| The Stirling Radioisotope Generator (SRG) is one of the advanced, high-efficiency, radioisotope power convertors being developed to provide spacecraft onboard electric power for future NASA missions. In support, a microfabricated regenerator is designed for reduced pressure drop and enhanced durability relative to present woven screen and random fiber designs. Under the present project, prototype units have been fabricated. Because some space and time resolved details of the flow and heat transfer cannot be measured in an engine-size regenerator having feature sizes as small at 14 mum, dynamic similitude is applied to develop a Large Scale Mockup (LSMU) of 30x scale. The LSMU experimental program is the topic of the present thesis. Experimental results from the LSMU show: (1) the value of using dynamic similarity in design, (2) the performance of the microfabricated regenerator relative to woven screen or random fiber performance, (3) the effect of doubling the channel length of each element of the microfabricated regenerator, (4) the effect of roughness that may arise during the microfabrication processing, (5) the performance of computational methods developed for regenerator design, and (6) the jet penetration effect of a round jet generator and a slot jet generator. Mounting evidence is that the microfabricated regenerator developed under this program represents a significant overall improvement in performance and durability over present regenerator designs. The measurements of the present study provide some of that evidence. |
