problem while using heat flux DEFINE_HEAT_FLUX

learningCFD

If I want to add a heat source on a wall named liquid_interface:

DEFINE_HEAT_FLUX(heat_flux, f, t, c0, t0, cid, cir) { int liquid_interface_id=16; /*the ID of liquid interface*/ if (THREAD_ID(t)==liquid_inter_id) { cid[0]=100 ; /*100 is the heat source */ } }

Is this right? Should I use "cid[0]=100" or "cid[0]=cid[0]=+100", I printed out some cid[] valudes from some walls, fount they have non-zero values. I don't know those values are coefficients calculated by Fluent or just random wrong numbers. Anyway, either "cid[0]=100" or "cid[0]=cid[0]=+100" didn't give me reasonable results. Any big guy gives me a light? Thanks very much in advance.