Performance Assessment of 239 Series Helium Sub-Cooling Heat Exchangers for the Large Hadron Collider

Abstract

Helium sub-cooling heat exchangers of the counter-flow type are used to minimize the vapor fraction produced in the final expansion of the 1.9 K distributed cooling loops used for cooling the superconducting magnets of the Large Hadron Collider (LHC). These components are of compact design, featuring low-pressure drop and handling very low pressure vapor at low temperature. Following a qualification phase of prototypes, a contract has been placed in European industry for the supply of 239 heat exchanger units. Different levels of extracted heat load require three different variants of heat exchangers. This paper will describe the manufacturing phase with emphasis on the main difficulties encountered to keep the production quality after a brief recall of the prototype phase. Finally, the acceptance tests performed at room temperature and at the nominal cryogenic condition at the factory and at CEA-Grenoble will be presented.

PIP-II Cryogenic System and the evolution of Superfluid Helium Cryogenic Plant Specifications

“…Additionally, for SP HX set, second law limitations are imposed through the use of device effectiveness value referenced from literature [5]. Apart from the effectiveness, the pressure drop across the SP HX has also been sourced from published literature [5,6]. Since the SP heat exchangers in the cryomodules are not designed yet, for preliminary studies, it is assumed that all these heat exchangers possess the same effectiveness and hydraulic characteristics.…”

Two low-cost, modular sub-λ test cryostats

“…The feedbox provides inlet and outlet connections for helium and contains the heat exchanger [6] (Fig. 3) and valves required for sub-atmospheric operation.…”