Investigation On1D/3D Coupling Simulation On Pump System During Transient Process

In many applications, the startup,shut down of a centrifugal pump and adjusting of valve opening may lead to transient performance and excessive loads of facilities and piping systems. In the transient process of complex pump system, the internal flow characteristics of centrifugal pump, valve and heat transfer such key components and transient hydraulic performance of complex pipeline system needs attention. CFD models for such systems are usually large (typically many hundreds of thousands of cells) and take considerable time to construct and validate, and one dimensional simulation cannot give details of key components’internal performance. To overcome those disadvantages and gives rise to uncertainty when specifying the values for boundary conditions at the component inlets/outlets, it is essentially important to study on the co-simulation of3D internal flow of the key component and1D transient performance of the surrounding flow circuit to be applied for transient process. This allows the simulation to take account of the performance of an individual component when considering the system transient performance. The method can provide references for the performance prediction and fluid control of the transient process in the applications of chemical pump and nuclear pump system.Taking pump system as the research object of this dissertation, the methods of1D/3D coupling simulation on key component and pipeline system were investigated and interactive program was developed. In view of single pump system and parallel pump system, the co-simulation methodology was tested to explore the relationship of component and surrounding system, the way co-simulation boundaries exchange data, improve simulation stability and efficiency. The major contents of the current dissertation consist of the following several aspects:First, interactive program between Flowmaster and Fluent was developed based on VB code to realize the automated operation for Flowmaster and Fluent and1D/3D co-simulation.Second, one dimension-three dimension coupling simulation was aapplied for the steady pump system to validate the precision of the program, and then was applied for the transient flow caused by the valve closure process to improve its validity. Methods to improve the stability and efficiency of co-simulation were explored including the choice of3D CFD simulation boundaries, iteration numbers, weighting factor and so on.Third, In view of single pump system, the co-simulation methodology was tested for pump CFD model caused by the pump’s startup process. The transient flow and system performance in the numerical system model was solved under the experimental rotational speed history. Comparisons of the explicit and internal results between numerical simulation and experiment were satisfactory.Fourth, In view of parallel pump system, the co-simulation methodology was tested for three pipe model caused by the pump’s startup process. Co-simulation were carried out to explore the relationship of component and surrounding system and the flow and pressure of the whole pipeline during the pump’s startup process.The research with the aid of the current commercial software to develop the interface pregame provides a method to realize the1D/3D coupling simulation of system and key component. The content was verified by practical examples analyzing can provide more quick and economical references for the performance prediction of the hydraulic machinery used in a variety of transient process. It is of great importance and academic value, and possesses great application value for exploring the transient performance of pump system during starting period.