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Engineering topics

Arthur, P. D.

Publications and source records attributed to Arthur, P. D..

5 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

2200 C oxidizing atmosphere furnace for space manufacturing

The design of a high temperature furnace is presented which uses electrically conducting ceramic oxide heating elements. The heating elements are made of either thoria or stabilized zirconia which become conductive when preheated to 700 to 1000 C. These heater elements can be operated to 2200 C in oxidizing or inert atmospheres. The furnace is being designed to have a temperature which can be controlled to within 11 C. By a replacement of the heater element, the working cavity can be changed from isothermal to a cavity with a selected specific axial temperature gradient of up to 200 C per centimeter. This furnace concept is appropriate for the growth of crystals which might be grown best in an oxidizing atmosphere such as sapphire (melting point 2040 C), yttrium aluminum garnet (1970 C) or yttrium orthoaluminate (1875 C).

Halbach, C. R.↗
NASA NTRS1972

Evaluation of advanced component concepts for an integrated environmental control/life support, resistojet control system

Flow restricting devices were studied for their suitability as liquid water propellant flow limiters for the biowaste resistojet. Flow limiting during the start-up transient is required to prevent thrustor instabilities and icing which could result in heater failure in the electrical resistance heated thrustor (resistojet). The study was directed toward simple devices which would function passively (i.e., without power except from the propellant flow itself), and would offer high reliability and simplicity. In addition to the flow limiting devices, a thermal pumping system was studied to determine whether CO2, desorbed from molecular sieves could be pumped thermally in a space station application. The thermal pump is considered a possible replacement for mechanical pumps. It involves a cyclic, constant volume cryopumping system which employs space radiators to achieve the cryotemperatures. The frozen CO2 would be vaporized periodically, using a waste heat loop, to attain sufficient pressure to transfer a large portion of the trapped CO2 to storage tanks.

Halbach, C. R.↗