احمد آذری

Failing of the compressor impeller has caused increasing operational costs in the Morvarid Petrochemical Company. The purpose of this study is to find out the reason for the problem and also investigate to recognize ways of reducing and preventing situations that cause this problem. Therefore, the causes of Turbo Expander blades breakdown are studied. In the following, ASPEN HYSYS software to determine the thermodynamic status of the flow stream in the Turbo Expander has been utilized, there are two approaches for thermodynamic studies to avoid two-phase condition: 1. The effect of adding methane to the inlet gas 2. The effect of adding hydrogen to the inlet gas The results showed that adding methane has a negative effect and its addition to the current leads to increase condensation. However, hydrogen has a positive effect and, if approximately 1100 kg/hr of hydrogen is added to the gas stream, the thermodynamic conditions of gas can be stable in terms of physical properties and phase change will not occur. Also to evaluate velocity, pressure and other key variables of the flow stream along with the domain commercial software ANSYS Fluent has been employed. Also, CFD modeling of the effect of flow hydrodynamics on the HP and LP compressor blades at different rotor speeds is investigated and analyzed. The results revealed that the maximum pressure of gas stream for the rotor speed of 18300, 25590 and 34500 has taken place in the area of a blade that already breakdown took place and the pressure gradient at HP compressor of the aforementioned rotor speed is 10000 (Pa), 20000 (Pa), and 40000 (Pa), respectively. It seems when the rotor speed increase, the pressure gradient will be grown. The wall shear stress (WSS) contours indicate the maximum of WSS occurs at the breakdown zone of the blade. The value of WSS for the HP compressor at the rotor speed of 18300, and 34500 approximately is 180 (Pa), and 360(Pa), respectively. The effect of two-phase flow on the blades was