Practical methods for constant temperature control in tunnel-shaped scientific facilities: Uniform vs. pressure-driven air supply with insights from SHINE

Maintaining constant temperature is critical in large-scale scientific facilities, such as circular or linear tunnel-shaped facilities (TSFs) used for high-energy physics experiments (e.g., particle acceleration or collision). Traditional ventilation designs with vertical unidirectional airflow and uniform air supply rates are better suited for regular rooms and are less practical for TSFs. After evaluating four typical tunnel ventilation schemes, this study proposed achieving effective constant temperature control in TSFs using the most feasible approach, i.e., supply-air-based semi-transverse ventilation. First, two simplified analytical models were developed to determine the steady-state longitudinal temperature profile and the response time to temperature fluctuations. Two air supply distribution approaches, i.e., uniform and pressure-driven, can be incorporated. The latter was developed based on fluid dynamics. Second, a 400-meter-long TSF from a Shanghai-based scientific facility (SHINE) served as the case study. Fluctuation sources and their ways of causing various temperature fluctuations were analyzed, including air handling units (e.g., supply air temperature or flow rates), cables, and scientific instruments. Third, the performance of uniform and pressure-driven air supply distributions was compared in overcoming single and coupled fluctuation sources. The thresholds for each source were summarized for SHINE. Results indicated that while uniform air supply reduces longitudinal temperature difference and mitigates double-source fluctuations better, pressure-driven distribution is more effective against single sources. Finally, the theoretical methods were compared and agreed with steady-state and transient CFD simulations. This study provides a rapid and practical method for designing ventilation schemes to achieve constant temperature in TSFs and minimize reliance on CFD.