[pxc3536]

Hello I am simulating flow through an electrostatic precipitator. I have defined user defined scalar equations in Fluent for two governing equations. The first equation is Poisson's Equation given by Laplacian(Phi) = -rho/epsilon. Phi is electric potential, rho is charge density, and epsilon is permittivity of air. The second equation is Divergence(rho*v) = 0 where v is the fluid velocity. This is the equation for conservation of charge in which I have neglected ionic drift and diffusion. The boundary conditions for phi are pretty straightforward, but for the charge density, I have to specify a value for charge density at the electrode. The equation for charge density as shown above is only a first-order differential equation, therefore I should only need the value at the electrode. But Ansys Fluent requires me to specify boundary conditions at all boundaries including flow inlet and outlet. I think this is why my results don't make sense. Is there any way to circumvent this problem? Is there anyone with experience with electrohydrodynamic flow?