The High-Luminosity upgrade of the Large Hadron Collider at CERN comprises the implementation of a new generation of high-field superconducting quadrupole and dipole magnets. The dipole fields of up to 12.1 T at nominal current require the use of high-critical-current Nb ₃ Sn strand for the fabrication of the coils. These coils will be up to 8 m long and represent the longest Nb ₃ Sn coils so far fabricated for operation accelerator magnets. This brittle A15 phase material requires coil winding prior formation of the superconducting material. The development program at CERN includes the construction of 2-m-long models and full-length prototypes by the wind-and-react technique. The process time and temperature uniformity are stringent during heat treatment and performed inside an EN 1.4841 (AISI Type 314) stainless-steel retort furnace with turbulent flow of Ar atmosphere. During the process, the coil is supported inside a reaction fixture made from 316LN. This paper presents temperature uniformity measurements and results from numerical simulations. The goal is to further improve the heat transfer in combination with turbulent flow generated by a ventilation system. This allows optimizing control parameters for improved heat performance during both the ramping and the dwell time.

Preheating furnaces, which are commonly used in many production sectors (e.g., iron and steel), are simultaneously one of the most energy-intensive devices used in the industry. Partial replacement of natural gas with biomass-derived synthesis gas as a fuel used for heating would be an important step towards limiting industrial CO₂ emissions. The time dependent computational fluid dynamics (CFD) model of an exemplary furnace was created to evaluate whether it is possible to obtain 40% of energy from syngas combustion without deterioration of thermal parameters of the treated load. As an outcome, a promising method to organize co-firing in the furnace was indicated. The obtained results show that the co-firing method (up to 40% thermal natural gas replacement with syngas), assuming low air-to-fuel equivalence ratio (λ_NG = 2.0) and even distribution of power among the furnace corners, lead to satisfactory efficiency of the heat treatment process—the heat transferred to the load exceeds 95% of the heat delivered to the load in the reference case), while carbon dioxide emission is reduced from 285.5 to 171.3 kg CO₂/h. This study showed that it is feasible (from the heat transfer point of view) to decrease the environmental impact of the process industries by the use of renewable fuels.