Investigation Of Flow Characteristics In Trapezoid Channel With Jet/ Swirl/ Film Flows

Recent developments in soluble core casting technology have allowed very intricate internal passages to be manufactured. This has opened up the possibility of cooling by impingement in turbine blades. Because of impingement jets with high heat transfer and small internal passage, the jets cause swirl flow which provides further heat transfer enhancement. This thesis details the experimental measurement of both channel and outlet hole flow fields which model the intricate passage in turbine blade. And the detailed knowledge of the heat transfer enhancement in this configuration is understood.The major works of this study are following:1)The velocity fields and pressures along channel wall are measured, which find out the characteristic of flow fields in the channel and the interaction between jets and swirl flow.2) The velocity and discharge coefficients of side-wall outlet holes and film holes are measured, which consider the influence of jet angle, jet Reynolds number and cross-flow.3) The velocity of the flow with high angle is measured by a seven-hole-probe. And this probe is systematically investigated, including designing, fabricating, calibrating and data collecting and experiment results post-proceed program developing.4) Numerical results from commercial software (FLUENT) are compared with the experiment results.The major conclusions of this study are following:1) The effects of jets, cross-flow and different position outflow on the flow fields in the channel are strong. In the investigated cooling channel with different angle stagger jets, the big jets cause swirl flow in the middle of channel and make the swirl flow stronger. The mass flow rate and position of film outflow are less effective on the flow field in the channel. Different mass flow rate of film outflow change the flow field near the target surface, but the flow field in the channel isn't influenced. There are no relation between mass flow rate of cross-flow and swirl flow intensity.2) The flow field in side-wall outflow hole changes with the cross-flow mass rate. The jet angle and Reynolds number, mass flow rate and position of the film hole don't affect the flow field in the outflow hole as well. The cross-flow influence the flow field of downstream outflow.3) The discharge coefficients of the side-wall outflow hole are affected by the jet angle and cross-flow mass flow rate. The variation of the jet Reynolds number doesn't change discharge coefficients of the side-wall outflow hole significantly. The jets Reynolds number affects the discharge coefficients of film hole located near the jet.4) The numerical simulation provides more detailed flow fields than the experimental data. The results from numerical simulation agree well with the experiment data. It is possible to get the near-wall flow field by numerical simulation, which is difficult to be hunted.