3D computational fluid dynamics analysis of PINI ion source back plate under high heat flux condition

Neutral Beam Injection (NBI) plays an essential role in Tokamak plasma heating and current drive. A positive ion-based NBI (PNBI) system is adopted in Steady State Superconducting Tokamak- 1 (SST-1). This PNBI system is capable of generating neutral hydrogen beam power of 1.7 MW at 55 keV. This system has a JET PINI (Positive Ion Neutral Injector) type of ion source. The Back Plate (BP) is a component of the PINI ion source. It consists of an SS 304 L magnet positioning & cover plate, and an OFE copper cooling plate. The back plate plays a vital role in removing the high heat load intercepted during beam operation. The present study describes 3D Computational Fluid Dynamics (CFD) analysis of the actual size back plate using the ANSYS version of R121. The 3D CFD analysis has been done under a 2.5 MW/m2 steady heat load incident on the OFE copper plate. Cooling water is provided in the Inlet header of the back plate with a mass flow rate of 1 kg/s at 34 degrees C. The analysis gives the surface temperature distribution over the OFE copper cooling plate with a maximum surface temperature of 174 degrees C and the average temperature is 122 degrees C. This result is in good agreement with High Heat Flux experimental results.