OCR Text |
Show Results and Conclusions A primary result of the model testing is that the R A H and C A H function as designed. That is, the R A H transfers heat at a rate that meets the design requirements, it accommodates the differential thermal expansion of the alloy and ceramic components, and it withstands the slagging ash corrosion. The testing of the C A H was similarly successful in that it matches the heat transfer effectiveness of the design, stands up to ash corrosion and offers the potential for expansion of the temperature range. Both the R A H and the C A H were instrumented to help evaluate their performance. In the R A H the backface of the refractory bricks, and the length and circumference of the alloy tubes have high temperature thermocouples judiciously placed to evaluate the radiative heat transfer and the temperature gradients in the R A H . These measurements are complemented by infrared detectors viewing the refractories. The results of some of these measurements indicate that for these air flow rates and furnaces conditions this scaled version of our R A H can raise the air temperature high enough and fast enough for our baseline designs. In practical terms it means the R A H design is successful in that it can: • Raise the temperature 400°F • Transfer heat at the design point 98,000 BTU/hr • Survive the high temperature corrosive atmosphere for significant lifetimes In turn, the performance of the RAH supports the design studies and cycle analysis which, at their optimum, result in thermal efficiencies of 5 5 % ( H H V ) while still adhering to cost goals and the operating ranges of present day materials. Acknowledgements This work was carried out under DOE contract DE-AC22-95PC95144 which is monitored by the Federal Energy Technology Center , Pittsburgh , Pennsylvania . The Contracting Officer's Representative is Arun Bose . |