Flat-opening type diffuser for engine test platform

Abstract

The invention provides a flat-opening type diffuser for an engine test platform, and the diffuser comprises a collection segment, a contraction segment and an equal-diameter expansion segment, wherein the collection segment comprises two half collection segments, and the two half collection segments are arranged oppositely to form a cylinder. The collection segment also comprises drive parts which are disposed on the half collection segments, and are driven by a driver to drive the two half collection segments to get close to each other or separate, so as to open or close the cylinder. The collection segment just consists of two parts, so the machining difficulty is small. Because the collection segment employs a flat-opening mode and the flat-opening distance is determined by the length and installation position of a screw and is not limited by the slotting width and length of an original type of collection segment on the cylinder, the installation space of a test model can be greatly enlarged. A drive and guide device of the collection segment is located at an outer side of the bottom of the collection segment and is far from the tail flame of an engine, so the impact from a hot air flow is very small. The two half collection segments just make radial translation motion, and an execution mechanism is simple, thereby greatly improving the operation reliability of the diffuser.

Description

technical field [0001] The invention belongs to the field of aerodynamic experiment equipment. More specifically, the invention relates to a flat diffuser for an engine test platform. Background technique [0002] The role of the diffuser is to convert part of the kinetic energy of the engine exhaust gas into pressure energy, and truly simulate the engine exhaust back pressure and ambient pressure conditions. It is one of the key components for the exhaust system of the test bench to decelerate, cool down and reduce the high-temperature and high-speed gas of the engine under test, so that the gas can smoothly enter the extraction system or be discharged into the atmosphere. [0003] Diffuser 8 is a pneumatic component such as figure 1 As shown, it is composed of four parts: collecting section 81, constricting section 82, equal straight section 83 and diffuser section 84. Generally, collecting section 81, constricting section 82 and equal straight section 83 are installed i...

AI Technical Summary

Problems solved by technology

[0005] 1. The collection section is a thin-walled and large-diameter part. Grooving on the upper and lower walls will reduce its strength and rigidity. In order to improve its strength and rigidity, separate processing is often used for assembly, which greatly increases the processing difficulty and workload.

[0006] 2. After the test model is installed in place, it is necessary to close and lock the slotted cover plate on the upper wall of the collection section to prevent the air flow from overflowing and affect the flow field. Due to the large size and quality of the cover plate, if manual closing and locking is used The method, installation difficulty and workload are very huge, so the opening and closing and locking of the cover plate are mostly realized by automatic mechanism, but when the engine is tested, the tail flame directly contacts the diffuser, and the diffuser will bear the impact of strong hot air flow, Vibration of the collection section and thermal deformation of the collection section and the cover plate are caused. After many tests, the automatic opening and closing and locking mechanism of the cover plate is difficult to ensure the position accuracy and working reliability of the cover plate, and failures often occur

[0007] 3. With the continuous increase of the size of the test model, the test model cannot be installed in place only by slotting the upper end of the collection section. It is also necessary to move the diffuser axially along the airflow direction. After the test model is installed in place, the expansion Therefore, the diffuser also needs to have the function of axial movement, which makes the design of the diffuser more difficult. In addition, the axial movement mechanism is also difficult to ensure the position accuracy and work after being repeatedly impacted by the heated airflow. reliability issues

[0008] 4. The diffuser needs to withstand the impact of high-temperature air flow when it is working. The split parts and cover plates of the diffuser need to be designed as a double-layer water-cooled structure, and circulating cooling water is needed for cooling. The compressor also often needs to move axially, and the water pipeline system needs to be connected with multiple metal bellows to ensure that the diffuser is cooled in place. Because the metal bellows have a large flow resistance and are easy to bend, it is difficult for the installation and operation of the cooling water system. to adversely affect

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