clear clc syms t u(t) v(t) z=0; R1 = 1.2e-2; R2 = 9.2e-3; Cin = 1.1e6/60; Cwall = 1.86e8/60; PN = 8000; qin = 20; qout = -15; u1 = diff(u); v1 = diff(v); eq0 = Cin*u1 == - (u - v)/R1; eq1 = Cin*u1 == PN - (u - v)/R1; eq2 = Cwall*v1 == (u - v)/R1 - (v - qout)/R2; eq3 = u(0) == qin; eq4 = v(0) == z; [uSol1(t), vSol1(t)] = dsolve(eq1, eq2, eq3, eq4); [uSol2(t), vSol2(t)] = dsolve(eq0, eq2, eq3, eq4); figure(1) subplot(2,2,1),fplot(t,uSol1,[0 60]) xlabel('时间/min'),ylabel('开启时室内温度') subplot(2,2,2),fplot(t,vSol1,[0 60]) xlabel('时间/min'),ylabel('开启时室内温度') subplot(2,2,3),fplot(t,uSol2,[0 60]) xlabel('时间/min'),ylabel('开启时室内温度') subplot(2,2,4),fplot(t,vSol2,[0 60]) xlabel('时间/min'),ylabel('开启时室内温度')
时间: 2023-11-17 15:08:14 浏览: 33
好的,将该代码改为使用ode45求解,可以按照以下步骤进行:
1. 定义一个函数,包含系统的ODE方程,例如:
```
function dydt = myODEfun(t, y)
% 定义参数和变量
R1 = 1.2e-2;
R2 = 9.2e-3;
Cin = 1.1e6/60;
Cwall = 1.86e8/60;
PN = 8000;
qin = 20;
qout = -15;
u = y(1);
v = y(2);
% 定义ODE方程
du_dt = y(3);
dv_dt = y(4);
dudt = Cin*du_dt + (u - v)/R1;
dvdt = Cwall*dv_dt - (u - v)/R1 + (v - qout)/R2 - PN;
% 返回ODE方程的结果
dydt = [du_dt; dv_dt; dudt; dvdt];
end
```
2. 定义初始条件和时间范围:
```
tspan = [0, 60];
y0 = [qin; z; 0; 0];
```
3. 调用ode45函数求解ODE方程:
```
[t, y] = ode45(@myODEfun, tspan, y0);
```
4. 绘制结果:
```
figure
subplot(2,2,1), plot(t, y(:,1)), xlabel('时间/min'),ylabel('开启时室内温度')
subplot(2,2,2), plot(t, y(:,2)), xlabel('时间/min'),ylabel('开启时室内温度')
subplot(2,2,3), plot(t, y(:,3)), xlabel('时间/min'),ylabel('开启时室内温度')
subplot(2,2,4), plot(t, y(:,4)), xlabel('时间/min'),ylabel('开启时室内温度')
```
这样就可以使用ode45求解该系统的ODE方程了。