Internally Generated Noise From Gas Turbine Engines. Measurement and Prediction

1967 ◽  
Vol 89 (2) ◽  
pp. 177-185 ◽  
Author(s):  
M. J. T. Smith ◽  
M. E. House
Keyword(s):  
Gas Turbine ◽  
Full Scale ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Test Results ◽  
Radiation Patterns ◽  
Noise Sources ◽  
Prediction Technique ◽  
Noise Measurements ◽  
Engine Compressor

The noise sources from gas turbine engines are defined and their radiation patterns identified from test results. Examination of single-stage and full-scale engine compressor noise measurements leads to a prediction technique being evolved for inlet and efflux levels.

On-Line Detergent Washing: Reducing the Environmental Effects on the LCAC Gas Turbine Engines

1992 ◽  
Author(s):  
Jeffrey S. Patterson ◽  
Soren K. Spring
Keyword(s):  
Gas Turbine ◽  
Systems Engineering ◽  
Present Method ◽  
Engine Performance ◽  
Turbine Engines ◽  
Harsh Environment ◽  
Gas Turbine Engines ◽  
Test Results ◽  
On Line ◽  
Air Cushion

The Landing Craft Air Cushion (LCAC) gas turbine engines operate in an extremely harsh environment and are exposed to excessive amounts of foreign contaminants. The present method of crank washing is effective when properly performed, but is labor intensive and increases craft downtime. Naval Ship Systems Engineering Station (NAVSSES) designed and installed a prototype on-line detergent wash system which reduced maintenance and craft downtime. Initial test results indicated that the system reduced engine performance degradation and corrosion.

scholarly journals Calculation of a 3D turbulent flow in aircraft gas turbine engine ducts

2020 ◽  
Vol 2020 (4) ◽  
pp. 65-71
Author(s):  
Yu.A. Kvasha ◽  
Keyword(s):  
Numerical Simulation ◽  
Turbulent Flow ◽  
Gas Turbine ◽  
Gas Flow ◽  
Turbine Engines ◽  
Gas Flows ◽  
Gas Turbine Engines ◽  
Compressor Inlet ◽  
Air Intake ◽  
Engine Compressor

This work is devoted to the development of approaches to the numerical simulation of 3D turbulent gas flows in different ducts of aircraft gas turbine engines, in particular in inlet device ducts. Inlet devices must provide large values of the total pressure recovery factor and flow uniformity at the engine compressor inlet. The aim of this work is the verification of the operability of a technique developed earlier for the calculation of the parameters of a 3D turbulent flow in complex-shape ducts. The basic approach is a numerical simulation of 3D turbulent gas flows on the basis of the complete averaged Navier¬–Stokes equations and a two-parameter turbulence model. The proposed technique of numerical simulation of a 3D gas flow was tested by calculating a 3D laminar flow in a square pipe bent at a right angle. The calculated flow pattern is in satisfactory agreement with the experimental data on the flow structure in a pipe elbow reported in the literature. Based on a numerical simulation of a 3D turbulent flow in the air duct of one of the air intake configurations for an aircraft turboprop engine, the efficiency of that configuration is assessed. The calculated flow parameter nonuniformity at the air intake outlet, i. e., at the compressor inlet, is compared with that obtained earlier for another air intake configuration for the same engine. It is pointed out that the air intake configuration considered earlier provides a much more uniform flow parameter distribution at the engine compressor inlet. On the whole, this work shows that the quality of subsonic air intakes for aircraft gas turbine engines can be assessed using the proposed numerical technique of 3D gas flow simulation. The results obtained may be used in the aerodynamic improvement of inlet devices for aircraft engines of different types.

Relight Envelope of a Military Gas Turbine Engine: An Experimental Study

2008 ◽  
Author(s):  
R. K. Mishra ◽  
G. Gouda ◽  
B. S. Vedaprakash
Keyword(s):  
Gas Turbine ◽  
Fuel Injection ◽  
Full Scale ◽  
Test Facility ◽  
Turbine Engines ◽  
Engine Fuel ◽  
Gas Turbine Engines ◽  
Turbine Engine ◽  
Start Up

A twin spool low bypass turbofan engine under development and its combustor in full-scale were tested independently at altitude conditions to establish the relight envelope of the engine. Demonstration of relight capability and defining its boundary are mandatory for military gas turbine engines and for single engine application in particular. The engine was first subjected to windmill to establish its windmilling characteristics. The full engine was then tested for light-off in an altitude test facility simulating windmilling conditions from 4 to 12 km altitude with flight Mach numbers from 0.2 to 1.0. The relight boundary is defined based on the successful light-off points achieved from engine tests. Similar tests were carried out on the full-scale combustion chamber in a stand-alone mode simulating altitude conditions at engine flame-out. The combustor test has defined the light-off and lean blow out limits of the at each point on the relight boundary. The information of fuel-air ratio at light-off and blow-out is very useful in setting the engine fuel schedule for altitude operation and relight. In this paper an attempt is made to highlight various tests carried out on engine and its combustor to define the relight boundary of the engine. The paper also emphasizes the experience of combustor development and associated problems in meeting the relight challenges of military engines. These problems include the necessity of higher fuel-air ratio at high altitudes, the role of additional localized fuel injection through start-up atomizers, and effect of single igniter on relight characteristics. The relight envelope demonstrated by the engine is very satisfactory to meet the first flight requirement where the flight mission generally concentrate in the zone of 0.6 to 0.8 Mach and altitude does not exceed 10 to 12 km. Combustor and atomizer modification is needed to improve relight performance and to shift the boundary to further left.

scholarly journals Why an Engine Air Particle Separator (EAPS)?

1990 ◽  
Author(s):  
Joe Thomas Potts
Keyword(s):  
Gas Turbine ◽  
Volcanic Ash ◽  
Vortex Generator ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Test Results ◽  
Turbine Engine ◽  
Industrial Pollutants ◽  
Air Intake ◽  
Particle Separator

The purpose of this technical paper is to describe how an Engine Air Particle Separator (EAPS) removes contaminant particles before they enter the gas turbine engine. Gas turbine engines perform poorly in air containing sand, volcanic ash, industrial pollutants, etc. Typical dirt related gas turbine malfunctions include: • Erosion of the engine and air cycle machinery rotating components. • Clogging and fouling of turbine section. • Wear of oil wetted components caused by contaminated lubricants. Contaminated air entering an EAPS is sent through a swirling motion induced by the vortex generator. This swirling motion causes the heavier dirt particles and water droplets to be thrown radially outward by centrifugal force so that they may be scavenged from the engine air intake. This report will provide test results of helicopters with and without EAPS and describes the steps necessary to design an EAPS for various air vehicles and engines.

scholarly journals The Evaluation of Fuel Property Effects on Air Force Gas Turbine Engines Program Genesis

1981 ◽  
Author(s):  
T. A. Jackson
Keyword(s):  
Gas Turbine ◽  
Air Force ◽  
Fuel Properties ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Test Results ◽  
Fuel Property ◽  
Fuel Nozzle ◽  
Fuel Effects ◽  
System Selection

The Air Force has conducted a series of investigations to quantify the effects of certain fuel properties on the operability and durability of its aircraft gas turbine engines. Initially these efforts were conducted on a small number of engines intended to be representative of the majority of gas turbine engines in the Air Force inventory. The testing was conducted exclusively in rigs representing the combustor and fuel nozzle components of these engines of interest. Test fuels for these programs were primarily blends of hydrocarbons. These test fuels exhibited significant variations in several major fuel properties. Based on results of these evaluations a second generation of test activity in fuel effects area was formulated. Engine system selection was broadened to include more considerations. Test fuels were reduced in number and priorities for modification of certain fuel properties were adjusted. This paper presents dominant test results of early fuel effects programs and supplemental background which dictated the structure of the second, more comprehensive program.

Development and Demonstration of a Stability Management System for Gas Turbine Engines

2006 ◽  
Author(s):  
D. Christensen ◽  
P. Cantin ◽  
D. Gutz ◽  
P. N. Szucs ◽  
A. R. Wadia ◽  
...  
Keyword(s):  
Real Time ◽  
Gas Turbine ◽  
Management System ◽  
Full Scale ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Engine Test ◽  
Aerodynamic Stability ◽  
The Stability ◽  
Rapid Transients

Rig and engine test processes and in-flight operation and safety for modern gas turbine engines can be greatly improved with the development of accurate on-line measurement to gauge the aerodynamic stability level for fans and compressors. This paper describes the development and application of a robust real time algorithm for gauging fan/compressor aerodynamic stability level using over-the-rotor dynamic pressure sensors. This real time scheme computes a correlation measure through signal multiplication and integration. The algorithm uses the existing speed signal from the engine control for cycle synchronization. The algorithm is simple and is implemented on a portable computer to facilitate rapid realtime implementation on different experimental platforms as demonstrated both on a full-scale high-speed compressor rig and on an advanced aircraft engine. In the multi-stage advanced compressor rig test, the compressor was moved toward stall at constant speed by closing a discharge valve. The stability management system was able to detect an impending stall and trigger opening of the valve so as to avoid compressor surge. In the full-scale engine test, the engine was configured with a one-per-rev distortion screen and transients were run with a significant amount of fuel enrichment to facilitate stall. Test data from a series of continuous rapid transients run in the engine test showed that in all cases the stability management system was able to detect an impending stall and manipulated the enrichment part of the fuel schedule to provide stall free transients.

scholarly journals NASA Broad-Specification Fuels Combustion Technology Program: Status and Description

1980 ◽  
Author(s):  
J. S. Fear
Keyword(s):  
Gas Turbine ◽  
Jet Fuel ◽  
Full Scale ◽  
Fuel Properties ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Aircraft Engines ◽  
Technology Program ◽  
Current Specification ◽  
Combustion Technology

The use of “broad-specification” fuels in aircraft gas turbine engines can be a significant factor in offsetting anticipated shortages of current-specification jet fuel in the latter part of the century. The changes in fuel properties accompanying the use of broad-specification fuels will tend to cause numerous emissions, performance, and durability problems in currently-designed combustion systems. The NASA Broad-Specification Fuels Combustion Technology Program is a contracted effort to evolve and demonstrate the technology required to utilize broad-specification fuels in current and next generation commercial Conventional Takeoff and Landing (CTOL) aircraft engines, and to verify this technology in full-scale engine tests in 1983. The program consists of three phases: Combustor Concept Screening, Combustor Optimization Testing, and Engine Verification Testing.

Evaluating Complex Inlet Distortion With a Parallel Compressor Model: Part 2—Applications to Complex Patterns

2011 ◽  
Author(s):  
Milt W. Davis ◽  
William T. Cousins
Keyword(s):  
Gas Turbine ◽  
Computer Model ◽  
Ease Of Use ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Test Results ◽  
System Operation ◽  
Minimal Impact ◽  
Compression System ◽  
Inlet Distortion

This paper is the second paper (Part 2) in a companion set and presents results of computer simulations using a parallel compressor model developed with the extended concepts presented in the previous paper (Part 1). The computer model, constructed using the parallel compressor theory with extensions, has been exercised and compared with test results from several gas turbine engines to demonstrate the usefulness of this simulation technique. Distortion patterns used in the tests were created using distortion-generator devices such as distortion screens. A technique to simplify complex distortion patterns through approximate means is presented. This simplification is implemented based upon the flow physics of the compression system, thus allowing the model to better represent the distortion pattern while providing minimal impact on the simulation output and the comparison to the test results. The usefulness of the extended parallel compressor model is demonstrated from its ease of use, simplicity, and ability for quick turn-around of results. Applying a timely analysis capability using the demonstrated parallel compressor model provides an additional physical understanding of the effects of complex distortion on compression system operation.

Gas Turbine Engine Noise

2008 ◽  
Author(s):  
R. Mankbadi
Keyword(s):  
Gas Turbine ◽  
Large Eddy Simulations ◽  
Turbine Engines ◽  
Computational Aeroacoustics ◽  
Gas Turbine Engines ◽  
Sound Generation ◽  
Noise Sources ◽  
Turbine Engine ◽  
Large Eddy ◽  
Radiated Sound

This article discusses the various noise sources associated with gas turbine engines and the computational aeroacoustics techniques used for predicting the aerodynamically-generated sound. Given a sound source, several tools are presented for predicting the corresponding radiated sound. Results for sound-generation mechanism are presented using large- or very-large eddy simulations, as well as other computational means. A brief summary of the main concepts for noise reduction are then presented.

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