Dum. Dum-Dum. Dum. ... DUMB!!

April 02, 2006[Baby] - Who's in Charge Here?

"Daniel had some trouble eating.  He couldn't seem to drink from his cup."  So said the nursery helper at Algood Assembly of God.  Daniel?  Mr. Independent?  We were shocked.  Not for long, though.  Liz and I aren't world-class detectives, but we can recognize tooth marks on the sippy cup lip when we see 'em.  Geez.  Sometimes, I wonder about the wisdom trusting someone else with my child.  Do I really have to let go?

Oh, and I need to take a shower.  I was carrying Daniel on my shoulders at Sam's.  Apparently he spit up.  My hair feels funny.  :(



In other news, it rained today.  A lot.  Torrential downpour would be more descriptive, I supposed.  It really started coming down as we were driving home from Sam's.  We got home to find our industrial-sized trash can 30 feet across the yard, lid open, trashed spilled out and strewn across the yard.  To compound the misery, I was followed around by two stray dogs including a pit bull.  I like dogs and am relatively rational, but I also know what kind of animals pit bulls are.  I don't like knowing that an animal bred for killing is around my home and family.  Needless to say, I stayed very close to Liz as we unloaded the car, and we let Daniel sleep inside.

[Church] - How Many?

At church this morning, a speaker said that 6 billion people saw the "Jesus Tape" in the last 30 years.  Last I heard, 6 billion was the approximate population of planet earth.  Somehow, I doubt that every person of every age worldwide saw this video.  Anyone else?

[School] - Smooth Sailing

Thermal Design work is progressing well.  I am currently writing some code for the final project.  Unfortunately, it's kinda taxing on the system.  For those of you that can recognize it, I'll post some below. For others, just know that it it looks like it will have to run the program about 700,000 times, and each time will have about 500 calculations-ish, so it will probably take a while to run.  Right now, I only have the part of the program that cycles through possible design variables.  Most of the actual calculations will have to come a little later.

counter = 0;

L_min = 10;     %Minimum Exchanger Length
L_int = 1;      %Interval of Exhchanger Length Steps
L_max = 100;    %Maximum Exchanger Length

D_min = 6/12;   %Minimum Tube Diameter
D_int = 1/12;   %Interval of Tube Diameter Steps
D_max = 22/12;  %Maximum Tube Diameter

Lf_min = 0;     %Minimum Fin Length (Extension)
Lf_int = 1/12;  %Interval of Fin Length Steps
                %Lf_max deteremined by D        
               
t_min = 1/12;   %Minimum Fin Thickness
t_int = 1/12;   %Interval of Fin Thickness Steps
t_max = 4/12;   %Maximum Fin Thickness

N_min = 0;      %Minimum Number of Fins
N_int = 1;      %Interval of Number of Fins
                %N_max determined by circumference and t

mat_min = 1; mat_int = 1; mat_max = 3;
%The 'mat' value will refer to one of the tube and fin material choices
%   mat = 1 will refer to aluminum
%   mat = 2 will refer to rough galvanized steel
%   mat = 3 will refer to smooth galvanized steel

for L = L_min : L_int : L_max                   %Exchanger Length
    for D = D_min : D_int : D_max               %Tube Diameter
        Lf_max = (2 - D) / 2;                   %Maximum Fin Length (Extension)
        for Lf = Lf_min : Lf_int : Lf_max       %Fin Length (Extension)
            for t = t_min : t_int : t_max       %Fin Thickness
                N_max = pi*D/t;                 %Maximum Number of Fins
                for N = N_min : N_int : N_max   %Number of Fins
                   
                    counter = counter + 1;
                   
                    %Index Counters
                    x_L = round( ( L - L_min ) / L_int + 1 );
                    x_D = round( ( D - D_min ) / D_int + 1 );
                    x_Lf = round( ( Lf - Lf_min ) / Lf_int + 1 );
                    x_t = round( ( t - t_min ) / t_int + 1 );
                    x_N = round( ( N - N_min ) / N_int + 1 );
                                       
                    %Geometric Calculations
                    Ac_i = ( pi / 4 ) * D^2;            %Inner Cross-Sectional Area
                    Ac_o = 6 - Ac_i - ( N * Lf * t);    %Outer Cross-Sectional Area
                    P_i = pi * D;                       %Inner Perimeter
                    P_o = 10 + pi * D + 2 * N * Lf;     %Outer Perimeter
                    Dh_i = 4 * Ac_i / P_i;              %Inner Hydraulic Dyameter
                    Dh_o = 4 * Ac_o / P_o;              %Outer Hydraulic Dyameter
                   
                    %Initial Assumptions
                    Th_o_1 = 50; %F
                    Th_o_2 = 0; %F
                    Tc_o_1 = 30; %F
                    Tc_0_2 = 0; %F
                    Q_1 = 1000; %cfm
                    Q_2 = 0; %cfm
                                       
                    while ( Th_o_1 - Th_o_2 ) / Th_o_1 > 0.01
                        Th_o_2 = Th_o_1;
                        Tc_o_2 = Tc_o_1;
                       
                        %Fluid Properties
                        Th_avg = ( 70 - Th_o_2 ) / 2;
                        Tc_avg = ( Tc_o_2 - 10 ) / 2;
                        density_i = %eq
                        density_o = %eq
                        dyn_visc_i = %eq
                        dyn_visc_o = %eq
                       
                        while ( Q_1 - Q_2 ) / Q_1 > 0.01
                            Q_2 = Q_1;
                           
                            Re_i = ( 4 * density_i * Q_2 ) / ( dyn_visc_i * P_i );
                            Re_o = ( 4 * density_o * Q_2 ) / ( dyn_visc_o * P_o );
                           
                            if Re_i < 10^5
                                f_i = .316 / ( Re_i ^ .25 );
                            else
                                f_i = .184 / (Re_i ^ .2 );
                            end
                           
                            if Re_o < 10^5
                                f_o = .316 / ( Re_o ^ .25 );
                            else
                                f_o = .184 / (Re_o ^ .2 );
                            end
                           
                            KL_i = ( f_i * L / Dh_i ) + 1.5;
                            KL_o = ( f_o * L / Dh_o ) + 1.5;
                           
                            HL_i = ( KL_i / ( 2 * 32.174 ) ) * ( Q_2 / Ac_i ) ^ 2;
                            HL_o = ( KL_o / ( 2 * 32.174 ) ) * ( Q_2 / Ac_o ) ^ 2;
                           
                            HL_total = HL_i + HL_o
                           
                            HL(x_L,x_D,x_Lf,x_t,x_N) = HL_total
                            
                        end
                   end
                                                        
                    L_val(x_L)=L;
                    D_val(x_D)=D;
                    Lf_val(x_Lf)=Lf;
                    t_val(x_t)=t;
                    N_val(x_N)=N;
                   
                end
            end
        end
    end
end
counter

display('Calculations Complete')