Optimal design of impinging jets in an impingement/effusion cooling system

To design an impingement/effusion cooling system that realizes the lowest thermal stress in an impingement/effusion cooling system, we conducted thermal analysis and optimization using a second-order response surface method. The optimal impinging jet system was based on four design variables: the spacing between the impinging jets and effusion holes (1.0 ≤ Sp ≤ 5.0), the channel height from impinging jet to effusion surface (1.0 ≤ Ht ≤ 3.0), the mass flux ratio of the crossflow to the impinging jet flow (0.1 ≤ G∗ ≤ 1.3, −1.3 ≤ G∗ ≤ −0.1), and the main flow temperature (1100 K ≤ Tm ≤ 1800 K). We considered several cases involving inlined and staggered jets, and two cooling flow direction: the same direction and reverse direction. Response surface functions were constructed to determine the impinging jet system with the lowest value among the maximum stresses calculated within the design ranges. In each case, the response surface function for determining the maximum stress was composed of combinations of the four design variables. These functions can be used to find the optimum design point that achieves the lowest stress around film cooling holes in hot components of a gas turbine.