[sola86]

When I used the population balance model (DQMOM) to simulate a two-phase flow (water and vapor) with UDF, some errors always appeared.

In steady simulations, the error message is "singular matrix". And in transient simulations, the error message is "unable to find rpvar 'pb/solve-interval'".

In fact, I don't konw how to set the VOF and m4 of the three second phases in BC. I only konw they need to be distanct from ansys help.

Do I have to choose "generate DQMOM vlaues from……"? What‘s the use of this step?

When I used QMOM to deal with the same case (transient), it can be calculated about 25 time steps. An error measage "ITMAX too small in gcfa too large" appeared. Then the calculation stopped with an error "floating point exception".

Did anyone ever met this problem?