Experimental and numerical investigation of impinging multi-jet system
The main emphasis of the present work is the experimental and numerical analysis of the impact of the swirling multi-jet system on a flat plate. To carry out this study, it was necessary at first to design and achieve an original experimental a test bench with three diffusers arranged in line. The diameter between the axes of their centers is fixed at 2D. The experiments were conducted with four different jet distances to impinging plate (H=2D, 4D, 6D and 8D). The swirling jet is obtained by a generator consists of 12 arranged vanes at 60 ° from the vertical placed just the diffuser exit. The current study is carried out under uniform heat flux condition for each diffuser at Reynolds number of 30·103, the air being the working fluid. Experiences concerning the fusion of several jets show that the resulting jet is clearly more homogenized under swirling influence. In this perspective, the paper discusses influence of different factors such as the multi swirling jets, the impact height, the conditions for entries temperatures and velocities, and the swirl direction of the central jet on the effectiveness of ventilation performance and optimizing the best configuration. The CFD investigations are carried out by an unstructured mesh to discretize the computational domain. In this work, the simulations have been performed using the finite volume method, in which the standard k-ε, is used for turbulence computations. The validation shows that the K-ε model can be used to simulate this case successfully. The results show that the examined parameters have a significant effect on the flow characteristics and behavior of multi swirling impinging jet.