Fri, 15 October, 2021
Three items of research undertaken by the Non-Metallic Innovation Centre (NIC) are to be presented at the upcoming NAFEMS World Congress 2021. The event, which is being held online from 25-29 October 2021, is the world’s only independent global conference focussed entirely on simulation and analysis, delivering an industry overview for the community, by the community.
TWI Project Leader Rachel Lunn will present an ‘Overview of Electro-static Discharge (ESD) Risk Assessment in Polymer Composite Pipes used in Gas Applications’ at 11:20 (CEST, Berlin) on 26 October.
This work by the NIC has developed an ESD modelling approach combining heat transfer, computational fluid dynamics, and electrostatics to provide a quantitative assessment of the risk of electrostatic charge build-up in the composite pipes used in natural gas transportation.
The transport of natural gas and particulates through non-metallic pipes can lead to the accumulation of static charge on the inner surface of the pipe. The non-conductive nature of the pipe walls mean that the charge is not dissipated and can therefore create a significant risk of explosion, damage, and injury to persons should it exceed a certain limit and discharge suddenly. In addition, if the charge conditions create an electric field that exceeds the dielectric strength of the pipe material, the subsequent discharge can melt a hole through the pipe wall (known as pin-holing). Current approaches to evaluating the risk of electrostatic discharge often use analytical approximations that can be over-conservative, while mitigation methods can be difficult to implement.
The NIC-developed modelling approach has already been validated in laboratory conditions to demonstrate its efficacy and used on real case scenarios from the field. Future developments to the model will look at validating the models over a broader set of conditions and validating the impact of sand particle concentration on the electrostatic charge developed on the non-metallic pipe.
Elsewhere, Saudi Aramco Technologies Company Phd student Ameen Al Obedan will present on, ‘Effect of Process Parameters on the Temperature Field During Electrofusion Welding of Glass/PE Thermoplastic Composite Pipes,’ on 26 October 2021 at 9:35 (CEST, Berlin).
This presentation will address the extension of the capabilities of thermoplastic pipes used in water and oil and gas applications through an investigation of electrofusion coupling as a replacement for metallic connectors so as to create a fully non-metallic system. This will provide a corrosion-free solution with improved sealing capacity and potentially lower costs.
In order to achieve this the behaviour of the reinforced composite laminate layer during welding needed to be assessed using finite element modelling. This project simulated the transient heat transfer during electrofusion welding of Glass-PE TCP with the aim of optimising the welding parameters and coupler design to achieve the required long-term joint performance. Temperature dependent material properties, thermal surface resistivity, material phase change and thermal expansion were also accounted for in the model and special attention given to the heat source model in order to better simulate the heat input into the pipe material during the welding process. A sensitivity analysis determined the influence of various parameters on the heat transfer including the power input, heating wire size and depth, contact between the fitting and the pipe, and thickness of the external pipe layer. Experimental validation conducted with a real pipe/fitting and the temperature profile was recorded during the entire welding cycle using an infrared camera and pre-installed thermocouples at different depths and locations in the pipe/fitting assembly, with the results used to calibrate the key model parameters at different welding times.
In addition, NIC PhD student Maciej Gierulski from the University of Sheffield will present on, ‘Finite Element Analysis of Electrofusion Joints in Thermoplastic Composite Pipes Under Load’ at 11am (CEST, Berlin) on 28 October 2021.
This work looked at the connection of thermoplastic pipes with electrofusion joints to create a viable alternative to the steel pipes that are used in the oil and gas sector. This presentation demonstrates the development of a finite element model for simulating two types of mechanical test, a hydrostatic pressure test and a whole pipe tensile test, in order to optimise the design of the electrofusion fitting. The extra challenge in creating the model is finding suitable input data on the mechanical performance of the different layers in the TCP; these properties are not readily available in the literature and hence have to be obtained by experiment. The TCP material is produced in the form of a pipe by tape winding, it does not exist as flat plates, which also makes testing difficult, as most standard tests require a flat sample. Therefore, a non-standard set of tests were developed in order to obtain the mechanical properties needed for the finite element analysis.
You can find out much more about this innovative work by joining the NIC’s NAFEMS World Congress presentation on 26 October.
The Congress also includes 10 industry-leading keynote presenters, over 450 other presentations with live Q&A sessions, numerous discussion sessions, NAFEMS short courses to boost your CPD hours, full downloads of submitted papers, and more.
You can get more details about the NAFEMS World Congress 2021 and register to attend, here.