模拟过程出现了温度交叉问题，怎么都解决不了

xiaohuangren · 发表于 1970-1-1 08:00:00

如题，模拟后出现了温度交叉问题，但是怎么修改都修改不了，而且还会出现一些新的问题，因为是新手，实在找不到解决办法了，求助大神帮忙解决。下面是模拟结果：

<< Run reinitialized 14:44:29 Thu Nov 12, 2015>>

->Processing input specifications ...

  Flowsheet Analysis :

Block $OLVER01 (Method: WEGSTEIN) has been defined to converge
      streams: 1       2

COMPUTATION ORDER FOR THE FLOWSHEET:
$OLVER01 TUR CON PUMP EVP
(RETURN $OLVER01)

->Calculations begin ...

> Beginning Convergence Loop $OLVER01 Method: WEGSTEIN
  Converging tear streams: 1       2

Block: TUR    Model: COMPR

Block: CON    Model: HEATX
  **  ERROR
   TEMPERATURE CROSSOVER DETECTED
   RE-CALCULATING WITH MINIMUM APPROACH TEMP. SPEC

Block: PUMP    Model: PUMP

Block: EVP    Model: HEATX

> Loop $OLVER01 Method: WEGSTEIN    Iteration 1
  Converging tear streams: 1       2
4 vars not converged, Max Err/Tol 0.10000E+07

Block: TUR    Model: COMPR

Block: CON    Model: HEATX

Block: PUMP    Model: PUMP

Block: EVP    Model: HEATX
  **  ERROR
   TEMPERATURE CROSSOVER DETECTED
   RE-CALCULATING WITH MINIMUM APPROACH TEMP. SPEC

> Loop $OLVER01 Method: WEGSTEIN    Iteration 2
  Converging tear streams: 1       2
2 vars not converged, Max Err/Tol 0.46243E+02

Block: TUR    Model: COMPR

Block: CON    Model: HEATX

Block: PUMP    Model: PUMP

Block: EVP    Model: HEATX
  **  ERROR
   TEMPERATURE CROSSOVER DETECTED
   RE-CALCULATING WITH MINIMUM APPROACH TEMP. SPEC

> Loop $OLVER01 Method: WEGSTEIN    Iteration 3
  Converging tear streams: 1       2
1 vars not converged, Max Err/Tol 0.75461E+01

Block: TUR    Model: COMPR

Block: CON    Model: HEATX

Block: PUMP    Model: PUMP

Block: EVP    Model: HEATX
  **  ERROR
   TEMPERATURE CROSSOVER DETECTED
   RE-CALCULATING WITH MINIMUM APPROACH TEMP. SPEC

> Loop $OLVER01 Method: WEGSTEIN    Iteration 4
  Converging tear streams: 1       2
1 vars not converged, Max Err/Tol  -0.19812E+01

Block: TUR    Model: COMPR

Block: CON    Model: HEATX

Block: PUMP    Model: PUMP

Block: EVP    Model: HEATX
  **  ERROR
   TEMPERATURE CROSSOVER DETECTED
   RE-CALCULATING WITH MINIMUM APPROACH TEMP. SPEC

> Loop $OLVER01 Method: WEGSTEIN    Iteration 5
  Converging tear streams: 1       2
# Converged             Max Err/Tol 0.00000E+00

->Generating block results ...

Block: EVP    Model: HEATX
  **  ERROR WHILE GENERATING RESULTS FOR UNIT OPERATIONS BLOCK: "EVP" (MODEL:
   "HEATX")
   TEMPERATURE CROSSOVER DETECTED
   RE-CALCULATING WITH MINIMUM APPROACH TEMP. SPEC

Block: CON    Model: HEATX

Block: PUMP    Model: PUMP

->Simulation calculations completed ...

  ***  No Warnings were issued during Input Translation ***

            ***  Summary of Simulation Errors  ***

               Physical
               Property       System       Simulation
  Terminal Errors    0             0             0
Severe Errors    0             0             0
         Errors       0             0             6
      Warnings    0             0             0

->Generating results ...

<< Run Saved >>

->Generating results ...

<< Run Saved >>

->Generating results ...

<< Run Saved >>

yzhsh90 · 发表于 1970-1-1 08:00:00

把冷热流体反接一下试试

feel_young · 发表于 1970-1-1 08:00:00

冷热物流随便哪个，增大流量，试试。

流量增大，换热量不变的情况下，温差自然减小，就更不易发生温度交叉。

yzt811520 · 发表于 1970-1-1 08:00:00

温度上下界没设好

xiaohuangren · 发表于 1970-1-1 08:00:00

feel_young 发表于 2015-11-12 15:56
冷热物流随便哪个，增大流量，试试。

流量增大，换热量不变的情况下，温差自然减小，就更不易发生温度交 ...

还是不行，还有别的办法不，谢谢喽！

xiaohuangren · 发表于 1970-1-1 08:00:00

yzt811520 发表于 2015-11-12 16:11
温度上下界没设好

改了好多组数据，还是不行，而且会出现新的错误，不过还是谢谢你！

xiaohuangren · 发表于 1970-1-1 08:00:00

yzhsh90 发表于 2015-11-12 15:02
把冷热流体反接一下试试

反接了一下，出现了这种情况，应该是要设置撕裂物流，设置过之后还是出现这种情况，不会解决了，该怎么做呢？谢谢喽！
<< All Blocks Reinitialized >>

<< Run reinitialized 10:20:19 Fri Nov 13, 2015>>

->Processing input specifications ...

  * WARNING IN THE "STREAM" PARAGRAPH WHICH BEGINS ON LINE 39
   STREAM NAME: 1
   COMP**NT MASS FLOWS OF SUBSTREAM: "MIXED"
   ARE NORMALIZED TO THE TOTAL MASS FLOW VALUE.

  Flowsheet Analysis :

Block $OLVER01 (Method: WEGSTEIN) has been defined to converge
      streams: 1       4

COMPUTATION ORDER FOR THE FLOWSHEET:
$OLVER01 EVP TUR CON PUMP
(RETURN $OLVER01)

->Calculations begin ...

> Beginning Convergence Loop $OLVER01 Method: WEGSTEIN
  Converging tear streams: 1       4

Block: EVP    Model: HEATX
  * WARNING
   AT LEAST ** FEED HAS ZERO FLOW
   BLOCK BYPASSED

Block: TUR    Model: COMPR
  * WARNING
   TOTAL FLOW IS ZERO. BLOCK IS BYPASSED.

Block: CON    Model: HEATX
  * WARNING
   AT LEAST ** FEED HAS ZERO FLOW
   BLOCK BYPASSED

Block: PUMP    Model: PUMP
  * WARNING
   MIXED SUBSTREAM HAS ZERO FLOW.  BLOCK BYPASSED.

> Loop $OLVER01 Method: WEGSTEIN    Iteration 1
  Converging tear streams: 1       4
  * WARNING
   VALUE IS MISSING FOR VARIABLE 8.
   THIS MAY BE CAUSED BY A ZERO-FLOW STREAM.
   THE PREVIOUS VALUE OF THE VARIABLE WILL BE USED.

2 vars not converged, Max Err/Tol 0.10000E+07

Block: EVP    Model: HEATX
  * WARNING
   AT LEAST ** FEED HAS ZERO FLOW
   BLOCK BYPASSED

Block: TUR    Model: COMPR
  * WARNING
   TOTAL FLOW IS ZERO. BLOCK IS BYPASSED.

Block: CON    Model: HEATX
  * WARNING
   AT LEAST ** FEED HAS ZERO FLOW
   BLOCK BYPASSED

Block: PUMP    Model: PUMP
  * WARNING
   MIXED SUBSTREAM HAS ZERO FLOW.  BLOCK BYPASSED.

> Loop $OLVER01 Method: WEGSTEIN    Iteration 2
  Converging tear streams: 1       4
# Converged             Max Err/Tol 0.00000E+00

->Generating block results ...

Block: EVP    Model: HEATX
  * WARNING WHILE GENERATING RESULTS FOR UNIT OPERATIONS BLOCK: "EVP" (MODEL:
   "HEATX")
   AT LEAST ** FEED HAS ZERO FLOW
   BLOCK BYPASSED

Block: CON    Model: HEATX
  * WARNING WHILE GENERATING RESULTS FOR UNIT OPERATIONS BLOCK: "CON" (MODEL:
   "HEATX")
   AT LEAST ** FEED HAS ZERO FLOW
   BLOCK BYPASSED

->Simulation calculations completed ...

  ***  Warning(s) were issued during Input Translation ***
  ***  Check the Run Status Results for more Information ***

            ***  Summary of Simulation Errors  ***

               Physical
               Property       System       Simulation
  Terminal Errors    0             0             0
Severe Errors    0             0             0
         Errors       0             0             0
      Warnings    0             0             11

->Generating block results ...

Block: EVP    Model: HEATX
  * WARNING WHILE GENERATING RESULTS FOR UNIT OPERATIONS BLOCK: "EVP" (MODEL:
   "HEATX")
   AT LEAST ** FEED HAS ZERO FLOW
   BLOCK BYPASSED

Block: CON    Model: HEATX
  * WARNING WHILE GENERATING RESULTS FOR UNIT OPERATIONS BLOCK: "CON" (MODEL:
   "HEATX")
   AT LEAST ** FEED HAS ZERO FLOW
   BLOCK BYPASSED

  * WARNING
   AT LEAST ** FEED HAS ZERO FLOW
   BLOCK BYPASSED

  * WARNING
   AT LEAST ** FEED HAS ZERO FLOW
   BLOCK BYPASSED

yzhsh90 · 发表于 1970-1-1 08:00:00

xiaohuangren 发表于 2015-11-13 10:20
反接了一下，出现了这种情况，应该是要设置撕裂物流，设置过之后还是出现这种情况，不会解决了，该怎么做 ...

你的这个版本太高了，我打不开

xiaohuangren · 发表于 1970-1-1 08:00:00

yzhsh90 发表于 2015-11-13 10:36
你的这个版本太高了，我打不开

我刚刚换了一个版本7.2版本的，你看一下。

feel_young · 发表于 1970-1-1 08:00:00

xiaohuangren 发表于 2015-11-13 10:04
还是不行，还有别的办法不，谢谢喽！

你流程图截一张图我看看。

爱是你我 · 发表于 1970-1-1 08:00:00

不知道你是设置的负荷还是冷热流体温度。主要思想都是要减小换热量。设的是负荷的话，减小负荷。设的是流体温度的话，减小进出口流体温差。

xiaohuangren · 发表于 1970-1-1 08:00:00

feel_young 发表于 2015-11-13 11:42
你流程图截一张图我看看。

麻烦你了！

feel_young · 发表于 1970-1-1 08:00:00

xiaohuangren 发表于 2015-11-13 12:58
麻烦你了！

你这是制冷循环吗？还是什么。

压缩机升压，你的PUMP能降压吗？不应该用阀门降压？

我还真有点儿搞不懂了。

xiaohuangren · 发表于 1970-1-1 08:00:00

feel_young 发表于 2015-11-13 15:15
你这是制冷循环吗？还是什么。

压缩机升压，你的PUMP能降压吗？不应该用阀门降压？

这个是有机朗肯循环，其实也就是电厂循环，有蒸发器、冷凝器、透平和泵，工质用的是有机工质R245fa（C3H3F5，1,1,1,3,3-五氟丙烷），蒸发段用热水换热，冷凝段用冷水换热。热源（热水）进口95℃，出口90℃，流量11.98kg/s；冷源（冷却水）进口0℃，出口5℃，流量9.94kg/s。我想模拟出透平输出的功率，您能帮我模拟一下吗？真的找不到解决方法了，谢谢！

feel_young · 发表于 1970-1-1 08:00:00

xiaohuangren 发表于 2015-11-13 18:27

登录/注册后可看大图

这个是有机朗肯循环，其实也就是电厂循环，有蒸发器、冷凝器、透平和泵，工质用的是有机工质R245fa（C3H3 ...

具体不太懂。如果只是shortcut设计模式的话。那么就无所谓换热面积和换热系数。

提醒几个事儿吧。

冷凝压力和蒸发压力设置是否合理？

冷凝温度和蒸发温度是否能保证一个是放热一个是吸热？

换热器冷热物流是否接错？一个是hot side，一个是cold side，这个一定要分清。

循环工质流量是否设置合理？

其实如果只是想设计计算的话，看宏观变化的话，很简单。和手算一个道理。

如果想校核计算的话，也就是换热器固定，透平和泵固定，那就得多研究研究了。比如我一直没解决的循环工质质量（kg）守恒的问题。

xiaohuangren · 发表于 1970-1-1 08:00:00

feel_young 发表于 2015-11-13 21:29
具体不太懂。如果只是shortcut设&# ...

嗯，我再试一下，很感谢！

feel_young · 发表于 1970-1-1 08:00:00

xiaohuangren 发表于 2015-11-13 22:46

登录/注册后可看大图

嗯，我再试一下，很感谢！

嗯，有问题再说。

你这个流程真的不难。如果只是设计模式。

standupxia · 发表于 1970-1-1 08:00:00

试试降低塔顶压力，或者调节进料流量

xiaohuangren · 发表于 1970-1-1 08:00:00

谢谢各位帮忙，问题已解决。

feel_young · 发表于 1970-1-1 08:00:00

xiaohuangren 发表于 2015-11-18 11:19
谢谢各位帮忙，问题已解决。

问题出在哪儿了？

怎么不总结一下发上来。{:1106_362:}

模拟过程出现了温度交叉问题，怎么都解决不了

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