ÐÞÕý¡£Ä¬ÈÏÇé¿ö£¬²»°üº¬Õâ¸öÐÞÕý£¬µ«ÊÇÔÚÎÊÌâÉèÖùý³ÌÖУ¬ÄãÄÜÓÃËü¡£ ÿÏàµÄÎÉÁ÷Ä£ÐÍ£¨Turbulence Model for Each Phase£©
×îÆÕͨµÄ¶àÏàÎÉÁ÷Ä£ÐÍΪÿһÏàÇó½âÒ»Ì×kand?ÊäÔË·½³Ì¡£µ±ÎÉÁ÷´«µÝÔÚÏà¼äÆðÖØÒª×÷ÓÃʱ£¬Õâ¸öÎÉÁ÷Ä£ÐÍÊǺÏÊʵÄÑ¡Ôñ¡£
×¢£ºÓÉÓÚFLUENTΪÿ¸öµÚ¶þÏàÇó½âÁ½¸ö¸½¼ÓµÄÊäÔË·½³Ì£¬Ã¿ÏàµÄÎÉÁ÷Ä£ÐͱȷÖÉ¢ÏàÎÉÁ÷Ä£ÐÍ´ó´óµØÔö¼ÓÁ˼ÆËãµÄÇ¿¶È¡£ ÊäÔË·½³Ì£¨Transport Equations£©
À×ŵӦÁ¦ÕÅÁ¿ºÍÎÉÁ÷Õ³¶È²ÉÓ÷½³Ì20.4.65ºÍ20.4.66¼ÆËã¡£ÎÉÁ÷Ô¤²â´ÓÏÂʽ»ñµÃ£º
??t,q?(?q?qkq)?????q?qUqkq????(?q?kq)???qGk,q??q?q?q???t?k NNN?????t,q?t,l??q?Klq(Clqkl?Cqlkq)??Klq(Ul?Uq)???l??Klq(Ul?Uq)?l?1l?1?l?ll?1?q?q £¨20.4.86£©
ºÍ
??t,q?q?(?q?q?q)???(?q?qUq?q)???(?q??q)?(C1??qGk,q?C2??q?q?q??t??kqN?????t,q?t,lC3?(?Klq(Clqkl?Cqlkq)??Klq(Ul?Uq)???l??Klq(Ul?Uq)???q))NNl?1l?1
?l?ll?1?q?q £¨20.4.87£©
ClqandCql¿ÉÒÔ½üËÆµÄдΪ£º
Clq?2
?lq £¨20.4.88£© Cql?2()1??lqÕâÀï?lqÓÉ·½³Ì20.4.78¶¨Òå¡£
Ïà¼äÎÉÁ÷¶¯Á¿´«µÝ£¨Interphase Turbulent Momentum Transfer£©
ÎÉÁ÷Ò·Á¦Ï·½³Ì20.4.9ÖеÄKpq(vp?vq)£©Ä£»¯ÈçÏ£¬ÕâÀïlÊÇ·ÖÉ¢Ïࣨ´úÌæ·½³Ì20.4.9ÖеÄp£©£¬qÊÇÁ¬ÐøÏࣺ
?? £¨20.4.89£©
???ÕâÀïUlandUÊÇÏà¼ÓȨËÙ¶È£¬£¨Ê¹Ó÷½³Ì20.4.85¼ÆË㣬ÓÃlÈ¡´úp£©¡£vdr,lqÊÇÏàlµÄÆ¯ÒÆËÙ¶È
×¢£ºFLUENTÖ±½Ó´ÓÊäÔË·½³Ì¼ÆËãÀ©É¢ÂÊÉ¢ÎÉÁ÷Ä£ÐÍ£©¡£
DlandDq£¬¶ø²»Ê¹ÓÃTchenÀíÂÛ£¨ÈçËüÓÃÓÚ·Ö
26
ÈçÉÏÃæÖ¸³öµÄ£¬Æ¯ÒÆËÙ¶ÈÆðÒòÓÚÌå»ý·ÖÊýµÄÎÉÁ÷²¨¶¯¡£µ±³ËÒÔ½»»»ÏµÊýKlqʱ£¬ÓÃÓÚÐÞÕýÎÉÁ÷Öе͝Á¿½»»»ÏĬÈÏÇé¿ö£¬Õâ¸öÐÞÕý²»°üÀ¨£¬µ«ÊÇÄãÄÜÔÚÎÊÌâÉèÖùý³ÌÖÐʹÓÃËü¡£ FLUENTÖеÄÿÏàµÄÎÉÁ÷Ä£ÐͽâÊÍΪÎÉÁ÷³¡ÖÐÒ»Ïà¶ÔÆäËüÏàµÄÓ°Ïì¡£Èç¹ûÄãÏëÐÞÕý»òÔöÇ¿¶àÏàÎÉÁ÷³¡Ö®¼äµÄÏ໥×÷ÓúÍÏà¼äÎÉÁ÷¶¯Á¿µÄ´«µÝ£¬Äã¿ÉÒÔʹÓÃÓû§¶¨Ò庯ÊýÌṩÕâЩÏî¡£ 20.4.8FLUENTÖеÄÇó½â·½·¨
¶ÔÅ·À¶àÏàÁ÷¼ÆË㣬¶ÔѹÁ¦ËÙ¶ÈñîºÏFLUENTʹÓÃPhase Coupled SIMPLE (PC-SIMPLE)Ëã·¨[244]¡£PC-SIMPLEÊÇSIMPLEËã·¨[172]ÔÚ¶àÏàÁ÷ÖеÄÀ©Õ¹¡£ËٶȵÄÇó½â±»ÏàñîºÏ£¬µ«ÊÇÓ÷ÖÀëµÄ·½Ê½¡£ÎÄÏ×[260]ÖÐÃèÊöµÄñîºÏÇó½âÆ÷²ÉÓõĶàÖØÍø¸ñ¿é´úÊý·½°¸ÓÃÀ´Í¬Ê±µØÇó½â¸÷ÏàËÙ¶È·ÖÁ¿ÐγɵÄʸÁ¿·½³Ì¡£È»ºó£¬Ñ¹Á¦ÐÞÕý·½³ÌÊÇ»ùÓÚ×ܵÄÌå»ýÁ¬Ðø¶ø²»ÊÇÖÊÁ¿Á¬Ðø½¨Á¢ÆðÀ´µÄ¡£ÎªÁËÂú×ãÁ¬ÐøÐÔµÄÔ¼ÊøÑ¹Á¦ºÍËٶȶ¼±»ÐÞÕý¡£ ѹÁ¦ÐÞÕý·½³Ì£¨The Pressure-Correction Equation£© ¶Ô²»¿ÉѹËõ¶àÏàÁ÷£¬Ñ¹Á¦ÐÞÕý·½³Ì²ÉÓÃÈçÏÂÐÎʽ£º
£¨20.4.90£©
*ÕâÀïvk'ÊǵÚkÏàµÄËÙ¶ÈÐÞÕý£¬vkÊÇvkµÄµ±Ç°µü´úÖµ¡£ËÙ¶ÈÐÞÕý±¾Éí±íʾΪѹÁ¦ÐÞÕýµÄº¯Êý¡£
???Ìå»ý·ÖÊý£¨Volume Fractions£©
Ìå»ý·ÖÊý´ÓÏàÁ¬ÐøÐÔ·½³Ì»ñµÃ¡£ÀëÉ¢ÐÎʽÏ£¬µÚkÏàÌå»ý·ÖÊý·½³ÌΪ£º
£¨20.4.91£©
ΪÁËÂú×ãËùÓÐÌå»ý·ÖÊýºÍΪ1µÄÌõ¼þ£¬»¹ÓУº
£¨20.4.92£©
20.5ÆøÑ¨Ó°Ï죨Cavitation Effects£©
µ±Ê¹ÓûìºÏÄ£ÐÍ»òÅ·ÀÄ£ÐÍʱ£¬ÆøÑ¨Ó°ÏìÊDZ»°üº¬ÔÚÁ½ÏàÁ÷Öеġ£Õⲿ·ÖFLUENTÖÐʹÓõĹØÓÚÆøÑ¨µÄÄ£ÐÍ¡£
20.5.1ÆøÑ¨Ä£Ð͸ÅÊö¼°Æä¾ÖÏÞ£¨Overview and Limitations of the Cavitation Model£© Ôں㶨ζÈ϶ÔÒºÌ彵ѹ£¬¿ÉÒÔ½µµ½±¥ºÍÕôÆûѹ֮Ï¡£ÔÚºãÎÂÏÂͨ¹ý½µµÍѹÁ¦Ê¹ÒºÌ寯ÁѵĹý³Ì³ÆÎªÆøÑ¨ÏÖÏó¡£ÒºÌå°üº¬Î¢Ð¡¿ÕÆøÅÝ»òºË£¬ÔÚ½µÑ¹ÏÂËüÃǻ᳤´ó²¢ÐÎ³ÉÆøÑ¨¡£ µ±¾Ö²¿Ñ¹Á¦Ð¡ÓÚÕô·¢Ñ¹Á¦Ê±£¬ÎªÁ½ÖÖ»¥Ïà¹á´©µÄÁ÷ÌåÉè¼ÆµÄÆøÑ¨Ä£ÐÍÄ£ÄâÁËÆøÅݵÄÐÅÏ¢¡£ÆøÑ¨Ä£ÐÍ¿ÉÒԺͻìºÏÄ£ÐÍ£¨ÓÐÎÞ»¬ÒÆËÙ¶È£©»òÅ·À¶àÏàÄ£ÐÍÒ»ÆðʹÓá£ ÆøÑ¨Ä£ÐÍÖÐ×÷ÁËÈçϼÙÉ裺
1£® µ÷²éÑо¿ÖнöÉæ¼°Á½ÏàµÄϵͳ¡£ 2£® ÆøÅݼȲ»´´ÔìÒ²²»ÆÆ»µ¡£
3£® ÿ¸öµ¥Î»Ìå»ýÄÚÆøÅݵÄÊýÁ¿ÊÇÔ¤ÏÈÖªµÀµÄ¡£ FLUENTÖÐÓ¦ÓÃÆøÑ¨Ä£Ð͵ľÖÏÞÈçÏ£º
1£® ÆøÑ¨Ä£ÐͲ»ÄܺÍVOFÄ£ÐÍÒ»ÆðʹÓã¬ÒòΪVOFÄ£Ð͵ıíÃæ¸ú×Ù·½°¸ºÍÆøÑ¨Ä£Ð͵ÄÏ໥
¹á´©µÄÁ¬ÐøÐÔ¼ÙÉèÊDz»ÏàÈݵġ£
2£® ÆøÑ¨Ä£ÐͽöÓÃÓÚʹÓÃʹÓûìºÏ»òÅ·ÀÄ£Ð͵ĶàÏàÁ÷Ä£Äâ²¢ÇÒÖ»ÄÜÉæ¼°Á½Ïà¡£Çó½âÆøÑ¨Ä£
ÐÍʹÓÃûÓл¬ÒÆËٶȵĻìºÏÄ£ÐÍ×ÜÊÇ¿ÉÈ¡µÄ£¬Èç¹ûÎÊÌ⽨ÒéÁ½ÏàÖ®¼äÓÐÖØ´óµÄ»¬ÒÆ£¬Å·
27
À¶àÏàºÍ»¬ÒÆËÙ¶ÈÓ¦´ò¿ª¡£
3£® ʹÓÃÆøÑ¨Ä£ÐÍ£¬Ö»ÄܵڶþÏàÊÇ¿ÉѹËõµÄ£¬Ö÷Ïà±ØÐëÊDz»¿ÉѹËõµÄ¡£ Ìå»ýºÍÆøÅÝÊýÁ¿£¨Volume and Number of Bubbles£© µ¥¸öÆøÅÝÌå»ý¹ØÓÚ¿Õ¼äºÍʱ¼äµÄ±ä»¯ÓÉÏÂʽ¸ø³ö
£¨20.5.1£©
ÕâÀïRÊÇÆøÅݵİ뾶¡£ Õô·¢µÄÌå»ý·ÖÊý¶¨ÒåΪ£º
£¨20.5.2£©
ÕâÀï?Êǵ¥Î»Á÷ÌåÈÝ»ýÄ򵀮øÅÝÊýÁ¿¡£
Ìå»ý·ÖÊý·½³Ì£¨The Volume Fraction Equation£©
Ìå»ý·ÖÊý·½³Ì´Ó»ìºÏ£¨m£©µÄÁ¬ÐøÐÔ·½³Ì»ñµÃ¡£¾¹ý´¦Àíºó£¬¼Ù¶¨²»¿ÉѹËõµÄÒºÌ壨l£©,¿ÉÒÔ»ñµÃÏÂÃæµÄ±í´ïʽ£º
£¨20.5.3£©
ÆøÅݶ¯Á¦Ñ§£¨Bubble Dynamics£©
ÓÉÓÚÆøÑ¨ÆøÅÝÔÚµÍÎÂÏÂÐγÉÒºÌ壬FLUENTµÈÎÂÄ£ÄâÆøÑ¨Á÷¶¯£¬ºöÂÔÁËÕô·¢Ç±ÈÈ¡£Rayleigh-Plesset·½³ÌÓëѹÁ¦ºÍÆøÅÝÈÝ»ý?Ïà¹Ø£º
£¨20.5.4£©
ÕâÀïpB±íÊ¾ÆøÅÝÄÚµÄѹÁ¦£¬ÓÉÕôÆûµÄ²¿·ÖѹÁ¦£¨pv£©ºÍ·ÇÄý½áÆøÌåµÄ²¿·ÖѹÁ¦£¨p£©Ö®ºÍÀ´Ãè»æ£¬?ÊDZíÃæÕÅÁ¦ÏµÊý¡£
ΪÁ˼ò»¯¼ÆË㣬FLUENT¼ÙÉèÆøÅݳɳ¤ºÍÆÆÁѵĹý³ÌÓÉÏÂʽ¸ø³ö£º
£¨20.5.5£©
20.6ÉèÖÃÒ»°ãµÄ¶àÏàÁ÷ÎÊÌ⣨Setting Up a General Multiphase Problem£© Õⲿ·ÖÌṩÁËʹÓÃVOFÄ£ÐÍ£¬»ìºÏÄ£ÐͺÍÅ·À¶àÏàÁ÷Ä£Ð͵ÄÓ÷¨ºÍÖ¸ÄÏ¡£
20.6.1ʹÓÃÒ»°ã¶àÏàÁ÷Ä£Ð͵IJ½Ö裨Steps for Using the General Multiphase Models£© ÉèÖúÍÇó½âÒ»°ã¶àÏàÁ÷ÎÊÌâµÄ²½ÖèµÄÒªµãÈçÏ£¬¸÷¸ö×Ó²¿·ÖÏêϸµÄ½²ÊöÔÚËæºóµÄÕ½ÚÖС£¼ÇסÕâÀï¸ø³öµÄ½öÊÇÓëÒ»°ã¶àÏàÁ÷¼ÆËãÏà¹ØµÄ²½Öè¡£ÓйØÄãʹÓÃµÄÆäËüÄ£ÐͺÍÏà¹ØµÄ¶àÏàÁ÷Ä£Ð͵ÄÊäÈëµÄÏêϸÐÅÏ¢£¬½«ÔÚÕâЩģÐÍÖкÏÊʵIJ¿·Ö¸ø³ö¡£ ¼ûSection 20.6.2Óмò»¯Å·À¶àÏàÁ÷Ä£ÄâµÄÖ¸ÄÏ¡£
1£®Ñ¡ÖÐÄãÏëҪʹÓõĶàÏàÁ÷Ä£ÐÍ£¨VOF, mixture, or Eulerian£©²¢Ö¸¶¨ÏàÊý¡£¶ÔVOFÄ£ÐÍ£¬Ò²Ö¸¶¨VOF¹«Ê½¡£ Define
Models Multiphase...
28
See Sections 20.6.3 and 20.6.4 for details. 2.´Ó²ÄÁÏ¿âÖи´ÖÆÃèÊöÿÏàµÄ²ÄÁÏ¡£
Define Materials...
Èç¹ûÄãʹÓõIJÄÁÏÔÚ¿âÖÐûÓУ¬Ó¦´´½¨Ò»ÖÖвÄÁÏ¡£¹ØÓÚ´Ó¿âÖи´Öƺʹ´½¨Ð²ÄÁϵÄÏêϸÄÚÈݼûSection 7.1.2. ¹ØÓÚΪ¿ÉѹËõÏà(VOF and mixture models only)Ö¸¶¨²ÄÁÏÊôÐÔµÄÏêϸÄÚÈÝÏê¼ûSection 20.6.16.
!!Èç¹ûÄãµÄÄ£ÐÍÖк¬ÓÐ΢Á££¨granular£©Ï࣬Äã±ØÐëÔÚfluid materials categoryÖÐΪËü´´½¨Ð²ÄÁÏ£¨not the solid materials category£©
3£®¶¨ÒåÏָ࣬¶¨Ïà¼äµÄÏ໥×÷Óã¨interaction£©(ÀýÈ磬ʹÓÃOVFÄ£ÐÍʱµÄ±íÃæÕÅÁ¦£¨surface tension£©£¬Ê¹ÓûìºÏÄ£ÐÍʱµÄ»¬Á÷ËÙ¶È£¬Ê¹ÓÃÅ·ÀÄ£ÐÍʱµÄdrag functions) Define Phases...
See Sections 20.6.7- 20.6.10 for details.
4.(½ö¶ÔÅ·ÀÄ£ÐÍ)Èç¹ûÁ÷¶¯ÊÇÎÉÁ÷£¬¶¨Òå¶àÏàÎÉÁ÷Ä£ÐÍ¡£
Define Models Viscous... See Section 20.6.13 for details.
5£®Èç¹ûÌå»ýÁ¦´æÔÚ£¬turn on gravity and specify the gravitational acceleration.
Define Operating Conditions... See Section 20.6.11 for details. 6£®Ö¸¶¨±ß½çÌõ¼þ£¬°üÀ¨µÚ¶þÏàÌå»ý·Ý¶îÔÚÁ÷¶¯±ß½çºÍ£¨Èç¹ûÔÚVOFÄ£ÄâÖÐÄãÄ£Äâ±ÚÃæ¸½½ü£©±ÚÃæÉϵĽӴ¥½Ç¡£
Define Boundary Conditions... See Section 20.6.14 for details. 7£®ÉèÖÃÄ£Äâ¾ßÌåµÄ½â²ÎÊý
Solve Controls Solution...
See Sections 20.6.12 and 20.7 for details. 8£®³õʼ»¯½âºÍΪµÚ¶þÏàÉ趨³õʼÌå»ý·Ý¶î¡£
Solve Initialize Patch... See Section 20.6.15 for details. 9£®¼ÆËãÇó½âºÍ¼ì²é½á¹û
See Sections 20.7 and 20.8 for details.
20.6.2Å·À¶àÏàÁ÷Ä£ÄâµÄ¸½¼ÓÖ¸ÄÏ£¨Additional Guidelines for Eulerian Multiphase Simulations£©
Ò»µ©Äã¾ö¶¨ÁËÅ·À¶àÏàÁ÷Ä£ÐÍÊʺÏÄãµÄÎÊÌ⣨as described in Sections 18.4 and 20.1£©£¬ÄãÓ¦µ±¿¼ÂÇÇó½âÄãµÄ¶àÏàÁ÷ÎÊÌâµÄÐèÇó¼ÆËãÄÜÁ¦¡£ÒªÇóµÄ¼ÆËãÄÜÁ¦ºÜÇ¿µÄÒÀÀµÓÚËùÇó½âµÄÊäÔË·½³ÌµÄ¸öÊýºÍñîºÏ³Ì¶È¡£¶ÔÅ·À¶àÏàÁ÷Ä£ÐÍ£¬ÓдóÊýÁ¿µÄ¸ß¶ÈñîºÏµÄÊäÔË·½³Ì£¬¼ÆËãµÄºÄ·Ñ½«ºÜ¸ß£¬ÔÚÉèÖÃÄãµÄÎÊÌâǰ£¬¾¡¿ÉÄܼõÉÙÎÊÌâµÄstatementµ½×î¼ò»¯µÄ¿ÉÄÜÐÎʽ¡£ ÔÚÄ㿪ʼµÚÒ»´ÎÇó½â³¢ÊÔ£¬È¡¶ø´úÖ®¾¡Á¦È¥Çó½â¶àÏàÁ÷¶¯µÄËùÓеĸ´ÔÓ·½Ã棬Äã¿ÉÒÔÒÔ¼òµ¥½üËÆµØ¿ªÊ¼²¢ÇÒÖªµÀÎÊÌⶨÒåµÄ×îÖÕÐÎʽ¡£¼ò»¯¶àÏàÁ÷ÎÊÌâµÄһЩ½¨ÒéÁоÙÈçÏ£º
1£® ʹÓÃÁùÃæÌå»òËıßÐÎÍø¸ñ£¨¶ø²»ÓÃËÄÃæÌå»òÈý½ÇÐÎÍø¸ñ£©¡£ 2£® ¼õÉÙÏàµÄÊýÄ¿¡£
Äã»á·¢ÏÖ¼´Ê¹¼òµ¥µÄ½üËÆÒ²»á¸øÄãµÄÎÊÌâÌṩÓÐÓõÄÐÅÏ¢¡£
See Section 20.7.3 for more solution strategies for Eulerian multiphase calculations.
20.6.3Ñ¡ÓöàÏàÁ÷Ä£ÐͲ¢Ö¸¶¨ÏàÊý£¨Enabling the Multiphase Model and Specifying the
29
.
Number of Phases£©
ΪÁËÑ¡VOF, mixture, Eulerian¶àÏàÁ÷Ä£ÐÍ£¬ÔÚMultiphase Model panel (Figure 20.6.1)ÏÂÑ¡Volume of Fluid, Mixture, or Eulerian as the Model¡£ Define
Models
Multiphase...
Figure 20.6.1: The Multiphase Model Panel
Õâ¸öÃæ°å½«À©Õ¹ÎªÏÔʾÒÑÑ¡ÔñµÄ¶àÏàÁ÷Ä£ÐÍÏà¹ØÊäÈë¡£ Èç¹ûÄãÑ¡µÄÊÇVOFÄ£ÐÍ£¬ÊäÈëÈçÏ£º
? ? ?
number of phases
VOF formulation (see Section 20.6.4)
(optional) implicit body force formulation (see Section 20.6.11)
Èç¹ûÄãÑ¡ÔñµÄÊÇ»ìºÏÄ£ÐÍ£¬ÊäÈëÈçÏ£º
? ? ? ?
number of phases
whether or not to compute the slip velocities (see Section 20.6.5) (optional) implicit body force formulation (see Section 20.6.11) (optional) cavitation effects (see Section 20.6.6)
Èç¹ûÄãÑ¡µÄÅ·ÀÄ£ÐÍ£¬ÊäÈëÈçÏ£º
30