a=70;  (* g/liter plasma protein *)
b=330;  (* g/liter blood protein *)
Pb=(a*(1-ϕ))+(b*ϕ);  (* g/liter total protei *)

(*  Plot protein content as a function of hematocrit ϕ  *)
Plot[Pb,{ϕ,0,0.7},PlotRange -> {0,300},PlotStyle->{Blue,Thick}]

μ=1.5*10^(-3);  (* viscosity of water *)
R=1.5*10^(-5);    (* tube radius *)
△P=1;   (* arbitrary pressure difference*)
L=1.91*10^(-3);   (* tube length *)
K=(Sqrt[μ/(1-(α*ϕ))]);   (*  terms from the Casson Equation *)
α=0.07Exp[2.49ϕ+1107Exp[-1.65ϕ]/310];

Q=((π*R^4*△P)/(8*K^2*L));    (* total volume flow rate *)

(*  Plot flow rate as a function of hematocrit ϕ  *)
Plot[Q,{ϕ,0,0.7},PlotStyle->{Blue,Thick}]

(*Protein flow rate and rbc flow rate plotted and scaled as a function of hematorcrit ϕ *)
Plot[{Pb*Q,500*ϕ*Q},{ϕ,0,0.7},PlotStyle->{Blue,Thick}]