Abstract: The basic heat pipe principle is employed to provide a self-contained passively cooled probe that may be placed into a high temperature environment. The probe consists of an evaporator region 13 of a heat pipe 10 and a sensing instrument 17. Heat is absorbed as the working fluid 22 evaporates in the probe. The vapor is transported to the vapor space 14 of the condenser region 15. Heat is dissipated from the condenser region and fins 20 causing condensation of the working fluid, which returns to the probe by gravity and the capillary action of the wick 18. Working fluid, wick and condenser configurations and structure materials can be selected to maintain the probe within an acceptable temperature range.

Abstract: The invention relates to a device which changes the Mach number capability of a wind tunnel without permanently altering the existing nozzle of the tunnel. An insert (14) is removably attached to the wall (17) of the existing nozzle expansion area (22) thereby creating a second minimum section (15) upstream of the model test section (21). The added insert (14) may be removed without complicated and expensive changes to the basic wind tunnel. In the embodiment illustrated in FIG. 2, a removable insert (25) is disposed within wind tunnel nozzle walls (17) with a portion of the flow boundary layer being bled off from the tunnel via passageway (29) and tunnel exit (28) to thereby reduce the extent of separated flow normally occuring upstream of the insert contraction section.