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

Kim, Chang H.; Doster, J. Michael; Bourham, Mohamed A.

doi:https://doi.org/10.3814/2009/797068

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Research Article | Open Access

Volume 2009 | Article ID 797068 | https://doi.org/10.3814/2009/797068

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

Chang H. Kim,¹J. Michael Doster,¹and Mohamed A. Bourham¹

Received15 Jun 2008

Accepted05 Jan 2009

Published08 Feb 2009

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.

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Copyright

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.

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