Variable Mach number rotating mechanism based on semicircular bearings

Abstract

The invention relates to a variable Mach number rotating mechanism based on semicircular bearings. The mechanism comprises a left side wall 1, an upper molding surface mechanism 2, a lower molding surface mechanism 3, an upper support plate 4, a lower support plate 5, an upper right semicircular bearing 6, an upper left semicircular bearing 7, a lower right semicircular bearing 8, a lower left semicircular bearing 9 and a right side wall 10. For a free jet spraying pipe with an open type outlet, the semicircular shaft lug design of the rotating mechanism effectively guarantees a rigid molding surface rotating center shaft as a spraying pipe molding surface outlet edge line so as to effectively guarantee the reference uniformity of the sectional area of the outlet of the spraying pipe and the throat way control height in the Mach number adjusting process; and a fixed molding surface driving end adopts an arc guide rail mode to effectively compensate the defect of incapability of locking the semicircular bearings, so that the adjustment of a driving mechanism is effective and fast.

Description

technical field [0001] The invention belongs to a test equipment design technology for a wind tunnel test or an aeroengine high-altitude platform aerodynamic test, and in particular relates to a variable Mach number rotating mechanism based on a semicircular bearing. Background technique [0002] The outlet of the supersonic nozzle of the traditional closed supersonic jet wind tunnel is straight to the experimental section. In other words, the outlet of the supersonic nozzle needs to be horizontally tangent to the experimental section to avoid the secondary shock wave at the outlet of the nozzle. For the closed rigid nozzle, because the outlet needs to be kept horizontal, a center of rotation is generally set near the outlet of the nozzle, and a smooth connection is made with the test section through a concave-convex arc. [0003] For the open-type free-jet high-altitude simulation test, the outlet of the open-type nozzle is a wide test chamber space, that is, the cross-sect...

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Problems solved by technology

If the design scheme with the rotation center near the nozzle outlet is adopted, the position of the end point of the nozzle outlet profile will inevitably change due to the rotation of the profile, that is, the height of the nozzle outlet will change. As we all know, the nozzle Mach number is controlled by adjusting the nozzle. The ratio of the area of ​​the pipe throat to the outlet of the nozzle is realized. If both of them change during the test, although a Mach number can also be obtained, it is difficult to ensure the precise control of the Mach number and the target Mach number. , according to the fixed profile designed according to the horizontal state of the nozzle outlet, after the outlet angle changes, the airflow quality and airflow angle will have a large deviation

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