Chamber pressure

About: Chamber pressure is a research topic. Over the lifetime, 2988 publications have been published within this topic receiving 30725 citations.

Computer study of nonequilibrium excitation in recombining nitrogen plasma nozzle flows

Abstract: The nonequilibrium neutral atom excited state densities, electron densities, electron and heavy particle temperatures are computed for a fully dissociated partially ionized nitrogen plasma expanding in a nozzle starting from equilibrium in the settling chamber. The degree of excitation nonequilibrium at the exit of a convergent-divergent nozzle having an area ratio of 22 is systematicall y investigated for chamber pressures between 0.01 and 1000 atm and chamber temperatures between 6000 and 18,000 °K. Thermal nonequilibrium at the exit rises to a maximum in the chamber pressure range between 1 and 10 atm, whereas excitation nonequilibrium is smallest in this pressure range, due to the competing effects of the three-body recombination and collisional coupling terms in the electron energy equation. Increasing chamber pressure above 10 atm produces increasingly severe and unexpected departure from excitation equilibrium.

An investigation of the swirling flow in a spinning end-burning rocket

Abstract: The purpose of this study was to determine the swirling flowfield which develops at various spin rates in the chamber of a spinning end-burning rocket. Cold flow experiments employing a porous plate to represent the propellant surface were conducted. The experiments were designed to simulate dynamically the conditions in a typical cylindrical rocket combustion chamber. Pressure measurements at the plate and in the flow were correlated with smoke traces to arrive at a physical description of the flowfield in which solid-body rotation gives way to a high-speed vortex in the chamber at sufficiently high motor spin rates. The experimental correlation of the onset of this flow transition with a critical value of the Rosby number is in agreement with a theoretical analysis, and it is concluded that the vortex development is a characteristic of the inviscid rotating flow. The experiments also indicate that significant interaction between the vortex and the propellant surface is little affected by chamber length or nozzle entrance shape.

Performance of a Rocket-Ramjet Combined-Cycle Engine Model in Ejector Mode Operation

Abstract: A rocket-ramjet combined cycle engine model, embedding twin rocket chamber on top wall side of a scramjet flow-pass, was tested in its ejector-mode operation under sea-level static conditions. The rocket chamber was driven with gaseous hydrogen and oxygen at nominal operation condition of 3 MPa in chamber pressure and 6.5~7.5 in mixture ratio. Gaseous hydrogen was also injected through secondary injector orifices to pressurize the ramjet combustor. Mixing between the hot rocket plume and cold airflow as well as combustion of residual fuel within the plume with the airflow caused entropy and static pressure increases in the constant-area mixing duct in our original flow-pass design, resulting in a high back-pressure to the incoming airflow and a limited airflow rate. Thus, the mixing duct was re-designed to have divergence from its onset to compensate the pressure-rise. With this modified flow-pass configuration, the airflow rate was increased by 40%. However, this flow-pass geometry resulted in generation of low speed area, through which pressure-rise due to secondary combustion (and flow-pass exit contraction to simulate secondary combustion) penetrate the mixing duct and reduced the incoming airflow rate. A contraction on the incoming airflow enabled choking condition of the incoming airflow to sustaining the airflow rate, while the rate itself was reduced. Contraction at the exit of the engine enhanced mixing, however, choking condition was not attained due to the higher pressure level associated with the high exit contraction. Balancing these factors and additional mixing enhancement are required. The engine performances were summarized.

A large-area transition radiation detector

Abstract: The construction and the operation of a large-area transition radiation detector (TRD) for the NA31 experiment at CERN are described. The TRD incorporates several novel features for stabilizing the detector response. The density of the gas mixture (xenon+helium+methane) in the detection chambers is matched to the carbon dioxide gas in the surrounding radiators by tuning the helium concentration to avoid a hydrostatic pressure difference, which would deform the chamber walls. The chamber pressure is continuously regulated by computer control to maintain it to within 1 μbar of the radiator pressure. The gas gain of each of the four chambers is regulated to better than 0.2% by changing the high voltage under computer control, using the pulse-height spectra of 16 109 Ca sources mounted on the chambers. The results of performance studies are described. The detector has a pion efficiency of 98.7% with an electron rejection of a factor of 10.