Showing papers on "Arcjet rocket published in 1976"
TL;DR: In this article, a gas diffusion-limited thermochemical ablation and liquid phase removal is proposed for tungsten, tengsten/25% rhenium, and molybdenum, and a good correlation for high and low-pressure arcjet tests, ballistic range firings, and sounding rocket flights has been obtained with these models.
Abstract: Refractory metals are attractive candidates for re-entry vehicle nosetips due to their high resistance to water droplet and ice particle erosion. Ablation models are presented for tungsten, tungsten/25% rhenium, and molybdenum, including gas diffusion-limited thermochemical ablation and liquid phase removal. Chemical eqtilibrium is assumed in the gas phase with kinetics for tungsten ablation considered only at the ablating surface. These models have been incorporated into computer programs that also include shape change, boundarylayer transition, surface roughness, and two-dimensional transient conduction. Good correlation for highand low-pressure arcjet tests, ballistic range firings, and sounding rocket flights has been obtained with these models.
10 citations
14 Nov 1976
7 citations
01 Mar 1976
TL;DR: In this paper, the free electron density of the centerline of an argon and helium arcjet plume is derived and the results of these calculations are used to ascertain the time rates of change of the free ion density attributable to the recombination and gas-dynamic processes separately.
Abstract: : Equations coupling the collisional-radiative recombination and gas- dynamic phenomena for the centerline of the freely expanding plume of an argon and helium arcjet are developed and solved for the free electron density. The results of these calculations are used to ascertain the time rates of change of the free electron density attributable to the recombination and gas-dynamic processes separately. Experimental data are presented which support the conclusions drawn from the analytical results. Therefore, based on these results, a more detailed approach than the collisional-radiative recombination model is necessary for the correct description of recombination mechanisms in the rapidly changing environment of the expanding arcjet plume.
2 citations
14 Nov 1976
1 citations
01 Jul 1976
TL;DR: In this paper, the acceleration effects on rocket performance have been well publicized, and the effects of acceleration augmentation on the performance of sustainer type propellants have been extensively studied.
Abstract: Some acceleration effects on rocket performance have been well publicized. The dynamic process, characterized by marked increases in 'localized' burning rate, produces excessive case heating, slag retention, pressure buildup, and/or internal flow alterations. Data are presented illustrating drastic effects at low accelerations for sustainer type propellants and its relevance to several recent failures. Normalized orientation dependence of rate augmentation appears coupled to acceleration level and base burning rate. Effects appear influenced by propellant composition. Predictions using subscale motor data show good agreement with observed performance for ground spin and flight tests. Subscale test methods and results are also discussed.