(104f) Enhancement of Mass Transfer with Square-Grooved Serrated Disc As Turbulence Promoter in Circular Tube

ENHANCEMENT OF MASS TRANSFER WITH SQUARE-GROOVED SERRATED DISC AS TURBULENCE PROMOTER IN CIRCULAR TUBE

D.S.Seetha Rama Raju^a*, M.Gangadhar^b, V Nageswara Rao^a, N.Chitti Babu^a

^aDepartment of Chemical Engineering, College of Engineering(A),

Andhra University, Visakhapatnam-530 003, Andhra Pradesh, INDIA

^bDepartment of Chemical Engineering, G.M.R. Institute of Technology, GMR Nagar,

Rajam, Srikakulam-532127, Andhra Pradesh, INDIA

*E-mail: sai_dandu@yahoo.co.in

ABSTRACT                                                                                     

Mass transfer data were obtained in circular conduit using an electrochemical technique with a potassium ferri-ferro cyanide couple.  In circular conduit coaxially placed entry region square-grooved serrated disc was used as turbulence promoter. The study comprised of evaluation of mass transfer rates at the outer wall of the electrochemical cell. Mass transfer coefficients were evaluated from the measured limiting currents. The study covered a wide range of geometric parameters such as diameter of the disc (d_d), thickness of the disc (d_t) and distance of the disc from the entrance of the test section (h). The results revealed that the mass transfer coefficient increased with increase in velocity, diameter of the disc (d_d), thickness of the disc (d_t) and decreased with increase in distance of the disc from the entrance of the test section (h). Within the range of variables covered, the augmentation achieved in mass transfer coefficients were up to 2.1 fold over the tube flow in absence of promoter. The entire mass transfer data were correlated with Colburn J_D factor and roughness Reynolds number. The following correlation was reported out of the study.

J_D = 128.40 (Re⁺)^-0.9753 (f₁)^0.9224(f₂)^0.1785 (f₃)^0.4109

Where f₁=d_d/d, f₂=d_t/d, f₃=h/d are dimensionless groups. d is diameter of test section

KEYWORDS: Mass transfer, Square- grooved serrated disc, Turbulence promoter