Modeling results for the ITER cryogenic fore pump

Abstract

Abstract. The cryogenic fore pump (CFP) is designed for ITER to collect and compress hydrogen isotopes during the regeneration process of torus cryopumps. Different from common cryopumps, the ITER-CFP works in the viscous flow regime. As a result, both adsorption boundary conditions and transport phenomena contribute unique features to the pump performance. In this report, the physical mechanisms of cryopumping are studied, especially the diffusionadsorption process and these are coupled with standard equations of species, momentum and energy balance, as well as the equation of state. Numerical models are developed, which include highly coupled non-linear conservation equations of species, momentum and energy and equation of state. Thermal and kinetic properties are treated as functions of temperature, pressure, and composition. To solve such a set of equations, a novel numerical technique, identified as the Group-Member numerical technique is proposed. It is presented here a 1D numerical model. The results include comparison with the experimental data of pure hydrogen flow and a prediction for hydrogen flow with trace helium. An advanced 2D model and detailed explanation of the Group-Member technique are to be presented in following papers.

Solid deposition in the ITER cryogenic viscous compressor

“…Note, as mentioned above, that the accuracy of the pressure data is 0.5% of the measurement, while that for the temperature is +/-0.03 K. The inlet hydrogen pressure follows the trend of the inlet helium coolant temperature in a delayed manner. These two measurements are used as input parameters for the transient 7…”

“…In spite of this agreement, the model used the reported measurements of the hydrogen pressure as one of the key input pieces of information. In the future it should be possible 7…”

“…In view of the complex nature of the CVC, both experimental and theoretical investigations have been carried out in order to characterize its operation and provide appropriate design guidelines. Oak Ridge National Lab has built and tested a scaled down model of the CVC [4][5][6], while efforts at the University of Wisconsin-Madison [7] have focused on the physical analysis and modeling. The results of the model display that the combination of conservation equations for mass (species), momentum, and energy allow one to determine the rate and location of mass deposition on the walls of the scaled-down CVC, as well as the temperature and pressure profiles through its length.…”