt Davis ◽  
Jim Sirbaugh
Keyword(s):  
Numerical Simulation ◽  
Computational Approach ◽  
The Other ◽  
Computational Tool ◽  
Additional Insight ◽  
Turbine Engine ◽  
Inlet Distortion ◽  
Full Knowledge ◽  
Engine System ◽  
Isolated Systems

Two primary aircraft propulsion subsystems are the inlet and the engine. Traditionally these subsystems have been designed, analyzed, and tested as isolated systems. The interaction between the subsystems is modeled primarily through evaluating inlet distortion in an inlet test and then simulating this distortion in engine tests via screens or similar devices. Recently, it has been recognized that significant improvements in both performance and operability can be realized when both the inlet and the engine are designed with full knowledge of the other. In this paper, a computational tool called Turbine Engine Analysis Compressor Code is used to evaluate the effect of inlet distortion on a three-stage military fan. This three-stage military fan is further connected to an F-16 inlet and forebody operating at an angle of attack and sideslip to demonstrate the effect of inlet distortion generated by flight maneuvers. The computational approach of simulating an integrated inlet-engine system is expected to provide additional insight over evaluating the components separately.

A Numerical Simulation Capability for Analysis of Aircraft Inlet – Engine Compatibility

2004 ◽  
Author(s):  
Alan Hale ◽  
Milt Davis ◽  
Jim Sirbaugh
Keyword(s):  
Numerical Simulation ◽  
Computational Approach ◽  
The Other ◽  
Computational Tool ◽  
Additional Insight ◽  
Turbine Engine ◽  
Inlet Distortion ◽  
Full Knowledge ◽  
Engine System ◽  
Isolated Systems

Two primary aircraft propulsion subsystems are the inlet and the engine. Traditionally these subsystems have been designed, analyzed, and tested as isolated systems. The interaction between the subsystems is modeled primarily through evaluating inlet distortion in an inlet test and then simulating this distortion in engine tests via screens or similar devices. Recently, it has been recognized that significant improvements in both performance and operability can be realized when both the inlet and the engine are designed with full knowledge of the other. In this paper, a computational tool called Turbine Engine Analysis Compressor Code (TEACC) is used to evaluate the effect of inlet distortion on a three-stage military fan. This three-stage military fan is further connected to an F-16 inlet and forebody operating at an angle of attack and sideslip to demonstrate the effect of inlet distortion generated by flight maneuvers. The computational approach of simulating an integrated inlet-engine system is expected to provide additional insight over evaluating the components separately.

Application of Numerical Analysis Tools for Airframe-Propulsion Integrated Test and Evaluation

2008 ◽  
Author(s):  
Milt W. Davis ◽  
Alan A. Hale ◽  
Charles Vining ◽  
William T. Cousins
Keyword(s):  
Numerical Solutions ◽  
System Development ◽  
Acquisition Process ◽  
Inlet Distortion ◽  
Test And Evaluation ◽  
Integrated Testing ◽  
Ground Test ◽  
Full Knowledge ◽  
Isolated Systems ◽  
Development Center

With increasing emphasis on streamlining the acquisition process, ground-test centers like the Arnold Engineering Development Center (AEDC) are re-evaluating their roles in the development of aerospace systems. Instead of merely providing data from ground-test facilities, the new emphasis challenges AEDC to become a team member that provides knowledge for risk management and decision making during the development and operation of an aerospace system. AEDC has developed an Integrated Test and Evaluation (IT&E) approach to support aerospace system development efforts. Two primary aircraft propulsion subsystems are the inlet and the engine. Traditionally these subsystems have been designed, analyzed, and tested as isolated systems although some integrated testing has been performed. The interaction between the subsystems is modeled primarily through evaluating inlet distortion in an inlet test and then simulating this distortion in engine tests via screens or similar devices. Recently, it has been recognized that significant improvements in both performance and operability can be realized when both the inlet and the engine are designed, tested and analyzed with full knowledge of the other. To aid in the airframe-propulsion integration process, numerical solutions of the forebody-inlet and engine compression system have been coupled and partially demonstrated in a limited manner to show the potential for enhancing the acquisition process.

Numerical Simulation and Analysis of Compartment Fire in Subway Train

2012 ◽  
Vol 166-169 ◽  
pp. 2726-2730
Author(s):  
Bo Si Zhang ◽  
Shou Xiang Lu
Keyword(s):  
Numerical Simulation ◽  
Transport System ◽  
Fire Safety ◽  
Urban Transport ◽  
The Other ◽  
Compartment Fire ◽  
Fire Simulation ◽  
Subway Train ◽  
Simulation Time

Subway plays an important role in urban transport system. Fire as the major risk of the subway, is gaining increasing concern. In this study, fire simulation is performed to estimate fire safety of different compartments of the subway train. Result shows that the two compartments in the middle become dangerous at 150s and the compartments in the two ends are not safe at 300s approximately. The other two compartments are always safe during the simulation time.

Contrast Study on the Radial Velocity of the Flow Field of the Hydrocyclones with Different Inlet Structures

2011 ◽  
Vol 339 ◽  
pp. 624-629
Author(s):  
Lian Cheng Ren ◽  
Zheng Liang ◽  
Jiang Meng ◽  
Lin Yang ◽  
Jia Lin Tian
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Radial Velocity ◽  
Axial Symmetry ◽  
Separation Efficiency ◽  
Great Influence ◽  
The Other ◽  
Contrast Study ◽  
The One ◽  
Tangential Inlet

On the base of numerical simulation and theoretical analysis, the flow field of a conventional single-tangential-inlet Hydrocyclone and a newly put forward axial-symmetry double-tangential-inlet hydrocyclone were contrasted. The study shows that the inlet structure of the Hydrocylone has a great influence on the radial velocity of the flow field in the hydrocyclone and that the radial velocity in the hydrocyclone with single-tangential-inlet is not symmetry about the axis of the hydrocyclone; and on the other hand the radial velocity in the hydrocyclone with axial-symmetry double-tangential-inlet is symmetry about the axis of the hydrocyclone. The magnitude of the radial velocity of the flow in the hydrocyclone with single-tangential-inlet is greater than that in the hydrocyclone with axial-symmetry double-tangential-inlet hydrocyclone, which means the hydrocyclone with axial-symmetry double-tangential-inlet has greater capability than the rival one with single-tangential inlet. The symmetry about the axis of the hydrocyclone of the radial velocity means the radial velocities in the place where the radio is the same are constant, which means the hydrocyclone has a great separation efficiency. The conclusion is that changing the conventional hydrocyclone into the one with axial-symmetry double-tangential-inlet structure can offer greater separation capability and efficiency.

Modeling Recrystallization for 3D Multi-Pass Forming Processes

2007 ◽  
Vol 558-559 ◽  
pp. 1201-1206 ◽  
Author(s):  
Mihaela Teodorescu ◽  
Patrice Lasne ◽  
Roland E. Logé
Keyword(s):  
Numerical Simulation ◽  
Grain Size ◽  
Present Model ◽  
Static Recrystallization ◽  
Volume Fraction ◽  
The Other ◽  
Finite Element Code ◽  
3D Numerical Simulation ◽  
Fraction Distribution ◽  
Simulation Results

The present work concerns the simulation of metallurgical evolutions in 3D multi-pass forming processes. In this context, the analyzed problem is twofold. One point refers to the management of the microstructure evolution during each pass or each inter-pass period and the other point concerns the management of the multi-pass aspects (different grain categories, data structure). In this framework, a model is developed and deals with both aspects. The model considers the microstructure as a composite made of a given (discretized) number of phases which have their own specific properties. The grain size distribution and the recrystallized volume fraction distribution of the different phases evolve continuously during a pass or inter-pass period. With this approach it is possible to deal with the heterogeneity of the microstructure and its evolution in multi-pass conditions. Both dynamic and static recrystallization phenomena are taken into account, with typical Avrami-type equations. The present model is implemented in the Finite Element code FORGE2005®. 3D numerical simulation results for a multi-pass process are presented.

Toxæmia in the Etiology of Mental Disease. a Discussion opened

1902 ◽  
Vol 48 (202) ◽  
pp. 434-450 ◽  
Author(s):  
T. S. Clouston
Keyword(s):  
Nerve Cell ◽  
General Trend ◽  
Mental Disease ◽  
The Other ◽  
British Association ◽  
Younger Men ◽  
Full Knowledge ◽  
The Subject ◽  
Definition Of ◽  
Do So

Dr. Clouston said that when he suggested toxæmia to the secretary as a suitable subject for a discussion at this meeting he had not intended to be the first speaker, because his object was to bring out more fully the views of the younger members who had recently committed themselves so strongly to the toxæmic and bacterial etiology of insanity, and so to get light thrown on some of the difficulties which he and others had felt in applying this theory to many of their cases in practice. It was not that he did not believe in the toxic theory as explaining the onset of many cases, or that he under-rated its importance, but that he could not see how it applied so universally or generally as some of the modern pathological school were now inclined to insist on. He knew that it was difficult for those of the older psychological and clinical school to approach the subject with that full knowledge of recent bacteriological and pathological doctrine which the younger men possessed, or to breathe that all-pervading pathological atmosphere which they seemed to inhale. He desired to conduct this discussion in an absolutely non-controversial and purely scientific spirit. To do so he thought it best to put his facts, objections, and difficulties in a series of propositions which could be answered and explained by the other side. He thought it important to define toxæmia, but should be willing to accept Dr. Ford Robertson's definition of toxines, viz., “Substances which are taken up by the (cortical nerve) cell and then disorder its metabolism.” He took the following extracts from his address at the Cheltenham meeting of the British Association (1) as representing Dr. Ford Robertson's views and the general trend of much investigation and hypothesis on the Continent.

A One Dimensional, Time Dependent Inlet / Engine Numerical Simulation for Aircraft Propulsion Systems

1997 ◽  
Author(s):  
Doug Garrard ◽  
Milt Davis ◽  
Steve Wehofer ◽  
Gary Cole
Keyword(s):  
Numerical Simulation ◽  
Gas Turbine ◽  
High Frequency ◽  
Gas Turbine Engine ◽  
Simulation System ◽  
Time Dependent ◽  
Propulsion Systems ◽  
Turbine Engine ◽  
One Dimensional ◽  
Supersonic Inlet

The NASA Lewis Research Center (LeRC) and the Arnold Engineering Development Center (AEDC) have developed a closely coupled computer simulation system that provides a one dimensional, high frequency inlet / engine numerical simulation for aircraft propulsion systems. The simulation system, operating under the LeRC-developed Application Portable Parallel Library (APPL), closely coupled a supersonic inlet with a gas turbine engine. The supersonic inlet was modeled using the Large Perturbation Inlet (LAPIN) computer code, and the gas turbine engine was modeled using the Aerodynamic Turbine Engine Code (ATEC). Both LAPIN and ATEC provide a one dimensional, compressible, time dependent flow solution by solving the one dimensional Euler equations for the conservation of mass, momentum, and energy. Source terms are used to model features such as bleed flows, turbomachinery component characteristics, and inlet subsonic spillage while unstarted. High frequency events, such as compressor surge and inlet unstart, can be simulated with a high degree of fidelity. The simulation system was exercised using a supersonic inlet with sixty percent of the supersonic area contraction occurring internally, and a GE J85-13 turbojet engine.

Numerical Simulation Research on the Shape of Top Coal Drawn-Body in Gently Inclined Seam

2012 ◽  
Vol 468-471 ◽  
pp. 2248-2254
Author(s):  
Qiang Li ◽  
Wan Kui Bu ◽  
Hui Xu ◽  
Xiao Bo Song
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Random Medium ◽  
Body Movement ◽  
The Other ◽  
Simulation Research ◽  
Research Results ◽  
Shape Equation ◽  
The Difference ◽  
Meso Scale

The numerical model of top coal drawing in gently inclined seam is built based on PFC2d software. By comparing with the theory of drawn-body movement law, it can be obtained that the shape of top coal drawn-body accords with the theory of random medium movement. The research results show that the form of the shape equation of top coal drawn-body is uniform while the top coal caving angle is different. On the other hand, with the difference of top coal caving angle and drawing height, the shape of top coal drawn-body is differential at the meso scale, which depends on the parameters of the shape equation of top coal drawn-body.

Numerical Investigation of Effect of Inlet Distortion on Compressor Flow Field and Stability

2017 ◽  
Author(s):  
HaoGuang Zhang ◽  
Kang An ◽  
Feng Tan ◽  
YanHui Wu ◽  
WuLi Chu
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Total Pressure ◽  
Tip Clearance ◽  
Numerical Work ◽  
Stall Margin ◽  
Numerical Investigations ◽  
Inlet Distortion ◽  
Compressor Rotor ◽  
The Stability

The compressor aerodynamic design is conducted under the condition of clean inlet in general, but a compressor often operates under the condition of inlet distortion in the practical application. It has been proven by a lot of experimental and numerical investigations that inlet distortion can decrease the performance and stability of compressors. The circumferential or radial distorted inlet in mostly numerical investigations is made by changing the total pressure and total temperature in the inlet ring surface of the compressors. In most of inlet distortion experiments, distorted inlets are usually created by using wire net, flashboards, barriers or the generator of rotating distortion. The fashion of generating distorted inlet for experiment is different from that for numerical simulation. Consequently, the flow mechanism of affecting the flow field and stability of a compressor with distorted inlet for experiment is partly different than that for numerical simulation. In the numerical work reported here, the inlet distortion is generated by setting some barriers in the inlet ring surface of an axial subsonic compressor rotor. Two kinds of distorted inlet are investigated to exploring the effect of distorted range on the flow field and stability of the compressor with ten-passage unsteady numerical method. The numerical results show that the inlet distortions not only degrade the total pressure and efficiency of the compressor rotor, but also decrease the stability of the rotor. The larger the range of distorted inlet is, the stronger the adverse effect is. The comprehensive stall margin for the inlet distortion of 24 degrees and 48 degrees of ten-passages is reduced about 3.35% and 5.88% respectively. The detailed analysis of the flow field in the compressor indicates that the blockage resulted from tip clearance leakage vortex (TLV) and the flow separation near the suction surfaces of some blades tip for distorted inlet is more serious than that resulted from TLV for clean inlet. Moreover, the larger the range of distorted inlet is, the larger the range of the blockage is. The analysis of unsteady flow shows that during this process, which is that one rotor blade passes through the region affected by the distorted inlet, the range of the blockage in the rotor passage increases first, then reduces, and increases last.

scholarly journals Robust-Output-Controlled Synchronization Strategy for Arrays of Pancreatic β-Cells

Complexity ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
David I. Rosas Almeida ◽  
Laura O. Orea Leon
Keyword(s):  
Numerical Simulation ◽  
Sliding Mode ◽  
Active Cell ◽  
The Other ◽  
Β Cells ◽  
Pancreatic Β Cells ◽  
Reference Cell ◽  
The Difference ◽  
Synchronization Scheme ◽  
Second Order Sliding Mode

This paper presents a synchronization strategy based on second-order sliding mode control, to obtain robust controlled synchronization in an array of uncertain pancreatic β-cells. This strategy considers a synchronization scheme with a reference cell, which incorporates the desired dynamics, and an array of cells, which does not demonstrate adequate synchronization. The array may be formed by active and inactive cells having different strengths in gap junctions. For an array with three cells, we design the coupling signal considering that only the output of an active cell of the array is available. The coupling signal is the signum of the difference between the output of the reference cell and the output of an active cell in the array; this ensures exact synchronization in finite time between both cells. Then, this coupling signal is applied to the other cells in the array, and we establish the conditions required to be satisfied to obtain approximate synchronization between the reference cell and all other cells in the array. The performance of this technique is demonstrated by the results of numerical simulations performed for several cases of connections for an array with three cells and the reference cell. Finally, we show through a numerical simulation that this technique can be applied to arrays with many β-cells.

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