Frequency response of a jet engine test facility air supply system

Author(s):  
M. FRANKE ◽  
M. ROSS
Author(s):  
Yang Ji Lee ◽  
Sang Hun Kang ◽  
Soo Seok Yang

Korea Aerospace Research Institute started on design and development of a hypersonic air-breathing engine test facility from 2000 and completed the test facility installation in July 2009. This facility, designated as the Scramjet engine test facility (SETF), is a blow-down type high enthalpy wind tunnel which has a pressurized air supply system, air heater system, free-jet type test chamber, fuel supply system, facility control/measurement system, and exhaust system with an air ejection. Unlike most aerodynamic wind-tunnel, SETF should simulate the enthalpy condition at a flight condition. To attain a flight condition, a highly stagnated air comes into the test cell through a supersonic nozzle. Also, an air ejector of the SETF is used for simulating altitude conditions of the engine, and facility starting. SETF has a storage air heater (SAH) type heating system. This SAH can supply a hot air with a maximum temperature of 1300K. Using the SAH, SETF can achieve the Mach 5.0 flight at an altitude of 20 km condition. SETF has a free-jet type test cell and this free-jet type test cell can simulate a boundary layer effect between an airplane and engine using the facility nozzle, but it is too difficult to predict the nature of the facility. Therefore it is required to understand the starting characteristics of the facility by experiments. In 2009, a Mach 3.5 test of SETF was done for acceptance testing which is a maximum air supply condition of 20 kg/s. SETF showed the facility efficiency of a 100% without a test model at the Mach 3.5 condition. In 2010, a Mach 6.7 aerodynamic test campaign with a scramjet engine intake. But SETF could not start at the Mach 6.7 condition with the existing ejector system at that time. To get a facility starting, we modified the ejector system. After modification of the ejector system, SETF started at the Mach 6.7 condition with a facility efficiency of 58%. In this paper, the starting characteristics of the SETF with various flight conditions, and modifications of the ejector system will be described.


1998 ◽  
Author(s):  
Robert Engers ◽  
John Erdos ◽  
William Swartwout ◽  
Nicholas Tilakos

Author(s):  
Matthew P. Dawson ◽  
Dara W. Childs ◽  
Christopher G. Holt ◽  
Stephen G. Phillips

An experimental facility and apparatus are described for measuring the dynamic impedance and leakage characteristics of annular gas seals. The apparatus currently has a top speed of 29,800 rpm and can accommodate seal diameters up to 114.3 mm. The air-supply system can provide up to 13.79 MPa (2,000 psi) of pressure at the seal inlet. Test seals are configured in a back-to-back arrangement inside the stator and air enters a central inlet annulus at two opposed radial positions. Labyrinth seals and bleed ports located outboard of each test seal are used to control the pressure drop across the test seals. Two orthogonal, external hydraulic shakers are used to excite the test stator at frequencies up to 400 Hz. At a given operating condition, the apparatus can measure the rotordynamic impedance of a pair of identical seals over a broad frequency range using a single pseudo-random excitation waveform. Measurements are also made of seal leakage rates and upstream and downstream temperatures and pressures.


2002 ◽  
Vol 124 (4) ◽  
pp. 958-962 ◽  
Author(s):  
M. P. Dawson ◽  
D. W. Childs ◽  
C. G. Holt ◽  
S. G. Phillips

An experimental facility and apparatus are described for measuring the dynamic impedance and leakage characteristics of annular gas seals. The apparatus currently has a top speed of 29,800 rpm and can accommodate seal diameters up to 114.3 mm. The air-supply system can provide up to 13.79 MPa (2000 psi) of pressure at the seal inlet. Test seals are configured in a back-to-back arrangement inside the stator and air enters a central inlet annulus at two opposed radial positions. Labyrinth seals and bleed ports located outboard of each test seal are used to control the pressure drop across the test seals. Two orthogonal, external hydraulic shakers are used to excite the test stator at frequencies up to 400 Hz. At a given operating condition, the apparatus can measure the rotordynamic impedance of a pair of identical seals over a broad frequency range using a single pseudo-random excitation waveform. Measurements are also made of seal leakage rates and upstream and downstream temperatures and pressures.


Author(s):  
R Holmes ◽  
M M Dede

This paper describes a test facility which reproduces the essential features of a twin-rotor assembly for a medium-size jet engine. Its purpose is to investigate phenomena experienced in an actual engine, which relate to system non-linearities. These phenomena include subharmonics, combination oscillations and jumps in frequency response. All such phenomena manifested themselves in the test facility and explanations are given as to their cause and possible elimination.


Author(s):  
Peter Montgomery ◽  
Rick Burdette ◽  
Jason Klepper ◽  
Al Milhoan

Meeting the test needs of future aircraft systems is the driving goal behind Arnold Engineering Development Center’s (AEDC) ongoing programs of turbine engine test facility modernization, improvement, consolidation, and streamlining. This paper will discuss the evolution of the AEDC J2 turbine engine test cell, its conditioned air supply system, and other related systems with emphasis on how modeling and simulation played a vital role throughout the evolutionary process. Modeling and simulation was used for the analysis of potential design changes, the coding and checkout of control system changes, as well as to improve control system performance and increase overall facility capabilities. These changes began under the Test Operations Modernization and Improvement Program (TOMIP) and continue today in the Propulsion Consolidation and Streamlining Program (PC&S). Already significant improvements have been made in facility capability, and these along with the steps still to come in the near future will be discussed as a turbine engine test facility continues to evolve to meet the test needs of tomorrow’s aircraft systems.


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