Add dispersion setting in advanced-reactor and initialize axial dispersion to zero in Reactor_PFR

dependencies/reactor_class.js

@@ -94,7 +94,7 @@ class Reactor_PFR {
         this.Fs = Array(n_inlets).fill(0.0); // fluid debits per inlet [m3 d-1]
         this.Cs_in = Array.from(Array(n_inlets), () => new Array(13).fill(0.0)); // composition influents
         this.OTR = 0.0; // oxygen transfer rate [g O2 d-1]
-        this.D = 0.1; // axial dispersion [m2 d-1]
+        this.D = 0.0; // axial dispersion [m2 d-1]
         
         this.kla = kla; // if NaN, use external OTR [d-1]