Aerodynamic investigation of impingement cooling in a confined channel with staggered jet array arrangement

• We study the flow characteristics and the aerodynamic parameters of a confined channel with a staggered jet array arrangement.
• The height of the passage has an important influence on the flow characteristics and the aerodynamic parameters of the confined channel.
• The jet impinges on the target wall effectively only in the upstream region of the passage.
• The vortices create secondary flows in the passage and push the high velocity flow to the side walls and the top wall.

An enlarged model of a confined channel with staggered circular impingement jet holes and an exit hole was built. The cross flow was induced in the passage by the outflow of the exit hole. Experiments were performed to measure the flow field in the passage. The variations of mass flux distribution, static pressure and discharge coefficient were also studied. Jet Reynolds number of 10,000, 25,000 and 65,000 with Zr (ratio of passage height to diameter of impingement hole) of 1, 3 and 5 were considered. Experimental results showed that the jets impinged the target wall effectively along the entire passage of Zr = 1. But they were deflected by the cross flow in the downstream region of passage of Zr = 3 and 5. The impingement induced strong secondary flows in the passage that caused high velocity flow moving to the side and top walls. The flow structure in the passage changed distinctly with the increases of Zr. Mass flux distribution, static pressure and discharge coefficient were mostly dominated by Zr under the present test condition.