燃烧室席壁冷却的性能预测与实验研究

On Wall Cooling of Combustion Chamber with "Mat" Type of Wall

在燃烧室流动条件下，对席壁冷却火焰筒的壁温分布及壁面热流等进行了预测，并用实验加以验证．结果表明，相对于原型火焰筒的分段气膜冷却，席壁冷却具有冷却均匀、壁温低、轴向壁温梯度小等显著优点．

A combustion chamber with' mat' type of wall was suggested by NPU (NorthwesternPolytechnical University) professor Zhu and Li (second author of this paper) in 1988. This type ofwall (called mat-wall) is made of longitudinal and transverse metal strips which alternately crossabove one strip and then under the next strip. Such a wall has many pores through which coolant canpass. Part of the heat is carried away by the coolant passing through these pores; moreover, coolantforms a protective film over the hot side of the mat-wall.For a control volume element of the mat-wall, the authors in this paper establish the energyconservation equations and corresponding boundary conditions. Employing numerical iteration, theauthors calculate the wall temperatures and wall heat flux of a flame tube with the mat-wall cooling,which are then compared with experimental results. The authors also obtain relationships connectingcoolant flow number to the following parameters: thermal effectiveness, wall temperature ratio, etc.Both calculated and experimcntal results indicate that, as compared with conventional film coolingof original name tube, the mat-wall cooling possesses obvious advantages: more uniform cooling,lower wall temperature, smaller axial gradient of wall temperature, and much saving of amount ofcooling air needed.