Topic
Chamber pressure
About: Chamber pressure is a research topic. Over the lifetime, 2988 publications have been published within this topic receiving 30725 citations.
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14 Jun 2011
TL;DR: In this article, permanent magnet microwave-driven Neutron Generators have been developed at Lawrence Berkeley National Laboratory (LBNL), where the axial magnetic field produced by the permanent magnets surrounding the plasma chamber is confined in an axial magnet field.
Abstract: Permanent magnet microwave-driven neutron generators have been developed at Lawrence Berkeley National Laboratory. The 2.45 GHz microwave signal is directly coupled into the plasma chamber via a microwave window. Plasma is confined in an axial magnetic field produced by the permanent magnets surrounding the plasma chamber. The source chamber is made of aluminum with a diameter of 4 cm and length of 5 cm. A stack of five alumina discs, which are 3 cm in diameter and total length of 3 cm, works as microwave window. Three permanent ring magnets are used to generate the axial magnetic field required for the microwave ion source. Both hydrogen and deuterium plasma have been successfully ignited. With 330W of microwave power, source chamber pressure of 5 mTorr, and an extraction aperture of 2 mm in diameter, the deuterium ion beam measured on the target was approximately 2.5 mA. Over 90% of the ions are atomic. With the ion source at ground potential and titanium target at -40 kV, the analysis of the activated gold foil and calibrated neutron dose monitor both indicated that roughly 10{sup 7} n/s of D-D neutrons have been produced. The D-D neutron yield can be easily scaled up tomore » 10{sup 8} n/s when the titanium target is biased at -100 kV.« less
17 citations
TL;DR: In this article, the average spray tip speeds were determined from simultaneously recorded needle lift signals and obscuration traces, and the Sauter mean diameter of penetrating fuel drops increased with an increase of the chamber pressure and decreased with an injection pressure.
17 citations
01 Nov 1974
TL;DR: In this paper, a series of scale model coaxial dump combustors from 2 inch to 5 inch D were tested on a thrust stand with JP-4 fuel over a wide range of ramjet test conditions.
Abstract: : A series of scale model coaxial dump combustors from 2 inch to 5 inch D were tested on a thrust stand with JP-4 fuel over a wide range of ramjet test conditions. Baseline conditions were selected to approximate 'pressure scaling criteria' in which chamber pressure times combustor diameter remains constant. JP-4 fuel was injected perpendicular to the airstream from eight plane tube injectors. Fuel/air ratio, chamber pressure and nozzle throat diameter were varied for each size chamber. Lean blow-out limit, combustion efficiency, combustor pressure drop, and combustion instability characteristics were obtained for each test point.
17 citations
Patent•
13 Sep 1971
TL;DR: An orificed pressure vessel has a combustion chamber adjacent the orifice and a propellant charge in the remainder thereof comprising wafer segments of propellant separated from each other by combustion barriers as mentioned in this paper.
Abstract: An orificed pressure vessel has a combustion chamber adjacent the orifice and a propellant charge in the remainder thereof comprising wafer segments of propellant separated from each other by combustion barriers; an electric igniter adjacent each propellant wafer has a thermally operated, normally open switch, so that the circuit is closed for each igniter as the adjacent wafer is burned; a pressure transducer in communication with the combustion chamber operates a master switch connected in series with the igniters and an electrical energy source to close the entire circuit or open it in response to a predetermined maximum and minimum chamber pressure; and valve means on the orifice permits withdrawal of gases from the combustion chamber for use as desired. Optional equipment includes a pressure relief valve in the combustion chamber and a capacitor connected in parallel between the energy source and the igniters.
17 citations
05 Jul 2006
TL;DR: In this paper, the effects of enhanced surface structures on heat flux using spray cooling were investigated on a heater block with a flat surface for baseline comparison purposes, and the results showed that the highest critical heat flux was attained using straight fins and porous tunnels.
Abstract: Experiments were conducted to study the effects of enhanced surface structures on heat flux using spray cooling. The surface enhancements consisted of embedded structures (dimples, pores, and tunnels) and compound extended surface enhancements (straight fins, cubic pin fins and dimples) machined on and within the top surface of copper heater blocks. Each copper block had a projected cross-sectional area of 2.0 cm2. Measurements were also obtained on a heater block with a flat surface for baseline comparison purposes. A 2times2 nozzle array was used with PF-5060 as the working fluid. Thermal performance data was obtained under nominally degassed (chamber pressure of 41.4 kPa) and gassy conditions (chamber with N2 gas at 101 kPa) with a bulk fluid temperature of 20.5 degC. Results for both the nominally degassed and gassy cases show that the highest critical heat flux (CHF) was attained using straight fins and porous tunnels. For the nominally degassed case, both had a CHF of ap142 W/cm2 while for the gassy case their CHF values increased to 175 W/cm2 . This gave an enhancement relative to the respective flat surface degassed/gassy cases of ap 77% and 62% respectively
17 citations