Heat transfer in the Aeropropulsion System Test Facility mixing header

The Object of this study was to determine the effec tiveness of a duct liner to reduce heat transfer effects on air flow and to allow quicker temperature changes in test conditions at the Aeropropulsion System Test Facility (ASTF). The heat transfer problem was analyzed in two ways: 1) in terms of an equivalent resistance model and 2) with a transient heat conduction computer program. The resistance to heat transfer was shown to be two times greater with a liner. However, the improvement in thermal response time of the facility flow was shown not to be significant enough to warrant implementation of the liner in the actual facility. The advantages and disadvantages of this solution were investigated.