Internal flow characteristics of centrifugal fire pump
WANG Yue1,2, LU Xin3, WANG Kai4*, LIU Houlin4, TAN Minggao4
1. School of Power and Energy, Northwestern Polytechnical University, Xi′an, Shaanxi 710072, China; 2. China Aviation Development Xi′an Power Control Technology Co., Ltd., Xi′an, Shaanxi 710077, China; 3. Xi′an Aerospace Power Research Institute, Xi′an, Shaanxi 710100, China; 4. National Research Center of Pumps, Jiangsu University, Zhenjiang, Jiangsu 212000, China
Abstract：In order to study the external characteristics, internal flow characteristics and cavitation characteristics of the centrifugal fire pump, numerical analysis was carried out based on the RNG k-ε turbulence model to compare the internal unsteady flow of the centrifugal fire pump with a specific speed of 24.7 under different working conditions. The results show that under the shut-off condition, a lot of stall vortices are generated in the impeller of the centrifugal fire pump, especially the vortex core distribution with large area and extremely high turbulent kinetic energy appears at the outlet of the impeller, which seriously affects the flow passage capacity and causes a lot of energy loss. With the increase of flow rate, the vortex in the channel disappears gradually, the flow field tends to be stable, and the distribution of vortex core basically fixed and symmetrical. With the continuous increase of flow rate, the axial force of centrifugal fire pump increases gradually, and the fluctuation of axial force is relatively strong under the conditions of minimum flow rate and maximum flow rate. With the increase of flow rate, the radial force decreases gradually, and the vector distribution of radial force under different working conditions presents a six tooth distribution. With the increase of flow rate, the influence of cavitation on the head characteristic curve of centrifugal fire pump is more obvious. When the head curve begins to decline, the NPSHR increases gradually, but the decline speed is relatively slow.
