source term defined by distributed ODE get wrong result

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Hi everyone,

I'm trying to calculate a transient solid heat transfer problem using comsol 6.2, where a domain within the solid has a heat source Q [W] (which is a function of temperature, via an interpolation table), which stops after reaching a total heat release of Hmax [J], and so I need to integrate Q over the domain in a time-series. To do this, I chose the distributed ordinary differential equation interface, the dependent variable is the energy H, and the source term is the heat source term Q*(H<Hmax)+0. According to the expected situation, it should be that the H integral reaches Hmax and then Q becomes 0. However, in the actual computation, there is a situation where the heat source still exists even if H>Hmax, and there are a lot of negative values for dH/dt, which feels like a computational error. For this reason I have encrypted the mesh and time step and changed the solver, but it still does not affect the phenomenon, what could be the reason for this? The model was migrated from Starccm+ and works fine in Starccm+.

Sorry that I cannot attach any result or .mph file due to confidentiality issues. Hope my description is easily understood.

Thanks a lot in advance!


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