Study Of Gas-liquid Two-phase Medium Of Hydraulic Turbine Force Characteristic

Hydraulic turbine is an energy recovery device, it can recycle the high pressure liquid energy in the process. The pressure liquid of the PAT is containing the gas medium in the actual industrial production. And the presence of the gas not only influence the internal flow of the PAT, but also influence the radial force and the axial thrust of the PAT. Therefore, research the internal flow of the pump as turbine and the influence of the radial force and the axial thrust of the pump as turbine is of great significance when it in the gas-liquid two-phase medium. The article by using the CFD method to numerical simulation the PAT modes in air content of φ=0.00、0.05、0.10、0.15and0.20. At the same time, research the radial force and the axial thrust of the PAT at five flow conditions of Q=78、83.2、88.4、93.6、98.8m3/h,and the main work and research results are as follows:1.Through the comparison and analysis of the external characteristics of the PAT in the different volume fraction of inlet gas we can make the conclusion that the PAT had the highest efficiency in the water medium, and the efficiency of PAT was decreasing gradually with the volume fraction of medium gas increased in the gas-liquid two-phase medium.It indicated that the gas was much more influenced the efficiency of the PAT. The power of the PAT in the gas-liquid two-phase medium was lower than it in the water medium, and it was decreasing gradually with the volume fraction of medium gas increased. Pressure head of the PAT was increasing gradually with the volume fraction of medium gas increased in the gas-liquid two-phase medium,and it was increasing gradually with the increased of flow rate in the gas-liquid two-phase medium.2.Through the analysis of the internal flow field of the PAT we get that the internal flow of gas-liquid two-phase medium of the PAT has become intensified with increasing volume fraction of inlet gas, and the relative speed becomes larger. The PAT internal was filled gas but the distribution of the gas is not very uniform.And the pressure was decreasing gradually from inlet to outlet of the PAT. Therefore, the gas expanded at the outlet of the PAT and made the gas volume fraction becomes larger.3.The radial force is one of the main factors affecting the stable operation of the PAT. By using the CFD method to numerical simulation the PAT we can get the radial force of the size and direction of the PAT in the different volume fraction of inlet gas,and analysis of radial force influence on the PAT.The radial force of the PAT in the different volume fraction of inlet gas was decreasing at first and than increasing as the flow increased and decreased rapidly as the air content increased. The direction of the radial force is concentrated in the Angle between80°to130°.4. The axial thrust is one of the main factors affecting the stable operation of the PAT. In order to quantitative analysis the axial thrust of the PAT and study on the axial thrust by the media influence and variation law with medium. By using the CFD method to numerical simulation the PAT we can get the axial thrust of the size of the PAT in the different volume fraction of inlet gas and different flow medium,and variation law of axial force and the radial force influence on the PAT.The axial thrust decreased at first and than increased with the increasing flow and decreased rapidly as the air content increased in the two-phase condition.