1、2015-2016 学年研究生工程电磁场数值计算试题 1 总结有限元法计算电磁场问题的步骤,并说明什么叫正问题和逆问题?( 20分) 答 :基本步骤分为三大步:前处理( Preprocession) , 求解( Solution) , 后处理( Postprocession) 。 前处理 主要包括 : 单元选择,材料定义, 几何模型 ,网络划分,模型局部调整 和 施加荷载。 求解 主要 包括 :分析问题的类型,设定分析参数, 添加 荷载条件,建立荷载工况 和 求解。 后处理主要 包括 :结果 的文字输出( Result list) ,结果 的云图输出( Result contour) ,结果
2、的矢量输出( Result vector) , 结果的路径输出( Result mapping) ,Element Table 的提取, Load Case 及组合。 正文题 : 已知场源 、边界和媒质,计算场量。给定 场 的计算区域、各区域的材料组成和特性,以及激励源的特性,求场域中的场量 随 时间、空间的分布规则。 逆 问题: 根据 场量分布要求,求取场源。根据 电磁装置 设定的场量值及其有关的特性 的 要求,求解该装置的的结构 、 尺寸、媒质性能参数和激励参数 等 。 2 设计一个高压点火器,用分析其电场分布,说明影响点火器起火的 主要参数,并说明怎样改变参数可以容易地点火? ( 20
3、分) 建立模型如图 选择两个尖端为路径,电位图和电场强度图如下图所示 程序如下: /BATCH /COM,ANSYS RELEASE 12.0.1 UP20090415 21:32:18 01/14/2016 /input,menust,tmp,1 /GRA,POWER /GST,ON /PLO,INFO,3 /GRO,CURL,ON /CPLANE,1 /REPLOT,RESIZE WPSTYLE,0 /REPLOT,RESIZE /FILNAME,T2,0 /PREP7 !* /NOPR /PMETH,OFF,1 KEYW,PR_SET,1 KEYW,PR_STRUC,0 KEYW,PR_
4、THERM,0 KEYW,PR_FLUID,0 KEYW,PR_ELMAG,1 KEYW,MAGNOD,0 KEYW,MAGEDG,0 KEYW,MAGHFE,0 KEYW,MAGELC,1 KEYW,PR_MULTI,0 KEYW,PR_CFD,0 /GO !* /COM, /COM,Preferences for GUI filtering have been set to display: /COM, Electric !* !* ET,1,PLANE121 !* !* MPTEMP, MPTEMP,1,0 MPDATA,PERX,1,1 MPTEMP, MPTEMP,1,0 MPDAT
5、A,RSVX,1,1e+10 FLST,3,1,8 FITEM,3,0,0.1E-02,0 K, ,P51X FLST,3,1,8 FITEM,3,-0.1E-02,0.2E-02,0 K, ,P51X FLST,3,1,8 FITEM,3,-0.1E-02,0.4E-02,0 K, ,P51X FLST,3,1,8 FITEM,3,-0.3E-02,0.4E-02,0 K, ,P51X FLST,3,1,8 FITEM,3,-0.3E-02,-0.4E-02,0 K, ,P51X FLST,3,1,8 FITEM,3,-0.1E-02,-0.4E-02,0 K, ,P51X FLST,3,1
6、,8 FITEM,3,-0.1E-02,-0.2E-02,0 K, ,P51X FLST,3,1,8 FITEM,3,0,-0.1E-02,0 K, ,P51X FLST,3,1,8 FITEM,3,0.1E-02,-0.2E-02,0 K, ,P51X FLST,3,1,8 FITEM,3,0.1E-02,-0.4E-02,0 K, ,P51X FLST,3,1,8 FITEM,3,0.3E-02,-0.4E-02,0 K, ,P51X FLST,3,1,8 FITEM,3,0.3E-02,0.4E-02,0 K, ,P51X FLST,3,1,8 FITEM,3,0.1E-02,0.4E-
7、02,0 K, ,P51X FLST,3,1,8 FITEM,3,0.1E-02,0.2E-02,0 K, ,P51X LSTR, 1, 2 LSTR, 3, 2 LSTR, 4, 3 LSTR, 5, 4 LSTR, 6, 5 LSTR, 7, 8 LSTR, 6, 7 LSTR, 9, 8 LSTR, 10, 11 LSTR, 9, 10 LSTR, 12, 13 LSTR, 12, 11 LSTR, 13, 14 LSTR, 14, 1 FLST,2,14,4 FITEM,2,4 FITEM,2,3 FITEM,2,2 FITEM,2,1 FITEM,2,6 FITEM,2,7 FITE
8、M,2,5 FITEM,2,10 FITEM,2,9 FITEM,2,8 FITEM,2,12 FITEM,2,11 FITEM,2,13 FITEM,2,14 AL,P51X ALLSEL,ALL CM,_Y,AREA ASEL, , , , 1 CM,_Y1,AREA CMSEL,S,_Y !* CMSEL,S,_Y1 AATT, 1, , 1, 0, CMSEL,S,_Y CMDELE,_Y CMDELE,_Y1 !* SMRT,6 SMRT,1 MSHAPE,0,2D MSHKEY,0 !* CM,_Y,AREA ASEL, , , , 1 CM,_Y1,AREA CHKMSH,ARE
9、A CMSEL,S,_Y !* AMESH,_Y1 !* CMDELE,_Y CMDELE,_Y1 CMDELE,_Y2 !* ALLSEL,ALL FINISH /SOL !* ANTYPE,0 /REPLOT,RESIZE /REPLOT,RESIZE FLST,2,4,4,ORDE,4 FITEM,2,1 FITEM,2,-2 FITEM,2,13 FITEM,2,-14 /GO !* DL,P51X, ,VOLT,0 FLST,2,4,4,ORDE,3 FITEM,2,6 FITEM,2,-8 FITEM,2,10 /GO !* DL,P51X, ,VOLT,7000 /REPLOT,
10、RESIZE /REPLOT,RESIZE /STATUS,SOLU SOLVE FINISH /POST1 !* /EFACET,1 PLNSOL, VOLT, 0 !* /VSCALE,1,1,0 ! !* PLVECT,EF, , , ,VECT,ELEM,ON,0 PATH,1,2,30,20, PPATH,1,0,0,0.001,0,0, PPATH,2,0,0,-0.001,0,0, /PBC,PATH,1 /REPLOT /PBC,PATH,0 !* !* PDEF, ,EF,SUM,AVG /PBC,PATH, ,0 !* PLPATH,EFSUM PLPATH,S FINIS
11、H ! /EXIT,ALL( 3) 分析 可得,物体击穿放电 主要 与 材料 ,形状,所加电压有关。 当采用 统一击穿物体放电 , 所加电压相同和 相处 距离相同时 ,尖对尖 最易 击穿放电,尖对 板 击穿放电 次之,板对板最不易放 。在 形状 相同 ,击穿介质一样时,一般所加电压越高越容易击穿。 综上 所述:使所 加 电压的物体之间距离越短,形状越接近尖对 尖 就越容易放电。 同时 ,选择 击穿 电压较低 的 介质 也是 实现 击穿 发电的途径。 3 如图 1 所示, 1 0.01mR 、 2 0.08mR , 3 0.12mR ,半径 1R 以内是金属球,其上电位为 2000V , 大于
12、半径 1R 小于半径 2R 之间为第一种电解质(即绝缘体),其相对介电常数为 1r ,大于半径 2R 小于半径 3R 之间为第二种电解质,其相对介电常数 2r ,第二种电解质外面是导体层,该导体层接地,试分 析当( 1)当 1 1r , 2 80r ,( 2) 1 80r , 2 1r ,两种情况时两种电解质内 E 和 D 的分布,并说明两种情况下 E 和 D 的分布不同的原因。 ( 20 分) 图 1 答 :( 1) 程序 : /BATCH /COM,ANSYS RELEASE 12.0.1 UP20090415 11:02:26 01/12/2016 /input,menust,tmp,1
13、 /GRA,POWER /GST,ON /PLO,INFO,3 /GRO,CURL,ON /CPLANE,1 /REPLOT,RESIZE WPSTYLE,0 /REPLOT,RESIZE /FILNAME,T3,0 !* /NOPR /PMETH,OFF,1 KEYW,PR_SET,1 KEYW,PR_STRUC,0 KEYW,PR_THERM,0 KEYW,PR_FLUID,0 KEYW,PR_ELMAG,1 KEYW,MAGNOD,0 KEYW,MAGEDG,0 KEYW,MAGHFE,0 KEYW,MAGELC,1 KEYW,PR_MULTI,0 KEYW,PR_CFD,0 /GO !
14、* /COM, /COM,Preferences for GUI filtering have been set to display: /COM, Electric !* /PREP7 !* ET,1,PLANE121 !* !* MPTEMP, MPTEMP,1,0 MPDATA,PERX,1,1 MPTEMP, MPTEMP,1,0 MPDATA,RSVX,1,1e+10 MPTEMP, MPTEMP,1,0 MPDATA,RSVX,2,1e+10 MPTEMP, MPTEMP,1,0 MPDATA,PERX,2,80 PCIRC,0.08,0.01,0,360, PCIRC,0.12,
15、0.08,0,360, FLST,2,2,5,ORDE,2 FITEM,2,1 FITEM,2,-2 AGLUE,P51X ALLSEL,ALL CM,_Y,AREA ASEL, , , , 1 CM,_Y1,AREA CMSEL,S,_Y !* CMSEL,S,_Y1 AATT, 1, , 1, 0, CMSEL,S,_Y CMDELE,_Y CMDELE,_Y1 !* CM,_Y,AREA ASEL, , , , 3 CM,_Y1,AREA CMSEL,S,_Y !* CMSEL,S,_Y1 AATT, 2, , 1, 0, CMSEL,S,_Y CMDELE,_Y CMDELE,_Y1
16、!* !* SMRT,6 SMRT,6 SMRT,1 MSHAPE,0,2D MSHKEY,0 !* FLST,5,2,5,ORDE,2 FITEM,5,1 FITEM,5,3 CM,_Y,AREA ASEL, , , ,P51X CM,_Y1,AREA CHKMSH,AREA CMSEL,S,_Y !* AMESH,_Y1 !* CMDELE,_Y CMDELE,_Y1 CMDELE,_Y2 !* FINISH /SOL FINISH /PREP7 ALLSEL,ALL FINISH /SOL FLST,2,4,4,ORDE,2 FITEM,2,9 FITEM,2,-12 /GO !* DL
17、,P51X, ,VOLT,0 FLST,2,4,4,ORDE,2 FITEM,2,5 FITEM,2,-8 /GO !* DL,P51X, ,VOLT,2000 /STATUS,SOLU SOLVE FINISH /POST1 FINISH /POST26 FILE,T3,rth,. /UI,COLL,1 NUMVAR,200 SOLU,191,NCMIT STORE,MERGE FILLDATA,191,1,1 REALVAR,191,191 FINISH /POST1 !* /EFACET,1 PLNSOL, VOLT, 0 !* /VSCALE,1,1,0 ! !* PLVECT,D,
18、, , ,VECT,ELEM,ON,0 !* /VSCALE,1,1,0 ! !* PLVECT,EF, , , ,VECT,ELEM,ON,0 FINISH ! /EXIT,ALL 图 3-1D 图 3-2 E ( 2)程序 /BATCH /COM,ANSYS RELEASE 12.0.1 UP20090415 11:02:26 01/12/2016 /input,menust,tmp,1 /GRA,POWER /GST,ON /PLO,INFO,3 /GRO,CURL,ON /CPLANE,1 /REPLOT,RESIZE WPSTYLE,0 /REPLOT,RESIZE /FILNAME
19、,T3,0 !* /NOPR /PMETH,OFF,1 KEYW,PR_SET,1 KEYW,PR_STRUC,0 KEYW,PR_THERM,0 KEYW,PR_FLUID,0 KEYW,PR_ELMAG,1 KEYW,MAGNOD,0 KEYW,MAGEDG,0 KEYW,MAGHFE,0 KEYW,MAGELC,1 KEYW,PR_MULTI,0 KEYW,PR_CFD,0 /GO !* /COM, /COM,Preferences for GUI filtering have been set to display: /COM, Electric !* /PREP7 !* ET,1,P
20、LANE121 !* !* MPTEMP, MPTEMP,1,0 MPDATA,PERX,1,80 MPTEMP, MPTEMP,1,0 MPDATA,RSVX,1,1e+10 MPTEMP, MPTEMP,1,0 MPDATA,RSVX,2,1e+10 MPTEMP, MPTEMP,1,0 MPDATA,PERX,2,1 PCIRC,0.08,0.01,0,360, PCIRC,0.12,0.08,0,360, FLST,2,2,5,ORDE,2 FITEM,2,1 FITEM,2,-2 AGLUE,P51X ALLSEL,ALL CM,_Y,AREA ASEL, , , , 1 CM,_Y
21、1,AREA CMSEL,S,_Y !* CMSEL,S,_Y1 AATT, 1, , 1, 0, CMSEL,S,_Y CMDELE,_Y CMDELE,_Y1 !* CM,_Y,AREA ASEL, , , , 3 CM,_Y1,AREA CMSEL,S,_Y !* CMSEL,S,_Y1 AATT, 2, , 1, 0, CMSEL,S,_Y CMDELE,_Y CMDELE,_Y1 !* !* SMRT,6 SMRT,6 SMRT,1 MSHAPE,0,2D MSHKEY,0 !* FLST,5,2,5,ORDE,2 FITEM,5,1 FITEM,5,3 CM,_Y,AREA ASE
22、L, , , ,P51X CM,_Y1,AREA CHKMSH,AREA CMSEL,S,_Y !* AMESH,_Y1 !* CMDELE,_Y CMDELE,_Y1 CMDELE,_Y2 !* FINISH /SOL FINISH /PREP7 ALLSEL,ALL FINISH /SOL FLST,2,4,4,ORDE,2 FITEM,2,9 FITEM,2,-12 /GO !* DL,P51X, ,VOLT,0 FLST,2,4,4,ORDE,2 FITEM,2,5 FITEM,2,-8 /GO !* DL,P51X, ,VOLT,2000 /STATUS,SOLU SOLVE FIN
23、ISH /POST1 FINISH /POST26 FILE,T3,rth,. /UI,COLL,1 NUMVAR,200 SOLU,191,NCMIT STORE,MERGE FILLDATA,191,1,1 REALVAR,191,191 FINISH /POST1 !* /EFACET,1 PLNSOL, VOLT, 0 !* /VSCALE,1,1,0 ! !* PLVECT,D, , , ,VECT,ELEM,ON,0 !* /VSCALE,1,1,0 ! !* PLVECT,EF, , , ,VECT,ELEM,ON,0 FINISH ! /EXIT,ALL 图 3-3 D 图 3
24、-4 E 4 一个螺旋管,如图 2 所示, 其中 ABCD 长方形为线圈骨架,其 EFGH 和 IJKL 两个长方形为线圈, 通过线圈的电流密度为 210A/mJ , MNPQ 长方形为包含整个螺旋管线圈的总待求区域的外边界,几个关键点坐标分别为 A( -0.025, -0.05) ,C( 0.025, 0.05), E(-0.028,-0.04) G(-0.025,0.04),I(0.025,-0.04),K(0.028,0.04),M(-0.03,-0.058),P(0.03,0.058)。 ( 1)当线圈骨架为木头,其相对磁导率为 1r ,( 2)当线圈骨架为铁磁性材料,其相对磁导率为
25、2000r ,分别求线圈骨架为两种材质时螺旋管内部和外部磁感应强度的分布。 ( 20 分) 图 2 答: ( 1) 当线圈 骨架是木头时: 程序: /BATCH /COM,ANSYS RELEASE 12.0.1 UP20090415 18:00:36 01/12/2016 /input,menust,tmp,1 /GRA,POWER /GST,ON /PLO,INFO,3 /GRO,CURL,ON /CPLANE,1 /REPLOT,RESIZE WPSTYLE,0 /FILNAME,T4,0 !* /NOPR /PMETH,OFF,1 KEYW,PR_SET,1 KEYW,PR_STRUC
26、,0 KEYW,PR_THERM,0 KEYW,PR_FLUID,0 KEYW,PR_ELMAG,1 KEYW,MAGNOD,1 KEYW,MAGEDG,0 KEYW,MAGHFE,0 KEYW,MAGELC,0 KEYW,PR_MULTI,0 KEYW,PR_CFD,0 /GO !* /COM, /COM,Preferences for GUI filtering have been set to display: /COM, Magnetic-Nodal !* /PREP7 !* ET,1,PLANE13 !* !* MPTEMP, MPTEMP,1,0 MPDATA,MURX,1,1 M
27、PTEMP, MPTEMP,1,0 MPDATA,RSVX,1,1e+10 MPTEMP, MPTEMP,1,0 MPDATA,RSVX,2,2e-8 MPTEMP, MPTEMP,1,0 MPDATA,MURX,2,1 MPTEMP, MPTEMP,1,0 MPDATA,MURX,3,1 MPTEMP, MPTEMP,1,0 MPDATA,RSVX,3,1e+10 /REPLOT,RESIZE RECTNG,-0.025,0.025,-0.05,0.05, RECTNG,-0.028,-0.025,-0.04,0.04, RECTNG,0.025,0.028,-0.04,0.04, RECT
28、NG,-0.03,0.03,-0.058,0.058, FLST,2,4,5,ORDE,2 FITEM,2,1 FITEM,2,-4 AOVLAP,P51X ALLSEL,ALL CM,_Y,AREA ASEL, , , , 5 CM,_Y1,AREA CMSEL,S,_Y !* CMSEL,S,_Y1 AATT, 1, , 1, 0, CMSEL,S,_Y CMDELE,_Y CMDELE,_Y1 !* FLST,5,2,5,ORDE,2 FITEM,5,2 FITEM,5,-3 CM,_Y,AREA ASEL, , , ,P51X CM,_Y1,AREA CMSEL,S,_Y !* CMSEL,S,_Y1 AATT, 2, , 1, 0, CMSEL,S,_Y CMDELE,_Y CMDELE,_Y1 !* CM,_Y,AREA ASEL, , , , 6 CM,_Y1,AREA CMSEL,S,_Y !* CMSEL,S,_Y1 AATT, 3, , 1, 0, CMSEL,S,_Y CMDELE,_Y CMDELE,_Y1 !* SMRT,6 SMRT,1 MSHAPE,0,2D