مدل سازي آزمايشگاهي و عددي جريان مخلوط آب و خاك رس به روشSPH

چكيده انگليسي :

Experimental and Numerical modeling of flow Clay water mixture Bentonite with SPH method Navid Naimi N naimi@cv iut ac ir Date of Submission 28 April 2012 Department of Civil Engineering Isfahan University of Technology Isfahan 84156 83111 IranDegree M Sc Language FarsiSupervisor Mohammad Reza Chamani mchamani@cc iut ac ir Advisor Mohsen Saghafian saghafian@cc iut ac ir AbstractDrilling is dated back to early civilization and with industrial development it becomes an importanttechnology The term drilling refers to the penetration in stone for making hole in the ground strata One ofthe problems for earth dam drilling road construction is to control the seepage In the construction of dams particularly in earth dams the waterproof walls are used to control the seepage The waterproof walls areusually made of bentonite mixture and have been implemented as discrete panels In rotary drilling pile bentonite mixture water and clay and paste cement drilling fluid prevents the loss of concrete during thecasting Bentonite can also act as a medium to cool the drilling tip and to help lubricating the rotary motion The performance of bentonite in drillings is affected by rheological properties and resistance behavior ofbentonite fluid flow in the cavity of ground strata In other word the workability and flow ability of bentonitehave a direct relation with the rheological properties In accordance with guidelines API 13A the drillingfluids must be used after 24 hours and the percentage of solids bentonite in water should be about 3 10 Themarsh funnel test is used to measure the workability and flow ability of bentonite Depending to the type ofground strata and construction consideration the discharge time of specific volume of fluid in the marshfunnel is used to determine the viscosity of fluid Various mathematical models represent the rheologicalbehavior of Non Newtonian fluid such as bentonite Some of these models are Bingham Herschel Bulkley and Casson In this investigation the effect of hydration time on the rheological properties of bentonite isstudied Samples 5 7 and 10 percent of the bentonite are made Rheological properties including the yieldstress and viscosity of the samples are measured with Viscometer model HAKKE RV12 The comparison ofrheological properties of bentonite samples shows that over the time the yield stress increases first and thenreduces The viscosity almost remains constant over the time The dam break problem test is performed forsamples of bentonite and past cement Flow profile of fluid during dam break test is obtained by imageprocessing in Matlab Software The flow regimes Laminar or Turbulent flow of dam break problem werealso examined Numerical simulations of dam break problem are done by SPH method Mesh free andLagrangian method and verified with experimental data The results show that numerical simulations ofturbulent and laminar flow are similar and both models are consistent with experimental results which showthat the SPH method is an appropriate method for simulation of large deformation and free surface problem In the simulation the fluid is considered as a homogenous fluid and Casson model are adopted as therhelogical model Finally two cases of 2 D numerical simulation of water flow in the marsh funnel test arepresented The results of simulation of discharge time in the marsh funnel test results are similar to analyticalresults Key Words Drilling Bentonite fluids Rheology Marsh funnel Viscometer Dam break Non Newtonianfluid SPH method

نعيمي، نويد

مدل سازي آزمايشگاهي و عددي جريان مخلوط آب و خاك رس به روشSPH

حفاري , سيال بنتونيت , رئولوژي , قيف مارش , ويسكومتر , شكست سد , سيال غير نيوتني