Quasi-Unsteady Numerical Simulation Of The Impeller-Volute Coupling Characteristics In Stamping-Welding Centrifugal Pump

The method of CFD is adopted to simulate the internal flow of stamping-welding centrifugal pump under the quasi-unsteady condition, on the basis of analyse of the relationship between impeller-volute coupling characteristics and hydraulic performance, the performance prediction is validated by experiments. At last, in view of the reflux and separate flow under the off-design conditions in the impeller and volute, the optimum methods are brought forward accordingly.Based on hydraulic design and the numerical simulation and experiment results, the performance and inner flow field of stamping-welding centrifugal pump are summaized. The main work is outlined as following:1．By means of the "frozen rotor method", the coupling characteristics between impeller and volute are simulated using 3-D quasi-steady method. The low-pressure section of tongue becomes to augment gradually along with the variety of impeller and volute relative positions. Under low flow rate condition, the inner flow field of impeller comes into being serious reflux; under large flow rate condition, the volute outlet presents obvious separate flow.2．The static pressure distribution of impeller and volute is discussed, which is situated at the circumferential direction of the impeller-volute coupling surface. The maximal and minimal static pressure are occurred in the range of sectionⅣand the tongue; because of the interaction between the tongue and the flow field of impeller outlet, the static pressure values has a sudden break nearby the tongue flow field.3．The quasi-steady-based numerical prediction is adopted to stamping-welding centrifugal pump. In the different relative positions stamping-welding centrifugal pump. In the different relative positions between impeller and volute, the predition values such as head,hydraulic power and hydraulic efficiency are fluctuated obviously; In comparison with performance prediction and experiments, the quasi-steady performance prediction has a good precision under the design condition, and under the off-design conditions, the maximal error between performance prediction and experiment results is no more than 10%.4．The radial force mathematical model of stamping-welding centrifugal pump is established. The maximal radial force occurs under the low flow rate condition, and the minimal radial force occurs under the large flow rate condition. Under the low flow rate condition, vector direction of radial force has a range from section Ⅲto sectionⅤ, as well as from sectionⅦto the tongue under the large flow rate condition.5．On the basis of numerical simulation and predition, the optimization and main measures are brought forward, which can effectively control the reflux at the impeller outlet and the flow separation at the volute outlet. Consequently, the hydraulic performances of stamping-welding centrifugal pump are improved, and the design requirements of non-overload characteristics are obtained.