Impinging jets are frequently adapted for cooling overheated parts. With the film cooling technique, this process improves thermal exchanges between walls and fluid. However if many works have concerned only the therm...Impinging jets are frequently adapted for cooling overheated parts. With the film cooling technique, this process improves thermal exchanges between walls and fluid. However if many works have concerned only the thermal aspect of this problem [1], its dynamic field has been rarely studied especially for multiple impingements. As the two phenomena cannot be totally dissociated, we have undertaken the aerodynamic and thermal study of jets impinging on a plane wall. Various techniques have been used as visualizations (spreading over method, LASER sheet visualizations), LDA measurements to propose a topology schema of the flow and infrared thermography.展开更多
Walls' cooling of aeronautic propeller combustion chamber is performed with the injection, through the combustion chamber wall, of a part of the air coming from compressors placed upstream. Measurements of the wal...Walls' cooling of aeronautic propeller combustion chamber is performed with the injection, through the combustion chamber wall, of a part of the air coming from compressors placed upstream. Measurements of the wall thermal fields are made by infrared thermography along the injection wall. This injection wall is pierced by 9 rows of 8 holes (α=90°) in staggered configuration (p/D=s/D=6). We propose a model using two heat transfer coefficients to represent the convective exchanges. The results are non-dimensioned and presented in comparison with the case without holes. The use of this model allows us to define 4 zones. Those 4 zones exist for the 5 blowing rates.展开更多
基金the Direchon desRecherches, EtUdes et Techniques.
文摘Impinging jets are frequently adapted for cooling overheated parts. With the film cooling technique, this process improves thermal exchanges between walls and fluid. However if many works have concerned only the thermal aspect of this problem [1], its dynamic field has been rarely studied especially for multiple impingements. As the two phenomena cannot be totally dissociated, we have undertaken the aerodynamic and thermal study of jets impinging on a plane wall. Various techniques have been used as visualizations (spreading over method, LASER sheet visualizations), LDA measurements to propose a topology schema of the flow and infrared thermography.
文摘Walls' cooling of aeronautic propeller combustion chamber is performed with the injection, through the combustion chamber wall, of a part of the air coming from compressors placed upstream. Measurements of the wall thermal fields are made by infrared thermography along the injection wall. This injection wall is pierced by 9 rows of 8 holes (α=90°) in staggered configuration (p/D=s/D=6). We propose a model using two heat transfer coefficients to represent the convective exchanges. The results are non-dimensioned and presented in comparison with the case without holes. The use of this model allows us to define 4 zones. Those 4 zones exist for the 5 blowing rates.
