Monte Carlo Approach for Transmission Probability & Radiation Heat Load and CFD Analysis for Cryopump Application

Abstract

In fusion Reactor during fusion process exhaust gases are produced. The gases pro- duced contain mainly isotopes of hydrogen and helium. So exhaust gases must remove from the fusion reactor. Removal of exhaust gases required very high pumping system. For fusion reactor Vacuum pumping system is facing challenges. The operation of mechanical pump with rotating parts faces problems due to eddy currents. Cryopump which has all static parts is an option to pump such machines. For this requirement cryopump is used. Cryopump is mainly designed for maximum transmission prob- ability,minimum radiation heat load on cryopanel and optimum temperature of gas particle striking on cryopanel. Geometry has to be optimized for it. Flow distribution of liquid He in cryopanel for liquid helium ow through cryopanel should be uniform and it maintains cryopanel temperature for cryopumping. Molecular ow can be simulated by Movak 3D software. In Movak 3D, modeling of geometry for simulation is di cult task due to repeat command logic development for new geometry. For that, use of CAD tool generation of complicated geometry is possible for it. Most of work is generation for modeling geometry for it with use of basic command like triangle, parallogram, circle, ring, cone. Thus, using with 3D transformation command (CAD feature) complicated geometry can be generated e ciently. And transmission probability of cryopump is geometry dependent. By varying geometry feature, geometry is optimized for this situation. Movak 3D code allows Monte Carlo Ray Tracing method for radiation analysis. In development of single panel cryopump Radiation heat load approximation is necessary. So by using Movak 3D code, radiation heat load on main component of single panel cryopump was nd out and CFD analysis was done in Ansys Fluent for ow distribution in cryopanel channel.