STUDY OF OPTICAL VISUALIZATION METHODS FOR EXHAUST JET OF ROCKET ENGINE

Two optical methods are studied which are used to visualize the flow field of exhaust free jet and jet impingement from a real solid rocket engine.One is equal thickness fringe F P interferometry which is constructed with two mirrors about 200mm in diameter.It features that the optical layout is co optical light path and seperated form,the distance between two mirrors is more than 20m and the resistance to vibration distortion is strong.Another is moire deflectometry which has an aperture over 400mm in diameter.In this method a big diameter collimated light beam is used to explore the flow field,then it is reduced and recollimated into a small diameter recollimated light beam and detected by a two gratings system to produce moire fringes.It is characterized by large aperture and simplicity of the method.The experimental results show that the equal thickness fringe F P interferometry can be used to visualize the flow field of the exhaust jet from a real solid rocket,and the moire deflectometry can be even used to visualize the extensive flow field of rocket exhaust jet impingement besides the exhaust free jet.