The turbine flow near the endwall is highly three-dimensional flow. The injection flow has been investigated widely as an effective way to increase turbine efficiency. For the current study, the interaction between the main flow and the injection control flow from flat endwall, is analyzed by numerical simulation. Flow injection were done using five endwall holes placed on a typical flat blade cascade near the blade suction side with six different inclination angles arrangements. In these test cases all the five holes has the same inclination angle. In addition, two new injection test cases, namely, mixing inclination angles in which each hole has an inclination angle independent of other holes. The new injection arrangements techniques have proved its effectiveness in increasing blade loading by 1.71 % more than baseline test case blade loading. Also, it proved its effectiveness in suppressing the flow losses by 2.1 % less than baseline test case losses. Moreover, all selected test cases gave positive different readings with respect to blade loading by increasing the static pressure on the blade surface and preventing boundary layer separation at the suction side and hence reducing the large undesirable effects of secondary flows.

The aerodynamics of the flow in a turbine stage is complex and still the subject of many ongoing researches. The secondary flow is the major source of aerodynamic losses in a turbine stage. Fluid injection from the endwall is used to improve the aerodynamic performance. For the current study, the change of injection blowing ratio has been investigated as an effective way to increase turbine efficiency by mitigating the strength of vortices. The interaction between the main flow and the injection flow from flat endwall is analyzed by numerical simulation. Five endwall injection holes were placed near the blade suction side on a typical flat blade cascade with two injection blowing ratios. In these cases, each hole has the same blowing ratio. Furthermore, two other test cases (mixing blowing ratio) in which every hole has its own blowing ratio independent of other holes. The new injection arrangements techniques have proved its effectiveness in increasing blade loading by 1.85 % more than baseline test case blade loading. In addition to suppression flow losses by 2.1 % less than baseline test case losses.