The inspection vehicle is a unique N.D.T. system, which has been developed and is currently used by British Gas to detect faults in the walls of gas pipelines. The vehicle travels along the pipeline as a result of pressure difference across its seal cups, with minimum disturbance to the flow. Magnetic detectors are commonly used to monitor wall flows and the accuracy of the results obtained are greatly dependent on controlling the vehicle speed variation in a fairly narrow band. Pipes of diameter greater than 600 mm carry high pressure gases typically at 75 bar, with gas speeds up to 10 m/s. This is well in excess of the inspection velocity. For the vehicle to stay within the speed limit a hydraulic speed control system exists on board, working on brakepads, which operate automatically. This system however encounters certain limitations, including high brush wear, limited power supply on board and erosion of pipeline walls. Thus bypass flow control of the vehicle speed can be used in conjunction with the hydraulic breaking system to give a more reliable and flexible system. This paper concentrates attention on describing and utilising a model to describe the effects of flow bypass and frictional braking on the vehicle's performance. As a result a series of equations have been developed which allow the modelling of the effect of flow bypass area provided by a series of axial vortex amplifiers on the vehicle's performance.
The modelling of vortex amplifiers on moving vehicles
Das Modell von Wirbelverstaerkern auf fahrenden Fahrzeugen
1988
5 Seiten, 7 Bilder, 3 Quellen
Conference paper
English
Compound hydraulic shear-modulated vortex amplifiers.
AIAA | 1977
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