Engineering topics

Erdos, John I.

Publications and source records attributed to Erdos, John I..

5 records

NASA NTRS1998

Dual Mode Shock-Expansion/Reflected-Shock Tunnel

NASA s HYPULSE facility at GASL has been reconfigured to permit free jet testing of the Hyper-X flowpath at flight Mach numbers of 7 and 10. Among the required changes are addition of a converging-diverging nozzle to permit operation in a reflected shock tunnel mode, a 7 ft. diameter test cabin and a 30 in. diameter contoured nozzle. However, none of these changes were allowed to interfere with rapid recovery of the prior shock-expansion tunnel mode of operation, and indeed certain changes should enhance facility usefulness and productivity in either mode. A previously-developed shock-induced detonation mode of driving the facility has been successfully applied to both reflected shock tunnel operation at Mach 10 flight conditions, with tailored interface operation, and shock-expansion tunnel operation at flight conditions corresponding to Mach numbers from 12 to 25. Tailored interface operation at Mach 7 has been achieved with an unheated helium driver. In the present paper, the rationale for a dual mode shock expansion/reflected shock tunnel is discussed, and the capabilities and limitations for each mode are outlined. The physical changes in the HYPULSE facility to achieve dual mode capability are also described. Limited calibration data obtained to date in the new reflected shock tunnel mode are presented and the anticipated flight simulation map with dual mode operation is also outlined.

Erdos, John I.↗

NASA NTRS1992

Pioneering scramjet developments by Antonio Ferri

The concept is summarized of a diffusive burning supersonic combustion ramjet engine (scramjet) envisioned by Antonio Ferri and some of the salient technologies are highlighted as developed by General Applied Science Labs, PIBAL, and NYU, under his direction.

Erdos, John I.↗

NASA NTRS1990

Progress in hypersonic combustion technology with computation and experiment

Design of successful airbreathing engines for operation at near-orbital speeds presents significant challenges in all the disciplines involved, including propulsion. This paper presents a discussion of the important physics of hypersonic combustion and an assessment of the state of the art of ground simulations with pulse facilities and with computational techniques. Recent examples of experimental and computational simulations are presented and discussed. The need for continued application of these tools to establish the credibility and fidelity of engineering design methods for practical hypersonic combustors is emphasized along with the critical need for improved diagnostic methods for hypervelocity reacting flows.

Anderson, Griffin Y.↗

NASA NTRS1989

Use of an Expansion Tube to Examine Scramjet Combustion at Hypersonic Velocities

Combustion testing at total enthalpy conditions corresponding to flight Math numbers in excess of 12 requires the use of impulse facilities. The expansion tube is the only operational facility of its size which can provide these conditions without excessive oxygen dissociation or driver gas contamination. Expansio tube operation is described herein and the operational parameters having the largest impact on its performance are determined. These are: driver-to-intermediate chamber pressure ratio, driver gas molecular weight and specific heat ratio, and driver gas temperature. Increases in the lase named parameter will markedly affect the test section static pressure. Preliminary calibration tests are discussed and test gas conditions which have been achieved are presented. Calculated and experimental test times are compared and the parameters affecting test time are discussed. The direction of future work using this important experimental tool is indicated.

Rizkalla, Oussama↗

NASA NTRS1989

Use of an expansion tube to examine scramjet combustion at hypersonic velocities

Combustion testing at total enthalpy conditions corresponding to flight Mach numbers in excess of 12 requires the use of impulse facilities. The expansion tube is the only operational facility of its size which can provide these conditions without excessive oxygen dissociation or driver gas contamination. Expansion tube operation is described herein and the operational parameters having the largest impact on its performance are determined. These are: driver-to-intermediate chamber pressure ratio, driver gas molecular weight and specific heat ratio, and driver gas temperature. Increases in the last-named parameter will markedly affect the test section static pressure. Preliminary calibration tests are discussed and test gas conditions which have been achieved are presented. Calculated and experimental test times are compared and the parameters affecting test time are discussed. The direction of future work using this important experimental tool is indicated.

Rizkalla, O.↗