|
|
|
| Numerical simulation investigation of entrapped air pocket based on TFM model and PIV test research |
| LUO Shuang1, CHEN Qi2, LIU Xia3, JIANG Jin1*, PENG Yu1 |
| 1. College of Power and Machinery, Hubei University, Wuhan, Hubei 430072, China; 2. Hubei Water Resources Research Institute, Wuhan, Hubei 430070, China; 3. Hubei Water Resources Technology Promotion Center, Wuhan, Hubei 430070, China |
|
|
|
|
Abstract In order to investigate the dynamics characteristics of entrapped air pocket in the summit of hydraulic pipeline, a more effective numerical simulation method is sought. The multiphase flow field of entrapped air pocket has been established by the two-fluid model(TFM), and the analysis has been conducted by compared with the prediction results of VOF model. In addition, the velocity distribution of the air pocket′s local flow field has been measured by the particle image velocimetry system(PIV). Thus, the rationality of the simulation method can be verified. The results indicated that: In the process of the entrapped air pocket moving downward with the flow, the great flow velocity gradient at the front of the entrapped air pocket makes the regional flow pattern disordered, leading to the failure of the surface tension of the entrapped air pocket to maintain its shape and then breakage occurs. VOF model cannot simulate the relative motion of gas and liquid phase, the predicted speed of the air pocket was significantly larger than the actual value.The TFM model fully considers the influence of momentum transfer and relative velocity between gas and liquid, which can accurately predict the dynamics beha-vior of air pocket and velocity distribution of flow field. In conclusion, compared with the VOF model, the TFM model can provide more reasonable prediction results.
|
|
Received: 05 March 2021
|
|
|
|
|
|
|
