Measurements Versus Predictions for the Dynamic Impedance of Annular Gas Seals—Part I: Test Facility and Apparatus

2002 ◽  
Vol 124 (4) ◽  
pp. 958-962 ◽  
Author(s):  
M. P. Dawson ◽  
D. W. Childs ◽  
C. G. Holt ◽  
S. G. Phillips
Keyword(s):  
Random Excitation ◽  
Supply System ◽  
Test Facility ◽  
Experimental Facility ◽  
Frequency Range ◽  
Labyrinth Seals ◽  
Dynamic Impedance ◽  
Air Supply ◽  
Gas Seals ◽  
Excitation Waveform

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.

Measurements Versus Predictions for the Dynamic Impedance of Annular Gas Seals: Part 1 — Test Facility and Apparatus

2001 ◽  
Author(s):  
Matthew P. Dawson ◽  
Dara W. Childs ◽  
Christopher G. Holt ◽  
Stephen G. Phillips
Keyword(s):  
Random Excitation ◽  
Supply System ◽  
Test Facility ◽  
Experimental Facility ◽  
Frequency Range ◽  
Labyrinth Seals ◽  
Dynamic Impedance ◽  
Air Supply ◽  
Gas Seals ◽  
Excitation Waveform

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.

Measurements Versus Predictions for the Dynamic Impedance of Annular Gas Seals—Part II: Smooth and Honeycomb Geometries

2002 ◽  
Vol 124 (4) ◽  
pp. 963-970 ◽  
Author(s):  
M. P. Dawson ◽  
D. W. Childs
Keyword(s):  
Control Volume ◽  
Test Facility ◽  
Radial Clearance ◽  
Cell Width ◽  
Volume Model ◽  
Numerical Predictions ◽  
Dynamic Impedance ◽  
Honeycomb Seals ◽  
Gas Seals ◽  
Honeycomb Cell

Results are presented from tests conducted using an experimental test facility to measure the leakage and dynamic impedance of smooth and honeycomb straight-bore annular gas seals. The test seals had a 114.3 mm (4.500 in.) bore with a length-to-diameter ratio of 0.75 and a nominal radial clearance of 0.19 mm (0.0075 in.). The honeycomb cell depth for both seals was 3.10 mm (0.122 in.), and the cell width was 0.79 mm (0.031 in.). Dynamic impedance and leakage measurements are reported using air at three supply pressures out to 1.72 Mpa (250 psi), three speeds out to 20,200 rpm, and exit-to-inlet pressure ratios of 40% and 50%. Comparisons to the predictions from the two-control-volume model of Kleynhans and Childs [1] are of particular interest. This model predicts that honeycomb seals do not fit the conventional frequency independent model for smooth annular gas seals. The experimental results verify this new theory. Numerical predictions from a computer program incorporating the new two-control-volume model of Kleynhans and Childs [1] correlate well with both measured seal leakage and dynamic impedances for the honeycomb seals.

scholarly journals Theory Versus Experiment for the Rotordynamic Coefficients of Annular Gas Seals: Part 1—Test Facility and Apparatus

1986 ◽  
Vol 108 (3) ◽  
pp. 426-431 ◽  
Author(s):  
D. W. Childs ◽  
C. E. Nelson ◽  
C. Nicks ◽  
J. Scharrer ◽  
D. Elrod ◽  
...  
Keyword(s):  
Pressure Ratio ◽  
Excitation Frequency ◽  
Tangential Velocity ◽  
Test Facility ◽  
Rotordynamic Coefficients ◽  
Air Supply ◽  
Theory Versus ◽  
Leakage Characteristics ◽  
Gas Seals ◽  
A Current

A facility and apparatus are described for determining the rotordynamic coefficients and leakage characteristics of annular gas seals. The apparatus has a current top speed of 8000 cpm with a nominal seal diameter of 15.24 cm (6 in.). The air-supply unit yields a seal pressure ratio of approximately 7. The inlet tangential velocity can also be controlled. An external shaker is used to excite the test rotor. The apparatus has the capability to independently calculate all rotordynamic coefficients at a given operating condition with one excitation frequency.

Measurements Versus Predictions for the Dynamic Impedance of Annular Gas Seals: Part 2 — Smooth and Honeycomb Geometries

2001 ◽  
Author(s):  
Matthew P. Dawson ◽  
Dara W. Childs
Keyword(s):  
Control Volume ◽  
Test Facility ◽  
Radial Clearance ◽  
Cell Width ◽  
Volume Model ◽  
Numerical Predictions ◽  
Dynamic Impedance ◽  
Honeycomb Seals ◽  
Gas Seals ◽  
Honeycomb Cell

Results are presented from tests conducted using an experimental test facility to measure the leakage and dynamic impedance of smooth and honeycomb straight-bore annular gas seals. The test seals had a 114.3 mm bore with a length-to-diameter ratio of 0.75 and a nominal radial clearance of 0.19 mm. The honeycomb cell depth for both seals was 3.1 mm, and the cell width was 0.79 mm. Dynamic impedance and leakage measurements are reported using air at three supply pressures out to 1.72 MPa, three speeds out to 20,200 rpm, and exit-to-inlet pressure ratios of 40% and 50%. Comparisons to the predictions from the two-control-volume model of Kleynhans and Childs [1] are of particular interest. This model predicts that honeycomb seals do not fit the conventional frequency independent model for smooth annular gas seals. The experimental results verify this new theory. Numerical predictions from a computer program incorporating the new two-control-volume model of Kleynhans and Childs [1] correlate well with both measured seal leakage and dynamic impedances for the honeycomb seals.

Study for Starting Characteristics of Scramjet Engine Test Facility (SETF)

2012 ◽  
Author(s):  
Yang Ji Lee ◽  
Sang Hun Kang ◽  
Soo Seok Yang
Keyword(s):  
Supply System ◽  
Test Cell ◽  
Test Facility ◽  
Engine Test ◽  
Free Jet ◽  
Air Supply ◽  
Type Test ◽  
Ejector System ◽  
Scramjet Engine ◽  
Starting Characteristics

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.

Thermal and mechanical improvement of the air supply system of a turbocharged piston engine

2021 ◽  
Vol 14 (2) ◽  
pp. 108-114
Author(s):  
Y. M. Brodov ◽  
L. V. Plotnikov ◽  
K. O. Desyatov
Keyword(s):  
Heat Transfer ◽  
Experimental Studies ◽  
Local Heat Transfer ◽  
Supply System ◽  
Scale Model ◽  
Piston Engine ◽  
Intake System ◽  
Gas Dynamic ◽  
Air Supply ◽  
Air Flows

A method of thermomechanical improvement of pulsating air flows in the intake system of a turbocharged piston engine is described. The main objective of this study is to develop a method for suppressing the rate of heat transfer to improve the reliability of a piston turbocharged engine. A brief review of the literature on improving the reliability of piston engines is given. Scientific and technical results were obtained on the basis of experimental studies on a full-scale model of a piston engine. The hot-wire anemometer method was used to obtain gas-dynamic and heatexchange characteristics of gas flows. Laboratory stands and instrumentation facilities are described in the article. The data on gas dynamics and heat exchange of stationary and pulsating air flows in gas-dynamic systems of various configurations as applied to the air supply system of a turbocharged piston engine are presented. A method of thermomechanical improvement of flows in the intake system of an engine based on a honeycomb is proposed in order to stabilize the pulsating flow and suppress the intensity of heat transfer. Data were obtained on the air flow rate and the local heat transfer coefficient both in the exhaust duct of the turbocharger compressor (i.e., without a piston engine) and in the intake system of a supercharged engine. A comparative analysis of the data has been carried out. It was found that the installation of a leveling grid in the exhaust channel of a turbocharger leads to an intensification of heat transfer by an average of 9%. It was found that the presence of a leveling grid in the intake system of a piston engine causes the suppression of heat transfer within 15% in comparison with the baseline values. It is shown that the use of a modernized intake system in a diesel engine increases its probability of failure-free operation by 0.8%. The data obtained can be extended to other types and designs of air supply systems for heat engines.

Odour and VOC confining in large enclosures using air curtains

2001 ◽  
Vol 44 (9) ◽  
pp. 165-171 ◽  
Author(s):  
M. Pavageau ◽  
E.M. Nieto ◽  
C. Rey
Keyword(s):  
Particle Image ◽  
Flow Dynamics ◽  
Leakage Flow ◽  
Experimental Facility ◽  
Tracer Gas ◽  
Air Curtain ◽  
Air Supply ◽  
Leakage Flow Rate ◽  
Image Velocimetry ◽  
Air Tightness

Experiments were conducted on a two stream air-curtain prototype designed for VOC and odour confinement in a truck unloading area. The emphasis was placed on the air supply device. Measurements using tracer gas techniques were performed to assess the effectiveness of the system in terms of air tightness. Leakage flow rate was estimated for various feeding arrangements. Flow visualisations and particle image velocimetry measurements were carried out for a better understanding of the flow dynamics. Evidence was given of the improvements brought by the herein referred to, “double flux” configuration in comparison to traditional designs. After a brief description of the experimental facility and the basic principle underlying the approach developed, the main results are reported and discussed and recommendations are drawn. Considerations about where the effort will be directed in future works are provided.

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