耦合 ODE 系统 - 换热器问题

Question

我正在解决热交换器问题，必须找到最终温度。这是一个颂歌系统，我写了下面的代码：它要求我定义 T 和 t，但它们是 x 的函数，我应该找到

import numpy as np
import matplotlib.pyplot as plt
from scipy.integrate import odeint

#propriedades trietileno glicol na entrada
T1 = 363 #K temperatura de entrada
Wt = 3.6 #kg/s vazão

#propriedades água na entrada
t1 = 298 #K 
Ww = 1.0
Ww = [0.1, 0.5, 1] #kg/s vazões

Di = 0.07792 #m diâmetro interno
L = 3.048 #m comprimento do tubo

U = 283.72 #W/m²K
pi= 3.1415

cpt = 1901.09#, 2.7683*T + 896.2] #J/kg*K calor específico
cpw = 4018.04#, -0.00003*(t^3) + 0.0403*(t^2) - 16.277*t + 6083.7] #J/kg*K calor específico
cp = [cpt, cpw]

def funct(y, x):   
    y = T, t
    dTdx = (U * Di * pi / (Wt * cpt)) * (T - t)
    dtdx = (U * Di * pi / (Ww * cpw)) * (T - t)
    x = np.linspace(0, L, 100)

    return dTdx, dtdx

# Vetor espaço


# Initial condition
y0 = T1, t1
sol = odeint(funct, y0 , x)

# plot
plt.plot(x, sol[:, 0], label='Trietilenoglicol')
plt.plot(x, sol[:, 1], label='Água')
plt.legend()
plt.xlabel('posição')

但它给了我以下错误信息：

NameError                                 Traceback (most recent call last)
<ipython-input-47-2f2a81626e49> in <module>
     35 # Initial condition
     36 y0 = T1, t1
---> 37 sol = odeint(funct, y0 , x)
     38 
     39 # plot

c:\users\idril\appdata\local\programs\python\python36\lib\site-packages\scipy\integrate\odepack.py in odeint(func, y0, t, args, Dfun, col_deriv, full_output, ml, mu, rtol, atol, tcrit, h0, hmax, hmin, ixpr, mxstep, mxhnil, mxordn, mxords, printmessg, tfirst)
    242                              full_output, rtol, atol, tcrit, h0, hmax, hmin,
    243                              ixpr, mxstep, mxhnil, mxordn, mxords,
--> 244                              int(bool(tfirst)))
    245     if output[-1] < 0:
    246         warning_msg = _msgs[output[-1]] + " Run with full_output = 1 to get quantitative information."

<ipython-input-47-2f2a81626e49> in funct(y, x)
     23 
     24 def funct(y, x):
---> 25     y = T, t
     26     dTdx = (U * Di * pi / (Wt * cpt)) * (T - t)
     27     dtdx = (U * Di * pi / (Ww * cpw)) * (T - t)

NameError: name 'T' is not defined

我已经阅读了很多回答的问题，但仍然找不到错误。

Answer 1

您想将 y 中的列表解包为单个变量，这必须按照与打包 y0,

时相反的方向编写

T,t = y

您想在与 y0

相同的点定义时间数组 x

你定义了两次Ww，第二次作为元组。没有算术元组运算。如果第二个定义没有特殊用途，请将其删除。

耦合 ODE 系统 - 换热器问题

System of coupled ODE - heat exchanger problem

python

numpy

scipy

ode

python-3.x