EFFECT OF LAMINAR-FLOW ON THE RATE OF MASS-TRANSFER INSIDE CUBICAL CAVITIES

An electrochemical technique which involved measuring the limiting cur rent of the cathodic reduction of potassium ferricyanide was used to s tudy the rate of mass transfer inside a cubical cavity machined in the wall of a vertical rectangular duct. Variables studied were side leng th, physical properties of the solution and flow rate of the solution. The mass transfer coefficient was found to decrease with increasing c avity size; in all cases, the mass transfer coefficient inside the cav ity was less than that at the duct wall. Mass transfer data inside the cavity were correlated by the equation Sh(c) = 0.525 (Sc Re d(e)/L)(0 .33). Comparison of the present results with the results obtained usin g other cavity geometries shows that cavity geometry plays an importan t role in determining the rate of mass transfer inside the cavity.