{"id":161696,"date":"2023-01-25T07:16:44","date_gmt":"2023-01-25T07:16:44","guid":{"rendered":"\/knowledge\/forums\/topic\/how-to-modify-dpm-injection-mass-flow-using-udf\/"},"modified":"2023-07-31T12:35:44","modified_gmt":"2023-07-31T12:35:44","slug":"how-to-modify-dpm-injection-mass-flow-using-udf","status":"publish","type":"topic","link":"https:\/\/innovationspace.ansys.com\/knowledge\/forums\/topic\/how-to-modify-dpm-injection-mass-flow-using-udf\/","title":{"rendered":"How to modify DPM injection mass flow using UDF?"},"content":{"rendered":"

If you want to modify injection inputs using UDF, you will require the following DPM macro DEFINE_DPM_INJECTION_INIT This macro provides access to particle variables like number of particles in a parcel “p->number_in_parcel”, DPM mass flow rate “P_FLOW_RATE(p)” etc. These variables are linked as follows: Stream mass flow rate = (Number of particles in a parcel) *(Mass of single particle) \/ ( Injection time interval) If you want to modify the mass flow rate, you should modify it using P_FLOW_RATE(p) and not by modifying p->number_in_parcel. This is because p->number_in_parcel is derived from P_FLOW_RATE(p). In general, p->number_in_parcel should never be modified in the UDF. Mass flow rate should be modified by changing P_FLOW_RATE(p) only.<\/p>\n","protected":false},"template":"","class_list":["post-161696","topic","type-topic","status-publish","hentry","topic-tag-4424","topic-tag-dpm","topic-tag-fluent","topic-tag-fluid-dynamics","topic-tag-general","topic-tag-other"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t