Projects
Projects: Projects for Investigator |
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| Reference Number | NIA_NGGT0008 | |
| Title | Develop novel mitigation method for high frequency main pipework vibration | |
| Status | Completed | |
| Energy Categories | Fossil Fuels: Oil Gas and Coal(Oil and Gas, Refining, transport and storage of oil and gas) 100%; | |
| Research Types | Applied Research and Development 100% | |
| Science and Technology Fields | ENGINEERING AND TECHNOLOGY (Mechanical, Aeronautical and Manufacturing Engineering) 100% | |
| UKERC Cross Cutting Characterisation | Not Cross-cutting 100% | |
| Principal Investigator |
Project Contact No email address given National Grid Gas Transmission |
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| Award Type | Network Innovation Allowance | |
| Funding Source | Ofgem | |
| Start Date | 01 February 2012 | |
| End Date | 01 December 2014 | |
| Duration | 34 months | |
| Total Grant Value | £202,000 | |
| Industrial Sectors | Technical Consultancy | |
| Region | London | |
| Programme | Network Innovation Allowance | |
| Investigators | Principal Investigator | Project Contact , National Grid Gas Transmission (100.000%) |
| Web Site | http://www.smarternetworks.org/project/NIA_NGGT0008 |
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| Objectives | The programme will theoretically evaluate a series of cost effective approaches to attenuate high frequency vibration within transmission pipe work. The programme will perform proof of concept trials with the currently favoured grouted ring concept. The programme will deliver an assessment of the latest high frequency vibration attenuation thinking with respect to gas transmission pipelines. This, coupled with the testing of the grouted ring dampener will give National Grid a wide range of effective solutions to deal with this phenomenon. | |
| Abstract | High frequency acoustic excitation of main transmission pipelines is characterised by excitation of pipe wall ‘shell’ modes, with local flexing around the circumference and along the length of the pipe section. At high levels, this behaviour can lead to acoustic fatigue at welded features such as pipe supports and small bore connections. A number of National Grid compressor facilities have experienced problems of this nature. Increased understanding leading to efficient and effective attenuation of these frequencies will lead to improved maintenance and inspection routines. The following programme of work is proposed to increase understand of the available techniques, and to develop the grouted ring concept into a working prototype: Review of mitigation methods for high frequency pipe wall vibration. Development of the grouted ring design and modelling to predict performance. Laboratory trials of design to validate modelling. Field trials on site with known high frequency vibration issues. Development of an application procedure. The project has been progressing well and as part of a stage gate meeting with GL, National Grid requested that additional elements of work be carried out prior to carrying out the field trials in order to have confidence in the solution for a thorough test programme. The additional aspects will give greater insight into the performance of the grouted rings and include: Construction, and analysis, of a dynamic Finite Element model of a bolted grouted ring prototype Undertaking dynamic FE analysis of the grouted ring prototype design, the FE model can be validated against the experimental results from subsequent testing and therefore provide confidence in this technique for future design purposes. Furthermore, validation can be undertaken by comparing dynamic analyses of the prototype grouted ring with stresses induced from experiments with a forced input, i.e. results from using a dynamic shaker (or equivalent). Hammer and shaker testing, for establishing attenuation performance, of a bolted grouted ring prototype on test pipe During previous laboratory trials, a grouted ring design was shown to greatly reduce dynamic stresses in the region of a welded feature, achieving up to an 85% reduction in amplitude. Whilst the tap testing undertaken has given considerable confidence in the rings’ ability to reduce dynamic stresses, several areas still remain to be investigated: Performance of ring design with clamp - a finite element study has been undertaken to design a suitable clamping method for the ring. A prototype will be manufactured and tested in order to confirm the design’s performance. Performance over large vibration amplitudes (linearity of performance) - whilst modal hammer testing has shown a reduction in response for a relatively low force input, measuring the response to large inputs (similar to those seen in the field) would confirm the likely performance of a final design. This can be achieved by using a forced input on the pipe, such as an electrodynamic shaker. Modal hammer testing of the system with bolted grouted rings shall be undertaken and the results compared against those previously obtained to identify any effects directly attributable to the flange connection modification. Shaker testing would then be undertaken using the method identified in section 1. Small-scale shaker testing of grout to prove its integrity under sustained vibration loading Grouted fixtures are used widely in tee and sleeve applications, however it has not previously been used in an area known to suffer from high frequency vibrations, with the purpose of reducing the dynamic stresses experienced by the pipework. It is therefore unknown as to whether performance may degrade over time if fatigue or other damage to the grout were to occur. It is proposed that a small-scale test be undertaken using an electro-dynamic shaker.Note : Project Documents may be available via the ENA Smarter Networks Portal using the Website link above | |
| Publications | (none) |
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| Final Report | (none) |
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| Added to Database | 09/08/18 | |
