With the ever-increasing need for transport of different fluids through pipelines being used in various industries, the nature of risk associated is very high and have led to catastrophic events in the past. Therefore, to eliminate or to minimise the associated risk is usually the number one priority of industries associated with such activities. The aftermath of disastrous accident on Piper Alpha Platform which engulfed the whole platform and left 167 people dead, lead valve and associated industry to develop more effective safety solutions. One of the solutions is an Automatic Shutoff Valve (ASV) which was initiated by Fluma Technology and Blackhall Engineering in 2004. The results available from the experimental tests of ASV are very insignificant and do not provide the full characteristics of the valve. This research thus aimed at determining the flow characteristics of the valve using CFD and based on that establishing valve configurations for various operating conditions. The Automatic Shutoff Valve design is based on the theory of the kinetic energy of fluids, which is the driving force behind its operation. The energy associated with the moving fluid helps in accomplishing the functioning of the valve. To operate any safety system energy in terms of electrical or mechanical is needed, however in case of ASV operation the energy is derived from the flow itself and thereby making it economically efficient and viable. Numerical studies have been conducted on DN150 (6NPS) Automatic Shut-off Valve to establish flow coefficient, pressure drop, obturator torque, trip velocity. The numerical studies have been validated against available experimental data provided by Blackhall. These parameters are established across full travel of the valve using different inlet velocities. Analytical expressions have been developed to represent the valve configuration at various obturator angles and associated parameters. The results are used to develop analytical expressions to establish various parameters at different obturator angles. In the final part of the study, the effect of aerofoil section on the obturator is studied by conducting simulations to quantify the torque contributed by the aerofoil geometry compared to the rest of the obturator geometry. Furthermore, standard NACA 0030 aerofoil section is developed from the non-standard existing aerofoil and is incorporated in the obturator design for standardisation purpose and simulation results confirmed close match to the existing design. Based on this standard design four new obturator design were modelled with aerofoil sections of varying chord lengths. Simulations were conducted on all of these models at different obturator angles and at different velocities to quantify associated torque and Cv values. From these results analytical expressions are developed to enable designers to select the correct combination of obturator angle, chord length, preset torque for the required trip velocity and Cv requirements.
| Date of Award | 11 Mar 2024 |
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| Original language | English |
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| Supervisor | Rakesh Mishra (Main Supervisor) |
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