4259

4030

كارشناسي ارشد

تبديل انرژي

اصفهان : دانشگاه صنعتي اصفهان، دانشكده مكانيك

1387

دوازده، 95، [II] ص. : مصور، جدول، نمودار

ص. ع. به: فارسي و انگليسي

احمد رضا عظيميان

حسن قاسمي

23/7/1387

احمد رضا صابونچي، محمد رضا سليم پور

مهندسي مكانيك

ID4030

به فارسي و انگليسي: قابل رويت در نسخه ديجيتال

AbstractToday Submarines have many applications in military activities oil explorations andoceanography Prediction of hydrodynamic forces exerting on a submarine to dynamicallycontrol it and to select propulsion system is one of the important problems in thesubmarine design In the present work viscous incompressible and turbulent flow around an underwaterbody is simulated by means of a commercial code which is using finite volume methods The flow is supposed to be steady and numerical solution of the flow is performed using anunstructured grid with 2800000 cells In this simulation the hydrodynamic coefficient ofthe forces acting on the submarine is estimated in for velocities ranging from 1 m s to 8 24m s and flow angle of attack changes from 12 to 12 degrees Results of the present workare in good agreement with the results of a marine research center It shows that submarinedrag coefficient in zero angle of attack decreases when Reynolds number increases andsubmarine lift coefficient in a constant velocity increases with an increase in angle ofattack Investigation of flow in the stern region of the submarine shows that fraction wakehas a 15 reduction with increasing submarine velocity Next flow around a 5 blaeded propeller is simulated using sliding mesh with unsteadyflow consideration The grid system used for this part consists of 540000 cells that aredistributed around the propeller using an unstructured scheme Simulation is done with twodifferent conditions at the inlet of the submarine propeller In the first case a uniform inletflow is used In the second case the non uniform flow at the submarine stern which wasobtained from our pervious run were used Results show a good agreement with the resultsobtained from Boundary Element method and also it shows that the thrust and torquecoefficients acting on the propeller decrease with increasing the advance ratio Study ofthrust distribution in the radial directions of the blades reveals that at the outer 40 of thepropeller there is about 63 8 percent of generated thrust while at the inner 20 there isonly 3 8 percent of the generated thrust Comparison of the results obtained from a uniforminlet velocity distribution with a non uniform velocity distribution shows that thehydrodynamic coefficients in the later case are higher than the former one

احمد رضا عظيميان

حسن قاسمي

احمد رضا صابونچي، محمد رضا سليم پور