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At least 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
NASA NTRS1971

Improved method for calculating pump thermodynamic suppression head

Method of calculation improves by introducing the sound velocity of two phase flow into the equation for the vapor to liquid volume ratio. Comparisons of required net positive suction head and thermodynamic suppression head are made for a head coefficient ratio of 0.98.

Kageyama, Y.↗
NASA NTRS1972

Liquid-propellant dynamics and suppression

Technology related to liquid-propellant interactions with space shuttle vehicles is reviewed. Potential problems unique to the shuttle include liquid-structure interactions resulting from coupled lateral and longitudinal deformations, traveling wave phenomena at shallow propellant levels, and liquid impact during abort, staging, or docking. Technology efforts to define the slosh dynamics under shuttle operating conditions are described with emphasis on analytical representations of the liquid by finite-element and marker-and-cell methods. In addition, slosh suppression is discussed and includes baffle damping and pressure loads for tanks fitted with multiple baffles both above and below the undisturbed liquid surface.

Stephens, D. G.↗
NASA NTRS1972

Noise suppression by time exposure oscilloscope photography.

We describe a simple and inexpensive means of enhancing repetitive signals obscured by noise with roughly equal amplitude. The signal and noise are displayed on an oscilloscope, and we perform a time average over many traces by time exposure photography. If the oscilloscope triggering is synchronous with the signal, the result is a significant suppression of the offending noise.

Huchital, G. S.↗
NASA NTRS1972

Fan noise suppression

The principal suppressor parameters and their relationships have been used to formulate a suppressor design methodology which has been applied to the design of several full-scale suppressors. Tests of these suppressors on several full-scale fans have demonstrated noise reductions of the order of 10 PNdB. The amount of suppression in several instances seems to have been limited by reaching noise floors that are not clearly at the estimated jet noise level but are not far above it. In addition to identifying noise floors, two other areas are considered. The first is attenuation by the fan exhaust suppressors, which seems in most cases to be less than that of the inlet. The second is the effectiveness of outer cowl treatment alone on multiple pure tones. This question relates to whether a high-speed fan can become as quiet as a low-speed fan without a substantial increase in the amount of treatment.

Feiler, C. E.↗
NASA NTRS1972

Study of Load Alleviation and Mode Suppression (LAMS) on the YF-12A airplane

The potentials and capability for implementing a LAMS (load alleviation and mode suppression) system on the YF-12A for the purpose of flight research were evaluated. The nature of the research is to minimize the design risk in application of LAMS to future aircraft. The results of the study show that the YF-12A would be a suitable test bed for continuing development of LAMS technology. This was demonstrated by defining five candidate LAMS systems and analytically evaluating them with regard to performance and mechanization. Each of the five systems used a different combination of force producers. A small canard vane or a mass-reaction device mounted near the cockpit was considered as a possible LAMS force producer, together with the existing inboard and outboard elevons. It was concluded that a combination of canard vane and outboard elevons would provide the most effective system for the YF-12A.

Edinger, L. D.↗
NASA NTRS1973

Internal performance of a wedge nozzle for a supersonic cruise aircraft with a multispoke primary for noise suppression

Nozzle performance was obtained with cold primary and secondary flows over a range of nozzle pressure ratio from 2 to 31 and corrected secondary-to primary-flow ratio from 0 to 11 percent. Several fixed shroud positions were tested to simulate a translating outer cylindrical shroud to provide data for both supersonic cruise and takeoff configurations. The addition of 14 spokes in the primary nozzle for noise suppression reduced the thrust efficiency 3 percent at supersonic cruise and 4.5 percent at takeoff.

Johns, A. L.↗