tailieunhanh - Sublayer effect near the wall in the presence of svedov bingham flow

In this paper we study the stationary flow of viscous- plastic fluid in the horizontal cylindrical tube (Svedov Bingham's flow) with the assumption of existence of the viscous adherent sublayer near the walL The obtained results are estimated and compared with those of Svedov - Bingham flow. We also inspect the "near the wall effect" which was showed in the work of Smoldurev & Xaponov and have some notes and estimation about it. | --_-_I Journal of Mechanics, NCNST of Vietnam T. XVI, 1994, No 4 (15 - 20) SUBLAYER EFFECT NEAR THE WALL IN THE PRESENCE OF SVEDOV- BINGHAM FLOW NGUYEN HUU CHI & PHAM HOAI THANH Hanoi Technology Un£vers£ty SUMMARY. In this paper we study the stationary flow of viscous- plastic fluid in the horizontal cylindrical tube (Svedov Bingham's flow) with the assumption of existence of the viscous adherent sublayer near the walL The obtained results are estimated and compared with those of Svedov Bingham flow. We also inspect the "near the wall effect" which was showed in the work of Smoldurev & Xaponov and have some notes and estimation about it. §1. INTRODUCTION The viscous- plastic liquid model (Svedov- Bingham's model) is used in some problems on oil production or fluid - solid mixture transport in pressure tube [2, 3, 4]. Many problems on stationary flow of viscous - plastic weve solved and showed in literatures. The problem on laminar stationary cylindrical tube flow of viscous - plastic mixture with viscous non - adherent sublayer near the wall has solved in [4]. Besides, it is known that all the fluids in sluries (fluid- solid mixtures) have adhesion in shear. In this paper we have studied the stationary laminar pressure flow of viscous - plastic fluid in the horizontal cylindrical tube with the assumption of existence of viscous - adherent sublayer with small thickness 8 and viscosity 1]o near the wall. The obtained system of correspondent motion equations with its boundary conditions has been solved completely. The velocity profile and discharge of considered flow were compared with those of Svedov- Bingham flow. We also have some estimations and compare with results showed in [4]. §2. SYSTEM OF MOTION EQUATIONS AND ITS SOLUTION Consider the one - dimensional stationary laminar pressure flow of viscous - plastic fluid in the horizontal cylindrical tube generated by constant pressure gradient with the assumption of existence of the viscous adherent sublayer