Improving pressure test rig for cyclic testing of cooling circuits

Abstract

This thesis presents the programming and commissioning work carried out on a high-pressure test rig delivered to the European Organization for Nuclear Research (CERN) by the University of Bath. The rig is designed to perform pressure tests up to 200 bars, primarily for applications related to the Compact Muon Solenoid (CMS) experiment’s tracker cooling system.

Cooling is key for tracker detectors at CMS where CO2 is used that operates at high pressures and several cycles are repeated during detector operation. Joint reliability is critical, and since non-standard joints are used, thorough quality control is essential. Cyclic testing plays a vital role in ensuring their performance and durability. However, initial tests done using the pressure test rig indicated that the system was unable to reach the desired pressure threshold.

To address this, a detailed investigation into the rig’s pressure control system, encompassing both hardware and software, was undertaken. Modifications were implemented to enhance system performance, stability, and accuracy.

A key focus of the project is the development of control programs to support a range of test scenarios, including both static and cyclic pressure tests. These programs are designed to allow testing of different sample volumes and ensure precise control to allow tests to be undertaken. over pressure application and monitoring. In parallel, significant effort is also devoted to understanding and applying safety requirements, both in the design of program logic and in the integration of protective mechanisms at the hardware level.

The commissioned system was then used to carry out initial tests on CMS Tracker cooling circuits, including on thin-walled Titanium pipes that are part of the design of CMS Upgrade. The aim is to make the pressure test rig functional for accelerated testing, so that the long-term effects of continuous and cyclic internal pressure loading on cooling pipes and joints are characterized.

The work also required creating an instructions manual which would guide the operations of the equipment along with the safety assessment for testing. The work documented in this thesis not only enabled the pressure rig to meet its operational goals but also established a framework for future upgrades and applications in high-pressure testing at CERN.