{"id":164562,"date":"2023-03-17T08:58:03","date_gmt":"2023-03-17T08:58:03","guid":{"rendered":"\/knowledge\/forums\/topic\/known-issue-blockage-factor-taken-into-account-twice-in-vistaccd-choke-calculation-class-3-error\/"},"modified":"2023-07-31T12:25:49","modified_gmt":"2023-07-31T12:25:49","slug":"known-issue-blockage-factor-taken-into-account-twice-in-vistaccd-choke-calculation-class-3-error","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/known-issue-blockage-factor-taken-into-account-twice-in-vistaccd-choke-calculation-class-3-error\/","title":{"rendered":"KNOWN ISSUE: Blockage factor taken into account twice in VistaCCD choke calculation (Class 3 Error)"},"content":{"rendered":"<p>SYMPTOM: When using the VistaCCD component of BladeGen, the choke flow calculation of the maximum mass flow, used in calculating how close the annulus is to choke, is incorrect. This will only significantly affect cases in which the annulus is close to choke, rather than the more common case of the inducer being close to choke.  PROBLEM: This is due to the blockage factor being taken into account twice in the maximum mass flow calculation.  WORKAROUND: The parameter m\/mch_a (mass flow over annulus choking flow) shown in the CCD results needs to be multiplied by a factor of 0.97363.  FIXED IN: ANSYS CFX Release 12.1.<\/p>\n","protected":false},"template":"","class_list":["post-164562","topic","type-topic","status-publish","hentry","topic-tag-4663","topic-tag-blademodeler","topic-tag-fluid-dynamics","topic-tag-general"],"aioseo_notices":[],"aioseo_head":"\n\t\t<!-- All in One SEO 4.9.10 - aioseo.com -->\n\t<meta name=\"description\" content=\"SYMPTOM: When using the VistaCCD component of BladeGen, the choke flow calculation of the maximum mass flow, used in calculating how close the annulus is to choke, is incorrect. This will only significantly affect cases in which the annulus is close to choke, rather than the more common case of the inducer being close to\" \/>\n\t<meta name=\"robots\" content=\"max-image-preview:large\" \/>\n\t<link rel=\"canonical\" href=\"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/known-issue-blockage-factor-taken-into-account-twice-in-vistaccd-choke-calculation-class-3-error\/\" \/>\n\t<meta name=\"generator\" content=\"All in One SEO (AIOSEO) 4.9.10\" \/>\n\t\t<meta property=\"og:locale\" content=\"en_US\" \/>\n\t\t<meta property=\"og:site_name\" content=\"Ansys Knowledge | Ansys Innovation Space\" \/>\n\t\t<meta property=\"og:type\" content=\"article\" \/>\n\t\t<meta property=\"og:title\" content=\"KNOWN ISSUE: Blockage factor taken into account twice in VistaCCD choke calculation (Class 3 Error) | Ansys Knowledge\" \/>\n\t\t<meta property=\"og:description\" content=\"SYMPTOM: When using the VistaCCD component of BladeGen, the choke flow calculation of the maximum mass flow, used in calculating how close the annulus is to choke, is incorrect. This will only significantly affect cases in which the annulus is close to choke, rather than the more common case of the inducer being close to\" \/>\n\t\t<meta property=\"og:url\" content=\"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/known-issue-blockage-factor-taken-into-account-twice-in-vistaccd-choke-calculation-class-3-error\/\" \/>\n\t\t<meta property=\"article:published_time\" content=\"2023-03-17T08:58:03+00:00\" \/>\n\t\t<meta property=\"article:modified_time\" content=\"2023-07-31T12:25:49+00:00\" \/>\n\t\t<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n\t\t<meta name=\"twitter:title\" content=\"KNOWN ISSUE: Blockage factor taken into account twice in VistaCCD choke calculation (Class 3 Error) | Ansys Knowledge\" \/>\n\t\t<meta name=\"twitter:description\" content=\"SYMPTOM: When using the VistaCCD component of BladeGen, the choke flow calculation of the maximum mass flow, used in calculating how close the annulus is to choke, is incorrect. This will only significantly affect cases in which the annulus is close to choke, rather than the more common case of the inducer being close to\" \/>\n\t\t<script type=\"application\/ld+json\" class=\"aioseo-schema\">\n\t\t\t{\"@context\":\"https:\\\/\\\/schema.org\",\"@graph\":[{\"@type\":\"BreadcrumbList\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/forums\\\/topic\\\/known-issue-blockage-factor-taken-into-account-twice-in-vistaccd-choke-calculation-class-3-error\\\/#breadcrumblist\",\"itemListElement\":[{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge#listItem\",\"position\":1,\"name\":\"Home\",\"item\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\",\"nextItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/topics\\\/#listItem\",\"name\":\"Topics\"}},{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/topics\\\/#listItem\",\"position\":2,\"name\":\"Topics\",\"item\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/topics\\\/\",\"nextItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/forums\\\/topic-tag\\\/fluid-dynamics\\\/#listItem\",\"name\":\"fluid-dynamics\"},\"previousItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge#listItem\",\"name\":\"Home\"}},{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/forums\\\/topic-tag\\\/fluid-dynamics\\\/#listItem\",\"position\":3,\"name\":\"fluid-dynamics\",\"item\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/forums\\\/topic-tag\\\/fluid-dynamics\\\/\",\"nextItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/forums\\\/topic\\\/known-issue-blockage-factor-taken-into-account-twice-in-vistaccd-choke-calculation-class-3-error\\\/#listItem\",\"name\":\"KNOWN ISSUE: Blockage factor taken into account twice in VistaCCD choke calculation (Class 3 Error)\"},\"previousItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/topics\\\/#listItem\",\"name\":\"Topics\"}},{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/forums\\\/topic\\\/known-issue-blockage-factor-taken-into-account-twice-in-vistaccd-choke-calculation-class-3-error\\\/#listItem\",\"position\":4,\"name\":\"KNOWN ISSUE: Blockage factor taken into account twice in VistaCCD choke calculation (Class 3 Error)\",\"previousItem\":{\"@type\":\"ListItem\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/forums\\\/topic-tag\\\/fluid-dynamics\\\/#listItem\",\"name\":\"fluid-dynamics\"}}]},{\"@type\":\"Organization\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/#organization\",\"name\":\"Ansys Knowledge\",\"description\":\"Ansys Innovation Space\",\"url\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/\"},{\"@type\":\"WebPage\",\"@id\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/forums\\\/topic\\\/known-issue-blockage-factor-taken-into-account-twice-in-vistaccd-choke-calculation-class-3-error\\\/#webpage\",\"url\":\"https:\\\/\\\/innovationspace.ansys.com\\\/knowledge\\\/forums\\\/topic\\\/known-issue-blockage-factor-taken-into-account-twice-in-vistaccd-choke-calculation-class-3-error\\\/\",\"name\":\"KNOWN ISSUE: Blockage factor taken into account twice in VistaCCD choke calculation (Class 3 Error) | Ansys Knowledge\",\"description\":\"SYMPTOM: When using the VistaCCD component of BladeGen, the choke flow calculation of the maximum mass flow, used in calculating how close the annulus is to choke, is incorrect. 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