//Kunii D., Levenspiel O., 1991. Fluidization Engineering(II Edition). Butterworth-Heinemann, MA, pp 491 //Chapter-6, Example 2, Page 151 //Title: Bubble Size and Rise Velocity in Geldart B Beds //========================================================================================================== clear clc //INPUT z=0.5;//Height of bed in m dt=0.5;//ID of tube in m rhos=2.6;//Density of catalyst in g/cm^3 dpbar=100;//Averge catalyst diameter in micrometer umf=0.01;//Velocity at minimum fluidization condition in m/s uo=0.45;//Superficial velocity in m/s dor=2;//Diameter of orifice in mm lor=30;//Pitch of perforated plate in mm g=9.80;//Acceleration due to gravity in m/s^2 pi=3.142857; //CALCULATION //Part(a).Bubble Size Nor=(2/sqrt(3))*(1/lor^2); dbo=5.5; //Method 1.Werther's procedure for finding bubble size z1=[0;5;10;20;30;50;70]; n=length(z1); i=1; while i<=n db(i)=0.853*((1+0.272*(uo-umf)*100)^(1/3))*(1+0.0684*z1(i))^1.21; i=i+1; end db1=0.163;//Since bubble size starts at dbo=5.5cm at z=0, we shift the curve accordingly to z=0.5m //Method 2.Mori and Wen's procedure for finding bubble size dbm=0.65*((pi/4)*((dt*100)^2)*(uo-umf)*100)^0.4; db2=dbm-(dbm-dbo)*exp(-0.3^(z/dt)); //Part(b).Bubble Velocity //Method 1.Procedure using Eqn.(12) ub1=1.6*((uo-umf)+1.13*db1^0.5)*(dt^1.35)+(0.711*(g*db1)^0.5); //Method 2.Werther's Procedure si=0.65; ub2=si*(uo-umf)+2*(dt^0.5)*(0.711*(g*db1)^0.5); //Using Eqn.(7) & Eqn.(8) ubr1=0.711*(g*db1)^0.5; ubr2=0.711*(g*db2/100)^0.5 ub3=uo-umf+ubr1; ub4=uo-umf+ubr2; //OUTPUT printf('\nBubble Size'); mprintf('\nInitial bubble size from Fig.5.14 for %fm/s = %fcm',uo-umf,dbo); printf('\n\n\tMethod 1.Werthers procedure for finding bubble size'); printf('\n\t\tHeight of bed(cm)'); printf('\t\t\tBubble size(cm)'); m=length(z1); j=1; while j<=m mprintf('\n\t\t%f',z1(j)); mprintf('\t\t\t\t%f',db(j)); j=j+1; end printf('\n\n\tMethod 2.Mori and Wens procedure for finding bubble size'); mprintf('\n\t\tMaximum expected bubble size=%fcm',dbm); mprintf('\n\t\tBubble size=%fcm',db2); printf('\nBubble Velocity'); printf('\n\n\tMethod 1.Procedure using Eqn.(12)'); mprintf('\n\t\tBubble velocity=%fm/s',ub1); printf('\n\n\tMethod 2.Werthers procedure'); mprintf('\n\t\tBubble velocity=%fm/s',ub2); printf('\nComparing the above results with the expressions of the simple two-phase theory'); printf('\n\tWerthers bubble size'); mprintf('\tBubble rise velocity=%fm/s\tBubble velocity=%fm/s',ubr1,ub3); printf('\n\tMori & Wens bubble size'); mprintf('\tBubble rise velocity=%fm/s\tBubble velocity=%fm/s',ubr2,ub4); //====================================END OF PROGRAM ======================================================