Reproducible direct exposure environmental testing of metalbased magnetic media
Abstract
A flow geometry and flow rate for mixed flowing gas testing is proposed. Use of an impinging jet of humid polluted air can provide a uniform and reproducible exposure of coupons of metalbased magnetic media. Numerical analysis of the fluid flow and mass transfer in such as system has shown that samples confined within a distance equal to the nozzle radius on the surface of impingement are uniformly accessible to pollutants in the impinging gas phase. The critical factor is the nozzle height above the surface of impingement. In particular, the uniformity of exposure is less than plus/minus 2% for a volumetric flow rate of 1600 cm(exp 3)/minute total flow with the following specifications: For a one inch nozzle, the height of the nozzle opening above the stage should be 0.177 inches; for a 2 inch nozzle  0.390 inches. Not only is the distribution uniform, but one can calculate the maximum delivery rate of pollutants to the samples for comparison with the observed deterioration.
 Publication:

4th NASA Goddard Conference on Mass Storage Systems and Technologies
 Pub Date:
 March 1994
 Bibcode:
 1994msst.conf..255S
 Keywords:

 Air Jets;
 Air Pollution;
 Contaminants;
 Deterioration;
 Exposure;
 Magnetic Storage;
 Metals;
 Data Storage;
 Flow Geometry;
 Flow Velocity;
 Gas Flow;
 Vapor Phases;
 Instrumentation and Photography