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D=0.005; %[m]
m=0.01; %[kg]
cp=500; %[J/kg*K]
T_p=283.15; %[K]
v=1; %[m/s]
sigma=5.67e-8; %[W/m^2*K^4]
Pr=0.7;
nu=1.81e-5; %[Pa*s]
k=0.025; %[W/m*K]
MW_air=0.028; %[kg/mol]
T0=298.15; %[K]
T_air=293.15; %[K]
t_fin=3600; %[s]
P=101325; %[Pa]
R=8.134; %[J/mol*K]
A=pi*D^2;
rho_air=P*MW_air/(R*T_air); %[kg/m^3]
Re=rho_air*v*D/nu;
Nu=0.4*Re^0.5*Pr*(1/3);



function dTdt=temperatura(t,T)

D=0.005; %[m]
m=0.01; %[kg]
cp=500; %[J/kg*K]
T_p=283.15; %[K]
v=1; %[m/s]
sigma=5.67e-8; %[W/m^2*K^4]
Pr=0.7;
nu=1.81e-5; %[Pa*s]
k=0.025; %[W/m*K]
MW_air=0.028; %[kg/mol]
T0=298.15; %[K]
T_air=293.15; %[K]
t_fin=3600; %[s]
P=101325; %[Pa]
R=8.134; %[J/mol*K]
A=pi*D^2;
rho_air=P*MW_air/(R*T_air); %[kg/m^3]
Re=rho_air*v*D/nu;
Nu=0.4*Re^0.5*Pr*(1/3);

Qrad=sigma*A*(T^4-T_p^4);
Qconv=Nu*k/D*A*(T_air-T);

dTdt=-Qrad/(m*cp)+Qconv/(m*cp);

end


tspan=[0 t_fin];
T0=298.15; %[K]
[t,T]=ode45(@temperatura, tspan, T0);

figure;
hold on;
plot(t, T, 'b-', 'LineWidth', 1.5);
xlabel('Tempo (s)');
ylabel('temperatura (K)');
title('Variazione temperatura in funzione del tempo');
grid on;

fprintf('Valore finali dopo 1 ora:\n');
fprintf('Temperatura finale: %.4f K\n', T(end));