Table of Contents
Scholarly Research Exchange
Volume 2009, Article ID 797068, 6 pages
http://dx.doi.org/10.3814/2009/797068
Research Article

Wide-Beam X-Ray Source Target Thermal Management Simulation Using Inner Jet Cooling

Department of Nuclear Engineering, College of Engineering, North Carolina State University, Raleigh, NC 27695-7909, USA

Received 15 June 2008; Accepted 5 January 2009

Copyright © 2009 Chang H. Kim et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

A wide-beam area X-ray source has been proposed as a practical replacement for synchrotron sources in clinical DEI applications. Due to a wide X-ray illumination area, a decrease in X-ray flux is expected and thus high electron beam currents up to 3A are considered. To ensure the target performance without deterioration, melting, cracking, or even evaporation, an active cooling system is required for the target block in order to remove the heat and allow for sufficient scanning time. In this study, jet cooling of the target back is investigated for a prototype proof-of-principle target. The prototype target was simulated with the transient k-ɛ turbulence multiphysics model in ANSYS CFX. The simulations were conducted at a heat flux of 1.8×107 W/m2, consistent with values anticipated for a full scale target. The simulation results show that the target temperature exceeds the copper melting point in 2 seconds at inlet velocities below 2 m/s. Also, critical heat flux calculations show that a 1.5 m/s inlet velocity at atmospheric pressure is a lower limit for prevention of target burnout using water as a coolant. Inlet velocities in excess of 2 m/s allows for steady-state operation while satisfying all thermal design constraints.