An experimental study of impingement cooling on latticework in a wide channel

Previous researches on latticework were focused on the convective heat transfer performance on pressure and suction sides of a blade model. Besides, it has an effect on leading edge by impingement. Thus, the present study provides heat transfer enhancement and pressure loss of jet impingement of a latticework on side wall in a wide channel (AR=4). Two latticework configurations with impingement effects are employed in this study. Three kinds of sub-channel models are used in this experiment, which is according to different cooling designs. The angle of the rib is 45° and the numbers of sub-channel are 4, 6 and 8, respectively. Reynolds number range is from 10000 to 30000 with an increment of 10000. The wall temperature is obtained by using wide band liquid crystal technique, and then the heat transfer coefficients on the target surface of the channel are achieved. Pressure drop of the latticework channel is also measured by pressure taps. The result shows that these two latticework models have different flow and heat transfer characteristics. The Nusselt number distribution is not similar to that of traditional jet array impingement. The range of Nusselt number enhancement is 2.3 to 6.4 compared to that of a smooth convective channel (the Nusselt number is based on the channel hydraulic diameter). The jet-to-target distance could reduce the overall averaged heat transfer on side wall. But it could also lead to a high Nu region. To the normal lattice model, more sub-channels there are, more pressure loss it has. To the novel lattice model, sub-channel number cannot affect the pressure loss, but the jet-to-target distance could affect the friction factor obviously.