CENTRIFUGAL COMPRESSOR HEAD CHARACTERISTIC OF A MICRO TURBOJET ENGINE BASED ON NUMERICAL SIMULATION

Shown the possibility of using the standard ANSYS CFX hydrodynamic software package for calculating the gasdynamic characteristics of the centrifugal compressor impeller of micro turbojet engines with different options for profiling blades which based on physical and numerical modeling. Presented a methodology for designing the impeller of a centrifugal compressor based on solving the inverse problem of gas dynamics. As a result of a numerical study, the head coefficient of various forms of the impeller was obtained and presented the dependences of the head coefficient and efficiency on the blade back sweep angle 2 β . b The article discusses the effect of the blade back sweep angle 2 β b on the compressor efficiency and the head characteristic for three different values of the blade back sweep angle 2 β b for example, the impeller with the back sweep angle  2 β b and with the radial blades  2 β 90 b and with blades bent forward  2 β b The centrifugal compressor was designed using Vista CCD programs in one-dimensional computing and Fluid flow CFX in three-dimensional computing. For blade profiling, the BladeGend program was used with different profiling options in order to improve compressor efficiency. The computational grid and the construction of a structured hexahedral mesh for the impeller was carried out in Ansys Turbogrid and the SST model of turbulence was selected in the calculation, which, with sufficient grinding of the mesh at the walls, adequately simulates separated flows at the channel walls, as well as the flow in the flow core. When constructing a grid along the walls between the channel blades, the parameter y + was controlled, which should not exceed 2. It is permissible to use a coarser grid in the flow core compared to the grid near the walls. The design grid of the impeller consists of 350000 elements.

The Technology Head Characteristic Frequency Reading and Research on Technology and Material Parametres Influence on AWJ Technology Manufacturing Systems Technology Head Reverberance

The paper describes a vibrations acceleration signals scanning and processing principle at technology head characteristic frequency reading during AWJ manufacturing process.