Cylindrical solar absorber cavity length to diameter ratio investigation

摘要

Recently,solar thermal rocket propulsion concepts have primarily focused on "Windowless" absorber designs.This investigation experimentally explored the gteometric aspect of the simple cylindrical solar thermal absorber cavity.The critical parameter used for the evaluation was the length to diameter ratio,which was varied from 2 to 8 (a dimensionless value).Two mateirals teats.Temperature profiles were geenrated using thermocouples on the outside of the insulated absorber shell.The data generated was analyzed and a new geometry comparison parameter ( PSI ) developed.This unique parameter is useful to indicate a range of length to diameter ratios,which optimizes the solar absorption and heat transfer process in a windowless,cylindrically shapoed,solar thermal absrober.The optimal ratio range was concluded to exist for the cyclinder shaped cavity in the rnage of 3 to 6 for the materials investigated.