مرتضي خيوي

The Aim of This Research was to Study The Impact of One of The Methods of Passive Controling Aerodinamic Instabilities of The Flow Such as Stall and Surge as The Vane Recessed Recirculation Cavity Casing Treatment In A Low Speed, One Stage, Laboratory Axial Flow Compressor. In This Study, The Flow Crossing The Axial Flow Compressor In Two Structure of With and Without Casing Treatment was Numerically Simulated and The Results has been eva‎luated. This Thesis Helps to Understand The Physical Process of The Flow Near to Stall and The Mechanism of Improving The Stall Margin by The Vane Recessed Recirculation Cavity Casing Treatment. Numerical Simulating In The Steady State was Done by ANSYS-CFX 2019 R2 Software With RANS Solver and SST Turbulence Model. The Simulated Results Indicated That Numerical Solution In The Steady State are Enough For Visualization of Reverse Flow Crossing From The Axial Flow Compressor and Vane Recessed Recirculation Cavity Casing Treatment. The Numerical Simulation Results Of The Axial Flow Compressor with Vane Recessed Recirculation Cavity Casing Treatment with (23.2%) Rotor Blade Tip Axial Chord Exposure and Solid Casing Structure were Validated by The Experimental Results of Supervisor Master Done in The Cranfield University. The Overall Performance characteristics of The Compressor had Good Conforming With The Experimental Results. In Order to Realize The Numerical Simulation, Several Assessments were done based on Functional Specifications by Using Three Main Parameters Pressure Ratio, Pressure Rise Coefficient and Efficiency. In This Study, The Attention has been Paid to Diagnosis The Best Performance Between Four Configurations of The Vane Recessed Recirculation Cavity Casing Treatment with Semi Tubular, Semi Circular, Semi Elliptical and Semi Hearted Shape. The Performace Of Different Configurations from The Perspective of The Stall Margin and Improving it and The Loss or Increasing The Efficiency was also Investigated. In The Point Of The View of Achieving Improvement or Sacrificing of The Efficiency, In The Situation Which Two Structures With or Without Casing Treatment on Numerical Calculations were Compared, The Most Improvement of Stall Margin Relative to Corrected Mass Flow Rate was related to Semi Tubular Configuration, with value (21.408%). The Mentioned Assessment, According to The Pressure Rise Coefficient, Indicated That The Most Percent of The Stall Margin In The Amount of (3.947%) Related to Semi Tubular Configuration. The Most Improvement In Stall Margin Based On Combined Equation of Pressure Rise Coefficient and Flow Coefficient was Obtained by Semi Tubular Configuration In The Amount of (22.868%). Based on Numerical Simulation Results, in Order to Achieving to The Highest Improvement of Total-Total Isentropic Efficiency According to Peak Point, The Semi Tubular was The Best Configuration with The Amount of (6.029%).

استال و سرج , جداره بهبوددهنده

Stall and Surge , casing treatment

Morteza Khivi

Dr. Akhlaghi