螺旋槳槳葉流固耦合動(dòng)力分析與試驗(yàn)研究.pdf

1、The prediction of vibratory excitation forces that are induced by the propeller is one of the most important tasks for tbe ship engineers and researchers. These forces are transmitted to the poop of the hull;the propelle

2、r produces the excitation to the hull,so the propeller structure can be regarded as the vibration source. The dynamic characteristics of the propeller should be study at first in the semi-immense water，and especially th

3、e hull surface boundary effect. In this thesis,the emphasis on the effect of the ship hull surface acts as the flexibility and rigid boundary, which can influence the fluid-structure coupling vibration result of propelle

4、r, relative to the effects of pressure release sea-surface. Both experimental and computational means can be used to assist the client in judging the propeller design to resport to predict its dynamic characteristies.

5、 FEM was applied to solve the dynamic characteristics，prior to accepting the FE results as representative of a correct solution useful for design purposes.The finite element(FE) model of the propellel was conducted for

6、natural frequencies computation in air and in water，based on the data measured from model-propeller firstly. And the FE model was utilized to analysisthe dynamic characteristics of the underwater structure in air and in

7、water through FE code ANSYS. The surface of the water was considered as pressm'e free,and the volume of fluid was assumed 10 times larger than the diameter of propeller；while the other surface asvelocity zero.It can be r

8、egarded as semi-immense fluid field. The nature frequency of the propeller in water obtained to compare with at in air.This vibration of propeller was affected by the reduced space between the propeller and the stern hul

9、l，very evident in hulls with light displacement.For different boundary.based on the location description of propellerand hull plate.the propeller disc is 0.12d forward of the stern waterline at the pointed condition.The

10、rigid hull surface is used to simulate the boundary condition；and then 2 kinds of plate(8mm and 70mm) were used to simulate flexibility hull surface.All the nature frequency results above had been used to comparision to

11、show the effect of hull surface. The numerical result is just one aspect to discuss the problem，while experiment should also provide the other face to aid the numerical result and amend the conclusion，Each node's informa

12、tion used in numerical simulation can be accepted in the test.The DASP system was introduced to analysis the vibration mode of the propeller structure. In most vibration problems，however，mode shape of the structure was i

13、nterested primarily.The modes in airwere tested using the DASP instrument,comparison with the numerical result as the otherstand proof. The numerical results and experiment data can be used to discuss the water influ

14、ence to the propeller blade,and also the different boundary condition.The conclusion or principle will be offered to aid the engineering usage.The frequency values of the semi-immense fluid field have already computed be