Thermal visualization of jet impingement inside semi-confined rib-roughed channel was tested by thermograph to investigate the effects of impinging Reynolds number

jet-to-surface spacing as well as the ribs arrangement on heat transfer characteristics.The discharge coefficient for jet impingement was also analyzed.Results show that the impingement cooling effectiveness of ribbed surface is affected extremely by the jet-to-surface spacing

and the best effectiveness is achieved under the jet-to-surface space equaling to 1;the rib pattern also exerts great impact on cooling effectiveness

in present research the V-shaped ribs have best performance;the discharge coefficient is enhanced with the increase of impinging Reynolds number and the best result is obtained in V-up channel.