Minimizing errors associated with multiplate radiation shields

Multiplate radiation shield errors are examined using the following techniques: 1) ray tracing analysis, 2) wind tunnel experiments, 3) numerical flow simulations, and 4) field testing. The authors' objectives are to develop guidelines for radiation shield and temperature sensor design, to build an improved shield, and to determine factors that influence radiational heating errors. Guidelines for reducing radiational heating errors are given that are based on knowledge of the temperature sensor to be used, with the shield chosen to match the sensor design. A new class of shield called a part-time aspirated multiplate radiation shield is introduced. This type of shield consists of a multiplate design usually operated in a passive manner but equipped with fan-forced aspiration capability to be used when necessary (e.g., low wind speed). A prototype shield reduced radiational heating errors from 2°to 1.2°C. In addition, nighttime low wind speed errors were reduced from 1.6°to 0.3°C. Existing passive shields may be modified to incorporate part-time aspiration, thus making them cost effective.