The Research On Potential Method In Open Water Performance Prediction Of Variable Parameters Of CLT Propeller

There are various forms of ship propellers,and the efficiency of the propeller is related to the energy consumption of the ship.In order to improve the economy of ship operations,scholars in the propulsion field have done a lot of propeller design work,whether it is to change the form of the propeller,such as ducted propeller,counter-rotating propeller,pod propeller,pump jet propeller,etc.,or Changing some specific geometric parameters,such as the number of blades,chord length,pitch ratio,etc.,are other performance improvements based on the premise of ensuring the thrust and efficiency of the propeller.The CLT(Contracted and Loaded Tip)propeller is also one of the results of the optimization of the propeller.The special end plate structure at the tip can isolate the flow field exchange on both sides of the blade,thereby increasing the pressure difference and increasing the thrust.In order to improve the accuracy of calculating the open water performance of the CLT propeller using the panel method,this article first starts from the three-dimensional coordinate formula of the conventional propeller,and analyzes the influence of the special end plate form of the CLT propeller on the geometric modeling,and rotates a certain angle in the blade profile.On the basis of,find a suitable modeling method for P1727 propeller,and compare it with the standard model given by ITTC,which verifies the rationality of this method.Subsequently,the modeling parameters for the end structure of the CLT propeller are given,and the basis for parametric modeling of the end plate is provided,which provides a model basis for the design of the CLT propeller.Based on the calculation of open water performance of the CLT propeller based on Star CCM+,the tip vortex structure and wake field distribution are simulated,the disk surface flow field is extracted for auxiliary analysis,and the comparison with the internationally published open water test values verifies the effectiveness of the calculation strategy sex.At the same time,the distribution and evolution of the main vortex and end plate vortex structure under different advancement coefficients are analyzed,and the tip vortex radius and pitch are extracted to provide a basis for the setting of the panel method empirical wake vortex model.According to the panel method to calculate the open water performance of the conventional propeller,the reason for the larger error in the panel method to calculate the CLT propeller is analyzed.According to the wake vortices at different advancing speeds calculated by Star CCM+,extract the pitch and radius distribution of the twin wake vortices,calculate the hydrodynamic pitch angle and use it as the input condition of the panel method to preset the wake vortex,consider the wake vortex contraction at low advancing speeds Impact.Change the grid distribution form to ensure the generation of high-quality grids of the propeller and wake surfaces.Combine the test values and the open water performance results calculated by Star CCM+ and the blade profile pressure distribution to verify the effectiveness of the method.Finally,the minimum end plate width model P1727-mod-S is established through the parametric modeling method of the end plate,and the applicability analysis of the CLT propeller design based on the panel method is carried out.It is ensured that the improved panel method calculation method is not only suitable for the open water calculation of the P1727 propeller,but also can be used for the open water performance prediction of various derivative propellers in the design stage.Finally,a series of maps with the P1727 propeller as the parent model are given,which can be used as a reference for designers of CLT propellers.