The invention belongs to the technical field of high-temperature flow field velocity testing, and discloses a PIV (particle image velocimetry) endoscopic protection device for measuring a high-temperature
airflow velocity field, which is suitable for measuring three-dimensional velocity field distribution in a
turbine channel, between stages and at an inlet and an outlet of a
turbine in a high-temperature and high-speed
airflow environment. The device is characterized by comprising a shell, an inner wall, a
sapphire glass tube, a partition plate, a
light guide window, a water
inlet channel, a water outlet channel, an optical element, a mounting seat and a cavity. The shell, the inner wall and the
sapphire glass tube are coaxially sleeved and respectively form two-stage interlayers; the space between the shell and the inner wall is divided into an n-shaped water
inlet channel and an n-shaped water outlet channel through a partition plate, circulating flowing of cooling water is achieved, and an
endoscope optical
assembly and a
sapphire glass tube are efficiently cooled.
Light guide windows are formed in the side wall of the shell from top to bottom in an equal-
diameter and equal-interval mode, and an optical element capable of moving up and down in the glass tube in the axial direction is combined, so that the narrow measurement section in the
turbine can be accurately measured; according to the structure, the temperature near the sapphire glass tube can be controlled below 500K under the extreme condition that the external environment temperature is up to 2000K, high temperature is effectively isolated, thermal
stress concentration is relieved, and stable
signal transmission and imaging measurement are ensured. Compared with the prior art, the
endoscope probe can accurately reach a measurement area which is difficult to cover by a traditional
light source, and efficient and stable measurement of a high-temperature, complex and narrow space flow field is achieved.