Heat Transfer Of "Impingement/Sparse Film Holes" Double-Plate In Static And Rotating State

With the improvements of aeroengine performance, turbine inlet temperature increases accordingly. General configuration of turbine blade can not go with the current, which requires new cooling method or cooling configuration. Impinging cooling combined with film cooling functions very well in cooling turbine vane with low cooling air consumption, and the cooling method is also applied in the leading edge region of turbine rotator blade."Lamilloy Blade"and"Double Plate Blade"have been paid enough attention by international researchers engaging in aeroengine hot-part cooling. These cooling methods have comprehensive advantages of hot-side film cooling, internal impinging cooling and convective cooling. They have been considered as promising cooling concepts to meet the requirements of modern advanced aircraft engines. Experimental and numerical study were conducted to investigate detailedly the heat transfer of"impingement/sparse film holes"double-plate, in order that it can be employed in turbine blade entirely.In static state, interior heat transfer investigation about"impingement/effusion"cooling have been carried out. The parameters which effect on the local heat transfer include impinging Reynolds Numbers, crossflow-to-jet mass flux ratio based on each channel/jet hole section area, film outflow-to-crossflow mass flux ratio based on film cooling hole/channel section, nodimensional channel-height and distance between jets and effusion in flow direction. What are the characteristics of local heat transfer near film holes and how effusion effect on impingement are made known based on the above research. That provides with theoretical knowledge for optimizing configuration and determining proportion of impingement. According to the experimental condition, numerical simulation has been done to reveal the details of the flow field in the test-section, in order that experimental result is explained with reason. The research above also indicates that heat transfer enhancement caused by impingement is much stronger than that caused by film bleed. In smaller distance between jets and effusion in streamwise or spanwise direction, it takes place that some part of jets flow through film holes directly without impinging and cooling the target wall very well. This results in reduction of impinging efficiency. In a certain distance between jets and effusion, the film outflow is helpful to heat transfer of target wall. One hand, film extraction can cause heat transfer enhancement. On the other hand, film outflow decreases the amount of crossflow which results in the deflect of jets.Impinging cooling and effusion cooling have each characteristic and affect each other. Heat conduction between external and internal blade wall will contribute to interior heat transfer very much. Rotation has effect on flow and heat transfer. In conclusion, a kind of"impingement/sparse film holes"double-plate is conducted, and it is employed anticipantly in rotating blade. Firstly flow and heat transfer in double-plate configuration is modeled and analysed in theory. Control equation solver expressed by function relation is obtained, that is to say, main factors affectting flow and heat transfer are found out. This provides the latter experimental and numerical research with theoretical support.In rotating state, exprimental investigation of internal heat transfer characteristics of"impingement/sparse film holes"double-plate have been carried out based on the above theoretical analysis. Jet Reynolds numbers and rotation numbers and wall-to-jet temperature difference ratios are varied, such that rotation effect on heat transfer is obtained. In order to know quantificationally contribution of clapboard to overall heat transfer of double-palte, experiment was made in condition of adiabatic clapboard at one time. Its experimental results compared with that in condition of heat-conduction. Research results indicate that target wall heat transfer is enhanced with increasing of impinging Reynolds Numbers. Rotation can weaken heat transfer. Buoyancy body force has very little effect on heat transfer in experimental parameter range. The effect of Coriolis and centrifugal forces on heat transfer relate nearly to coolant flow structure and outflow mode. It indicates that the heat transfer in condition of heat conduction clapboard is 15% stronger than that in condition of adiabatic clapboard.Then, detailed numerical investigation of internal flow and heat transfer characteristics of double-plate configuration has been carried out. Numerical condition is the same with that of experiment. Details of flow and temperature field were shown detailedly and roundly, especially for new flow field chacteristics caused by rotation. Numerical results show that jet bending, impinging roll-vortex, secondary flow and film bleed patterns affect heat transfer very much. Numerical results also explain the experimental conclusion well.At last, numerical study about heat transfer of double-plate midchord region heated by hot gas is carried out in actual aeroenging condition. The results about double-plate also compared with that about fully film and that without interior convection cooling, and the performance of double-plate configuration is better than those of the latters. The coolant pressure-drop caused by doubule-plate may improve the film cooling efficiency.