对于热交换器建模,我想在Matlab中给出不同的方程,并解决关于方程关系的未知数。例如,这些是不同的方程式和参数:
。 。
syms D L n Aflow X
Ga=m1a/(pi*D^2/4*n);
Red=Ga*D/nua;
F1=(delpaa-(Ga^2*(1/rhoao-1/rhoai)))*rhoa*0.5*D/(L*Ga^2)-f; %%Equation 1
%%Pressure Drop in Gas Side
delpag=Pin1g-Pout1g;
rhogo=(Pout1g/287*Tout1g)
rhogi=rhogo*Pin1g*Tout1g/(Pout1g*Tin1g);
rhog=0.5*(rhogo+rhogi);
Gg=m1g/(Aflow);
X=Do/D;
Dh=4*Aflow/n*pi*Do;
Redh=Gg*Dh/nug;
F2=(delpag-(Gg^2*(1/rhogo-1/rhogi)))*rhog*0.5*Dh/(L*Gg^2)-fo;
ratio=Redh/Red;
fo=f*ratio^-0.2; %f=0.046*Redh^-0.2
F3=0.95*Ga*0.5*f*(power(Pra,-2/3))-h;
F4=cpg*Gg*0.5*fo*(power(Prg,-2/3))-ho;
F5=(UA/(h*n*pi*D*L))+(UA/(ho*n*pi*Do*L))-1;
% UAho=1-Uah;
Adim=Aflow/n*D^2;
S = solve(F1,F2,F3,F4,F5,D, L, n, Aflow, X);
S.D
S.L
S.n
S.Aflow
S.X
。 。
“未定义的函数或变量'Do'。X = Do / D;”
但是,我已经将D和X放到了syms中,它也应该猜测Do,不应该吗?