Rarefied gas flow between parallel plates based on the discrete ordinate method.
Rarefied gas flow between parallel plates based on discrete ordinate method
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Rarefied gas flow between parallel plates based on discrete ordinate method
Radiative and forced convective heat transfer to flowing gas with carbon particles
Free-floating piston in a vertical column accurately measures and records low gas-flow rates. The system may be calibrated, using an adjustable flow-rate gas supply, a low pressure gage, and a sequence recorder. From the calibration rates, a nomograph may be made for easy reduction. Temperature correction may be added for further accuracy.
A technique for aerosol seeding of gas flows by laser-induced particle formation is demonstrated using a pulsed Nd:YAG laser (1.06 microns) for optical breakdown of a mixture of SF6 and H2 in an inert carrier gas. It is noted that, contrary to the smoke-wire approach, the laser-induced particles form first in zones of high turbulence, since mixing enhances coagulation. The method also allows seeding to be performed in locations hardly accessible otherwise and is mechanically nonintrusive. Finally, a study of the mixture and the breakdown effects indicates that for H2:SF6 ratios between 3:1 and 15:1 the particle formation is only limited by the physics of the gas/particle conversion.
Optimum thrust nozzle contours for chemically reacting gas flows, obtaining set of partial differential equations for gas dynamic properties
Optimum thrust nozzle contours for chemically reacting gas flows, obtaining set of partial differential equations for gas dynamic properties
Unsteady liquid and gas flow with heat addition and shock perturbation
Radiation and forced convective heat transfer to seeded flowing gas from arc enclosed by quartz tube
Frozen flow and nonequilibrium flow of real gas past pointed bodies, solving partial differential equation by integral relations method
Frozen flow and nonequilibrium flow of real gas past pointed bodies, solving partial differential equation by integral relations method
Here, we present a tracker gas flow quality control method developed for the Mu2e straw tube tracker. Using time-dependent current measurements, we quantify the onset time of ionization gain induced by an 55 F source during gas exchange, which is correlated to the gas conductance in the straw. This allows for the identification of channels with inadequate flow. This approach is broadly applicable to other gaseous detectors that require high-channel-count screening.
Fluid mechanical model of electric arc balanced magnetically in gas flow, based on photographs showing arc must simulate solid body
Formation of gas flow before flame front
Rarefied gas flow through passages with static boundaries noting development of theoretical models
Rarefied gas flow through passages with static boundaries noting development of theoretical models
The two principal areas of advanced propulsion investigated are the ram accelerator and the flowing gas radiation heater. The concept of the ram accelerator is presented as a hypervelocity launcher for large-scale aeroballistic range applications in hypersonics and aerothermodynamics research. The ram accelerator is an in-bore ramjet device in which a projectile shaped like the centerbody of a supersonic ramjet is propelled in a stationary tube filled with a tailored combustible gas mixture. Combustion on and behind the projectile generates thrust which accelerates it to very high velocities. The acceleration can be tailored for the 'soft launch' of instrumented models. The distinctive reacting flow phenomena that have been observed in the ram accelerator are relevant to the aerothermodynamic processes in airbreathing hypersonic propulsion systems and are useful for validating sophisticated CFD codes. The recently demonstrated scalability of the device and the ability to control the rate of acceleration offer unique opportunities for the use of the ram accelerator as a large-scale hypersonic ground test facility. The flowing gas radiation receiver is a novel concept for using solar energy to heat a working fluid for space power or propulsion. Focused solar radiation is absorbed directly in a working gas, rather than by heat transfer through a solid surface. Previous theoretical analysis had demonstrated that radiation trapping reduces energy loss compared to that of blackbody receivers, and enables higher efficiencies and higher peak temperatures. An experiment was carried out to measure the temperature profile of an infrared-active gas and demonstrate the effect of radiation trapping. The success of this effort validates analytical models of heat transfer in this receiver, and confirms the potential of this approach for achieving high efficiency space power and propulsion.
Physical and mathematical models of gas flows with chemical and radiative effects
Oblique shock wave parameter correlation for some specific heat ratios with application to real gas flows