『求助』分析思路问题

我建立了一个模型，有几个体组成，先前的几个体划分都还可以，但划分最后一个体的时候提示*** ERROR *** CP= 646.719 TIME= 09:35:32
Volume 16 cannot be meshed. A gap between triangle facets on the
boundary exist. Check line 63.

*** ERROR *** CP= 646.812 TIME= 09:35:37
Volume mesh failure - perhaps due to:
　　(1) Poorly shaped triangle facets: Mesh surfaces with tris, modify
mesh control to get good tri mesh, then VMESH again.
　　(2) Complex geometry: Subdivide volume and try again.

后来我压缩了一下merge,compress后，划分网格，结果出现的错误又变了
*** ERROR *** CP= 672.047 TIME= 09:37:19
Internal error in the requested meshing operations. Process aborted.
(Reference: ..\source\FEM_geoEntity.c, line: 711).

*** ERROR *** CP= 672.172 TIME= 09:39:44
Relating to the previous message, please send your data to your ANSYS
Technical Support Provider.
不过中间merge过程中有下面的警告

*** WARNING *** CP= 659.250 TIME= 09:36:44
After NUMMRG,ALL, node 96025 (and possibly others) is associated with
more than one solid model entity. Future commands which depend on the
node to solid model connectivity (meshing, mesh clearing, solid BC
transfer, etc.) may not operate properly.


请各位高手指点一下，确实急得很。谢谢。

现在有台设备，一开始管子里面30度运行，运行15分钟后280度流体突然注入，再运行15分钟30流体注入，如此循环，请问这种温度载荷如何施加？
在热分析有的介绍说施加载荷步，请问怎么操作施加？一开始0-30，然后到15时对应280依次类推?