نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشکده ی مهندسی مکانیک، دانشگاه صنعتی اراک
2 دانشکده ی مهندسی مکانیک - دانشگاه صنعتی اراک
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
The present study investigates the speed effect of rotational rotors on the
performance of contra-rotating axial compressor and flow behavior. In the
present study, a two-stage contra-rotating axial flow compressor with rotor-stator-rotor configuration is considered. The results are presented based
on numerical viscous flow simulation in three dimensions by solving Navier-Stokes, continuity, and energy equations using Ansys CFX commercial
software. Initially, to validate the results, the absolute and relative flow
angle curves for each rotor in the radial direction were extracted using the
present simulation and compared with the other investigations. To investigate
the effect of different rotor speeds, five different speeds of the second rotor
are considered. In the first and second cases, the second rotor speed is
reduced by 20 to percent compared to the reference case (in the third case,
the speeds of the first and second rotors are equal) and in the fourth and
fifth cases, the speed of the second rotor is increased by to percent. The
results show that increasing the second rotor speed in the fourth and fifth
cases decreases the vortex flows, the blockage in the blade passage and
consequently, decreases the flow entropy. The compressor performance curve
shows a higher mass flow rate and pressure ratio. In contrast, decreasing the
second rotor speed results in undesirable behavior in the flow structure even
under design and choke conditions, leading to enhanced tip leakage flow and
increased flow entropy which in turn decreases pressure ratio and mass flow
rate as well. Results show that by reducing the revolution of the second rotor
(in Cases I,II), the tip leakage flow is stronger, resulting in the interface of the main flow and tip clearance flow to upstream which creates vertical flows in design and chock conditions as well as stall condition. This occurrence causes an increase in the original losses and entropy in the compressor.
کلیدواژهها [English]
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