5538

5198

كارشناسي ارشد

مهدسي مكانيك

اصفهان: دانشگاه صنعتي اصفهان، دانشكده مكانيك

1389

هفده،80ص.: مصور،جدول،نمودار

ص.ع.به فارسي و انگليسي

احمدرضا عظيميان

احمدرضا زماني

29/8/89

ابراهيم شيراني، محمود اشرفي زاده

مهندسي مكانيك

ID5198

به فارسي و انگليسي: قابل رويت در نسخه ديجيتالي

Numerical Investigation of Flow around a Marine Contra Rotating Propellers CRP Seyed Mohammad Hasheminejad M Hasheminejad@Gmail com 5 22 2010 Department of mechanical engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Ahmad Reza Azimian Email azimian@cc iut ac ir Abstract Among the marine propulsion systems Contra Rotating Propellers CRP are one of the systems with highest efficiency The Contra Rotating Propellers principle comprising two coaxial propellers sited one behind the other and rotating in opposite directions This kind of propulsions in addition of generating more thrust have the hydrodynamic advantage of recovering part of the slip stream rotational energy which would otherwise be lost compared to the conventional single systems Furthermore because of two propeller configuration Contra Rotating Propellers posses a capability for balancing the torque reaction from the propulsur which is an important matter for torpedo and other similar propulsion problems In this study flow around a Contra Rotating Propellers system is simulated using FLUENT code and then its hydrodynamic performance is investigated This investigation contains three parts that in each one of those effect of a specific parameter on the hydrodynamics of a Contra Rotating Propellers system is investigated First flow around a Contra Rotating Propellers system with the same geometry and angular velocity for both of fore and aft propellers are investigated and hydrodynamics performances including efficiency thrust and torque coefficients are obtained at a wide range of advance ratios The flow simulation was done for two similar five bladed propellers The diameters of both propellers were 2 meters and several different spaces between the two propellers from 0 2D Diameter to 1D were selected At the second part the effect of the rotaion ratio of two propellers on the hydrodynamics performance is investigated In the both cases simulations were done at the open water conditions In this condition calculation is done based on a uniform inlet velocity Finally hydrodynamics performance of the Contra Rotating Propellers system in open water condition is compared with the results obtained when the Contra Rotating Propellers

احمدرضا عظيميان

احمدرضا زماني

ابراهيم شيراني، محمود اشرفي زاده