SIMULATION OF CHARGING AND COUPLED AIR-FLOWS IN CORONA DEVICES

A hybrid algorithm for simulating electrohydrodynamic (EHD) flows in c harge generating devices is described. The computational scheme is a r obust time-transient hybrid technique using the boundary integral equa tion method (BIEM) and the method of characteristics (MOC). This algor ithm alternates between solution of the fluid and electrostatic proble ms. The Navier-Stoke's equations for the fluid problem, inclusive of E HD effects, are solved using a vorticity-streamfunction BIEM formulati on that does not require vorticity boundary conditions to be specified a priori. The non-linearities are handled as volume terms tracked alo ng trajectories as they evolve using the MOC. The electrostatic proble m is solved using a combination of the BIEM for charge conservation, a nd the MOC for current continuity. Very rapid time-stepping is achieve d by pre-computing all spatial integrals as influence coefficient matr ices (ICMs). This measure simplifies re-analysis and re-calculation of fields to algebraic matrix operations. The speed of this algorithm al lows rapid dynamic computation and visualization on a SparcStation 2 c lass Unix workstation. Sample results, including: space charge, couple d airflows, and electrostatic fields, are presented for the simulation of corotron charging of a xerographic electroreceptor.