Dynamic simulation of CHL at SNS

Abstract

A dynamic simulation model of Central Helium Liquefier (CHL) has been developed by the process simulation software; EcosimPro™. CHL consists of 4 K and 2 K cold boxes to sustain the operation of LINear ACcelerator (LINAC) which is composed of Superconducting Radio Frequency (SRF) cavities installed in the Cryomodules. 4 K cold box is a modified Claude cycle refrigerator, having LN₂ precooler with two Brayton Cycle turbines, followed by the series connected Turbines (Tu3 and Tu4), and a Supercritical Helium (SHe) turbine (Tu5) for high thermodynamic efficiency. The product of 125 g/s of SHe is subcooled at the LHe immersed Heat eXchanger (HX) before supplying to Cryomodules, which has its own precooled HX for He II vapor vs. SHe, to have high liquid yield for He II at 2.1 K. Four series connected Cold Compressors (CCs) keep the LINAC pressure at 0.04 bar for the proton beam acceleration. The paper discusses the modeling of CHL, including four CCs. The benchmark of the model against a design specification of CHL and the validation of CC model is also described in detail.