Proof-of-principle demonstration of a virtual flow meter-based transducer for gaseous helium monitoring in particle accelerator cryogenics

Abstract

A transducer based on a virtual flow meter is proposed for monitoring helium distribution and consumption in cryogenic systems for particle accelerators. The virtual flow meter allows technical and economical constraints, preventing installation of physical instruments in all the needed measurement points, to be overcome. Virtual flow meter performance for the alternative models of Samson [ http://www.samson.de (2015)] and Sereg-Schlumberger [ http://www.slb.com/ (2015)] is compared with the standard IEC 60534-2-1 [Industrial-process control valves-Part 2-1: Flow capacity-sizing equations for fluid flow under installed conditions (2011), https://webstore.iec.ch/publication/2461], for a large temperature range, for both gaseous and liquid helium phases, and for different pressure drops. Then, the calibration function of the transducer is derived. Finally, the experimental validation for the helium gaseous state on the test station for superconducting magnets in the laboratory SM18 [Pirotte et al., AIP Conf. Proc. 1573, 187 (2014)] at CERN is reported.

Soft metrology based on machine learning: a review

“…There are two main approaches used to develop a soft metrology system: model-driven approaches, which develop a model using phenomenological knowledge of the process [17,[54][55][56], and data-driven approaches, that use observed information of the process (a database) to develop the model [32]. Due to its flexibility, and the possibility of creating a model without precise knowledge of the process dynamics, the second approach is widely used [35,57,58].…”

“…Another term that has been used to refer to indirect measurement devices is virtual sensor [16]. This term originated in the context of virtual instruments (software implementations that perform the functions of an instrument in a process) and it has been used in reference to indirect flow measurement [8,17,18] and other applications like control systems, automobiles and buildings [13]. However, this term has also been used with a different connotation, to denote the information generated by a computer program that replaces real world values in a simulation [30].…”

“…In this sense, technologies and strategies have been developed to use the available information of other variables in the process and computational models infer the value of those that cannot be directly measured [1][2][3][4][5]. These strategies have been used in several contexts, such as oil refinery [6], chemical industry [7], air conditioning systems [8], automobiles [9], semiconductor manufacturing [10], and the quantification of properties determined by human perception (such as smell, taste, color, etc), among others [11][12][13][14][15][16][17]. Depending on the context, the type of indirect measurement strategy addressed in this paper can be referred to as soft sensor, virtual sensor, estimator, inferential sensor, virtual metrology, soft metrology, among others.…”

Automatic LHC accelerator warm-up and cool-down experience during the Long Shutdown 2

“…As consequence, all the double-cells will be cooled-down/warmed-up at similar speeds, guarantying a minimum thermal gradient over the arc. Note that to ensure these massflows, each CV 920 is driven by a PID controller (FC) regulating the flow over the circuit using a Virtual Flow-meter (V FT ), see [3] for details.…”

Non-linear Model Predictive Control for cooling strings of superconducting magnets using superfluid helium

“…Virtual flow meters -soft sensors used to provide actual values of mass flowrates without the need of installing actual instrumentation are widely used at the LHC cryogenics to monitor and control the helium flows around the system (Arpaia et al (2015); Ödlund (2007)).…”