Procast充型無(wú)法完成的原因及解決方法

1、Procast充型無(wú)法完成的原因及解決方法充型無(wú)法完成的原因及解決方法？無(wú)法充滿的原因：檢查PREFIXp.ou戊件。1、 Solution is not converging （計(jì)算程序跳出）原因：邊界條件、材料參數(shù)、網(wǎng)格等可能有問(wèn)題，導(dǎo)致計(jì)算不收斂。解決方法：檢查precast中的邊界條件，初始條件等；修改CGSQ參數(shù)，采用不用的求解模型；增大收斂公差 CONVV （最大0.5）;重新劃網(wǎng)格。2、 A cold shut switch off has been initiated at （流場(chǎng)計(jì)算停止，溫度場(chǎng)計(jì)算繼續(xù)，但出現(xiàn)異常。 Thermal Only Model ）原因：冷隔算法默認(rèn)

2、為啟動(dòng)狀態(tài)，如鑄件溫度降低太多，則停止充型計(jì)算。如果實(shí)際上并無(wú)冷隔產(chǎn)生，則需調(diào)整參數(shù)重新計(jì)算。解決方法：調(diào)整界面換熱系數(shù)，降低冷卻速度。在PREFIXp.dat中添加參數(shù)：COLDSHUT 0,關(guān)閉冷隔算法。裹氣的判斷對(duì)于裹氣缺陷的判斷，采用v。1 d s選項(xiàng)，觀察充型過(guò)程中的氣體分布，同時(shí)考慮周 圍的排氣情況，及金屬液溫度。主要的參數(shù)設(shè)置RPProCAST provides the access to many Run parameters, in order to allow the treatment of all kind of situations. However, for an

3、everyday use, only a few Run parameters have to be set or modified. This section is presenting the most "popular" Run Parameters that should be set, with proposed values, for each main family of processes. These parameters recommendations may be slightly different from previous ver

4、sions, as the solver algorithms have been modified. These recommended Run parameters correspond to the one which are pre-defined in the "Pre-defined Run Parameters" window. It is thus advised to activate the "pre-defined" set corresponding to the process and then

5、to set the appropriate stopping criteria.For all processesStopping criteria(it is advisable to set a stopping criterion in order to limit the CPU time and avoid unnecessary storage of results)TFINALTSTOPPorosityPOROS = 1 (this model is now recommended for all processes)MACROFS = 0.7FEEDLEN = X (The

6、value FEEDLEN depends upon the size of the mushy zone and thus, the size of the casting. A value ranging from a few millimeters to a few centimeters is recommended. This should be calibrated with experiments. A value of 0 is not advised as this will produce a uniform microporosity throughout the par

7、t, beside the macroshrinkage)Gravity castingTimestep handlingDT = 1e-3 DTMAXFILL = 1e-1DTMAX = 0.5 - 5 (depending upon the size of the model and thus the solidification time)PorosityPIPEFS = 0.3GATEFEED = 0FillingWSHEAR = 2FREESFOPT = 1WALLF = 0.8LVSURF = 0.98High pressure die casting (HPDC)Timestep

8、 handlingDT = 1e-6 to 1e-4 (it depends upon the initial velocity of the first stage)DTMAXFILL = 1e-2DTMAX = 0.2 - 1 (depending upon the size of the model and thus the solidification time)PorosityPIPEFS = 0.0GATEFEED = 1FillingWSHEAR = 2FREESFOPT = 1WALLF = 0.99LVSURF = 1.0PINLET = 1 for a pressure f

9、illing or PINLET = 0 for a velocity/inlet fillingLow pressure die casting (LPDC)Timestep handlingDT = 1e-3DTMAXFILL = 1e-2 (it is important to limit the timestep during the filling of an LPDC part. A value of 1e-2 is recommended for filling time of about 5-20 s.).DTMAX = 0.2 - 1 (depending upon the

10、size of the model and thus the solidification time)PorosityPIPEFS = 0.0GATEFEED = 1FillingWSHEAR = 0 (never use WSHEAR = 2 for LPDC)FREESFOPT = 1WALLF = 0.8LVSURF = 1.0PINLET = 1 for a pressure filling or PINLET = 0 for a velocity/inlet fillingTilt castingTimestep handlingDT = 1e-3DTMAXFILL = 1e-1DT

11、MAX = 0.5 - 5 (depending upon the size of the model and thus the solidification time)PorosityPIPEFS = 0.3GATEFEED = 0FillingWSHEAR = 2FREESFOPT = 1WALLF = 0.8TILT = 1DETACHTOP = 1Centrifugal castingTimestep handlingDT = 1e-3DTMAXFILL = 1e-1DTMAX = 0.5 - 5 (depending upon the size of the model and th

12、us the solidification time)PorosityPIPEFS = 0.3GATEFEED = 0FillingWSHEAR = 2FREESFOPT = 1WALLF = 0.8RELVEL = 1由于材料名稱造成的計(jì)算出錯(cuò)在材料數(shù)據(jù)庫(kù)中添加材料時(shí)，其名稱中不能包含特殊字符。在運(yùn)行 datacast 中，可能會(huì)出錯(cuò)，其出錯(cuò)信息如下：An enthalpy function is referenced in 5 0 data set 2 which has not been given.分析可能原因：該字符與計(jì)算中的某些關(guān)鍵字沖突。多次澆注模擬分期澆注，與補(bǔ)澆工藝略有不同，

13、也可以說(shuō)補(bǔ)澆是一種特殊的分期澆注，完全充滿然后收縮一定量后再次澆注。1、網(wǎng)格不宜太大，澆注系統(tǒng)厚度方向也要保證3 層網(wǎng)格以上， （要想得到更好的充型結(jié)果，對(duì)于其他模擬同樣適用。 ）2、直澆道和鑄件分開建模，鑄件按正常情況設(shè)置熱交換系數(shù)，直澆道適當(dāng)保溫（設(shè)置較小的熱交換系數(shù)） ，防止金屬凝固。3、設(shè)置正常的邊界條件，定義時(shí)間變化曲線。4、運(yùn)行參數(shù)，改LVSURF為一個(gè)大于1的值，防止提前終止流場(chǎng)計(jì)算。5、在P.dat 中手動(dòng)添加參數(shù)： DETACHTOP1 （更好的控制金屬液與鑄型頂部的分離）COLDSHUT （關(guān)閉冷隔計(jì)算）0如何使用 niyama 準(zhǔn)則 niyama 準(zhǔn)則依賴于溫度梯度，網(wǎng)格

14、變化會(huì)影響結(jié)果，目前看來(lái)并不是非常準(zhǔn)確。當(dāng)采用默認(rèn)單位時(shí)： cm C色標(biāo)設(shè)置一般為：0-3045使用切面分析內(nèi)部的危險(xiǎn)點(diǎn)（ spot ）選擇適當(dāng)?shù)闹?，設(shè)置Cutoff 來(lái)顯示分布情況一般來(lái)說(shuō) procast 自帶的 shrinkage porosity 更準(zhǔn)確， 但通過(guò) niyama 準(zhǔn)則可以更好的分析 早期凝固區(qū)域中未形成孤立液相區(qū)的缺陷。重力鑄造-參數(shù)設(shè)置FREESFBAL = 2 (to be added manually in the p.dat file)This can be used in Gravity casting (and only in Gravity casting)

15、 when you have an important horizontal free surface. Sometimes, the free surface is getting quite agitated. FREESFBAL = 2 is calming down this free surface which corresponds much more to the reality. In the code, it correspond to a more accurate treatment of the mass balance at the free surface, whi

16、ch removes the kind of instability that we observed in large horizontal free surfaces.重力鑄造-澆注速度設(shè)置本帖最后由 奔跑 于 2009-6-1 20:58 編輯實(shí)際澆注時(shí)，澆包距離澆口一般約 1020cm ，這時(shí)金屬液到達(dá)澆口的速度約為1m/s2m/2 ，所以在設(shè)置速度邊界條件時(shí)，要注意控制入流面積來(lái)保證速度，否則充型 結(jié)果會(huì)產(chǎn)生較大偏差。In usual casting conditions,the ladle(or crucible) is very often at a minium of 10 o

17、r 20 cm above the top of the pouring cup. Thus,physically,it is advised to set an inlet velocity(at the limit of the model) between 1 and 2 m/s and not smaller. As a consequence, the inlet diameter should be set accordingly in order to have the right inflow of metal. If a too small inlet velocity is

18、 defined (e.g.10cm/s), the inlet diameter should be too large and due to the strong acceleration on the first centimers, the diameter of the accelerating liquid jet will decrease very much. This situation is quite difficult to be modeled and shoule be avoided.Finally, one should always be careful that the mesh size bel