Investigation Of Impingement/Effusion Float-wall Cooling Of Flame Tube

With the rapid development of modern aeroengine, various novel cooling methods and configurations of combustor flame tube have been developed. The impingement/effusion cooling float-wall (I/ECFW for short) flame tube is one of the most prospective configurations.In this thesis four main research works are conducted. Firstly, an experimental investigation of flow and heat transfer process of I/ECFW composite cooling is studied. The discharge coefficient of the equivalent holes, impingement heat transfer coefficient on the cold side of the effusion wall, convective heat transfer on film side of effusion wall and inside effusion holes, and adiabatic wall film cooling effectiveness are studied in details. The empirical formulas of heat transfer are correlated based on the experimental data.Secondly, the cooling effectiveness of a single swirler sector combustion chamber and a full size annular combustion chamber are experimentally studied respectively. Both combustion chambers adopt the I/ECFW cooling method. By the former experiment, the cooling effectiveness of several combinations of impingement holes and effusion holes are compared. This study lays the foundation for optimizing the cooling configuration. The latter experiment is carried out under the real engine condition to validate the cooling effectiveness.And then, the three dimensional temperature field of the I/ECFW is numerically calculated by using the heat analysis module of ANSYS code. The results show a reasonable agreement with the experimental data.At last, the prospect of how to reliably and efficiently use I/ECFW composite cooling technique on high performance aeroengine are discussed. Some suggestions are arisen.The main results of the study are as follows,1. The I/ECFW flame tube requires less cooling air, which is only about 18%~20% of the total inlet flow rate of the flame tube. The temperature of flame tube is less than 900℃. Temperature gradient is relatively small. For a float-wall tile the maximum temperature difference in the flow direction is about 200℃that is far smaller than the corresponding film slot cooling flame tube.2. There are many factors that influence cooling effectiveness of the I/ECFW configuration. These factors often have conflict effect and act against each other. So the I/ECFW configuration should be designed and adjusted carefully. 3. The calculation method for 3D temperature field of float-wall tile is feasible for engineering use, which has reasonable accuracy and can provide the required data for estimating the intensity and life span of flame tube.