Nuclear Blast Response of Airbreathing Propulsion Systems: Laboratory Measurements With an Operational J-85-5 Turbojet Engine

1982 ◽  
Vol 104 (3) ◽  
pp. 624-632 ◽  
Author(s):  
M. G. Dunn ◽  
J. M. Rafferty
Keyword(s):  
Frequency Response ◽  
Blast Wave ◽  
Test Section ◽  
Maximum Speed ◽  
Laboratory Measurements ◽  
Propulsion Systems ◽  
Pressure Transducers ◽  
Ludwieg Tube ◽  
Turbojet Engine ◽  
Blast Response

This paper describes an experimental technique that has been developed for the performance of controlled laboratory measurements of the nuclear blast response of airbreathing propulsion systems. The experiments utilize an available G.E. J-85-5 turbojet engine located in the test section of the Calspan Ludwieg-tube facility. Significant modifications, described herein, were made to this facility in order to adapt it to the desired configuration. The J-85 engine had previously been used at Calspan for other purposes and thus came equipped with eight pressure transducers at four axial locations along the compressor section. These transducers have a frequency response on the order of 40 KHz. Pressure histories obtained at several circumferential and axial locations along the compressor are presented for blast-wave equivalent overpressures up to 17.2 kPa (2.5 psi) at corrected engine speeds on the order of 94 percent of maximum speed.

A technique for measuring frequency response of pressure, volume, and flow transducers

1979 ◽  
Vol 47 (2) ◽  
pp. 462-467 ◽  
Author(s):  
A. C. Jackson ◽  
A. Vinegar
Keyword(s):  
Frequency Response ◽  
Pressure Transducer ◽  
Test System ◽  
Good Frequency ◽  
Pressure Transducers ◽  
Response Characteristics ◽  
Measuring Frequency

A device and methodology is presented for testing the frequency response of pressure, volume, or flow transducers. Also reported are responses of selected transducers of all three types over the range of 2--120 Hz. Several pressure transducers tested had good frequency response when connected to the test system with a minimum of interconnecting fittings; others did not. Use of additional connectors degraded the response as did the addition of air-filled catheters. The frequency response of the pneumotachometers tested were influenced largely by the response characteristics of the associated pressure transducer and interconnecting fittings. These results emphasize the need to test the response characteristics of any transducer with specific connectors and fittings that are to be used to make the actual measurements of pressure, volume, or flow.

Defining the Ecological Coefficient of Performance for an Aircraft Propulsion System

2018 ◽  
Vol 35 (2) ◽  
pp. 171-180 ◽  
Author(s):  
Yasin Şöhret
Keyword(s):  
Performance Indicator ◽  
Propulsion System ◽  
Coefficient Of Performance ◽  
Design Parameters ◽  
Propulsion Systems ◽  
Turbojet Engine ◽  
Energy Conversion Systems ◽  
And Performance ◽  
Aircraft Propulsion System ◽  
Aircraft Propulsion

Abstract The aircraft industry, along with other industries, is considered responsible these days regarding environmental issues. Therefore, the performance evaluation of aircraft propulsion systems should be conducted with respect to environmental and ecological considerations. The current paper aims to present the ecological coefficient of performance calculation methodology for aircraft propulsion systems. The ecological coefficient performance is a widely-preferred performance indicator of numerous energy conversion systems. On the basis of thermodynamic laws, the methodology used to determine the ecological coefficient of performance for an aircraft propulsion system is parametrically explained and illustrated in this paper for the first time. For a better understanding, to begin with, the exergy analysis of a turbojet engine is described in detail. Following this, the outputs of the analysis are employed to define the ecological coefficient of performance for a turbojet engine. At the end of the study, the ecological coefficient of performance is evaluated parametrically and discussed depending on selected engine design parameters and performance measures. The author asserts the ecological coefficient of performance to be a beneficial indicator for researchers interested in aircraft propulsion system design and related topics.

Effects of gas density on the frequency response of gas-filled pressure transducers

1979 ◽  
Vol 47 (3) ◽  
pp. 631-637 ◽  
Author(s):  
G. Francis ◽  
R. Gelfand ◽  
R. E. Peterson
Keyword(s):  
Frequency Response ◽  
Esophageal Pressure ◽  
Quiet Breathing ◽  
Gas Density ◽  
Pressure Transducers ◽  
Response Characteristics ◽  
Frequency Responses ◽  
Respiratory Flow ◽  
Esophageal Balloon ◽  
Frequency Response Characteristics

The effects of gas density on the frequency responses of four pressure transducers were determined at gas densities from 1.2 to 25.0 g/l. Transducers tested included three sensitive differential types used with pneumotachographs to measure respiratory flow (Validyne DP-45 and DP-103; Medistor P-11) and a transducer commonly used to measure esophageal pressure (Statham P23Dd). Three different responses were obtained. The Validyne DP-103 was overdamped and its response was essentially independent of gas density. The frequency response of this transducer is adequate for use with quiet breathing only. The Validyne DP-45 and Medistor P-11 responses were underdamped. The resonant peaks of these transducers decreased markedly in frequency as the gas density increased. The Statham P23Dd was also underdamped; however, its resonant frequency increased as gas density increased. An esophageal balloon did not alter the frequency response characteristics of this tubing-transducer system. Both increases in length and decreases in diameter of connecting tubing reduced the frequency of resonant peaks of underdamped pressure transducers.

Paper 2: Accuracy in Cylinder Pressure Measurement

1965 ◽  
Vol 180 (7) ◽  
pp. 8-16
Author(s):  
W. T. Lyn ◽  
A. J. Stockwell ◽  
C. H. T. Wang
Keyword(s):  
Frequency Response ◽  
Pressure Transducer ◽  
Continuous Recording ◽  
Cylinder Pressure ◽  
Pressure Transducers ◽  
Shock Chamber ◽  
Magnetic Type ◽  
Definition Of ◽  
Engine Development

The paper commences with a definition of the requirements of cylinder pressure measurements for (1) general engine development work, (2) frequency spectrum analysis in engine noise investigation, and (3) thermodynamics and combustion analysis. Methods for the determination of the frequency response of cylinder pressure transducers are then treated both theoretically and experimentally. For the continuous recording type of transducer a shock chamber technique is used. For the balanced pressure type of pick-up a comparison with a continuous recording type, of known frequency response, is made. These techniques do not completely simulate engine conditions and comparisons of the two types of pressure transducers were made dynamically under engine conditions. The results showed that all the continuous recording types of pressure transducer so far tested were sensitive to transient heat transfer owing to combustion. A rig was therefore developed to simulate such conditions outside the engine. Detailed descriptions are given of examples of both types of pressure transducer as developed at C.A.V. The method of recording timing marks is presented in some detail and the advantage of the ‘closed circuit’ magnetic type of degree pick-up is described.

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