Ejector for engine test bed exhaust system

Abstract

The invention discloses an ejector for an engine test bed exhaust system. The ejector comprises a low-pressure chamber, a transition section, a mixing convergence section, a mixing equal-straight section and a mixing expansion section, all of which are sequentially and coaxially connected. The low-pressure chamber comprises a low-pressure chamber shell and a flange. An annular flow diverting and guiding device, an ejecting airflow conveying pipeline, an ejecting airflow convergence section and an ejecting airflow expansion section are sequentially and coaxially connected into the low-pressure chamber. An inlet of the annular flow diverting and guiding device is connected with an ejecting airflow intake manifold, the center line of the ejecting airflow conveying pipeline coincides with that of the low-pressure chamber shell, an outlet of the low-pressure chamber and an outlet section of the ejecting airflow expansion section are located on the same vertical plane, the low-pressure chamber is connected with an ejector fixed support, and the mixing equal-straight section is connected with an ejector movable support. The ejector is high in ejection performance, testing efficiency is improved, the testing cost is reduced, and the ejector movable support absorbs the axial length change caused by thermal expansion and cold shrinkage of the ejector in a connected mode.

Description

technical field [0001] The invention relates to an ejector, in particular to an ejector used for the exhaust system of an engine test bench. Background technique [0002] When simulating the high-altitude flight state of the engine on the ground, the engine is usually installed in the high-altitude simulation cabin first, and the high-altitude simulation cabin is pumped with air extraction equipment so that the pressure in the high-altitude simulation cabin is the same as the ambient pressure at the altitude of the engine when it is flying at high altitude. In the same way, the engine is ignited and the high-altitude flight simulation test is carried out. During the test, the pressure in the high-altitude simulation cabin must always be kept the same as the ambient pressure at the altitude of the engine when it is flying at high altitude. This requires the exhaust gas from the engine to be discharged to high altitude immediately In the prior art, an ejector is usually used f...

AI Technical Summary

Problems solved by technology

[0002] When simulating the high-altitude flight state of the engine on the ground, the engine is usually installed in the high-altitude simulation cabin first, and the high-altitude simulation cabin is pumped with air extraction equipment so that the pressure in the high-altitude simulation cabin is the same as the ambient pressure at the altitude of the engine when it is flying at high altitude. In the same way, the engine is ignited and the high-altitude flight simulation test is carried out. During the test, the pressure in the high-altitude simulation cabin must always be kept the same as the ambient pressure at the altitude of the engine when it is flying at high altitude. This requires the exhaust gas from the engine to be discharged to high altitude immediately In the prior art, an ejector is usually used for air extraction, and the ejector uses a relatively high-pressure ejector to eject a low-pressure (or no-pressure) ejected airflow to complete the ejected airflow to suck the ejected airflow. The device for blending injection or delivery, because the ejector has no moving parts, is reliable in use, and is widely used in the exhaust system of the engine test bench; and for the ejection part that provides the ejection airflow and the blending part of the blending ejection Geometry and positional relationship are the key factors to determine the performance of the ejector, but in the prior art for the ejector of the exhaust system of the engine test bench, there is no mature and reasonable geometry between the ejector part and the blending part. , positional relationship, resulting in low ejector ejection performance, reducing the efficiency of the test, and increasing the cost of the test. In addition, the gas discharged from the high-altitude engine is high-temperature gas, and its temperature is usually above 350 ° C. When the engine When the exhausted high-temperature gas flows inside the metal pipe, the pipe will expand axially due to the property of metal thermal expansion and contraction. After the high-temperature gas flows, the metal pipe will be shortened to its original length as the metal pipe returns to normal temperature. Now The pipe support cannot absorb the axial length change of the metal pipe due to thermal expansion and contraction, which will cause the pipe support to deform or even break

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