Rocket

About: Rocket is a research topic. Over the lifetime, 14018 publications have been published within this topic receiving 95852 citations. The topic is also known as: rockets.

Recession behavior of graphitic nozzles in simulated rocket motors

Abstract: A has been conducted to predict nozzle recession behavior in two different rocket motors and for broad variations of propellant formulations and motor operating conditions. Results show that the recession rate is largely determined by the diffusion of the major oxidizing species (H2O and CO2) to the nozzle surface. The free volume in the motor, the concentration of the major oxidizing species as affected by the aluminum content of the propellant, and the chamber pressure exert a strong influence on the recession rate. A correlation to predict the throat recession in terms of the above governing parameters has been developed. This correlation is in good agreement with experimental data in the two different motors considered.

Higher order sensitivities in structural systems

Abstract: sound oscillations has to be considered in the evaluation of the thermodynamic functions of high-temperature gases only at high densities. Gases with a considerable acoustic noise background are encountered in various high-temperature engineering systems, such as gas turbines, jet engines, rocket exhausts, etc. The theory presented permits calculation of the free energy AF of the acoustic degrees of freedom in such systems, provided that the acoustic noise is in thermal equilibrium. Considerably larger free-energy contributions are to be expected under nonequilibrium conditions, particularly if the acoustic fluctuations exhibit intensity levels corresponding to turbulence.

Hybrid-LO2-LH2 low cost launch vehicle

Abstract: A low-cost rocket or thruster has a low-cost propellant injector, in which fluid fuel and oxidizer are injected into a combustion chamber. The walls of the combustion chamber are protected from the high temperatures of the combustion by a grain of solid propellant, the surface of which tends to melt andor vaporize in the presence of combustion temperatures, and thereby protects the walls of the chamber. The low-cost propellant injector may not mix the fluid fuel and oxidizer effectively, so that pockets of noncombusted gas may occur within the chamber. The ratio of fluid fuel and oxidizer is selected to be slightly oxidizer-rich, so that any pockets of unburned gas tend to be oxygen-rich. When the pockets come into contact with the solid fuel, the excess oxygen combusts with the gaseous solid fuel, and when the mixture is near stoichiometric, the fluid fuel combusts. Thus, an inexpensive bipropellant injector together with a solid fuel grain simultaneously allows use of solid fuel instead of insulation to protect the combustion chamber walls, and the combustion is stabilized by the presence of the solid fuel. Ideally, the amount of excess oxidizer should be sufficient to completely combust the solid fuel. The preferred propellants are LO2 and LH2, and the preferred solid fuel is HTPB.

Wavelength modulation spectroscopy near 5 $$\upmu$$m for carbon monoxide sensing in a high-pressure kerosene-fueled liquid rocket combustor

Abstract: A laser absorption sensor was developed for carbon monoxide (CO) sensing in high-pressure, fuel-rich combustion gases associated with the internal conditions of hydrocarbon-fueled liquid bipropellant rockets. An absorption feature near 4.98 $$\upmu$$ m, comprised primarily of two rovibrational lines from the P-branch of the fundamental band, was selected to minimize temperature sensitivity and spectral interference with other combustion gas species at the extreme temperatures (> 3000 K) and pressures (> 50 atm) in the combustion chamber environment. A scanned wavelength modulation spectroscopy technique (1f-normalized 2f detection) is utilized to infer species concentration from CO absorption, and mitigate the influence of non-absorption transmission losses and noise associated with the harsh sooting combustor environment. To implement the sensing strategy, a continuous-wave distributed-feedback (DFB) quantum cascade laser (QCL) was coupled to a hollow-core optical fiber for remote mid-infrared light delivery to the test article, with high-bandwidth light detection by a direct-mounted photovoltaic detector. The method was demonstrated to measure time-resolved CO mole fraction over a range of oxidizer-to-fuel ratios and pressures (20–70 atm) in a single-element-injector RP-2-GOx rocket combustor.