The Brake Performance of Hydraulic Retarder and Simualtion Research on Its Application for Aircraft Arrestment
|School||Harbin Institute of Technology|
|Course||Power Engineering and Engineering Thermophysics|
|Keywords||Hydraulic retarder Aircraft arrestment Performance prediction and Simulation|
Aircraft arrestment system (AAS) is an important safeguard device for airports. It’s utilized to arrest the aircraft that rush out of the runway because of accident to provide safety for pilot and aircraft. The performance of an arrestment system will directly influence the overloading an aircraft can bear, the overrunning length in safety and the changes of belt tensile force. So the system configuration parameters of the system should be studied synthetically in order to be optimal when the system is under design. Because the hydraulic retarder has similarity of structure with water turbine, also compact and easy for maintenance, the dissertation takes hydraulic retarder as research object. Then its structure characteristics and torque performance prediction are analyzed. The analysis results can be valued as practical reference for the retarder’s structure design and performance analysis.The dissertation consists of two parts: one part is about the performance calculation of the hydraulic retarder. At first we calculated the brake torque by three means of hydraulic numeration (1 dimensional calculation), similar numeration and computational fluid dynamics (CFD) method. Focused on the CFD method, we worked out the modeling of circle cavities using software UG, displayed the flow field of interior cavity, the pressure field and the velocity field were also showed using CFX, a CFD software. At last the torque quantity was obtained. The other part is about the simulation analysis of hydraulic braking system for aircraft arrestment. First of all, the structure and principle of hydraulic brake system was analyzed, the rule of arrestment force was discussed, also the process of arrestment was analyzed using kinematics and dynamics, the mathematics model of hydraulic braking course was established and the changes’connection between velocity and force was obtained as well. Then we simulated the arrestment system, and the relations that some variables like arrestment force, velocity and overloading vary with time were observed. In this course, we also discussed the principle how the hydraulic retarder provided constant brake torque by varying oil fill during the hydraulic arrestment procedure.Comparing with CFD performance prediction, the hydraulic numeration will bring biggish error when the retarder revs even at high speed. That’s because the hydraulic numeration refers to many experiential coefficient and they correlate with working conditions. However, the CFD performance prediction synthesizes the changes of working condition and the particular details of inside flow; it will produce a better believable result, and provide an effective tool for torque analysis and calculation.