Numerical Observation of Flow Re-stabilizing via Air Injection during the Rotating Stall through a Single-stage Axial Compressor by a 2-D Finite-Volume Approach

تاثيرات تزريق هواي ورودي بر رفتار آيروديناميكي و مشخصه هاي يك كمپرسور محوري بصورت عددي مورد بررسي قرار گرفته است. منحني عملكرد در ناحيه كاركرد يك كمپرسور آزمايشگاهي مشخص بدون تزريق هوا بصورت عددي گرفته شد. براي اعتبار بخشيدن به تحليلگر حجم محدود دو بعدي غير يكنواخت كه بر اساس الگوريتم جداسازي شار ون- لير كه مربوط به محدود كننده هاي TVD و مدل توربولانتK-? بنا نهاده شده است، نتايج محاسبه شده تطابق خوبي با نتايج آزمايشگاهي را نشان مي دهد. در مرحله بعد، براي نشان دادن بهبود منحني عملكرد در حين تزريق هوا نقاط عملكرد به مقادير ناپايدار و خطوط جريان ناپايدار آيروديناميكي تغيير داده شده و در نتيجه كاهش كارآيي محسوسي مشخص مي شود. سپس، براي توجيه عددي تكنيك تزريق هوا، تزريق هواي مورد نياز ورودي بصورت عددي فراهم گرديد و تمامي شكلهاي ناپايدار جريان توسط بهبود مشخص كارآيي برطرف گرديد.

In the present work, the air-injection as an active flow stabilizing techniques were numerically examined during the aerodynamic behavior and the characteristics of an axial compressor. First, in design condition, the characteristic curve was numerically captured for a specified test compressor. The computed results showed good agreements with those obtained from the experiments. They validate the finite-volume solver which was developed based on Van Leer’s flux splitting algorithm in conjunction with TVD limiters and the ?-? turbulence model. At the second step, to examine the performance of the air injection technique unstable condition, the operating points were set for the unstable condition upon the operating map, and the expected unstable flow patterns were captured. At the final step, the numerical simulation was completed with the air injection, and surprisingly, the unstable flow patterns became highly re-stabilized. Consequently, a significant recovery of the performance was augmented. The study could successfully demonstrate the capability of the numerical studies for simulating the active flow controls specifically the inlet air-injection technique using a 2-D finite volume approach.