توجه: محتویات این صفحه به صورت خودکار پردازش شده و مقاله‌های نویسندگانی با تشابه اسمی، همگی در بخش یکسان نمایش داده می‌شوند.
۱NUMERICAL INVESTIGATION ON COMPRESSIBLE FLOW CHARACTERISTICS IN AXIAL COMPRESSORS USING A MULTI BLOCK FINITE VOLUME SCHEME
اطلاعات انتشار: International Journal of Engineering، پانزدهم،شماره۱، February ۲۰۰۲، سال
تعداد صفحات: ۱۴
An unsteady two–dimensional numerical investigation was performed on the viscous flow passing through a multi–blade cascade. A Cartesian finite–volume approach was employed and it was linked to Van–Leer''s and Roe''s flux splitting schemes to evaluate inviscid flux terms. To prevent the oscillatory behavior of numerical results and to increase the accuracy, Monotonic Upstream Scheme for Conservation Laws (MUSCL) was added to flux splitting schemes. The Baldwin–Lomax (BL) turbulence model was implemented to solve the turbulent case studies. Implicit solution was also provided using Lower and Upper (LU) decomposition technique to compare with explicit solutions. To validate the numerical procedure, two test cases are prepared and flow over a NACA0012 airfoil was investigated and the pressure coefficients were compared to the reference data. The numerical solver was implemented to study the flow passing over a compressor cascade. The results of various combinations of splitting schemes and the MUSCL limiter were compared with each other to find the suitable methods in cascade problems. Finally, the convergence histories of implemented schemes were compared to each other to show the behavior of the solver in using various methods before implementation of them in flow instability studies.

۲A 2–D NUMERICAL INVESTIGATION ON THE MODAL CHARACTERISTICS OF ROTATING–STALL WITH A VARIABLE–CASCADE– LENGTH APPROACH IN AN AXIAL COMPRESSOR
اطلاعات انتشار: International Journal of Engineering، شانزدهم،شماره۱، April ۲۰۰۳، سال
تعداد صفحات: ۱۰
The Rotating–Stall (RS) through a rotor–cascade of an axial compressor were numerically investigated with an unsteady two–dimensional finite–volume density based computer code. To validate the computer code, a test case was prepared and the good agreement of the compared results has given the adequate assurance of the code. The RS was incepted with a 40% reduction in flow coefficient and a 0.4% increase in the load coefficient from their normal operating values. The velocity traces from numerical probes, for all chosen number of blades had a periodic behavior, during RS effect. It was also concluded that the captured modal characteristics of RS may vary with varying the number of blades and this variation may cause various modes of RS. Moreover, in each mode, decreasing the number of blades may cause phase lag times in stall progress. In studied cases, approximately two modes and a transient mode were captured which had different rotational speeds and modal characteristics. Finally, a minimum required number of the blades for the RS inception studies (in spite of large numbers in previous works) was proposed, to intensify the probability of using shorter cascades in stability margin calculations of a compressor.
نمایش نتایج ۱ تا ۲ از میان ۲ نتیجه