The Research On The Parametric Design Of Centrifugal Pump Blade And It's Optimization

Recently, with the development of the flow computational technology, the computation technology for pump inner flow has achieved rapid progress, and it doesn't confine to single-phase flow and steady flow in pump. The Two-Phase Flow (Liquid/Gas or Liquid/Solid) and the unsteady flow in pump have become the main topic for the researchers, and they have made much progress in it. But the progress in the inverse design of hydraulic machinery impeller and its optimization are very slow. The main reason is the inner flow in pump is highly complicated 3D turbulent flow, the complex geometry boundary of impeller, and the affection of the revolving reference frame. The researches in this dissertation were carried out on parametric design and its optimization for centrifugal pump impeller. The main work and achievements include:1. The parametric design method for the meridian plane of centrifugal pump impeller is proposed. The quartic Bezier curve with five control points is used to design the meridian plane, the first three control points are collinear, and so does the last three control points. The partial differential equation for meshing is used to discretize the impeller meridian plane. To get the orthogonal mesh, orthogonal iteration is implemented, and the nonlinear function is used to control the discretization of the impeller meridian plane boundary. The approximate orthogonal mesh line are considered the streamline of the meridian plan and the cross-sectional line, according to the group of line, we can implement the area checking.2. The quartic Bezier curve is also used to control the distribution of angular coordinates on meridian streamline of hub and shroud. So, the pump blade boundary is controlled by some control points, the parametric design of pump blade boundary is achieved.3. The partial differential equation(PDE) is used to produce the blade surface, and then the inverse design of centrifugal pump blade is transformed into the boundary-value problem of partial differential equation. Get the numerical solution of the PDE, and we can construct the centrifugal pump blade surface. We can control the blade surface by controlling the boundary condition and some parameters of the PDE. We can get the sculpt of blade and impeller consider the blade thickness. The parametric design of centrifugal pump blade is realized.4. According to the parametric design of centrifugal impeller, the response surface method (RSM) based on experimental design is used to the optimal design of centrifugal impeller. Second-order response surface model analysis with two influencing factors is proposed to centrifugal impeller design under much numerical examination. The numerical calculation software is used to numerical simulation for the pump inner flow, and the model experimentation is replaced by numerical experimentation. Analysis the response surface model, and we can get the maximum point, which is the optimal design of the impeller under two influencing factors5. To control the centrifugal pump blade more freely, one more influencing factor is add to control the blade profile. It is the stack condition for the streamline. The errors between the experimental data and the RSM model with three influencing factors are very large whenever second-order or 3rd-order model is adopted. Then high-order partial differential equation is proposed to construct the hypersurface. On the boundary of the control volume with three influencing factors the experimental data is fitted with spline surface, then we can get the first boundary condition of the boundary-value problem. The second boundary condition can be inverse calculated according to the experimental data on centre point in the control volume. So there is no error between the experimental data and the hypersurface model. Analysis the hypersurface model on control volume, and we can also get the optimal design centrifugal impeller.6. At last, the optimizing result is analyzed. The distribution of the flow field parameters of the optimal impeller and the relation between the jet-wake characteristic and the hydraulic loss in impeller are discussed. The distribution of blade angle on the optimal impeller hub and shroud is discussed also.