scholarly journals A Method of Sizing Multi-Cycle Engines for Hypersonic Aircraft

1990 ◽  
Vol 112 (2) ◽  
pp. 217-222
Author(s):  
J. J. Kolden
Keyword(s):  
Iterative Procedure ◽  
Engine Performance ◽  
Computer Code ◽  
Propulsion System ◽  
Hypersonic Vehicles ◽  
Trade Off ◽  
Hypersonic Aircraft ◽  
Engine Size ◽  
Engine Cycle

A method of sizing multi-cycle engines for integration with hypersonic vehicles has been developed. The new procedure independently sizes the inlet, each engine cycle, and the nozzle during the vehicle sizing loop to optimize propulsion/aircraft integration. Using uninstalled engine performance for each cycle of a multi-cycle engine along with inlet and nozzle performance and an estimate of aircraft drag, an iterative procedure is utilized to size each component simultaneously. A propulsion system is defined that meets the aircraft thrust requirements at all mission points. The inlet is sized to provide airflow such that the maximum Mach cruise and/or combat thrust conditions are met. Each cycle is sized independently to meet all thrust requirements while minimizing either inlet drag or engine size. Nozzle sizing must trade off thrust, drag and nozzle weight. This methodology has been incorporated into a computer code entitled “Multi-Cycle Engine Sizing Program,” MCESP.

scholarly journals A Method of Sizing Multi-Cycle Engines for Hypersonic Aircraft

1989 ◽  
Author(s):  
Jennifer J. Kolden
Keyword(s):  
Iterative Procedure ◽  
Engine Performance ◽  
Computer Code ◽  
Propulsion System ◽  
Hypersonic Vehicles ◽  
Trade Off ◽  
Hypersonic Aircraft ◽  
Engine Size ◽  
Engine Cycle

A method of sizing multi-cycle engines for integration with hypersonic vehicles has been developed. The new procedure independently sizes the inlet, each engine cycle, and the nozzle during the vehicle sizing loop to optimize propulsion/aircraft integration. Using uninstalled engine performance for each cycle of a multi-cycle engine along with inlet and nozzle performance and an estimate of aircraft drag, an iterative procedure is utilized to size each component simultaneously. A propulsion system is defined that meets the aircraft thrust requirements at all mission points. The inlet is sized to provide airflow such that the maximum Mach cruise and/or combat thrust conditions are met. Each cycle is sized independently to meet all thrust requirements while either minimizing inlet drag or engine size. Nozzle sizing must trade-off thrust, drag and nozzle weight. This methodology has been incorporated into a computer code entitled “Multi-Cycle Engine Sizing Program”, MCESP.

Implementation of Engine Loss Analysis Methods in the Numerical Propulsion System Simulation

2005 ◽  
Author(s):  
Bryce A. Roth ◽  
Erin M. McClure ◽  
Travis W. Danner
Keyword(s):  
System Simulation ◽  
Engine Performance ◽  
General Purpose ◽  
Propulsion System ◽  
Accurate Estimation ◽  
Analysis Tool ◽  
Cycle Model ◽  
Loss Analysis ◽  
Analysis Methods ◽  
Engine Cycle

This paper describes the implementation and application of a new set of thermodynamic loss analysis tools in the Numerical Propulsion System Simulation. This analysis tool set is intended to enable fast, accurate estimation of losses in an engine cycle model with minimal effort on the part of the user. The basic thermodynamic concepts and analysis methods are first described. Next, the implementation of the necessary thermodynamic calculation functions is described. These functions are intended to be used in conjunction with a general-purpose loss analysis element to facilitate estimation of all losses in an engine cycle model. The loss analysis element is described in detail and is subsequently used to analyze a mixed flow turbofan engine. Typical performance and loss results are presented. The resultant detailed loss information is not normally available when using standard cycle analysis methods. The information gained from this analysis is useful in that it yields insight into the underlying losses that contribute to the overall engine performance.

Integration of Turbo-Expander and Turbo-Ramjet Engines in Hypersonic Vehicles

1994 ◽  
Vol 116 (1) ◽  
pp. 90-97 ◽  
Author(s):  
B. Zellner ◽  
W. Sterr ◽  
O. Herrmann
Keyword(s):  
System Performance ◽  
Combined Cycle ◽  
Propulsion System ◽  
Hypersonic Vehicles ◽  
Performance Simulation ◽  
Hypersonic Aircraft ◽  
High Speeds ◽  
University Of Munich ◽  
Turbo Expander ◽  
Ramjet Engines

Turbo-expander-ramjet and turbo-ramjet are two engine concepts considered for hypersonic aircraft designs with a flight regime between Mach 0 and 7. To establish any performance or integration aspects for these two combined-cycle engine types, an extended study of a variety of influence parameters is necessary, because the interaction between aircraft and propulsion system is even stronger than on conventional aircraft. In fact, the propulsion system is very sensitive to intake and nozzle/afterbody design at these high speeds. This paper presents the engine configurations chosen for comparison and describes the computer program used for the propulsion system performance simulation, including all relevant integration aspects. Furthermore, some results of propulsion system performance for a generic hypersonic aircraft and a typical ascent profile will be compared to indicate the special characteristics of the engines. Finally, some thoughts concerning the suitability and relevant technological requirements of the two engine types—seen from an aircraft manufacturer’s view—are included. The paper includes the results of two diploma theses, written by W. Sterr [1] and B. Zellner [2] at the Technical University of Munich, supervised by Prof. H. Rick (LFA) and O. Herrmann (MBB).

Integration of Turbo-Expander- and Turbo-Ramjet-Engines in Hypersonic Vehicles

1992 ◽  
Author(s):  
B. Zellner ◽  
W. Sterr ◽  
O. Herrmann
Keyword(s):  
Combined Cycle ◽  
Propulsion System ◽  
Hypersonic Vehicles ◽  
Extended Study ◽  
Hypersonic Aircraft ◽  
High Speeds ◽  
Turbo Expander ◽  
Ramjet Engines

Turbo-Expander-Ramjet and Turbo-Ramjet are two engine concepts considered for hypersonic aircraft designs with a flight regime between Mach 0 and 7. To establish any performance or integration aspects for these two combined-cycle engine types, an extended study of a variety of influence parameters is necessary, because the interaction between aircraft and propulsion system is even stronger than on conventional aircraft. In fact, the propulsion system is very sensitive to intake and nozzle/afterbody design at these high speeds.

Steady Performance Measurements of a Turbofan Engine With Inlet Distortions Containing Co- and Counter-Rotating Swirl From an Intake Diffuser for Hypersonic Flight

2000 ◽  
Author(s):  
Norbert R. Schmid ◽  
Dirk C. Leinhos ◽  
Leonhard Fottner
Keyword(s):  
Low Frequency ◽  
Engine Performance ◽  
Propulsion System ◽  
Performance Measurements ◽  
Turbofan Engine ◽  
Frequency Measurements ◽  
Hypersonic Aircraft ◽  
Inhomogeneous Flow ◽  
Left And Right ◽  
Unsteady Performance

The influence of distorted inlet flow on the steady and unsteady performance of a turbofan engine which is a component of an airbreathing combined propulsion system for a hypersonic transport aircraft is reported in this paper. The performance and stability of this propulsion system depends on the behavior of the turbofan engine. The complex shape of the intake duct causes inhomogeneous flow at the engine inlet plane, where total pressure and swirl distortions are present. The S-bend intakes are installed axisymmetrically left and right into the hypersonic aircraft hence generating axisymmetrical mirror inverted flow patterns. Since all turbo engines of the propulsion system have the same direction of rotation, one distortion corresponds to a co-rotating swirl at the low pressure compressor (LPC) inlet while the mirror inverted image counterpart represents a counter-rotating swirl. Therefore the influence of the distortions on the performance and stability of the ‘CO’ and ‘COUNTER’ rotating turbo engine are differing, respectively. Both distortions were generated separately by an appropriate simulator at the inlet plane of a LARZAC 04 engine. The results of low frequency measurements at different engine planes yield the relative variations of thrust and specific fuel consumption and hence the steady engine performance. High frequency measurements were used to investigate the different influence of CO and COUNTER inlet distortions on the development of LPC instabilities.

Steady Performance Measurements of a Turbofan Engine With Inlet Distortions Containing Co- and Counterrotating Swirl From an Intake Diffuser for Hypersonic Flight

2000 ◽  
Vol 123 (2) ◽  
pp. 379-385 ◽  
Author(s):  
Norbert R. Schmid ◽  
Dirk C. Leinhos ◽  
Leonhard Fottner
Keyword(s):  
Low Frequency ◽  
Engine Performance ◽  
Propulsion System ◽  
Performance Measurements ◽  
Turbofan Engine ◽  
Frequency Measurements ◽  
Hypersonic Aircraft ◽  
Inhomogeneous Flow ◽  
Left And Right ◽  
Axisymmetric Mirror

The influence of distorted inlet flow on the steady and unsteady performance of a turbofan engine, which is a component of an air-breathing combined propulsion system for a hypersonic transport aircraft, is reported in this paper. The performance and stability of this propulsion system depend on the behavior of the turbofan engine. The complex shape of the intake duct causes inhomogeneous flow at the engine inlet plane, where total pressure and swirl distortions are present. The S-bend intakes are installed axisymmetrically left and right into the hypersonic aircraft, generating axisymmetric mirror-inverted flow patterns. Since all turbo engines of the propulsion system have the same direction of rotation, one distortion corresponds to a corotating swirl at the low pressure compressor (LPC) inlet while the mirror-inverted image counterpart represents a counterrotating swirl. Therefore the influence of the distortions on the performance and stability of the ‘CO’ and ‘COUNTER’ rotating turbo engine are different. The distortions were generated separately by an appropriate simulator at the inlet plane of a LARZAC 04 engine. The results of low-frequency measurements at different engine planes yield the relative variations of thrust and specific fuel consumption and hence the steady engine performance. High-frequency measurements were used to investigate the different influence of CO and COUNTER inlet distortions on the development of LPC instabilities.

A Flight Simulation Vision for Aeropropulsion Altitude Ground Test Facilities

2005 ◽  
Vol 127 (1) ◽  
pp. 8-17 ◽  
Author(s):  
Milt Davis ◽  
Peter Montgomery
Keyword(s):  
System Performance ◽  
Engine Performance ◽  
Aircraft Engine ◽  
Flight Simulation ◽  
Propulsion System ◽  
Test Facility ◽  
Flight Testing ◽  
Test Environment ◽  
Ground Test ◽  
Aircraft System

Testing of a gas turbine engine for aircraft propulsion applications may be conducted in the actual aircraft or in a ground-test environment. Ground test facilities simulate flight conditions by providing airflow at pressures and temperatures experienced during flight. Flight-testing of the full aircraft system provides the best means of obtaining the exact environment that the propulsion system must operate in but must deal with limitations in the amount and type of instrumentation that can be put on-board the aircraft. Due to this limitation, engine performance may not be fully characterized. On the other hand, ground-test simulation provides the ability to enhance the instrumentation set such that engine performance can be fully quantified. However, the current ground-test methodology only simulates the flight environment thus placing limitations on obtaining system performance in the real environment. Generally, a combination of ground and flight tests is necessary to quantify the propulsion system performance over the entire envelop of aircraft operation. To alleviate some of the dependence on flight-testing to obtain engine performance during maneuvers or transients that are not currently done during ground testing, a planned enhancement to ground-test facilities was investigated and reported in this paper that will allow certain categories of flight maneuvers to be conducted. Ground-test facility performance is simulated via a numerical model that duplicates the current facility capabilities and with proper modifications represents planned improvements that allow certain aircraft maneuvers. The vision presented in this paper includes using an aircraft simulator that uses pilot inputs to maneuver the aircraft engine. The aircraft simulator then drives the facility to provide the correct engine environmental conditions represented by the flight maneuver.

Simulation of the Airflow Characteristics of a Two-Stroke Natural Gas Engine With an Articulated Crank

2003 ◽  
Author(s):  
J. Adair ◽  
A. Kirkpatrick ◽  
D. B. Olsen ◽  
H. Gitano-Briggs
Keyword(s):  
Natural Gas ◽  
Gas Flow ◽  
Computer Code ◽  
Gas Engine ◽  
Natural Gas Engine ◽  
Cylinder Bank ◽  
Pressure Profiles ◽  
Flow Processes ◽  
Maximum Temperatures ◽  
Engine Cycle

The topic of this paper is the simulation of the airflow characteristics of a large bore two stroke natural gas fueled engine. The modeling was performed with the program WAVE, a computer code developed for engine cycle simulations. The engine studied was a four cylinder Cooper GMV engine. This engine has an articulated crankshaft connecting even and odd bank cylinders. Due to the articulation, the even bank cylinders have different piston profiles, port profiles, and compression ratios than the odd bank cylinders. Due to the non-symmetric timing and articulated geometry of the odd and even banks, the gas flow processes are not the same for each cylinder bank. The different manifold and port pressure profiles result in different amounts of trapped mass in the odd and even banks. The even bank is predicted to have a smaller amount of trapped mass and slightly lower trapping and scavenging efficiencies. Finally, the model predicts that the even bank cylinders attain higher maximum temperatures, which would produce increased NOx.

SECONDARY POWER SYSTEM EVALUATIONS FOR ADVANCED AIRCRAFT

1999 ◽  
Vol 23 (1B) ◽  
pp. 117-127
Author(s):  
R. Lykins ◽  
M. Ramalingam ◽  
B. Donovan ◽  
E. Durkin ◽  
J. Beam
Keyword(s):  
Power Systems ◽  
Power System ◽  
Data Transfer ◽  
Engine Performance ◽  
Air Power ◽  
Power Extraction ◽  
Resultant Data ◽  
Shaft Power ◽  
The Impact ◽  
Engine Cycle

A computerized analytical program is being developed to help investigate the impact of power system requirements on aircraft performance. The program has an user interface that operates in MS-EXCEL, linking several subsystems analysis programs for execution and data transfer in the power systems analysis. The program presently includes an encoded propulsion engine cycle code, which allows the inspection of power extraction effects on engine performance. To validate the results of the encoded engine program, a study was conducted to investigate the separate effects of shaft power extraction and pneumatic bleed. The selected engine cycle was that for a standard tactical fighter, with a flight condition of varied altitude (sea level to 40,000 ft) and constant Mach Number (0.9). As expected the resultant data showed that the engine performance was more sensitive to pneumatic bleed than to shaft power extraction. The paper’s efficiency comparisons between shaft power and bleed air power helps indicate the higher efficiency for the power system of a more-electric type aircraft. Present efforts on the analytical interface are to incorporate a fuel thermal management analysis capability.

Exhaust System Gas-Dynamics in Internal Combustion Engines

2006 ◽  
Author(s):  
R. Pearson ◽  
M. Bassett ◽  
P. Virr ◽  
S. Lever ◽  
A. Early
Keyword(s):  
Gas Dynamics ◽  
Internal Combustion Engines ◽  
Engine Performance ◽  
Exhaust System ◽  
Combustion Engines ◽  
Cycle Simulation ◽  
Model Following ◽  
Analytical Tools ◽  
Empirical Approaches ◽  
Engine Cycle

The sensitivity of engine performance to gas-dynamic phenomena in the exhaust system has been known for around 100 years but is still relatively poorly understood. The nonlinearity of the wave-propagation behaviour renders simple empirical approaches ineffective, even in a single-cylinder engine. The adoption of analytical tools such as engine-cycle-simulation codes has enabled greater understanding of the tuning mechanisms but for multi-cylinder engines has required the development of accurate models for pipe junctions. The present work examines the propagation of pressure waves through pipe junctions using shock-tube rigs in order to validate a computational model. Following this the effects of exhaust-system gas dynamics on engine performance are discussed using the results from an engine-cycle-simulation program based on the equations of one-dimensional compressible fluid flow.

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