78,687 research outputs found
A high-pressure premixed flat-flame burner for chemical process studies
A premixed flat-flame burner was designed and tested with methane-air mixtures at pressures from 1.1 to 20 atm and equivalence ratios from 0.7 to 1.1. Reactant velocity in the burner mixing chamber was used to characterize the range of stable flames at each pressure-equivalence-ratio condition. Color photographs of the flames were used to determine flame zone thickness and flame height. The results show that this burner can be used for chemical process studies in premixed high pressure methane-air flames up to 20 atm
An experimental study of the oxidation of graphite in high-temperature supersonic and hypersonic environments
Graphite oxidation in high temperature supersonic and hypersonic streams of air and air-nitrogen mixture
High pressure flame system for pollution studies with results for methane-air diffusion flames
A high pressure flame system was designed and constructed for studying nitrogen oxide formation in fuel air combustion. Its advantages and limitations were demonstrated by tests with a confined laminar methane air diffusion flame over the pressure range from 1 to 50 atm. The methane issued from a 3.06 mm diameter port concentrically into a stream of air contained within a 20.5 mm diameter chimney. As the combustion pressure is increased, the flame changes in shape from wide and convex to slender and concave, and there is a marked increase in the amount of luminous carbon. The height of the flame changes only moderately with pressure
Pollutant emissions from flat-flame burners at high pressures
Maximum flame temperatures and pollutant emission measurements for NOx, CO, and UHC (unburned hydrocarbons) are reported for premixed methane air flat flames at constant total mass flow rate over the pressure range from 1.9 to 30 atm and for equivalence ratios from 0.84 to 1.12. For any given pressure, maxima typically occur in both the temperature and NOx emissions curves slightly to the lean side of stoichiometric conditions. The UHC emissions show minima at roughly the same equivalence ratios. The CO emissions, however, increase continually with increasing equivalence ratio. Flame temperature and NOx emissions decrease with increasing pressure, while the opposite is true for the CO and UHC emissions. The NOx data correlate reasonably well as a function of flame temperature only. Four flameholders, differing only slightly, were used. In general, the temperature and emissions data from these four flameholders are similar, but some differences also exist. These differences appear to be related to minor variations in the condition of the flameholder surfaces
Performance estimation of interior permanent-magnet brushless motors using the voltage-driven flux-MMF diagram
The flux-magnetomotive force (flux-MMF) diagram, or "energy conversion loop," is a powerful tool for computing the parameters of saturated interior permanent-magnet brushless motors, especially when the assumptions underlying classical dq theory are not valid, as is often the case in modern practice. Efficient finite-element computation of the flux-MMF diagram is possible when the motor current is known a priori, but in high-speed operation the current regulator can lose control of the current waveform and the computation becomes "voltage-driven" rather than "current-driven." This paper describes an efficient method for estimating the motor performance-average torque, inductances-by solving the voltage-driven problem. It presents experimental validation for a two-pole brushless interior permanent-magnet motor. The paper also discusses the general conditions under which this method is appropriate, and compares the method with alternative approaches
Pre and post processing using the IBM 3277 display station graphics attachment (RPQ7H0284)
A graphical interactive procedure operating under TSO and utilizing two CRT display terminals is shown to be an effective means of accomplishing mesh generation, establishing boundary conditions, and reviewing graphic output for finite element analysis activity
On some question of electromagnetic waves diffraction on plasma formations
Electromagnetic wave propagation and diffraction in plasma
On pattern structures of the N-soliton solution of the discrete KP equation over a finite field
The existence and properties of coherent pattern in the multisoliton
solutions of the dKP equation over a finite field is investigated. To that end,
starting with an algebro-geometric construction over a finite field, we derive
a "travelling wave" formula for -soliton solutions in a finite field.
However, despite it having a form similar to its analogue in the complex field
case, the finite field solutions produce patterns essentially different from
those of classical interacting solitons.Comment: 12 pages, 3 figure
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