Virtual instrumentation: Introduction of virtual

The Large Hadron Collider (LHC) is the next large particle accelerator developed at CERN, constructed to enable studies of particles. The acceleration of the particles is carried out using magnets operating at about 1.9 K, a temperature achieved by regulating flow of superfluid helium. For economical reasons, control of the helium flow is based on feedback of virtual flow meter (VFT) estimates instead of real instrumentation.The main purpose of this work is to develop a virtual flow meter with the possibility to estimate the flow by means of two different flow estimation methods; the Samson method that has previously been tested for the LHC, and the Sereg- Schlumberger method that has never before been implemented in this environment.The virtual flow meters are implemented on PLCs using temperature and pressure measurements as input data, and a tool for generating the virtual flow meters and connect them to the appropriate physical instrumentation has also been developed…


1 Introduction
1.1 CERN – European Organization for Nuclear Research
1.1.1 AB-CO-IS
1.1.2 Cryogenics
1.2 Problem definition
1.2.1 Limitations
1.2.2 Outline of the report
2 Background
2.1 The LHC project
2.2 Overview of the cryogenics system
2.2.1 Cooling down of a sector
2.2.2 Final cooling down of a cell
2.3 Virtual flow meters
2.4 Test String
3 Theory
3.1 Helium
3.1.1 He II state properties
3.1.2 HEPAK
3.2 Valves
3.3 Joule-Thomson effect
3.3.1 Joule-Thomson valves
3.4 Mass flow measurement
3.4.1 Describing reality with a model
3.4.2 Real and ideal gases
3.4.3 Density, heat capacity, and heat capacity ratio
3.4.4 Samson method
3.4.5 Sereg-Schlumberger method
3.4.6 Comparison between the Samson and the Sereg- Schlum-berger algorithms
4 Implementation
4.1 Development environment
4.2 Generation of virtual flow meters
4.3 Supervision
4.4 Interpolation
4.4.1 Interpolation in two dimensions
4.4.2 Bilinear interpolation
4.4.3 Data tables
4.5 Error estimation
4.6 Testing of the code
4.6.1 Problems arisen during the testing
5 Results
5.1 Comparison between the Samson and the Sereg-Schlumberger meth-ods
5.1.1 Effects of the γ calculation on the output flow rate
5.2 Linear versus polynomial interpolation
6 Summary and conclusions
6.1 Summary
6.1.1 Conclusions
6.2 Suggestions for future work
6.2.1 Conceivable improvements of the current application
A Error estimation

Author: Ödlund, Erika

Source: Linköping University

Download URL 2: Visit Now

Leave a Comment