Experimental study of the flow structures of the concave surface with inclined impingement in limited space

Smoke wire flow visualization was used to investigate the characteristics of the flow structures of a round jet inclined impingement on the concave surface in limited space.Reynolds number of impingement,inclined jet angle,the ratio of the jet distance to the diameter of the jet hole and the relative curvature(the ratio of the diameter of jet hole to the diameter of concave surface) were changed to study the rules of flow structures varying with these parameters.At the same time,the developing and disappearing phenomena of the induced vortex were analyzed.All the experimental results show that,around the stagnation region,it can form swirl structure and generate vortex because of inclined jet and curvature of target concave.The central angle of the impingement fluid separated from the target surface became larger with the increase of jet Reynolds.And the separating angle also increased with the increasing ratio of the jet distance to the diameter of the jet hole,while the range of induced vortex became smaller.It was also found in experiments that,because of the influence of the inclined impingement’s angle,it is easier to generate vortex at the left of the stagnation region where the relative jet angle is smaller.